Drying and Denaturation Kinetics of Beta-Lactoglobulin during Convective Drying J. Food Eng. (IF 3.099) Pub Date : 2018-05-21 M. Amdadul Haque, Md. Moinul Hosain Oliver, Aditya Putranto, Benu Adhikari
Beta-Lactoglobulin (β-Lg) is the major fraction of whey protein that comprises more than 65%. Therefore, denaturation of β-Lg during drying can affect the protein functionality where the whey protein is used as an ingredient in food products. This study was carried out to understand the drying and denaturation kinetics of β-Lg during the drying process. A convective drying environment was used to predict the moisture content and temperature kinetics of the drying droplets of β-Lg using Reaction Engineering Approach (REA) models. The predicted values were then coupled with the first order reaction equation to determine the denaturation kinetics. Single droplets of β-Lg (10% w/v; 1.5±0.1 mm initial diameter) were dried at two different temperatures (65 °C and 80 °C) at a constant air velocity (0.5 m/s) for 10 minutes. The real time denaturation of β-Lg protein was quantified at different drying stages using a reversed phase HPLC. These experimental data from single droplet drier, and HPLC were used to validate the model predictions. The REA model predictions fitted well with the experimental data for moisture-time (±5.70% error) and temperature-time (±3.50% error) profiles. Similarly, the first order kinetics model was also able to predict the denaturation kinetics of β-Lg protein with an average error of 6.00 %. The conformation study by FTIR observed that the drying stress increased the secondary structural properties random coil and β-sheet which was compensated by uncoiling of α-helix and transformation of β-turn into β-sheet. The morphology study found that initially β-Lg droplet showed flexible nature but formed firm skin with increasing drying time.
Effects of thermal pre-treatment on physicochemical properties of nano-sized okara (soybean residue) insoluble dietary fiber prepared by wet media milling J. Food Eng. (IF 3.099) Pub Date : 2018-05-21 Ikram Ullah, Tao Yin, Shanbai Xiong, Qilin Huang, Zia-ud-Din, Jin Zhang, Allah Bakhsh Javaid
Effect of different biopolymers on the stability of hesperidin-encapsulating O/W emulsions J. Food Eng. (IF 3.099) Pub Date : 2018-05-17 Ilyes Dammak, Paulo José do Amaral Sobral
Modelling uncontrolled solar drying of mango waste J. Food Eng. (IF 3.099) Pub Date : 2018-05-16 Ross Wilkins, James Brusey, Elena Gaura
Kiln-dried fruit drying time is readily predicted from initial moisture content since the environment is tightly controlled. For uncontrolled environments, such as a greenhouse solar dryer, a product's drying time varies depending on ambient conditions and is thus more difficult to predict. Prediction of the drying time is needed to better schedule dryer use. Data was obtained from a set of wireless scales that weigh the waste during solar drying after initial moisture content measurement of a sample. A set of linear and quadratic models for drying rate are tested with the best yielding a 39% reduction in RMSE over traditional models. The results indicate that the modelling approach is likely to be useful for open solar dryers where the temperature, and thus the drying rate, is not controlled.
Influence of pulsed electric field (PEF) pre-treatment on the convective drying kinetics of onions J. Food Eng. (IF 3.099) Pub Date : 2018-05-17 R. Ostermeier, P. Giersemehl, C. Siemer, S. Töpfl, H. Jäger
This work discusses the effect of pulsed electric field (PEF) parameters on the convective drying process of fresh onions. First, the PEF treatment parameters and their influence on the cell disruption were investigated by applying various PEF settings (W = 0.2 – 20.0 kJ/kg, E = 0.36 – 1.07 kV/cm). The diffusion coefficient De was calculated and mathematic modeling was conducted. PEF was found to enhance the internal diffusion, but not necessarily to result in an increased drying rate. The shortest drying time at a drying temperature of 60 °C was achieved for onion samples treated at 4 kJ/kg and 1.07 kV/cm. Subsequent drying trials were performed at the pre-determined PEF settings and different drying temperatures resulting in a PEF related drying time reduction of 30.3 %, 21.4 % and 6.4 % at 45 °C, 60 °C and 75 °C to reach a residual moisture (Mr) of 7 %, respectively.
Effect of water sorption on the glass transition temperature and texture of deep-fried models J. Food Eng. (IF 3.099) Pub Date : 2018-05-16 Jakia Sultana Jothi, Tomomi Ebara, Yoshio Hagura, Kiyoshi Kawai
The purpose of this study was to understand effect of water sorption on the glass transition temperature (Tg) and texture of deep-fried models, namely, bits of deep-fried tempura batter. Two types of deep-fried models (normal and glucose-added samples) were employed. Tg was investigated by thermal rheological analysis (TRA); although TRA measurements for pellet samples showed an unclear glass transition, the measurements for bulk samples showed a large force-drop induced by this effect. Isothermal mechanical relaxation measurement confirmed that the Tg value of the deep-fried samples could be evaluated from the departure point of the force-drop. The Tg decreased with increase in water content because of the water plasticizing effect; the glucose-added sample had a higher Tg than the normal sample at each water content. The fracture property of the samples changed from brittle to ductile at the critical water content and/or water activity (i.e., those at Tg = 25 °C).
Cheese feed to powder: Effects of cheese age, added dairy ingredients and spray drying temperature on properties of cheese powders J. Food Eng. (IF 3.099) Pub Date : 2018-05-15 Denise Felix da Silva, Cosima Hirschberg, Lilia Ahrné, Anni Bygvrå Hougaard, Richard Ipsen
The effects of cheese age and addition of dairy ingredients on cheese powder properties have not been previously investigated. Hence, the effect of addition 2% sodium caseinate plus 2% buttermilk powder (B2S2) or 4% buttermilk powder (BMP) were evaluated. The addition of these ingredients led to a decrease of the Power Law consistency index in cheese feeds made from 16 and 30 weeks old Danbo cheeses. Powders containing B2S2 presented homogeneous particle size distributions, lower amount of free fat and better flowability, due to improved fat emulsification, confirmed by confocal laser microscopy. Powders with BMP presented higher browning index, cohesiveness and spontaneous primary agglomeration. These powders were also more sensitive to an increased temperature difference (∆T) between inlet and outlet spray drying temperatures, causing more browning. Cheese powder properties could thus be significantly improved by addition of 2% SC plus 2% BMP, whereas no improvements were observed using only BMP.
