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  • Effects of packaging parameters on the inactivation of Salmonella contaminating mixed vegetables in plastic packages using atmospheric dielectric barrier discharge cold plasma treatment
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-20
    Su Yeon Kim, In Hee Bang, Sea. C. Min

    Effects of packaging parameters on the inactivation of Salmonella contaminating mixed vegetables in plastic packages using atmospheric dielectric barrier discharge cold plasma treatment (ADCPT) were investigated. The inactivation rate of indigenous aerobes of grape tomatoes in low density polyethylene packaging (1.2 log CFU/tomato) was higher than that in polyethylene terephthalate packaging (0.8 log CFU/tomato). Increasing oxygen concentration in the package headspace by 85% did not affect the Salmonella reduction rate. However, an increase in the volume ratio of headspace to sample from 30:1 to 43:1, a change from indirect treatment to direct treatment, and the use of secondary packaging led to an increase in the Salmonella reduction rates by 1.2, 2.3, and 0.7 log CFU/tomato, respectively. The water vapor permeability of the tested packages increased after ADCPT by 16.7–41.7%, while tensile properties, transparency, glass transition temperature, and surface morphology did not change. Differences in inactivation effects according to package shape were eliminated by shaking during treatment. The results demonstrated the packaging parameter-dependent efficacy of in-package ADCPT and effective ADCPT for mixed vegetable decontamination with minimal package property modification.

    更新日期:2018-08-20
  • Physico-chemical and biochemical properties of low fat Cheddar cheese made from micron to nano sized milk fat emulsions
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-18
    Bal Kumari Sharma Khanal, Chrysanthea Budiman, Mark P. Hodson, Manuel R.R. Plan, Sangeeta Prakash, Bhesh Bhandari, Nidhi Bansal

    Milk fat emulsions from sodium caseinate (NaCas) and anhydrous milk fat (AMF) were prepared in the size range from 1 to 0.24 µm. These emulsions were used as source of fat to prepare low fat Cheddar cheese (LFC) and their properties such as composition (at day 7), proteolysis, texture profile analysis (TPA), color and microstructure (by confocal laser scanning electron microscopy) were studied during ripening for 180 days. Emulsion size affected the textural, microstructure, compositional, proteolysis and color properties of LFCs, but did not make them comparable to control FFC (control full fat cheese) and textural properties did not change significantly during ripening. This was possibly due to the relatively small size of emulsions added and their inertness that did not lead to higher moisture retention during cheese making and did not coalesce during ripening.

    更新日期:2018-08-18
  • Towards understanding the mechanism of fibrous texture formation during high-moisture extrusion of meat substitutes
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-15
    J.L. Sandoval Murillo, R. Osen, S. Hiermaier, G. Ganzenmüller

    This paper investigates the physical mechanisms of structure formation during high-moisture extrusion of vegetable proteins. Our model starts from the observation that extrudates with fibrous, meat-like structures exhibit water-rich and protein-rich domains. The origin and structure of these domains is attributed to a spinodal phase-separation process which occurs upon cooling of the extrudate. We investigate the process using continuum-mechanics simulations, considering the combined effects of viscous flow, thermal diffusivity, and the mixing thermodynamics of water and protein. This multi-physics problem is numerically solved using an unconventional mesh-free approach, the material point method (MPM), combined with the Cahn- Hilliard model of phase separation. The method incorporates both Eulerian and Lagrangian aspects, and is well suited to model multicomponent flows of history-dependent materials. Our simulations show that fiber-like structures are obtained when the ratio of phase separation rate, heat conduction rate, and flow rate are matched within a narrow window. Our results predict that the shape of the temperature profile within the cooling channel determines the structure of the phase-separated state. These findings suggest that the physical mechanism which causes fibrous structure formation is given by spinodal phase separation under the influence of a temperature gradient.

    更新日期:2018-08-15
  • Expanding Solid-State Phosphorus Nuclear Magnetic Resonance Insights into Mozzarella Cheese Ageing
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-14
    Jason P. Hindmarsh, Jeremy R. Smith, Alistair J. Carr, Philip J. Watkinson

    With the addition of reference spectra and 1H-31P cross-polarisation kinetics we have increased the analysis available by 31P NMR of the cheese ageing process. A previous study demonstrated that solid-state 31P NMR can be used to monitor the state of phosphorus in ageing cheeses. It is possible to differentiate between the mobile and immobile phosphorus species present in the cheese casein micelles. In this work, proton to phosphorus cross polarisation (CP) kinetic experiments (1H-31P CP-MAS) (where MAS = magic angle spinning) enable the observation of the state of the colloidal calcium phosphate (CCP) and phosphoserine (PSer) separately in the casein micelles. Also, 1H-31P CP-MAS spectra can be used to indirectly monitor the levels of micellar calcium. From the data gathered, we were able to conclude these points about the ageing process of Mozzarella cheese; in the first 20 days the cheese texture is dependent on the dynamics of free water and immobile calcium and phosphate, the CCP phosphate is mobilised at an exponential rate with the majority mobilised within the first 20 days, the driving force for CCP mobilisation is possibly the migration of water from the cheese serum into the casein proteins and CCP phosphorus is preferentially mobilised while immobile phosphoserine levels remains relatively unchanged during the early (40 days) of Mozzarella cheese ageing.

    更新日期:2018-08-15
  • Nanoemulsion prepared by homogenizer:The CFD model research
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-13
    Bo Jiang, Yanbin Shi, Guimei Lin, Deyin Kong, Du Jian

    Two CFD models A and B were developed based on APV high-pressure homogenizer and it was determined that the mathematical model and analysis method of B were more consistent with the actual homogenization process. The internal flow field of the high-pressure micro-jet homogenizer was simulated using Fluent software. The homogenization pressure, ratio of oil to water, and temperature were investigated. The optimal parameter combination obtained from numerical simulation of orthogonal experiment was 20 °C, 70 MPa, and 1:12. APV high-pressure homogenizer orthogonal experiment was conducted and the optimal experimental parameter combination obtained was 50 °C, 70 MPa, and 1:15. The two groups of optimal parameters were used in the homogeneous experiments. TEM images were used for comparative analysis of the particle size,and the particle size obtained by numerical simulation was slightly larger. A comparison of experimental and numerical simulation results indicate that the single factor experiment and the orthogonal experiment were not entirely chime. The reason for the discrepancy is because the emulsifier was added in the homogeneous experiment such that there were more flow field variation factors in the homogenization process and the numerical process did not define all relevant conditions. However, the highly similar development trend verifies the effectiveness of the B model, which can provide an important reference in the development and use of homogenizers.

    更新日期:2018-08-14
  • Ultrasound-assisted extraction of lipids from Mortierella isabellina
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-14
    Daniela Sallet, Paola Oliveira Souza, Lauren Theisen Fischer, Gustavo Ugalde, Giovani L. Zabot, Marcio A. Mazutti, Raquel C. Kuhn
    更新日期:2018-08-14
  • Influence of a shear post-treatment on rheological properties, microstructure and physical stability of emulgels formed by rosemary essential oil and a fumed silica
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-14
    J. Santos, M. Jimenez, N. Calero, M.C. Alfaro, J. Muñoz

    Nanoemulsions containing rosemary essential oil, a natural food preservative, were developed by the microfluidization technique and emulgels were formed by adding a fumed silica (Aerosil 200). The influence of homogenization pressure on droplet size was examined. The nanoemulsion prepared at 5000 psi in Microfluidizer showed the lowest Sauter diameter and it was selected as the starting point. The influence of shear on rheological properties, stability and microstructure was studied for both the nanoemulsion and the emulgel formed. The emulsion showed recoalescence induced by shear, while the emulgel exhibited an alignment of a 3D-network. In addition, the prepared emulgel exhibited time-dependent behaviour. In spite of the fact that the viscoelastic functions of the emulgel decreased as a result of shear, a significant improvement in physical stability was detected by means of the Multiple Light Scattering technique.

    更新日期:2018-08-14
  • Simultaneous Multi-Product Sterilization: Revisited, Explored, And Optimized
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-13
    R. Simpson, C. Ramirez, D. Jiménez, S. Almonacid, H. Nuñez, A. Angulo

    An interesting potential improvement and challenge in thermal processing of packaged foods is the implementation of simultaneous multi-product sterilization.The aim of this research was to analyze, explore, and optimize simultaneous multi-product sterilization through thermal processing simulation of packaged foods considering both constant (CRT) and variable retort temperature (VRT) profiles.The research was approached through three main tasks, which were defined to discover potential opportunities for simultaneous multi-product sterilization with the attempt to recommend the steps to follow to practically implement it.In most cases, simultaneous multi-product sterilization for CRT processing was feasible, however, it was limited to low retort temperature and restricted to products with similar fh. In contrast, in VRT profiles a higher flexibility for simultaneous multi-product sterilization was found.The opportunity to carry out simultaneous multi-product sterilization provides flexibility to optimize retort utilization, reduce energy consumption, and increase processing plant productivity.

    更新日期:2018-08-13
  • Mimicking 3D food microstructure using limited statistical information from 2D cross-sectional image
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-13
    Antonio Derossi, Kirill M. Gerke, Marina V. Karsanina, Bart Nicolai, Pieter Verboven, Carla Severini

    We used statistical correlation functions (CFs) to describe food microstructure and to reconstruct their 3D complexity by using limited information coming from single 2D microtomographic images. Apple fleshy parenchyma tissue and muffin crumb were chosen to test the ability of the reconstructions to mimic structural diversities. Several metrics based on morphological measures and cluster functions were utilized to analyze the fidelity of reconstructions. For the apple, reconstructions are accurate enough proving that lineal, L2, and two-point, S2, functions sufficiently describe the complexity of apple tissue. Muffin structure is isotropic but statistically inhomogeneous showing at least two different porosity domains which reduced the fidelity of reconstructions. Further improvement could be obtained by using more CFs as input data and by implementation of the techniques dealing with statistical non-stationarity. Novel stochastic reconstruction and CF-based characterization methods could improve the fidelity of reconstruction and future advances of this technology will allow estimating macroscopic food properties based on (limited) 2/3D input information.

    更新日期:2018-08-13
  • Evaluation of the cold chain management options to preserve the shelf life of frozen shrimps: A case study in the home delivery services in Taiwan
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-11
    Nodali Ndraha, Wen-Chieh Sung, Hsin-I. Hsiao

    Increasing demand for chilled and frozen temperature food products led to the growth of home delivery cold chain services. This service is becoming popular because of its convenience and affordability. However, home delivery cold chains could face difficulties, especially in temperature control during the delivery of packages, such as too frequent door opening and closing, which can raise considerable food quality and food safety issues. In this study, we evaluated the temperature situation during transportation by four major home delivery service providers in Taiwan. Automatic temperature data loggers were used to record the temperature profile during transportation. The obtained data were then simulated with various scenarios to estimate the remaining shelf life and food loss probability by using the Monte Carlo algorithm with 10,000 iterations. The results showed that abusive temperature in real conditions could reduce the remaining shelf life of frozen shrimp by more than 70 %. Lowering the maximum temperature to 15 °C or even to 7 °C had almost no impact on preserving the shelf life or reducing the quality of frozen shrimp. Among the developed scenarios, better preservation of remaining shelf life could be obtained by narrowing the fluctuation to -18 ± 3 °C. This scenario is recommended as an integral part of temperature management control in the home delivery cold chain, particularly in frozen food. These findings may help the food managers in the food cold chain industry to preserve the quality of low-temperature food product. Additionally, this study may be applied to manage the temperature in home delivery cold chain in other country with a similar condition.

    更新日期:2018-08-13
  • Maximization of the polyphenols extraction yield from green tea leaves and sequential clarification
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-10
    Marlon Menezes Maciel Bindes, Vicelma Luiz Cardoso, Miria Hespanhol Miranda Reis, Daria Camilla Boffito
    更新日期:2018-08-11
  • The effectiveness of combined infrared and hot-air drying strategies for sweet potato
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-09
    Daniel I. Onwude, Norhashila Hashim, Khalina Abdan, Rimfiel Janius, Guangnan Chen

    This study examined the performance of different combined infrared (IR) and hot-air drying (HAD) strategies for sweet potato. Experiments were conducted for simultaneous infrared and hot-air drying, two-stage sequential hot-air and infrared drying, two-stage sequential infrared and hot-air drying, and intermittent infrared and hot-air drying in a laboratory scale combined infrared and hot-air dryer. The drying air temperature varied between 50 – 70 ºC, the infrared intensity was 1100W/m2, the air-velocity was 1.5 m/s, and the pulse ratio (PR) ranged from 1 – 3. Results indicated that the drying rate, drying time, effective moisture diffusivity, shrinkage, specific energy consumption (SEC), colour attributes and phytochemical compounds of sweet potato were affected by the different drying combination strategies. The drying kinetics, product shrinkage, and sample temperature were also influenced by drying time and air temperature. The two-term exponential model adequately explained the drying behaviour of sweet potato for all the different combination strategies. The intermittent IR and HAD combination strategy proved to be the most suitable based on the combined effect of total drying time (113-120 min), SEC (27.67 - 41.44 kWh/kg), total colour change (17.15-26.48) and bioactive compounds.

    更新日期:2018-08-10
  • Characterization and effectiveness of short-wave ultraviolet irradiation reactors operating in continuous recirculation mode to inactivate Saccharomyces cerevisiae in grape juice
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-10
    Oscar Antonio-Gutiérrez, Andrea López-Díaz, Enrique Palou, Aurelio López-Malo, Nelly Ramírez-Corona

    Short-wave ultraviolet (UVC) irradiation is an emerging process that has been reported as an effective method for inactivating bacteria that contaminate water. Research regarding this technology in foods has focused on treating certain liquids inoculated with particular target microorganisms. We evaluated different UVC reactor arrangements with recirculation to inactivate Saccharomyces cerevisiae in grape juice. Tested juice was inoculated with S. cerevisiae and processed at three flow rates (5.2, 17.1, or 31 mL/s) during 60 min. Selected arrangements of UVC reactors were assessed by varying the length (30 or 80 cm) of the UVC lamp (254 nm), the number of lamps (1 or 2), and the thickness of the gap in the reactor (1.0 or 0.5 cm) for the 30 cm UVC lamp. Additionally, UVC dosages of studied arrangements were evaluated through dye degradation in order to determine the effect of flow rate in the recirculating systems. In UVC reactors consisting of a single lamp, approximately 2.5 log-cycle reductions were achieved with flow rates of 17.1 or 31 mL/s, whereas at 5.2 mL/s only 2 log-cycle reductions were attained. With two UVC lamps in series, 5 log-cycle reductions were achieved after 45 min of treatment regardless the length of the lamp but only at the high flow rates tested. With the reactor of the smallest tested thickness, 6 log-cycle reductions were achieved at 17.1 mL/s or 31 mL/s. In general, reduction of juice film thickness allowed greater reductions of S. cerevisiae; furthermore, important differences were observed among the evaluated systems when comparing the effect of flow rate.

    更新日期:2018-08-10
  • Laser backscattering imaging as a control technique for fluid foods: Application to vegetable-based creams processing
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-07
    Samuel Verdú, Alberto J. Pérez, José M. Barat, Raúl Grau

    In this work, the application of a laser backscattering image technique as a non-destructive quality control technique for fluid food matrices was studied. The used food matrices were vegetable-based creams, which were modified according to the combination of four production factors (raw material, biopolymer type, biopolymer concentration and homogenisation system) in order to obtain a wide space of variance in terms of physico-chemical properties (52 different creams). All the creams were characterised based on that imaging technique using pre-designed descriptors extracted from the captures of the generated laser patterns. The capacity to characterise creams presented by the imaging and physico-chemical data (rheology and syneresis) was compared, and the effect of each production factor on their captured variance was evaluated. Both characterisations were similar. This parallelism was proved by modelling the relationship between them by carrying out regression studies. The regression coefficients were successful for most physico-chemical variables. However, the prediction of creams’ properties was maximised when done over the linear combination of them all. Thus the imaging descriptors collected enough variance from the cream categories to place them according to their physico-chemical properties into the generated space of physico-chemical variance. The results allowed us to conclude that this technique can be applied for the non-destructive quality control of fluid-food matrices for production processes with a wide spectrum of product categories.

    更新日期:2018-08-08
  • Full title: Cold plasma pretreatment enhances drying kinetics and quality attributes of chili pepper (Capsicum annuum L.)
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-06
    Xiao-Lin Zhang, Chong-Shan Zhong, Arun S. Mujumdar, Xu-Hai Yang, Li-Zhen Deng, Jun Wang, Hong-Wei Xiao

    Chili pepper is difficult to dry as the outermost surface is covered with an epicuticular wax layer, which hinders moisture transfer. Chemical dipping pretreatments and thermal blanching methods are often employed to enhance its drying process. However, chemical pretreatments hold the issues of chemical additives residue and thermal blanching methods tend to result in a high loss of bioactive compounds. Cold plasma is an ionized gas that contains different electrons, ions, and reactive neutral species. In current work, the feasibility of cold plasma as a non-thermal pretreatment technology for chili pepper drying is explored. The effects of different cold plasma pretreatment time (15, 30, 45, 60 s) on hot air drying kinetics and quality attributes of chili pepper, such as colour, red pigment retention, antioxidant activity, and microstructure were investigated. Results indicate that cold plasma can enhance the drying rate and the exposure time of 30 s achieves the optimum result. Microstructure observations show the existence of micro-holes, which explain how plasma treatment can enhance the drying kinetics. Quality attributes showed that the colour parameters had no significant changes under various treatment times. The retention of red pigment content was improved by plasma treatment of 30 s, whereas longer exposure times had a negative effect. The antioxidant activity of samples increased with the increase of cold plasma exposure time. Results indicate that cold plasma is a promising pretreatment technology for chili peppers as it enhances drying kinetics and quality attributes of chili pepper.