Oil mill coadjuvants: aggregation due to moisture and action on olive-pomace oils J. Food Eng. (IF 3.099) Pub Date : 2018-05-15 Manuel Moya, Sonia Alcalá, María Teresa Ocaña, Alfonso Vidal, Francisco Espínola
Pomace is an oil mill byproduct and the raw material for extracting olive pomace oil. The pomace is stored several months in ponds until it is processed. Tests have been carried out in stored olive pastes, malaxated with and without different coadjuvants. These pastes have been equated to the oil mill pomace. Coadjuvants increase the water pH in 0.8 units. 89.5% of the initial oil is recovered from pastes without coadjuvant; 91.1% from pastes with calcium carbonate and 80.5% from pastes with talc. The free acidity is 1.9%, 2.6% and 2.1% respectively. The maximum amount of refined pomace oil is obtained when calcium carbonate is used and the minimum when talc is used. Moisten the adjuvants affects talc and calcium carbonate differently, although both of them easily releases the original micro-powder. Moisture does not affect the technological action of the coadjuvants or modify their physical characteristics.
Understanding the break-up phenomena in an orifice-valve high pressure homogenizer using spherical bacterial cells (Lactococcus lactis) as a model disruption indicator J. Food Eng. (IF 3.099) Pub Date : 2018-05-14 Nicola Coccaro, Giovanna Ferrari, Francesco Donsì
The break-up phenomena occurring in a high pressure homogenizer equipped with an interchangeable orifice valve were investigated by measuring the inactivation of Lactococcus lactis. Data were collected at varying the orifice size (80, 100, and 150 μm), the operating pressure (100–200 MPa), the number of passes (1–10), and the fluid viscosity (2.5–7.9 mPa s, changed by adding 0–50 % wt PEG 200 to buffered peptone water) to identify the correlations of the fragmentation occurring in the valve with the main fluid dynamic phenomena (turbulence, elongational and shear stresses, and cavitation). In addition, also the effects of a purely shearing or ultrasound treatment on cell break-up were considered. The results show that the most intense break-up phenomena occur for the smallest orifice size, highest pressure, and lowest viscosity. However, at low viscosity, turbulence, together with the elongational stresses appear to be the controlling factors of cell break-up, whereas, at higher viscosities, the shear stresses become increasingly important. The occurrence of cavitation is only slightly affected by viscosity, and mainly depends on the velocities reached in the homogenization valve.
Application of a novel S3 nanowire gas sensor device in parallel with GC-MS for the identification of Parmigiano Reggiano from US and European competitors J. Food Eng. (IF 3.099) Pub Date : 2018-05-12 Marco Abbatangelo, Estefania Núñez Carmona, Veronica Sberveglieri
Parmigiano Reggiano is a typical Italian product known all over the world. Appreciated for its qualities, it is also one of the most counterfeit foods. To avoid this, two different techniques has been used: GC-MS with SPME and S3 gas sensor. With the first one, characteristic VOCs of different cheeses has been found. The most present classes are alcohols, aldehydes, hydrocarbons, esters and ketones, for a total of 58 compounds. Statistical analysis has shown that only 6 of them could be used to distinguish between Parmigiano Reggiano and its competitors. Instead, S3 is a new, rapid, economic and user-friendly approach. Assessing the variation of sensors resistances, it has been possible to discriminate between different kind of cheeses with an accuracy higher than 80%. Data analysis was performed considering PLS to have a visual representation of samples, the SFS algorithm for features selection and PLS-DA as classifier.
Biaxial extensional viscosity in wheat flour dough during baking J. Food Eng. (IF 3.099) Pub Date : 2018-05-10 F.M. Vanin, T. Lucas, G. Trystram, C. Michon
Lubricated squeezing flow (LSF) experiments on wheat flour dough were conducted at a constant biaxial extensional rate followed by relaxation experiments. The effect of temperature on the rheology of the dough was studied in the range 25–95 °C under small and large strain to characterize changes in the dough through a possible pathway to simulate the dough-crumb transition during the first step of the baking process. A strain hardening effect was shown over the whole temperature range. Like extensional viscosity measured at 0.1 and 0.65 biaxial strain, the consistency index (K K ) decreased from 25 °C to 45 °C and increased at temperatures above 50 °C. Two levels of the behaviour index (n n ) were found: 0.35–0.40 below 45 °C, and 0.1–0.2 above 45 °C. The relaxation degree also changed dramatically but only at higher temperatures (56–60 °C), below which it remained almost constant (99-99%), once the dough became a viscoelastic liquid, above this temperature the main physical-chemical reactions (starch and protein) started to occur, leading to more solid properties. These results complement those of LSF. LSF experiments at large biaxial strain (0.75), combined with a relaxation experiment, were successfully used for dough/crumb characterisation at a temperatures ranging from 25 °C to 74 °C. Alpha values estimated from Launay's model were incorporated in the flow behaviour index, underwent the same type of changes as a function of temperature as n n but with a less marked transition; n n was divided by two and K K increased by about one decade.
Energy efficient primary atomization of viscous food oils using an electrostatic method J. Food Eng. (IF 3.099) Pub Date : 2018-05-09 P.W. Vesely, R.J. Schick, J.S. Shrimpton, F. Mashayek
Food oil coating applications typically require spraying with relatively viscous liquids. Traditional spray methods can by inefficient, requiring a large amount of energy to produce a uniform coating and/or producing a significant degree of overspray. The electrostatic charge injection atomization technique is shown to be appropriate for these viscous and dielectric food oils, where an additional electrical power of ≈0.1W ≈ 0.1 W is required. Electrical performance data and also spray imaging and quantitative drop size measurement using phase Doppler interferometry are presented for atomizer orifice diameters of 150 and 250 μm μ m and liquid injection velocities of 10 m/s. The typical average drop diameter is typically 70% of the orifice diameter. The results show the atomization performance is independent of liquid viscosity over a viscosity range of factor 50.
Assessment of Tomato Soluble Solids Content and pH by Spatially-Resolved and Conventional Vis/NIR Spectroscopy J. Food Eng. (IF 3.099) Pub Date : 2018-05-09 Yuping Huang, Renfu Lu, Kunjie Chen
Spatially-resolved spectroscopy (SRS) enables better interrogation of tissue properties at different depths, and it thus has the potential for enhancing quality assessment of horticultural products like tomato, which are heterogeneous in structure and chemical composition. This research was aimed at assessing quality of tomato fruit by using a newly developed SRS system with 30 detection optic fibers covering the wavelength range of 550-1,650 nm and comparing its performance with two conventional single-point (SP) spectroscopic instruments covering the visible and shortwave near-infrared (Vis/SWNIR) (400-1,100 nm) and near-infrared (NIR) (900-1,300 nm) regions, respectively. Spatially-resolved (SR) spectra and SP interactance spectra were acquired for 600 ‘Sun Bright’ tomato fruit. Partial least squares (PLS) models for individual SR spectra and their combinations and for SP Vis/SWNIR and NIR spectra were developed for prediction of soluble solids content (SSC) and pH. Results showed that SSC and pH predictions by SRS varied depending on the light source-detector distance, with the correlation coefficient of prediction (rp) ranging 0.608-0.791 and 0.688-0.800, respectively. Combinations of two or more SR spectra resulted in better, more consistent SSC and pH predictions. SR predictions of pH (rp=0.819) were better than for SP Vis/SWNIR (rp=0.743) and NIR (rp=0.741) predictions, whereas SR predictions of SSC (rp=0.800) were comparable to SP NIR predictions (rp=0.810) but better than SP Vis/SWNIR predictions (rp=0.729). This research showed that owning to its ability of acquiring spatially-resolved spectral information, the SRS technique has advantages over conventional SP spectroscopy for enhancing quality assessment of tomatoes.
Novel approaches to oil structuring via the addition of high-pressure homogenized agri-food residues and water forming capillary bridges J. Food Eng. (IF 3.099) Pub Date : 2018-05-08 Waleed Mustafa, Gianpiero Pataro, Giovanna Ferrari, Francesco Donsì
The suspension of micronized agri-food residues, such as tomato peels and spent coffee grounds, at 25% vol in peanut oil, results in the formation of a sample-spanning network (capillary suspension) upon the addition of a secondary immiscible fluid, such as water (at 0.17–0.57 vol with respect to the oil), to preferentially wet the particle surface, thus forming capillary bridges. The strength of the capillary bridges, measured through the rheological characterization of the structured oil suspensions, depends on (a) the surface properties of the particles (in both cases prevalently hydrophilic, with the three-phase contact angles < 90°), (b) the fraction of added water, and (c) the mean particle size of the residues. In fact, the suspensions prepared with high-pressure homogenized particles (70 MPa, 3 passes) exhibit an apparent yield stress more than one order of magnitude higher than those prepared with coarser, high-shear mixed particles (>100 Pa vs. < 10 Pa). Finally, also the addition of a surfactant to the water phase dramatically affects the formation of the capillary bridges, reducing the interfacial tension at the oil/water interface. These results suggest a potential alternative route to vegetable oil structuring, to develop innovative foods and food ingredients based on low-calorie, health-beneficial agri-food residues, which not only induce the formation of a oleogel structure, but which also replace a fraction of the lipids.
Rheological Properties and Microstructure of Soy Protein Isolate /κ-Carrageenan Gels under High-Speed Shear Treatment J. Food Eng. (IF 3.099) Pub Date : 2018-05-05 Chong-hao Bi, Ying-dan Zhu, Lu-tong Li, Yu-lai Zhang, Zhe Hua, Jia-yi Zhu, Yi Liu, Yu-de Liu, Zhi-gang Huang
Contacting ultrasound enhanced hot-air convective drying of garlic slices: Mass transfer modeling and quality evaluation J. Food Eng. (IF 3.099) Pub Date : 2018-05-03 Yang Tao, Jinglin Zhang, Sirui Jiang, Yiqun Xu, Pau-Loke Show, Yongbin Han, Xiaosong Ye, Mingru Ye
A self-designed hot-air convective dryer coupled with contacting ultrasound system was used for the dehydration of garlic slices. Contacting ultrasound significantly accelerated the drying process. Compared with non-ultrasound treated samples, the drying time of garlic samples sonicated at 1513.5 W/m2 was shortened by 35.0% at 50 °C, 48.5% at 60 °C and 50.0% at 70 °C. According to water transport simulation using a diffusion model considering sample shrinkage, both water effective diffusivity and external mass transfer coefficient were enhanced when garlic samples contacted ultrasound directly during drying. In the meantime, internal water diffusion was more affected by contacting ultrasound. Furthermore, contacting ultrasound had a positive effect on the preservation of organosulfur compounds in garlic slices during drying. The browning problem of garlic products during hot-air drying was also alleviated if contacting ultrasound treatment was performed properly. Besides, no over-heating problem was observed during contacting ultrasound enhanced drying within the studied experimental range.
Intensified Recovery of Lactose from Whey using Thermal, Ultrasonic and Thermosonication Pretreatments J. Food Eng. (IF 3.099) Pub Date : 2018-05-02 Rajeshree A. Khaire, Parag R. Gogate
Recovery of valuable products such as proteins and lactose from dairy industry effluents offers promise due to the value addition and reduction in the environmental concerns. The current work deals with understanding the effects of application of different pre-treatment approaches as thermal, sonication and thermosonication on the recovery of lactose from paneer (cottage cheese) whey using actual commercial samples procured locally. Ultrasonic horn (20 kHz) with varying power levels over the range of 100 W to 250 W has been used with different levels of ultrasonic exposure for ultrasound and thermosonication experiments. Ultrafiltration has been subsequently used for the separation of proteins and lactose from whey followed by anti-solvent sonocrystallization of lactose using ethanol. Combined pretreatment using ultrasound and heating resulted in maximum recovery as 94.59±1.26%. Detailed understanding into the effect of different pretreatment conditions allowed for maximizing the recovery of lactose. Overall present work has clearly established that pretreatment using ultrasound in combination with thermal treatment results in enhanced recovery of lactose from whey.