    更新日期:2018-08-07
  • A Comparative Study on the Effect of Superheated Steam and Hot Air Drying on Microstructure of Distillers’ Spent Grain Pellets Using X-ray Micro-computed Tomography
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-06
    Chyngyz Erkinbaev, Rani Puthukulangara Ramachandran, Stefan Cenkowski, Jitendra Paliwal

    The spatially correlated microstructure of a material during any processing operation such as drying is very important as it influences the thermo-physical properties of the material. The heterogeneity of the distillers’ spent grain (DSG) pellets’ microstructure was evaluated using the X-ray micro-computed tomography. The effect of two drying methods, i.e. hot air and superheated steam (SS) drying on the microstructure of this porous material was compared. The DSG pellets were prepared by mixing different amounts of distillers’ solubles (10, 30, and 50% w/w) with the coarse grain fraction of the spent grains. The effect of solubles on the microstructure (total porosity, open porosity, closed porosity, and connectivity) and stability (dimensional/volumetric changes and change in density) of the pellet prior to and post drying (hot air and SS drying) was analyzed statistically. The results showed that SS drying caused an overall expansion of the pellet in the range of 90–133%. The increase in the open porosity of the pellet during SS drying enhanced the drying process resulting in a decrease in the drying time by about 81% when compared to hot air drying. Also, by increasing the concentration of solubles above 30% w/w, the dimensional stability of pellets improved by 50% for both drying methods thereby improving the mechanical strength of pellets. These results are crucial in optimizing the composition of pellets from the point of view of the pellet’s dimensional stability and drying efficiency.

    更新日期:2018-08-06
  • Comparative study on crystallization behaviors of physical blend- and interesterified blend-based special fats
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-06
    Tingwei Zhu, Xia Zhang, Hong Wu, Bing Li

    Crystallization behavior of special fats has a crucial influence on their physical properties. A comparative study was carried out on the crystallization characteristics of physical blend- and interesterified blend-based fast-frozen special fats (PBSF and IBSF). The content of trisaturated TAGs (SSS) decreased from 27.3% for PBSF to 12.5% for IBSF. At 0-45 °C, the SFC of PBSF and IBSF varied from 60.2% to 16.3% and from53.1% to 2.9%, respectively. XRD results indicated that PBSF and IBSF had β′ and β crystals with double chain length structures, but IBSF had more β′ crystal content. Isothermal and non-isothermal crystallization kinetics studied by pNMR and DSC revealed that the nucleation and growth mechanism of PBSF and IBSF was different during crystallization. For IBSF, there were a large amount of spherical crystals with small size present in the crystal network. However, rod-like crystals with big size were distributed throughout the crystal network of PBSF.

    更新日期:2018-08-06
  • Investigation of the moisture-induced caking behavior with various dietary salts
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-03
    Hansol Doh, Min Hyeock Lee, Hyun Jin Park

    Caking of dietary salt is a well-known problem in food industries. In this study, caking behavior of various kinds of dietary salt, including refined salt, sea salt (from South Korea and France), bamboo salt, rock salt, and sodium chloride (used as control group) was investigated. According to our results, these dietary salts had different mineral content and moisture sorption isotherm. The sea salt had more minerals than the other salts. As a result, the deliquescence relative humidity of the sea salt was significantly lower than that of the other dietary salt, which resulted in higher water sorption ability. After salts were stored in two humidity cycle conditions, the change in moisture content, caking strength, passed ratio, and morphology was determined. In the case of sea salt, the highest caking strength, the lowest passed ratio, and lots of crystal bridges caused by caking were observed.

    更新日期:2018-08-03
  • Protein recovery and anti-nutritional factor removal from soybean wastewater by complexing with a high concentration of polysaccharides in a novel quick-shearing system
    J. Food Eng. (IF 3.197) Pub Date : 2018-08-01
    Xingfei Li, Jie Long, Yufei Hua, Yeming Chen, Xiangzhen Kong, Caimeng Zhang

    In this study, to recover proteins and minimize anti-nutritional factor (ANF) levels in soybean wastewater, a novel quick-shearing system was used to obtain homogeneous electrostatic complexes between soybean whey protein (SWP) and a high concentration (4%, w/v) of polysaccharide. During processing, protein recovery and trypsin inhibitory activity loss induced by complexing with sulfated and carboxylated polysaccharides were investigated as function of polysaccharide type, pH, protein to polysaccharide mass ratio, and the physical state (solid, liquid). The removal of 80% of ANF levels and recovery of 90% of proteins were achieved using solid sulfated polysaccharides. Large amounts of particle complexes were observed for sulfated polysaccharides as compared to carboxylated polysaccharides by confocal laser scanning microscopy. A 100-kDa polyethersulfone ultrafiltration membrane was effective in recovering proteins (80%) from ι-carrageenan/SWP complexes, and a small amount of loss of the polysaccharides was observed for each cycle.

    更新日期:2018-08-01
  • 更新日期:2018-07-31
  • Data-Driven Soft Sensor Modeling Based on Twin Support Vector Regression for Cane Sugar Crystallization
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-31
    Yanmei Meng, Qiliang Lan, Johnny Qin, Haifeng Pang, Kangyuan Zheng

    Cane sugar crystallization is a complex physical and chemical process and is related with many parameters. Due to the restriction of technical condition, some key parameters such as mother liquor purity and supersaturation, cannot be measured directly by existing sensors. This hinders the implementation of automatic control in cane sugar crystallization seriously. To handle this problem, a data-driven soft sensor modeling based on twin support vector regression is proposed to estimate the mother liquor purity and supersaturation. Seven easy-to-measure variables are chosen as input, including vacuum degree, temperature, massecuite level, steam pressure, steam temperature, feeding rate and massecuite brix. Two difficult-to-measure variables are chosen as output, including mother liquor supersaturation and mother liquor purity. The model parameters are optimized by combining the particle swarm optimization and the ten-fold cross-validation method. Experimental result indicates that this method performs well in aspects of prediction, approximation, learning speed, and generalization ability compared with BP, RBF and ELM, and is proved to have great effectiveness and reliability in cane sugar crystallization control.

    更新日期:2018-07-31
  • Effect of lyophilization on food grade liposomes loaded with conjugated linoleic acid
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-28
    María A. Vélez, María C. Perotti, Erica R. Hynes, Ana M. Gennaro

    The effect of lyophilization and rehydration medium on a liposome system for conjugated linoleic acid (CLA) delivery was studied. Liposomes were prepared by ethanol injection method employing soy phosphatidylcholine and CLA isomers 9c, 11t and 10t, 12c. Two rehydration media were assessed: a food simulant (distilled water) and the original medium used for liposome preparation (ethanol: water 1:9). Rehydrated liposomes were characterized in size, morphology, CLA encapsulation efficiency and membrane fluidity, at 3 and 30 days of cold storage. CLA loaded liposomes presented better stability and lower size than control liposomes without CLA through storage time, regardless of the rehydration medium. These facts could be related with spin label EPR measurements: CLA disordered the outer part of the lipid bilayer increasing fluidity, and ordered the inner part of the bilayer decreasing fluidity, which indicates a more packed membrane in the hydrophobic region. In all cases Transmission Electronic Microscopy images showed nanometric sized and oligo-lamellar vesicles. Liposomes preserved CLA isomers with high encapsulation efficiency: no differences were noticed between fresh and lyophilized samples. No influence of rehydration medium was noticed for the majority of the studied parameters. We have successfully developed efficient liposomal systems for bioactive compounds delivery in food applications.

    更新日期:2018-07-29
  • Protein Content Evaluation of Processed Pork Meats Based on a Novel Single Shot (Snapshot) Hyperspectral Imaging Sensor
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-26
    Ji Ma, Da-Wen Sun, Hongbin Pu, Qingyi Wei, Xiaomei Wang

    Protein is an important nutrient for people diet, and protein content is one of the most vital properties in quality assessment of pork meat. The potential of line-scanning based hyperspectral imaging (HSI) has been proved to be able to assess the protein content of meat, however quality of images obtained from line-scanning HSI is affected by sample transformation conditions. A novel single shot (snapshot) HSI sensor was employed to evaluate the protein content of numerous processed pork meat by using back propagation - neural network (BP-NN) and partial least squares regression (PLSR) predictive models. The results of BP-NN were better than that of PLSR. The best spectral profile was selected from reflectance, absorbance, and Kubelka–Munk (K–M) spectra by comparing the performances of their BP-NN models. The BP-NN model combined with absorbance spectra showed the best performance for evaluating the protein content of various processed pork meats with determination coefficient of cross-validation set (R2CV) = 0.8318, and root mean square error of cross-validation set (RMSECV) = 8.38 mg/g, respectively. Results indicated the feasibility of determining the protein content of pork meats by means of single shot HSI.

    更新日期:2018-07-26
  • Effective recovery of trans-resveratrol from the leaching solution of muscat grape pomace by developing a novel technology of foam fractionation
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-26
    Zhaoliang Wu, Na Li, Xin Zhang, Yanyan Xu, Ting Shu, Wei Liu, Bin Hu

    Resveratrol (2,5,4’-trihydroxystilbene) is a naturally occurring phytoalexin produced by some spermatogphytes and it has recently attracted the increasing attention of agronomists and pharmacologists owing to its satisfactory bioactivities. The objective of this work was to develop a cost-effective technology of foam fractionation to recover trans-resveratrol (trans-Res) from the leaching solution of muscat grape pomace on the assistance of molecular imprinting modified SiO2 nanoparticles. First, trans-Res was leached from muscat grape pomace through the method of alkaline extraction. Under the suitable leaching conditions, the leaching yield of trans-Res reached 84.34%. Adsorption experiments were performed for describing the adsorption behavior of trans-Res on the molecular imprinting modified SiO2 nanoparticles. Results indicated that their adsorption could be fairly described by Freundlich model and fitted well with the pseudo-second-order kinetics model. Moreover, the molecular imprinting modified SiO2 nanoparticles could effectively maintain the stability of trans-Res through avoiding the cis-trans photo-isomerization and oxidative degradation. Finally, foam fractionation was carried out for recovering trans-Res from the leaching solution, in which the concentration of trans-Res was as high as 29.09 mg/L. The molecular imprinting modified SiO2 nanoparticles were used as the collector. Under the suitable conditions of loading liquid volume 250 mL, particle size of molecular imprinting modified SiO2 nanoparticles 436.0 nm, sapindus saponin concentration 0.075 g/L, volumetric gas flow rate 100 mL/min and pore diameter of gas distributor 0.180 mm, the enrichment ratio and the recovery percentage of trans-Res reached 13.68±1.03 and 89.73±3.57%, respectively. This work is expected to provide a new technology for selectively recovering non-surface-active materials from the solution with their isomers or analogues, and to facilitate the industrialization of foam fractionation.

    更新日期:2018-07-26
  • Chitosan thymol nanoparticles improve the antimicrobial effect and the water vapour barrier of chitosan-quinoa protein films
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-25
    Estefanía Medina, Nelson Caro, Lilian Abugoch, Alexander Gamboa, Mario Díaz-Dosque, Cristian Tapia

    The aim of this work was to improve the performance of quinoa protein/chitosan edible films on the extension of postharvest life of blueberries and tomato cherries by addition of chitosan thymol nanoparticles prepared by ionic gelation. These nanoparticles were effective at inhibiting the mycelial growth of Botrytis cinerea. Films with nanoparticles were significantly more effective in reducing water vapour permeability than were films with sunflower oil and film control without nanoparticles. Films with nanoparticles were applied as an internal coating to a polyethylene terephthalate (PET) clamshell container to store blueberries and tomato cherries, and the weight loss was evaluated. The weight loss for both foods stored in modified PET clamshells was significantly lower than that in the unmodified PET clamshell during storage at 7 °C and 85% RH for 10 days. Thus, chitosan thymol nanoparticles have a potential application as an antimicrobial for preservation of fresh fruits and as a water vapour barrier when these particles are added into chitosan-quinoa protein films.

    更新日期:2018-07-25
  • Pulsed electric stimulated changes in potatoes during their cooking: DMA and DETA analysis
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-25
    Jiří Blahovec, Pavel Kouřím

    The internal cortex of potato (two varieties: Dali and Agria) was tested using dynamic mechanical analysis (DMA) combined with dielectric thermal analysis (DETA), in air of 90% humidity in temperature scans between 30 and 90 °C. Temperature plots of storage (SM i.e. elastic) and loss (LM i.e. inelastic) moduli were obtained. DETA, based on alternated current of frequency 20 kHz, continually determined both components of impedance. The PEF (pulse electric field) was applied prior to the DMA/DETA test; the experiments were arranged into four sets: b (no PEF), c (one 10 ms long pulse of alternated field 500 V/cm), d (two same pulses with a 0.1 s interval between them), e (the same pulses with a 1 s interval). The impedance was recalculated giving parameters of a single model represented by parallel connection of a resistor Re and a capacitor with capacitance ωC. The temperature range was divided into three stages: A (30–60 °C), B (60–80 °C), and C (80–90 °C). For set b and stage A parameter Re decreased, whereas capacitance was nearly constant. Both parameters were constant in stage C. In part B, between 70 and 80 °C, Re sharply decreased and the capacitance showed a sharp peak, both indicating either collapse of the cellular membranes or starch gelatinization. Application of PEF led to reduction of the peak but the process was more effective when application of PEF was repeated (sets d and e) and mainly if longer time interval between the pulses was used (e). PEF causes disintegration of cellular membranes and water release from vacuoles so that free vacuole's water makes possible that starch gelatinization appears at lower temperatures. The role of PEF as a disintegration source was tested and it was found that its efficiency is strongly enlarged when it is combined with heating.

    更新日期:2018-07-25
  • Alcoholic extraction of sesame seed cake oil: Influence of the process conditions on the physicochemical characteristics of the oil and defatted meal proteins
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-24
    Maria C. Capellini, Larissa Chiavoloni, Vanessa Giacomini, Christianne E.C. Rodrigues
    更新日期:2018-07-25
  • Commercial forced-air precooling of strawberries: a temperature distribution and correlation study
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-24
    Samuel Mercier, Jeffrey K. Brecht, Ismail Uysal

    Forced-air precooling of strawberries is rarely ideal due to the non-uniform cooling rate inside precooling facilities and the simple heuristics used to select precooling duration. The aim of this work was to investigate the product temperature distribution during commercial forced-air precooling of strawberries, quantify the relationship between the ambient and product temperature and assess precooling durations. Our field studies showed that the half-cooling time (HCT) on the inside of precooling tunnels is approximately twice the HCT on the outside, facing the incoming air, but is relatively constant along the length of the tunnel and vertically within pallets. The HCT on the outside of the tunnel is strongly correlated to the HCT on the inside, enabling temperature predictions from a limited number of sensors. Temperature variations of up to 7 °C were observed at the end of precooling, suggesting that precooling should be extended in some instances to improve uniformity.

    更新日期:2018-07-24
  • Analysis of Mass Transfer and Morphometric Characteristics of White Mushroom (Agaricus bisporus) Pilei during Osmotic Dehydration
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-23
    J.E. González-Pérez, E.M. López-Méndez, J.J. Luna-Guevara, H. Ruiz-Espinosa, C.E. Ochoa-Velasco, I.I. Ruiz-López

    The shrinkage-deformation (SD) behavior and mass transfer characteristics of white mushroom (Agaricus bisporus) pilei during osmotic dehydration (OD) were investigated. The morphometric characteristics of the product (including product contours, cross-sectional area and roundness) were obtained from digital images. Moreover, product contours were averaged to extract relevant deformation characteristics of osmodehydrated samples. An unsteady state 2D-diffusion model taking into account both radial and angular mass transfer, where product is shaped as a hemispherical shell was proposed to describe experimental data. Water and solute diffusivities in product were estimated with and without considering product shrinkage, defined as the shortening of radial dimension. Besides, diffusion coefficients were obtained using simplified models for both the proposed hemispherical shell geometry and a simpler sphere-shaped product, in the latter, under different similitude criteria. Estimated water and solute diffusivities reflecting dimensional changes of product were in the ranges of 1.1-4.6×10-10 and 1.5-1.8×10-10 m2/s, respectively, and are overestimated in about 39 to 113% for water and in about 24 to 66% for solute when shrinkage is not included in the OD model. Moreover, diffusion coefficients can also be corrected for geometry using the appropriate similitude criterion.

    更新日期:2018-07-24
  • Oxidative Stability of Microencapsulated Fish Oil with Rosemary, Thyme and Laurel Extracts: A Kinetic Assessment
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-23
    Ahmet Faruk Yeşilsu, Gülsün Özyurt

    Antioxidant activity of rosemary (R), thyme (T) and laurel (L) extracts was evaluated for protection of fish oil during microencapsulation and heat-induced degradation. For this purpose, oil stability was optimised by comparing oxidation levels of fish oils which are exposed to high temperatures ie., 23°C, 40°C, and 60°C in the presence of natural and commercial antioxidants ie., 1000 (1) 1500 (2) ppm extracts and two control groups without and with BHT (250 ppm) (C1, C2). Then, peroxide formation kinetics of the microcapsules were also determined. Peroxide values (PV) of microencapsulated fish oil in the presence of 1500 ppm rosemary (R2) were lower (3.08 mEq O2/ kg oil) than the control group with commercial antioxidant (C2, 4.25 mEq O2/ kg oil). Thiobarbituric acids (TBA) of R2, R1, and L2 (0.36 mmol MDA/kg oil, 0.56 mmol MDA/kg oil, 0.59 mmol MDA/kg oil respectively) were also lower than C2 (0.64 mmol MDA/kg oil). Besides, R2 and R1 (31.62 kJ/mol, and 30.82 kJ/mol) had higher activation energies than C2 (30.46 kJ/mol). As a result, it is revealed that rosemary and laurel extracts can successfully be applied to anchovy oil for improving the oxidative stability in microencapsulation by spray drying.

    更新日期:2018-07-24
  • Thermo-hydrous behavior of dried un-blanched potato samples
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-23
    I. Boutelba, S. Zid, P. Glouannec, S. Youcef-ali, A. Magueresse, N. Kimouche

    This study concerns a purely convective drying of parallelepiped un-blanched potato slices. A numerical model for heat and mass transfer has been developed in Lagrangian referential to overcome the structural changes. The thermo-physical properties of the slices vary with the temperature and moisture content. The finite volume method combined with a typically implicit time pattern was used to solve the model equations. The evaporated mass flux was calculated using the transfer surface area by which the water evaporates, and heat transfer coefficient was estimated using Nusselt number; The inverse method was used in this computation. The experiments were carried out under several thermo-aeraulics conditions in order to determine the most influent operating variable on the drying kinetic. A good agreement between experimental and simulated results was obtained with a moisture content determination coefficient (R2) higher than 0.9980; Whereas, the surface and center temperatures are higher than 0.9328 and 0.9305 respectively. The results have shown that the air temperature is the most important parameter that controls the drying kinetic.