In-pipe coconut water rheological characterization with ultrasonic waves. J. Food Eng. (IF 3.099) Pub Date : 2018-05-02 Didier Laux, Olivier Gibert, Jean-Yves Ferrandis, Eric Rosenkrantz, Med Abderrahmane Mograne, Alexia Prades
We propose in this paper to use a simple and robust experimental protocol based on longitudinal ultrasonic velocity measurement in order to evaluate the viscosity of coconut water in a cylindrical stainless-steel pipe. Seven samples with Soluble Solids Content (SSC) ranging from 6.7 to 44.2°Brix were studied using conventional Couette viscometry and high-frequency ultrasonic methods. Calibration laws linking the ultrasonic velocity measured at 5 MHz to the shear viscosity and to the SSC are proposed. These laws are in very good agreement with previous measurements carried out several years ago using a plane 25 MHz transducer directly introduced into the coconut water with SSC of up to 60 °Brix.
3D computational simulation for the prediction of coupled momentum, heat and mass transfer during deep-fat frying of potato strips coated with different concentrations of alginate J. Food Eng. (IF 3.099) Pub Date : 2018-04-30 Enayat-Allah Naghavi, Jalal Dehghannya, Babak Ghanbarzadeh
Computational simulation of transfer phenomena has been known as a widely used and valuable tool for optimization and design purposes, controlling process, and improving quality properties of processed food. A 3D model was developed to simulate momentum, heat and mass transfer during deep-fat frying of uncoated or coated potato strips. The effects of different concentrations of sodium alginate (1, 1.5, and 2% w/v) and four different locations of potatoes in fryer on moisture content (MC), oil uptake (OU), core (Tco) and surface (Tsurf) temperatures of the samples, oil temperature (To), and oil velocity ( u → o ) were investigated. To validate the simulation, model predictions were compared to measured data. The results revealed that different locations of potatoes did not have significant effect (p > 0.05) on the profiles of studied variables. Compared to control samples, MC and OU in the coated samples significantly reduced (p < 0.05). Moreover, the rates of Tco and Tsurf increased in the strips and To and u → o fields were affected by coating. The maximum values of simulated u → o were 4.46×10-3–5.62×10-3 m/s during frying of control and coated samples. Also, the results of the simulation were in a good agreement with experimental data (except for OC with E% > 18%). The results of this study can be used to provide valuable insight into the effect of food coating on transfer phenomena and may be very useful to optimize frying operation as well as to improve quality of coated potatoes during frying.
The size of eye-shaped bubbles in Danish pastry in relation to the size of fat fragments; A reverse engineering approach of the alveolar structure J. Food Eng. (IF 3.099) Pub Date : 2018-04-25 Lucas Tiphaine, Collewet Guylaine, Bousquières Josselin, Deligny Cécile
This study characterized the size distributions of eye-shaped bubbles as a function of different number of fat layers (NFL) (4-128) in Danish pastry. This allowed for the first time, without which it is difficult to objectively define a coarse crumb texture typical of craft products, a too fine crumb texture typical of over-lamination, or and the sizes of the bubbles typical of maximum lift. Ten to 20 mm wide bubbles did not differ in number with the NFL, except in over-laminated pastry in which their number decreased. Five-10 mm wide bubbles increased in number between 16 and 48 fat layers and explained the difference in crumb texture (more regular) and lift (+16%). One to 5 mm wide bubbles, rather round in shape, increased with the NFL, contributing to more regular crumb texture and predominated in over-laminated pastry. The number of eye-shaped bubbles was then correlated with the number of fat fragments, giving a ratio of 5 of the widths of bubbles to fat fragments. This result was logical knowing that bubbles also increase in size in the fat layers, as demonstrated earlier by MRI monitoring of Danish pastry during proving. This result also offered the opportunity of optimizing the alveolar structure of finish Danish pastry from the lamination step, using the degree of fat fragmentation at this step. The impact of these results on the usual view of bubble growth in Danish pastry is last discussed.
Impact of pulsed electric field (PEF) pretreatment on process performance of industrial French fries production J. Food Eng. (IF 3.099) Pub Date : 2018-04-23 T. Fauster, D. Schlossnikl, F. Rath, R. Ostermeier, F. Teufel, S. Toepfl, H. Jaeger
The application of pulsed electric fields in industrial scale potato processing was investigated regarding its impact on process performance and product quality. The PEF induced cell disintegration was measured by impedance analysis and texture softening was analyzed by cutting force measurements. Softening of the tissue was found to improve the cutting behavior leading to a smoother cutting surface and up to 80% less feathering. Thereby, starch loss was reduced and a significant reduction of fat uptake from 7.5 to 6.8% was found. The breaking loss decreased significantly from 11.0 to 6.0% regardless of the applied energy input (0.2–1.0 kJ/kg), due to improved elastic properties of the potato sticks. No effect was detectable on the peeling behavior of potato and on rheological characteristics of processing by-products such as puree, although the lump formation in puree produced from PEF pretreated potato increased. Overall, PEF was shown to deliver similar and higher quality improvements conventionally achieved by applying thermal preheating at much lower energy consumption.
Encapsulation of betacyanins and polyphenols extracted from leaves and stems of beetroot in Ca(II)-alginate beads: A structural study J. Food Eng. (IF 3.099) Pub Date : 2018-04-23 Tatiana Rocio Aguirre Calvo, Mercedes Perullini, Patricio R. Santagapita
The aim of this work was to use the recovery of antioxidant compounds (betacyanin and polyphenols) derived from beetroot industrial wastes (stems and leaves), and their subsequent encapsulation in Ca(II)-alginate beads containing sugars, providing a detailed structural characterization of these systems determined by SAXS from the molecular (arrange of Ca(II)-alginate dimers) to the supramolecular (interconnection of the rods composing the hydrogel microstructure). Water extract contained significant quantities of betacyanin and polyphenol, which were retained in Ca(II)-alginate beads between 15 and 60%, depending on the formulation, retaining also the antioxidant activity. Both the inclusion of sugars as synthesis additives and beetroot extracts induced main structural changes, which can have counteracting effects. We revealed that, though being overlooked in most alginate encapsulation research, the presence of natural extracts prompts important structural changes in the alginate network, affecting key parameters which define the encapsulation performance in most of industrial and environmental applications.