    更新日期:2018-07-24
  • Can high-pressure homogenization cause thermal degradation to nutrients?
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-23
    Andreas Håkansson

    Although originally developed for fat globule disruption in dairy applications, high-pressure homogenizers are extensively used in other food processing applications. Two newer applications are in forming nanoemulsion for delivering supplemented nutrients and as a preservation technique, both using higher pressures than traditional applications. This has raised concern that friction heat created in the homogenizer causes thermal degradation to temperature sensitive molecules such as nutrients. This contribution uses a numerical model to give insight into temperature profiles for drops in a homogenizer valve and investigates when homogenization at elevated pressures is expected to cause thermal degradation. A fast method for estimating the extent of degradation for a given application is also proposed. It is concluded that no thermal degradation is expected inside the valve, almost regardless of operating conditions, due to the short residence time. Provided that cooling is applied after the homogenizer, degradation downstream of the valve can also be avoided.

    更新日期:2018-07-24
  • The effect of pH on the wetting and dissolution of milk protein isolate powder
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-23
    Shaozong Wu, John Fitzpatrick, Kevin Cronin, Song Miao

    Milk protein Isolate (MPI) powder is an important food ingredient powder but it has poor wettability and dissolution ability which limit its functional usage. The effect of pH (5.4-8.4) on the wettability and dissolution of MPI powder is evaluated in this study. Contact angle and Washburn methods were used to measure the wetting behaviour of MPI powder. Its dissolution ability was measured by static light scattering in real-time after a pre-mixing step. The results showed that the contact angle of droplets on compacted powder tablets exhibited no significant difference between pH conditions (p 0.05) and this was supported by the results of the Washburn method. It was found that MPI dissolution was strongly correlated with the appearance of submicron size casein micelles in the solution. During dissolution, higher pH caused an earlier appearance of this casein micelle submicron peak and a higher swelling peak associated with the swelling of casein micelle aggregates. This swelling of casein micelle aggregates indicates greater water penetration and loosening of the aggregate structure at higher pH, which facilitated faster dissolution of MPI powder, especially at a pH of 8.4. This study indicates changing alkaline environment could be potential to apply in MPI rehydration.

    更新日期:2018-07-23
  • Rapid identification of tea quality by E-nose and computer vision combining with a synergetic data fusion strategy
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-20
    Min Xu, Jun Wang, Shuang Gu

    This research demonstrates a rapid detection method of jointly using electronic nose (E-nose) and computer vision system (CVS) to detect tea aroma and tea appearance for tea quality identification. Feature-level and decision-level fusion strategies were introduced for analyzing the fusion signals of E-nose and CVS. K-nearest neighbors (KNN), support vector machine (SVM) and multinomial logistic regression (MLR) were applied for classification modelling. The results showed that the decision making based on fusion strategies synergistically integrated the advantages of E-nose and CVS and obtained better performance than independent decision in tea quality identification. The decision-level fusion combining the SVM results of both E-nose and CVS was the most effective strategy with the classification accuracy rates of 100% for training and testing sets. This study manifests the simultaneous utilization of E-nose and CVS combined with the decision-level fusion strategy could be worked as a rapid detection method to identify tea quality.

    更新日期:2018-07-21
  • Olive oil droplet coalescence during malaxation
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-20
    Eleni P. Kalogianni, Despoina Georgiou, Stylianos Exarhopoulos

    Coalescence of olive oil droplets during malaxation is a crucial phenomenon since it is responsible for the effective oil separation in the following processing steps. Yet it has been scarcely examined. The aim of this work was to study in detail the evolution of droplet size distribution during malaxation in actual processing conditions. For that reason experiments took place in an industrial scale olive oil extraction plant. The effect of malaxation time and the effect of water dilution on the droplet size distribution were examined. The results depict the progressive olive oil droplet coalescence and show a clear effect of water dilution on the rate of coalescence. The higher coalescence rate in the diluted paste was attributed to the decrease in viscosity. Finally it was shown that separation of the diluted paste in a two-phase decanter resulted into smaller droplet sizes (and therefore lower oil content) remaining in the paste.

    更新日期:2018-07-21
  • Pressurized liquid extraction of bioactive compounds from grape marc
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-20
    Débora Tamires Vitor Pereira, Adriana Gadioli Tarone, Cinthia Baú Betim Cazarin, Gerardo Fernández Barbero, Julian Martínez

    Extracts rich in monomeric anthocyanins (MAC) and total phenolic compounds (TPC) were obtained from grape marc by Pressurized Liquid Extraction (PLE). PLE was performed using ethanol and water mixtures (acidified or not) (50% w/w), pure ethanol and acidified water at temperatures from 40 to 100 °C. The best PLE conditions for MAC extraction (ethanol-water pH 2.0 [50% w/w]) resulted in 10.21 mg of malvidin-3-O-glucoside/g of dried grape marc (dr). Fifteen anthocyanins were identified and quantified in PLE extracts by UHPLC-UV-Vis. PLE with ethanol-water (50% w/w) as solvent at 100 °C achieved the highest TPC content (65.68 mg GAE/g dr) and antioxidant capacity by ORAC (772.11 μmol TE/g dr) and FRAP (1452 mg TE/g dr) among the evaluated conditions. Based on the results for extraction of monomeric anthocyanins and phenolics compounds, a sequential PLE process was performed and proved to be viable for the recovery of two different extract fractions.

    更新日期:2018-07-20
  • Modelling of Listeria monocytogenes Scott A after a mild heat treatment in the presence of thymol and carvacrol: Effects on culturability and viability
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-18
    Stefania Arioli, Chiara Montanari, Michael Magnani, Giulia Tabanelli, Francesca Patrignani, Rosalba Lanciotti, Diego Mora, Fausto Gardini

    The combined effect of thymol, carvacrol and mild heat treatments against Listeria monocytogenes Scott A was assessed in buffered system by plate counting and flow cytometry (FCM). The susceptibility of cells increased when heat treatment was combined with terpenes. The data modelling with Bigelow and Weibull equations showed that the latter was more appropriate to describe the inactivation kinetics. After treatments, cells were no longer able to form colonies on plates; nevertheless, FCM indicated that most of the cells were damaged rather than dead. Treated cells were not able to recover the damage after 6 h. This opens the question if they could recover in a food matrix. FCM can be a helpful technique to better comprehend the physiological state of microorganisms. In the perspective of industrial applications, studies based on predictive microbiology, as well as a deeper comprehension of the action mechanisms of antimicrobials, play a key role for process optimization.

    更新日期:2018-07-19
  • Operational efficiencies of six microwave based extraction methods for orange peel oil
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-18
    Seyed Elyas Razzaghi, Akbar Arabhosseini, Mohammad Turk, Thibault Soubrat, Aurélie Cendres, Mohamad Hosein Kianmehr, Sandrine Perino, Farid Chemat

    Microwave is a very efficient energy carrier for the extraction of essential oils from aromatic plants in unit operations intended for distillation. The aim of this work was to compare six extraction processes: four Microwave Assisted Extraction (MAE) and two conventional processes for the extraction of orange essential oils. The comparison was based on different processing and qualitative criteria such as extraction yield, power efficiency, biochemical and sensorial attributes. Two multiple criteria methods were developed to select the most efficient process. The first method is based on the income over energy cost index. The results show that among the set of extraction processes studied only Microwave Hydrodiffusion and Gravity (MHG) would be operational cost efficient. The second method combines both processing and qualitative criteria. The results show that the extraction processes with combination of microwaves and steam are best ranked followed by those with just microwaves.

    更新日期:2018-07-19
  • Towards a Decision Support Framework for Technologies used in Cold Supply Chain Traceability
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-17
    Kristín Óskarsdóttir, Guðmundur Valur Oddsson

    In recent years, a need for product traceability in the cold supply chain has emerged. The purpose of this study was to identify and map out different kinds of identification technologies and techniques used for cold supply chain traceability. This was done by looking into what traceability solutions are available right now through literature review. The results from this review were then further analyzed to obtain a basis for the current state of knowledge, technical solutions and to identify possible traceability structures in the cold chain. A Decision Support Framework (DSF) was constructed for choosing a suitable technical solution. It consists of a table listing different functions and attributes of technologies and a decision-tree. The DSF created from this work will help the user to identify what kind of traceability technology and structure best suits his products. This is important, as it can often be difficult for the user to decide which technology is most beneficial for his company. That is why this decision support framework will enable him to decide what is technologically feasible, practical, economical, can sustain reputation, quality and safety of the products.

    更新日期:2018-07-18
  • Effect of mono- and diglycerides on physical properties and stability of a protein-stabilised oil-in-water emulsion
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-17
    Chia Chun Loi, Graham T. Eyres, E. John Birch

    Mono- and diglycerides (MDGs) are emulsifiers used to modify physical properties and creaming stability in protein-stabilised emulsions. This study aims to understand the effect of different MDGs and sodium stearate on oil droplet size and creaming stability of emulsions. Model emulsions with eight MDG compositions and a control (protein only) were prepared by microfluidisation. Emulsion droplets and creaming stability were characterised by droplet size, zeta potential, viscosity and creaming index during aging (28 days at 25 °C). Emulsions containing 0.2% MDGs produced 15–30% smaller oil droplets and 17–27% lower polydispersity indices compared to the control. Sodium stearate (6% of MDGs) increased zeta potential by 12.6–17.3 mV in emulsions containing saturated MDGs and 1.8–5.0 mV in unsaturated MDGs. Unsaturated MDGs showed better creaming stability than the control after 28 days of aging with no improvement observed for saturated MDGs. Unsaturated MDGs are promising emulsifiers to improve creaming stability of protein-stabilised emulsions.