AFM-based local thermal analysis is a suitable tool to characterize the impact of different grinding techniques on sucrose surface properties J. Food Eng. (IF 3.099) Pub Date : 2018-04-21 D. Middendorf, U. Bindrich, P. Mischnick, K. Franke, V. Heinz
Influence of roller and ball mill grinding technology applied for sucrose particles in a lipophilic suspension was investigated considering both particle properties and suspension's flow behavior. Especially particle surfaces after grinding were analyzed using a novel approach by combining atomic force microscopy (AFM) and AFM-local thermal analysis (AFM-LTA). This technique is able to characterize local distributions of different surface states on sucrose particles in nano- and microscale by determining local softening temperatures. For the first time, it was possible to demonstrate on molecular level that applied grinding technologies resulted in different surface characteristics with respect to adhesion forces and state of sucrose using AFM-LTA. Differences in flow behavior despite same particle size distributions and solid contents were traced back to the distribution of crystalline and amorphous areas on sucrose particle surfaces.
Optimization of Piston Type Extrusion (PTE) Techniques for 3D Printed Food J. Food Eng. (IF 3.099) Pub Date : 2018-04-20 Namsoo Peter Kim, Jae-Seok Eo, Diana Cho
The piston type extrusion (PTE) method with the employ of the Internet of Things (IoT) technology for ejecting bio-materials and high viscosity material by using an extruder have been successfully optimized in terms of the head traveling speed and the piston pressure with food materials of various viscosities. Along with mathematical approach by using Hagen Poisoulle (HP) equation governing high viscosity flow, the study demonstrated that the material's qv (volumetric flow rate) has constant output at 3.6×10-8 m3/s with the material viscosity of 0.001 - 1000 Pa.S. and the PTE method has shown to be effective when the water content is higher than 33 wt. %. When the high viscosity material is stacked more than 20 layers at an optimized height, the three-dimensional shape can be maintained between the head traveling speed of 1.5×10-2 and 2.0×10-2 m/s.
Modelling of heat and water transport in plantain during steeping to predict gelatinization and in vitro starch digestibility J. Food Eng. (IF 3.099) Pub Date : 2018-04-19 A. Giraldo Toro, A. Briffaz, O. Gibert, D. Dufour, T. Tran, P. Bohuon
A better understanding of starch-process interactions is the key point to better control banana starch digestibility and degree of cooking. This study aims at investigating and modelling the evolution of both the degree of cooking and in vitro digestibility of plantain starch as a function of steeping conditions. A 2D-axial-symmetric model considering a single Harton plantain cylinder being steeped in water was developed and adjusted to experimental data collected at 25, 50, 75 and 100 °C. Experimental temperature distribution was well predicted, with a thermal diffusivity of 1.5 × 10−7 m2.s−1. The model was also validated against degree of starch gelatinization kinetics obtained by DSC at 100 °C. Two modes of water transport were found, depending on the starch state. At 25 °C or high degree of starch gelatinization (α ≥ 0.38), molecular diffusion was observed with an apparent water diffusivity of 2.4 × 10−9 m2.s−1, which may be due to structural cellular effects. At 50 °C, capillary diffusion was observed due to gas desorption, with an apparent water diffusivity of 10 × 10−9 m2.s−1. Starch digestibility was governed by gelatinization process which strongly depends on heat transport. This approach could be used to identify some steeping conditions that modulate both banana starch digestibility and degree of starch gelatinization.
A successful comparison between a non-invasive measurement of local profiles during drying of a highly shrinkable food material (eggplant) and the spatial reaction engineering approach J. Food Eng. (IF 3.099) Pub Date : 2018-04-19 Aditya Putranto, Xiao Dong Chen
A reliable mathematical model is useful for predicting internal profiles inside materials during drying. In this study, for the first time, the spatial reaction engineering approach (S-REA) is employed to model the local profiles of food materials during drying. The REA is applied as the local rate of phase change and combined with a set of equations of conservation of heat and mass transfer to yield the spatial profiles of temperature and concentration during drying. The S-REA predictions are benchmarked against the Magnetic Resonance Imaging (MRI) data. The study indicates that the S-REA is applicable to model the internal profiles inside food materials during drying. The S-REA predictions also show closer agreement towards the experimental data than the effective diffusion model. While the S-REA predictions are accurate, it requires minimum number of experiments to generate the drying parameters. The S-REA has contributed to better analysis of transport phenomena inside food materials during drying through generation of local profiles. The S-REA predictions can potentially be implemented to interpret the sensory and quality matters during drying.
Effect of high coacervation temperature on the physicochemical properties of resultant microcapsules through induction of Maillard reaction between soybean protein and chitosan J. Food Eng. (IF 3.099) Pub Date : 2018-04-18 Yan-Li Du, Guo-Qing Huang, Hai-Ou Wang, Jun-Xia Xiao
The mixture of soybean protein isolate-emulsified vitamin E emulsion and chitosan was incubated at 50 °C, 70 °C, and 90 °C for 12 h to check whether Maillard reaction could occur between the two polyelectrolytes during coacervation and its effects on the properties of resultant microcapsules. Color measurements and FTIR analysis revealed that Maillard reaction occurred during microencapsulation and was favored by higher coacervation temperatures. Coacervation at the three temperatures effectively reduced the aggregation and significantly increased the particle size and zeta potential of the microcapsules. The microencapsulation performance was promoted in higher temperatures and coacervation at 90 °C led to a yield of 89.15% compared with 56.30% of the control. Besides, the Maillard reaction-modified microcapsules exhibited better flowability, higher bulk density, and greater stability. It is concluded that the coacervation temperature is an important processing parameter to control the morphology and properties of microcapsules prepared by protein – polysaccharide coacervation.
Applications of power ultrasound in oriented modification and degradation of pectin: A review J. Food Eng. (IF 3.099) Pub Date : 2018-04-18 Wenjun Wang, Weijun Chen, Mingming Zou, Ruiling Lv, Danli Wang, Furong Hou, Hao Feng, Xiaobin Ma, Tian Ding, Xingqian Ye, Donghong Liu
Recently modified pectin (MP) showed improved functional properties and bioactivities than the native one. Ultrasound, as one of the green technologies, was investigated to degrade and modify bioploymers with high efficiency and low cost. In an aqueous system with pectin, ultrasonication creates localized high temperature and pressure spots, and produces “microjets” and free radicals, which contribute to modify the structural, functional, and bioactive properties of pectin. The factors influencing pectin modification include ultrasound frequency, power intensity, temperature, treatment time and duty cycle. Precise control of these parameters is critical for ultrasound technology to produce products with consistent and predictable properties. This work summarizes recent advances in applications of power ultrasound technology in oriented degradation and modification of pectin. Different degradation processing situations and the degradation phenomena of pectin during extraction have been reviewed. Furthermore, future trends to better utilize this green technology have also been purposed.