    更新日期:2018-07-18
  • Extraction of High Stearic High Oleic Sunflower Oil (HSHO): Effect of Dehulling and Hydrothermal Pretreatment
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-17
    A.K. de Figueiredo, M.B. Fernández, S.M. Nolasco

    The effect of a hydrothermal pretreatment on the solvent extraction of oil and minor compounds (tocopherols) from high stearic high oleic sunflower seeds (HSHO), partially dehulled and undehulled, was analyzed. Samples of sunflower seeds of different origins and oil contents (high oil, 43.0% d.b., and low oil 35.1% d.b.) were used. The oil yield increased significantly due to the hydrothermal pretreatment (p< 0.05) for HSHO samples with high oil content, both partially dehulled and undehulled. The pretreated HSHO samples with low oil content did not show significant differences in oil yield compared to the untreated samples. The effective diffusion coefficients for the hydrothermally pretreated seeds (2.12.10-11 m2.s-1) and the untreated samples (7.07.10-12 m2.s-1) were determined based on the oil extraction from the partially dehulled high oil HSHO samples. For both types of partially dehulled HSHO seeds, a significant increase in tocopherol content in the oils extracted from the pretreated samples was observed.

    更新日期:2018-07-18
  • Regression analysis for predicting the fermentation state of packaged Kimchi using a colorimetric indicator
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-12
    Su-Ji Kim, Jae Yong Lee, So-Ra Yoon, Hae-Won Lee, Ji-Hyoung Ha

    The application of a colorimetric indicator for monitoring the degree of fermentation in Kimchi was studied. Changes in total color difference (TCD) occurred continuously from the initial to final fermentation stage with a maximum TCD value of 36.08 ± 0.72 after 28 days. The experimental data for the converted color response function, F(Xc) were demonstrated to be more linear (R2 = 0.986) than for TCD values. The coefficients of determination of pH: F(Xc) (R2 = 0.9583) and titratable acidity: F(Xc) (R2 = 0.9828) were sufficient to meet the zero-order reaction. Results of standardized residuals evidenced their normal distribution, indicating that 95% of the residuals of predicted pH or titratable acidity were in the range of −1.96 to 1.96. The coefficients of determination between predicted- and observed data were 0.841 (pH) and 0.912 (titratable acidity). Based on regression analysis, the colorimetric indicator could thus be applied as a Kimchi fermentation indicator.

    更新日期:2018-07-12
  • New insights into cooked rice quality by measuring modulus, adhesion and cohesion at the level of an individual rice grain
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-09
    L. Yu, T. Witt, M.Rincon Bonilla, M.S. Turner, M. Fitzgerald, J.R. Stokes

    Causal relationships between physical properties and structure/composition of cooked rice are difficult to quantify when mechanical measurements are performed on bulk samples using large deformations that alter the structure irreversibly. We demonstrate here methods involving small-deformation to characterise the elastic modulus (E), adhesion and cohesion at the individual grain level, and show distinct differences between freshly cooked rice and shelf-stable retorted rice. On average, retorted rice is harder and less adhesive and cohesive than freshly cooked rice, but their distributions in each of these mechanical properties overlap. E is independent of adhesion and weakly correlated with moisture content. In addition, a ring-shear tester is shown to distinguish the bulk cohesion and flowing ability between rice samples. Measuring the inherent physical properties of individual grains has the potential to enable a more sensitive evaluation of new processes and grain varieties, and development of quantitative structure-property-processing relationships for rational design of products to perform optimally at different stages, from manufacturing through to oral processing.

    更新日期:2018-07-09
  • Physical properties of açai-berry pulp and kinetics study of its anthocyanin thermal degradation
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-05
    Henrique C.B. Costa, Danylo O. Silva, Luiz Gustavo M. Vieira

    Knowledge about physical properties of food materials is essential for processing design and optimization. Although the market of açai-based products has been growing in these last few years, little information about physical properties of the açai pulp is available in the literature. This work evaluates the effects of solids content (dry matter – %) and temperature on the properties of açai, namely thermal conductivity and diffusivity, specific heat, density and volumetric thermal expansion coefficient. Both solids and temperature had a significant effect on the physical properties and the experimental data were in agreement with the predictive models of Choi and Okos. Also, a study of anthocyanin thermal degradation of the açai pulp was carried-out for the temperature range from 40 °C to 80 °C, which resulted in an activation energy of 24.16 kJ mol−1 and half-life times between 10.7 and 28.6 h. The achievements presented in this work may contribute with the açai industry and may be useful in other studies about açai pulp processing.

    更新日期:2018-07-08
  • Impact of hydrocolloid addition and microwave processing condition on drying behavior of foamed raspberry puree
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-06
    M. Ozcelik, S. Ambros, A. Heigl, E. Dachmann, U. Kulozik

    In this study, foamed raspberry puree was dried by microwave-assisted freeze drying (MWFD). The combined use of microwaves and a foamed structure was intended to accelerate the drying process, while creating an innovative product structure with intense aroma impact for consumption as a snack. The influence of potato protein as foaming agent, maltodextrin as foam stabilizer and microwave (MW) power on the drying characteristics of raspberry foams during MWFD was investigated.conventional freeze drying (FD) experiments were performed as a reference. MD concentration was shown to significantly influence product temperature. As higher MD concentrations yielded smaller bubbles and a more uniform bubble size distribution, lower drying temperatures were needed to reach the same final moisture content.Varying MW power did not did not significantly influence the drying time. MWFD at 1.0 W g-1 yielded a 3 to 4-fold decrease in total drying time as compared to FD. The addition of 10% protein led to the most gentle drying at high MW power input due to structural changes enabling a lower resistance against water vapor mass transfer. There was a high correlation between the foam characteristics and the drying behavior. An overrun above 450% led to gentle drying at all tested microwave power input levels. Foam bubble size and bubble size distribution correlated well with drying velocity. Overall, MWFD was shown to be a much faster and more gentle alternative to FD for the production of fruit foams.

    更新日期:2018-07-08
  • Electrohydrodynamic drying of multiple food products: evaluating the potential of emitter-collector electrode configurations for upscaling
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-07
    Thijs Defraeye, A. Martynenko

    Electrohydrodynamic (EHD) drying is a promising, non-thermal drying technology, based on ionic wind generation between an emitter and a collector electrode. This simulation-based study evaluates impact of various emitter-collector configurations for EHD drying in order to assess their potential towards industrial upscaling. The conventional wire-to-plate configuration, which creates impinging flow, is found not to be an optimal solution for EHD drying of multiple food products in a fast and uniform way. With a single wire (emitter), it is found that the products placed more downstream dry slower due to the progressive loading of the air with water vapor. With multiple emitters, up to a threefold increase in drying time of the food products is found, compared to a single wire. This increase is caused by the recirculation of most air. To avoid moisture accumulation in the drying zone, a wire-to-mesh configuration is proposed. The mesh collector minimizes interference of neighboring airflows and avoids recirculation of moist air in the drying zone. As such, the wire-to mesh configuration provides more uniform drying between adjacent products, but also within a product, as it can dry from all its surfaces. An increase in emitter density for the wire-to-mesh configuration leads to an overall increase in airspeed, but surprisingly not to increased product drying rates. The reason is that the high-speed EHD airflow is always generated very locally in the vicinity of the emitter and collector. Thereby the convective drying process is not affected so much by the emitter density.

    更新日期:2018-07-08
  • Evaluation of drying of edible coating on bread using NIR spectroscopy
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-07
    Swathi Sirisha Nallan Chakravartula, Federica Balestra, Chiara Cevoli, Angelo Fabbri, Marco Dalla Rosa

    Edible coatings are recently gaining attention for potential applications in bakery products to extend the shelf-life and incorporate functional characteristics, like probiotics, antimicrobial or an antioxidant compound, for which drying of the coating is an essential step. The aim of this work was to utilize near infrared (NIR) spectroscopy as a tool to rapidly monitor and develop predictive model for the drying of edible coating on bread (mini-burger buns) surfaces. The buns coated with edible coating were dried at two different temperature regimes, at 25 °C and 60 °C for one layer of coating and one temperature regime at 60 °C for two layers of coating. NIR spectra were collected and moisture content was determined at different drying times. The spectral data were pre-treated and subjected to Principal component analysis (PCA) for discrimination of drying times and subsequently to Partial least squares (PLS) regression for moisture prediction for given temperature, time and surface. Results show that NIR spectroscopy was able to reflect the drying process and discriminate between the various surfaces of bread and times of drying, primarily by the differences in water and protein absorption bands (1940 nm, 1500 nm, 2050 nm). Also, the subsequent PLS regression of the spectral data was found to describe satisfactorily the drying behaviour and the optimal drying moment with RMSE values ≤ 3% for the calibration and cross validation data sets. The procedure proposed could be used for faster quantification of moisture during drying process.

    更新日期:2018-07-08
  • Active gelatin films incorporated with pickering emulsions encapsulating hesperidin: Preparation and physicochemical characterizations
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-04
    Ilyes Dammak, Rodrigo Vinicius Lourenço, Paulo José do Amaral Sobral

    In the present contribution, we focus on the fabrication and characterization of active gelatin-based films incorporated with oil-in-water (O/W) Pickering emulsions stabilized with chitosan nanoparticles (ChiNP) and encapsulating hesperidin (Hesp). Results revealed Pickering emulsions with d3,2 of 5.4 μm and PDI of 0.3. Hesp was found to improve the physical stability of the emulsions, suggesting that ChiNP adsorb more efficiently, in the presence of Hesp. Films were produced by the casting method incorporating different emulsion’ levels (5, 10, 20, 30 and 50 g oil/100 g of gelatin). Microstructure analysis with confocal laser scanning microscopy (CLSM) images showed a similar droplets size and size distribution in the film matrix, endowing the films with homogeneous distributions of oil droplets over their 3D network architecture of films. Scanning electron microscope (SEM) suggested that this phenomenon might be related to Pickering stabilization effect of oil droplets incorporated into the film matrix. With increase of incorporation level, film’ surfaces were more heterogeneous. Interestingly, the incorporation of Pickering emulsions was effective to produce films with good compatibility between interface of oil droplets and gelatin matrix. Films showed less resistance to tension, and more flexibility. The water vapor barrier properties of films improved by increasing the incorporation level. X-ray analysis revealed a good compatibility among the composite films. Films incorporated with encapsulated hesperidin showed a noticeable antioxidant activity. These findings are important to better design composite active films incorporated with Pickering emulsions, in order to optimize film formulation in a rational manner towards their eventual application as food packaging.

    更新日期:2018-07-05
  • Freezing pre-treatments on the intensification of the drying process of vegetables with different structures
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-04
    Francisca Vallespir, Óscar Rodríguez, Valeria S. Eim, Carmen Rosselló, Susana Simal

    The effect of different freezing pre-treatments on the drying kinetics (50 °C and 1 m/s), and quality of vegetables with different structures such as beetroot, apple and eggplant has been studied. Samples cubes of 0.01 m edge were frozen at temperatures of −20 °C, −80 °C, or by immersion in liquid nitrogen (−196 °C). Then, frozen samples were dried at 50 °C and 1.0 m/s. Freezing pre-treatments promoted a significant (p < 0.05) increment of the drying rate, leading a reduction of the drying time up to 17, 27, and 34% in beetroot, apple and eggplant, respectively. A diffusion model was proposed to identify both the effective diffusion (De) and the external mass transfer (hm) coefficients during convective drying. The identified De in untreated (non-frozen samples) beetroot, apple and eggplant was of 4.2 ± 0.1 × 10−10, 4.7 ± 0.1 × 10−10 and 5.1 ± 0.3 × 10−10 m2/s, respectively. This coefficient was significantly higher in treated samples. Increments ranged from 18 to 31%, from 42 to 64%, and from 18 to 72% in beetroot, apple and eggplant, respectively and in all cases the higher figure was observed when samples were frozen at −20 °C. The identified hm was of 7.0 ± 0.5 × 10−4, 4.2 ± 0.2 × 10−4 and 2.3 ± 0.2 × 10−4 kg water/(m2 s) for beetroot, apple and eggplant drying, respectively. Regarding quality parameters, colour change and microstructure were deeply affected by both the freezing pre-treatment and the drying process. The extension of this effect varied accordingly to the porosity of the sample. The eggplant colour and microstructure, with a higher porosity, was the most affected, particularly by freezing pre-treatment at −20 °C.

    更新日期:2018-07-05
  • Dielectric properties of kiwifruit associated with a combined radio frequency vacuum and osmotic drying
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-04
    Xu Zhou, Rui Li, James G. Lyng, Shaojin Wang

    To develop a novel combination drying method combining radio frequency (RF) with vacuum and osmotic dehydration (OD), information on dielectric properties is essential so as to understand the interaction between the electromagnetic field and the matrix undergoing drying. In this paper, the dielectric properties of kiwifruit samples were determined across the frequency range of 10 and 3000 MHz using an open-ended coaxial-line probe and impedance analyzer at moisture contents ranging from 19.8% to 79.6% on a wet basis (w.b.) and temperatures between 20 and 80 ºC. The effect of pre-treatments including OD and hot air drying (AD) on the dielectric properties, physicochemical properties and RF-vacuum drying characteristics of kiwifruit were also studied. The results showed that both the dielectric constant and loss factor decreased with decreasing moisture content and increasing frequency. At high moisture contents (above 65% w.b.), the dielectric constant decreased slightly with increasing temperature, whereas at lower moisture contents (below 50% w.b.), the dielectric constant increased sharply with increasing temperature. In addition, the OD resulted in less kiwifruit quality deterioration than AD in terms of titratable acidity, ascorbic acid, soluble solids and color. Although dielectric permittivities of OD treated kiwifruits were slightly lower than those of AD treated samples, the effect of the OD treatment on RF energy coupling was negligible compared to the AD. Therefore, OD may provide an alternative way for AD as a pre-treatment before RF drying for kiwifruits with high-quality characteristics.

    更新日期:2018-07-05
  • ADSORPTIVE RECOVERY OF PHENOLICS FROM APPLE JUICE via BATCH AND FIXED BED COLUMN
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-03
    E. Aytunga Arık Kibar

    Apple juice contains many phenolic compounds, including flavonols, flavanols, anthocyanins, hydroxycinnamic acids, and dihydrochalcones, with many reported health benefits. Patulin is the main toxic microbiological contaminant associated with apple products. In the present study, adsorption of phenolic compounds from apple juice concentrate onto polymeric resin was investigated with the goal of recovering antioxidant components. Simultaneous adsorption risk of the contaminant patulin with the phenolics was also evaluated. The adsorption kinetics was studied in batch experiments. Three kinetic models, Thomas, Adams–Bohart, and Yoon–Nelson, were applied to experimental data to predict dynamic behaviour of fixed bed column using nonlinear regression, and thus to determine the characteristic parameters that are useful for process design.

    更新日期:2018-07-04
  • Synergistic effects of ultrasound and soluble soybean polysaccharide on frozen surimi from grass carp
    J. Food Eng. (IF 3.197) Pub Date : 2018-07-03
    Wenhong Gao, Rui Hou, Xin-an Zeng

    Ultrasound and water soluble soybean polysaccharide (SSPS) were applied during the freezing of grass carp surimi. Ultrasound-assisted immersion freezing (UF) process was observed from 0 °C to -15 °C. Based on characteristic freezing time, tempering-stage freezing rate and the quality change of surimi after a 14-day storage period, the optimal sonication was performed 5 times at 300 W, for 10 s, with 40 s intervals. The cryoprotective effects of SSPS content on surimi myofibillar protein were subsequently investigated during 28-day frozen storage at -18 °C. The Ca2+-ATPase activity, total sulphydryl content, active sulphydryl content, salt extractable protein content, whiteness and water-holding capacity of frozen surimi were determined after adding SSPS (0%, 1%, 3% and 5%). The results showed that synergism of SSPS and UF occurred. Consequently 3% SSPS was best for mitigating the protein denaturation during processing.

    更新日期:2018-07-04
  • Influence of the drying step in the steam-jet granulation process of dairy powders
    J. Food Eng. (IF 3.197) Pub Date : 2018-06-27
    Mathieu Person, Bernard Cuq, Agnès Duri, Cécile Le Floch-Fouéré, Pierre Schuck, Romain Jeantet

    Steam-jet granulation process agglomeration consists in agglomeration mechanisms promoted by the wetting of fine particles and colliding them to generates the agglomerates, and in consolidation mechanisms of the agglomerates by drying stage consolidating the formed bridges by drying to obtain agglomerates. The aim of the present study was to evaluate the influence of the drying step on the properties of the agglomerates. Experiments were conducted using an original pilot system with different drying conditions (time and temperature). We demonstrated that the mechanisms induced by drying stage contribute to the final structure and characteristics of the agglomerates. On the other hand, the changes in drying temperature (70, 90, or 110°C) drying kinetics did not significantly impact the structural properties. The rehydration properties of the agglomerates were found to depend on the changes in water content. During the first minutes of drying, Over short periods, a rapid decrease of the wetting time of the agglomerates was observed and associated with rapid lactose crystallization. For long drying times, Over long periods, the large decrease in water content induced a considerable increase in the glass transition temperature, leading to a delay in the plasticization effect of the water during rehydration. The drying stage is a Drying conditions are key factor to control the stability and functional properties of agglomerates.

    更新日期:2018-06-28
  • Effect of High Pressure Carbon Dioxide on tomato juice: inactivation kinetics of pectin methylesterase and polygalacturonase and determination of other quality parameters
    J. Food Eng. (IF 3.197) Pub Date : 2018-06-27
    A.E. Illera, M.T. Sanz, E. Trigueros, S. Beltrán, R. Melgosa

    Tomato juice, Lycopersicon esculentem cv. Canario, has been treated by HPCD as non-thermal preservation treatment. The inactivation kinetics for pectinmethylesterase (PME) and polygalacturonase (PG) were determined at different pressures (8.5 to 20 MPa) and temperatures (35 to 55 ºC). At the highest operating pressure and temperature essayed in this work, it was found that PME could be almost completely inactivated, whereas PG resulted to be more HPCD resistant at the working conditions. PME enzyme inactivation curves were properly described by a Weibull type model, while the fractional conversion model was the most appropriate for the PG with a sharp initial decrease in activity. On the contrary, high hydrostatic pressure led to a nearly complete inactivation of PG while PME was very resistant at 600 MPa. It was also found that HPCD treatment led to a smaller particle size distribution of tomato juice.