Physicochemical properties of apple juice influenced by induced potential difference (induced electric field) during disposable continuous-flow treatment J. Food Eng. (IF 3.099) Pub Date : 2018-04-11 Mengyue Zhang, Na Yang, Lunan Guo, Dandan Li, Shilin Wu, Fengfeng Wu, Zhengyu Jin, Xueming Xu
A disposable continuous-flow system was established by treating apple juice with induced electric field (IEF). Under synchronous alternating magnetic flux, rather than electrodes, the electrical treatment was implemented in multi-series coils consisting of the flowing sample. An activation effect at 50 °C and inactivation effect at 70 °C were observed under IEF. High excitation voltage (900 V) caused a significant decrease in the residual activities (RA). As the flow rate decreased from 87.5 to 17.5 mL/min, RA of PPO and POD were changed without applying IEF indicated shear effect of the pump had an impact on the RAs. At 17.5 mL/min, PPO was inactivated after IEF treatment for 7.6 min. The fluid impedance was increased at 70 °C and 80 °C under IEF, whereas it was decreased at 30 °C and 40 °C. IEF had no adverse influence on the color and volatile compounds of apple juice in this system.
Engineering the rheological and thermomechanical properties of model imitation cheese using particle fillers J. Food Eng. (IF 3.099) Pub Date : 2018-04-11 Pere R. Ramel, Alejandro G. Marangoni
In this study we investigated the mechanisms involved in the reinforcement of the protein matrix by oat fiber particles in a model imitation cheese made with canola oil instead of milk fat by performing dynamic rheological tests. With the addition of oat fiber particles at 5% volume fraction to the canola oil made cheese, the hardness of the cheeses increased due to the increase in rigid fillers in the matrix. Oat fiber particles also acted as “breakers” in the matrix (like solid milk fat), that allows for yielding at lower strain values, which in turn can be correlated with less rubbery properties of the cheese. The possible interactions between oat fiber and canola oil resulted in a similar melting behavior of the cheese made with canola oil to that of cheese made with milk fat. These results indicate that the addition of oat fiber particles to canola oil made cheese results in similar rheological behavior with that of milk fat, which in turn, results in similar percievable macro-properties such as similar level of firmness and melting behavior.
Quality assurance in microwave food processing and the enabling potentials of solid-state power generators: A review J. Food Eng. (IF 3.099) Pub Date : 2018-04-11 J.C. Atuonwu, S.A. Tassou
The widespread deployment of microwave food processing in domestic and industrial settings, necessitates quality assurance. This review critically assesses key microwaved-food quality assurance issues such as process lethality, product degradation mechanisms, non-uniform heating and volumetric temperature sensing. Non-uniform heating, the root-cause of quality assurance problems, is shown to have negative consequences on process energy consumption, and linked to the poor controllability of conventional microwave power sources, magnetrons. A case is therefore made for the use of solid-state generators as alternative power sources by a cost-benefit analysis, which includes energy and reliability aspects. The feasibility of a paradigm shift to solid-state power delivery in the development of smart processing systems, is shown, and potential commercialisation opportunities, identified.
Temperature sensitive smart packaging for monitoring the shelf life of fresh beef J. Food Eng. (IF 3.099) Pub Date : 2018-04-10 Suman Singh, Kirtiraj K. Gaikwad, Myungho Lee, Youn Suk Lee
We successfully developed temperature-sensitive packaging using a eutectic mixture of soybean oil and tetradecane (S+T) as a thermo-regulating material (TRM). The eutectic mixture was vacuum impregnated inside expanded graphite (EG/S+T) to increase the thermal conductivity of the TRM. A thermal insulation coating (EG/RH/S+T) was prepared and applied inside the walls of the expanded polypropylene (EPP) boxes using EG/S+T and a rice byproduct, i.e., rice husk (RH), to enhance the thermal buffering. The developed eutectic mixture (S+T), EG/S+T, and thermal insulation coating (EG/RH/S+T) were characterized using scanning electron microscopy (SEM), thermogravimetric analysis, Fourier transform infrared (FTIR) spectroscopy, and differential scanning calorimetry (DSC). The SEM analysis indicated that the S+T TRM was sufficiently absorbed into the EG porous network. The FTIR results revealed that the S+T TRM and EG did not undergo chemical reactions however, physical interactions were observed. The DSC results revealed that the S+T TRM melts at −0.31 °C with a latent heat of 71.06 J/g, and it solidifies at −2.01 °C with a latent heat of 74.89 J/g. The thermal insulation coating melts at −0.94 °C with a latent heat of 19.49 J/g, and it solidifies at −3.93 °C with a latent heat of 19.35 J/g. Temperature sensitive package further studied with fresh beef to determine weather is could provide temperature maintain or not up to-8 days. Meat sample place inside the small PET container and cover with cling film. PET tray transfer to temperature sensitive package.The quality of the fresh beef was determined based on its pH, color, texture, total volatile basic nitrogen, and total plate count. EPP boxes with EG/RH/S+T coatings and a G-Pack show excellent temperature control during 3 h of storage at ambient temperature. All the quality parameters for fresh beef are within the acceptable range when using the temperature-sensitive packaging. The developed temperature-sensitive packaging is useful to control the temperature of fresh beef from the store to preparation and consumption.
Modeling radio frequency heating of granular foods: Individual particle vs. effective property approach J. Food Eng. (IF 3.099) Pub Date : 2018-04-10 Zhi Huang, Ashim K. Datta, Shaojin Wang
Radio frequency (RF) heat treatment is one of the most promising methods for disinfestations and pasteurizations of granular foods but the combined effects of geometry and dielectric properties of granular materials on the non-uniformity of heating in RF are poorly understood. A coupled thermal-electromagnetic model for RF heating (27.12 MHz, parallel plate) of a single layer of spherical particles (1–5 cm diameter) was developed using two different formulations of the particles− − an approach that considers the geometry of individual particles and a simplified approach that considers the effective properties of an air-particle mixture. The spherical particles, prepared from soybean powder, represented dry granular foods. Model predictions were validated using point and spatial temperature measurements. Results show that while an effective properties approach can be sufficient for smaller (∼1 cm diameter) particles (with internal temperature range of 3 °C), consideration of the exact geometry (individual particles) would be needed for accurate prediction of heating non-uniformities (with internal temperature range of 39 °C) in larger diameters (diameter of 5 cm). Heating non-uniformities are present due to corner/edge heating, focusing effect, as well as contact heating between particles or between a particle and the tray. Results should greatly benefit computer-aided design and optimization of RF heating processes for granular products.
Fish fillet authentication by image analysis J. Food Eng. (IF 3.099) Pub Date : 2018-04-09 Silvia Grassi, Ernestina Casiraghi, Cristina Alamprese
The work aims at developing an image analysis procedure able to distinguish high value fillets of Atlantic cod (Gadus morhua) from those of haddock (Melanogrammus aeglefinus). The images of fresh G. morhua (n=90) and M. aeglefinus (n=91) fillets were collected by a flatbed scanner and processed at different levels. Both untreated and edge-based segmented (Canny algorithm) regions of interest were submitted to surface texture evaluation by Grey Level Co-occurrence Matrix analysis. Twelve surface texture variables selected by Principal Component Analysis or by SELECT algorithm were then used to develop Linear Discriminant Analysis models. An average correct classification rate ranging from 86.05 to 92.31% was obtained in prediction, irrespective the use of raw or segmented images. These findings pave the way for a simple machine vision system to be implemented along fish market chain, in order to provide stakeholders with a simple, rapid and cost-effective system useful in fighting commercial frauds.
Coalescence stability of Pickering emulsions produced with lipid particles: A microfluidic study J. Food Eng. (IF 3.099) Pub Date : 2018-04-06 Anja Schröder, Joris Sprakel, Karin Schroën, Joep Spaen, Claire C. Berton-Carabin
In the quest to find approaches to prepare food grade Pickering emulsions, we studied the formation and stability to coalescence of colloidal lipid particle (CLP)-stabilized emulsions within a cross-flow microfluidic device. We show that the particles can either stabilize or destabilize the emulsions depending on the particle adsorption rate versus droplet formation rate, and on the resulting surface coverage when the droplet is formed. At low surface coverage, when droplet formation is significantly faster than adsorption, CLPs have a destabilizing effect as incomplete surface coverage leads to droplet-droplet bridging. At high surface coverage, the dense particle layer results in an effective barrier against droplet coalescence, resulting in physically stable emulsions. The observed non-monotonic dependency of emulsion droplet stability on surface coverage of CLP-stabilized emulsions is in stark contrast to what is observed for conventional surfactant-stabilized emulsions, and thus should be taken into account for the rational design of Pickering emulsions.
Linking the physicochemical properties of bulking agents to the sensory characteristics of fat-based suspensions J. Food Eng. (IF 3.099) Pub Date : 2018-04-05 Davy Van de Walle, Robbe Heymans, Koen Dewettinck
Consumers are becoming more aware of the importance of healthy foods but do not want to bargain on their sweet sins. The pressure to reduce sucrose intake increases but poses major challenges at the technological level. Two main quality defects of fat-based suspensions are adherence and grittiness which are believed to be mainly related to the flow behaviour and particle size of these suspensions. This research wanted to investigate a possible link between the physicochemical properties (moisture content, particle density, particle morphology, particle size, solid state, solubility and viscosity) of several alternative bulking agents (i.e.isomalt ST, fructo-oligosaccharides, inulin and rice starch) and the mouthfeel of the corresponding sucrose-free fat-based suspensions. Sensory tests performed by a trained panel showed that the solid state and solubility of the bulking agents, and the viscosity of their solutions have a direct impact on grittiness and adherence. These insights will help the food industry in screening bulking agents for their applicability in sugar-free or sugar-reduced fat-based suspensions.
Improved extractability of carotenoids from tomato peels as side benefits of PEF treatment of tomato fruit for more energy-efficient steam-assisted peeling J. Food Eng. (IF 3.099) Pub Date : 2018-04-04 G. Pataro, D. Carullo, Md A. Bakar Siddique, M. Falcone, F. Donsì, G. Ferrari
The combination of steam blanching (SB) with Pulsed Electric Fields (PEF) treatments of whole tomatoes, in addition to reducing the energy required for tomato peeling, can significantly contribute to the recovery of carotenoids from the peels. In this work, PEF (0.25-0-75 kV/cm, 1 kJ/kg) and SB (1 min at 50-70°C), as pre-treatment prior to hand peeling, were investigated to assess their ability, separately and in combination, to induce the cell permeabilization of tomato peels, and hence to improve the carotenoids extraction in acetone (4 h at 25°C). PEF and SB, by inducing significant damages at the cuticular level, caused the increase of the yield in total carotenoids (up to 188% for PEF and 189% for SB) and antioxidant power (up to 372% for PEF and 305% for SB) with respect to the peels from untreated tomatoes. The application of a combined treatment (PEF+SB) significantly increased the carotenoid content and the antioxidant power of the extracts, with a synergistic effect observed already at 60°C (37.9 mg/100 g fresh weight tomato peels). HPLC analyses revealed that lycopene was the main carotenoid extracted and that neither PEF nor SB caused any selective release or degradation of lycopene.
Modifications in the Rushton turbine for mixing viscoplastic fluids J. Food Eng. (IF 3.099) Pub Date : 2018-04-03 Houari Ameur
The mixing characteristics of complex non-Newtonian fluids in a cylindrical vessel without baffles are determined in this paper. The working fluid has a shear thinning behavior with yield stress modeled by the Hershel-Bulkley model. Effects of the impeller design are explored; it concerns some modifications in the blade of a Rushton turbine mounted centrally at the half of the tank. Different shapes of cuts have been introduced in the blade of impeller, namely: U-, 2U, V- and W-cuts. We focus on the determination of flow patterns, cavern size and power consumption for various shapes and Reynolds numbers. The obtained results revealed that the cut introduced in the blade gives a reduction in power consumption accompanied with a reduction in cavern size than that obtained with the plain blade. The best compromise between energy saving and well-mixed region size allows to select the impeller with V- or W-cut blade as the best one from all cases studied.