    更新日期:2018-06-28
  • PRODUCTION AND CHARACTERISATION OF BIODEGRADABLE PLA NANOPARTICLES LOADED WITH THYMOL TO IMPROVE ITS ANTIMICROBIAL EFFECT
    J. Food Eng. (IF 3.197) Pub Date : 2018-06-28
    Ismael Marcet, Shihan Weng, Sara Sáez, Manuel Rendueles, Mario Díaz

    Thymol is widely recognised as an antibacterial compound. However, its use in food technology is hindered by its high volatility, its light sensitivity and its low solubility in water. To overcome these drawbacks, the preparation of nanoparticles using polylactic acid (PLA) is proposed in this study.The average size of the nanoparticles and thymol encapsulation efficiency parameters were studied using different PLA and thymol concentrations. Furthermore, the morphology, the storage stability of the nanoparticles at several pHs and the in vitro thymol release profile were also studied, as well as their thermal degradation profile. Finally, their antimicrobial activity on a real food model was measured, using for this purpose apple pieces previously inoculated with E. coli.The PLA was found to be the key variable in optimizing the nanoparticle preparation, producing spherical nanoparticles with a thymol encapsulation efficiency of 60.3 ± 8%. These nanoparticles showed a high storage stability at several pHs and improved antimicrobial properties in comparison with the non-encapsulated thymol.

    更新日期:2018-06-28
  • Effects of intense pulsed light on Cronobacter sakazakii inoculated in non-fat dry milk
    J. Food Eng. (IF 3.197) Pub Date : 2018-06-26
    Dongjie Chen, Justin Wiertzema, Peng Peng, Yanling Cheng, Juer Liu, Qingqing Mao, Yiwei Ma, Erik Anderson, Paul Chen, David J. Baumler, Chi Chen, Zata Vickers, Joellen Feirtag, Laurence Lee, Roger Ruan

    Cronobacter sakazakii is known to have caused life-threatening infections in neonates with a fatality rate of 40–80%. Contaminated powdered food, especially powdered infant formula (PIF), has been epidemiologically linked with these foodborne outbreak infections. Clinical symptoms of C. sakazakii infection include necrotizing enterocolitis, bacteremia, and meningitis. Traditional thermal processing of PIF has been used to kill foodborne pathogens, but it has an undesirable flavor and quality attributes that are unacceptable for industrial usage. Thus, there is a need for new bactericidal technologies for dry powdered foods. In this study, an intense pulsed light (IPL) treatment system was developed, and processing parameters such as relative humidity, environmental temperature, initial water activity, initial temperature, and residence time were evaluated for a bactericidal effect on C. sakazakii in non-fat dry milk (NFDM). The results indicated that a synergistic effect of IPL and an appropriate temperature of ∼57.5 ± 0.7 °C exhibited maximum inactivation of 3.18 log10 CFU/g for C. sakazakii in NFDM with little agglomeration at the initial temperature of 25 °C, at the water activity level of 0.25, and a residence time of 28 s. In addition, significantly higher inactivation was observed when IPL was combined with a vibratory feeder (p < 0.05). No significant change in the amino acid composition, particle physical appearance, and typical volatile compounds were observed after IPL treatment. Overall, the study demonstrates that IPL treatment is promising for inactivation of C. sakazakii in NFDM with minimal quality degradation.

    更新日期:2018-06-27
  • New insights into the apple fruit dehydration process at the cellular scale by 3D continuum modeling
    J. Food Eng. (IF 3.197) Pub Date : 2018-06-26
    Kevin Prawiranto, Thijs Defraeye, Dominique Derome, Pieter Verboven, Bart Nicolai, Jan Carmeliet

    An accurate understanding of the dehydration kinetics of biological materials is essential to optimize their dehydration processes and to produce high-quality dried products. For a soft, cellular material like fruit, the underlying mass transport and deformation mechanisms at the cellular scale play a key role here. To improve our insight into the cellular scale dehydration kinetics, a 3D model is developed to quantify the impact of the changes in the cellular structure of apple (parenchyma) cells during dehydration on the tissue sorption isotherm and water permeability. As a step beyond the current state-of-the-art models, the model incorporates the changes in the cellular structure over entire dehydration process, starts from a turgid cell down to the occurrence of (free) shrinkage, plasmolysis (detachment of the cell membrane from the cell wall) or lysis (rupture of the cell membrane). Regarding the tissue sorption isotherm, plasmolysis induced a reduction in the equilibrium water content (up to 60%) compared to the free-shrinkage or lysis cases at the same water activity level. On the other hand, the tissue water permeability was found to increase up to five times when lysis occurs, compared to free shrinkage or plasmolysis. A parametric study also quantified the dependency of tissue permeability on the cell wall thickness, the membrane permeability, the cell size and the elongation aspect of the cell. We identified that the dehydrated, shrunken cellular tissue, reduces the outgoing water flux compared to fresh tissue for the same water potential gradient. As such, dehydrated tissue forms a kind of barrier against further moisture removal from the fresh tissue below.

    更新日期:2018-06-27
  • Cherry (Prunus avium) phenolic compounds for antioxidant preservation at food interfaces
    J. Food Eng. (IF 3.197) Pub Date : 2018-06-26
    Maria F. Basanta, Ana M. Rojas, Manuela R. Martinefski, Valeria P. Tripodi, Maria D. De’Nobili, Eliana N. Fissore

    Cherry phenolics extracted by 90°C-water were loaded in a low-methoxyl-pectin (LMP) film for antioxidant preservation. Dark red films (pH = 3.46) contained flavonols (dihydrokaempferol-glucoside, quercetin-3-O-rutinoside), hydroxycinnamic acids (neochlorogenic, chlorogenic, 3-p-coumaroylquinic acids), and anthocyanins (cyanidin-3-O-glucoside, cyanidin-3-O-rutinoside), with a 6.97 × 10−12 m2/s diffusion coefficient. Phenolics’ stability was studied at constant relative humidity (RH: 57.7; 75.2%) and 25.0 °C. The pseudo-first-order degradation rate was the highest (t1/2 = 3-2 months) and increased with the equilibration RH in darkness for anthocyanins, with simultaneous red vanishing by water nucleophilic attack. Instead, flavonols remained stable (t1/2 >1.5 years). Light (75.2%RH) induced the highest phenolics-degradation-rates, especially for anthocyanins (t1/2 = 11d), sensitizer, and film red color. Flavonols-decay was the slowest (t1/2 = 7–12 months). Antioxidant capacity paralleled phenolics-content. Hydroxycinnamic acids followed by flavonols could scavenge the singlet oxygen. Light-triggered LMP-matrix―phenolic interactions were determined, producing the lowest film water content and deformability. Cherry phenolics stabilized as a colored film constituted a food preserving antioxidant barrier.

    更新日期:2018-06-27
  • Innovative photonic system in radiofrequency and microwave range to determine chicken meat quality
    J. Food Eng. (IF 3.197) Pub Date : 2018-06-26
    Maria Victoria Traffano-Schiffo, Marta Castro-Giraldez, Ricardo J. Colom, Pedro J. Fito

    Nowadays, one of the most important challenges of poultry industry is to determine individually the meat quality class (pale, soft and exudative, normal and dark, firm and dry meats) by non-invasive, accurate and fast technique. For this purpose, dielectric spectra in radiofrequency and microwave ranges were studied. In radiofrequency range, the permittivity was measured by a non-destructive sensor conformed by three points with blunt-ended electrodes connected to an Agilent 4294A impedance analyser, and in microwave range an Agilent 85070E open-ended coaxial probe connected to an Agilent E8362B Vector Network Analyser were used. This work demonstrates the direct relation between the pH evolution and the dielectric constant at α-dispersion, and also, that the main structural proteins degradation has direct relation with the dielectric constant at β-dispersion, being possible to segregate meat depending on the level of protein degradation. Finally, this paper ends with a classification model for quality poultry meat based on a photonic analysis at radiofrequency range by using the Traffano-Schiffo model.

    更新日期:2018-06-27
  • ASSESSMENT OF TEXTURE AND STORAGE CONDITIONS OF MANGOES SLICES DRIED BY A CONDUCTIVE MULTI-FLASH PROCESS
    J. Food Eng. (IF 3.197) Pub Date : 2018-06-26
    Jade Varaschim Link, Giustino Tribuzi, Jaqueline Oliveira de Moraes, João Borges Laurindo

    Glass transition temperature (Tg) and sorption isotherms can be used to establish state diagrams that help to assess storage conditions to keep the food as an amorphous material in a glassy state. In this study, state diagrams and mechanical properties were assessed to predict the storage conditions of mangoes dried by 1) air-drying; 2) freeze-drying; 3) vacuum-drying and 4) conductive multi-flash drying (KMFD - four cycles of heating/vacuum pulse followed by vacuum-drying). Dried mangoes showed a typical sorption isotherm behavior of hygroscopic materials. In the relative humidity (RH) range investigated (between 11.3% and 90.3%), Tg of processed samples decreased from 44 °C to -68 °C, due to the plasticizing effect of water. Dried mangoes stayed structurally stable at room temperature (25 °C) if storage RH was kept at 25%, in this conditions the moisture content was 0.036 g.g -1 (d.b.). The puncture tests results confirmed that, at room temperature, samples stored at RH higher than 30% lost their crispness.

    更新日期:2018-06-27
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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