Effects of combined high pressure (HPP), pulsed electric field (PEF) and sonication treatments on inactivation of Listeria innocua J. Food Eng. (IF 3.099) Pub Date : 2018-04-02 Taras Pyatkovskyy, Mykola V. Shynkaryk, Hussein M. Mohamed, Ahmed E. Yousef, Sudhir K. Sastry
Suspensions of non-pathogenic Listeria innocua ATCC 33090 in water were exposed to different combinations of high hydrostatic pressure (HPP), pulsed electric field (PEF) and sonication treatments. Treatments were conducted individually, or in various combinations – sequential HPP-PEF; sequential PEF-HPP, simultaneous HPP-PEF, sequential HPP-sonication and sequential sonication-HPP. The greatest reduction by an individual treatment was obtained with HPP, wherein exposure to 400 MPa for 100 s resulted in an 8 log reduction in CFU. Both PEF (30 kV, 10-3 s) and sonication (250s) treatments gave about 2 log reduction in the Listeria population. Sequentially applied HPP-PEF, and PEF-HPP treatments demonstrated mostly additive effects. Notably, however, a synergistic effect was observed when PEF and HPP were applied simultaneously. Combinations of HPP and sonication treatments demonstrated synergistic effects when HPP treatment was followed by sonication, but additive effects when sonication was followed by HPP. A relationship between Listeria innocua inactivation and increase in the suspension zeta potential was observed. However, protein content of the supernatant was found insignificant, indicating that leakage from cells were non-protein cell constituents.
Optimizing Twin-Screw Food Extrusion Processing through Regression Modeling and Genetic Algorithms J. Food Eng. (IF 3.099) Pub Date : 2018-04-02 Ryan J. Kowalski, Chongjun Li, Girish M. Ganjyal
Response surface analysis has become a standard for characterization of extrusion experiments in recent years. While response surface experiments provide large amounts of useful data, the problem persists in how data can be used to successfully design specified products for a consumer. The use of genetic algorithms was explored as a potential tool that can help solve response surface data to identify extrusion conditions needed for desired product design. Response surface regression was conducted on five varieties of peas and the regression equations were used to create a way of measuring fitness in a genetic algorithm model routine. In doing so, extrusion conditions of screw speed and temperature for were successfully predicted for response factors (radial expansion, density, WAI, WSI, pressure, motor torque, SME, and color) of all the pea varieties with strong fitness (>0.90). Results suggest that optimization using genetic algorithms can have a beneficial impact selecting extrusion conditions.
Effect of High Pressure Homogenization (HPH) on functional and rheological properties of hazelnut meal proteins obtained from hazelnut oil industry by-products J. Food Eng. (IF 3.099) Pub Date : 2018-04-02 Furkan Turker Saricaoglu, Osman Gul, Aysegul Besir, Ilyas Atalar
The effect of high pressure homogenization (HPH) on functional and rheological properties of hazelnut meal proteins was investigated. Hazelnut meal proteins were extracted from hazelnut oil industry by-products. Protein patterns remained unchanged up to 75 MPa, and band intensity decreased when pressure reached 100 MPa. HPH treatment decreased particle size, produced higher zeta potential and hence, improved water solubility, which resulted in higher emulsifying and foaming properties. Hazelnut meal protein suspensions displayed shear thinning behavior and higher G' than Gʹ' which means suspensions had soft-gel network. For better understanding of internal structure, elastic and viscous behavior, creep and recovery tests were explained by Burgers and exponential decay models. Final percentage recovery increased after 100 MPa due to strengthened solid-like structure of protein suspensions. As a result, functional and rheological properties of proteins can be successfully improved by HPH treatment, and thus hazelnut oil industry by-products have added value once processed by HPH.
Effect of pulsed electric field coupled with vacuum infusion on quality parameters of frozen/thawed strawberries J. Food Eng. (IF 3.099) Pub Date : 2018-04-02 Elena Velickova, Urszula Tylewicz, Marco Dalla Rosa, Eleonora Winkelhausen, Slobodanka Kuzmanova, Santina Romani
In this study, pulsed electric field (PEF) was coupled with vacuum infusion (VI) to impregnate strawberries with cryoprotectants. Electroporation of fruits was reached with 5 bi-polar, rectangular pulses of 100 μs width with a nominal electric ﬁeld strength of 850 V/cm. After PEF treatment, the strawberries were vacuum infused with a cryoprotective solution (12 g/100 g trehalose and 0.2 g/100 g acclimated winter wheat extract containing antifreeze proteins) for 14 min. The strawberries were frozen in liquid nitrogen and thawed in air at 20 oC. Cell survival, texture and color were evaluated before and after freezing and thawing cycle. The fruit pre-treated with PEF prior to VI exhibited higher cell viability in epidermal layer and 30% more red color retention compared to just VI samples. However, no further improvement on strawberry quality in terms of drip loss and texture was observed upon the application of PEF.
OHMIC BLANCHING OF TETSUKABUTO PUMPKIN: EFFECTS ON PEROXIDASE INACTIVATION KINETICS AND COLOR CHANGES J. Food Eng. (IF 3.099) Pub Date : 2018-04-02 Carolina Feistauer Gomes, Júlia Ribeiro Sarkis, Ligia Damasceno Ferreira Marczak
The present work aimed to evaluate the application of an alternative technology for food blanching, the ohmic heating process, and compare it to conventional blanching of hybrid Tetsukabuto pumpkin. The influence of both treatments on the inactivation kinetics of peroxidase and on color changes of pumpkins was investigated. Different kinetic models were evaluated, and the Weibull distribution model showed the best fit to the experimental data. It was verified that ohmic heating accelerated the enzymatic inactivation process; for a reduction higher than 90% in peroxidase initial activity it took 2 minutes of ohmic blanching, while conventional blanching took 4 minutes to achieve the same degree of inactivation. Also, no significant differences (p > 0.05) between ohmic and conventional treatments were observed on the color of the samples. The overall results indicated that ohmic technology was efficient to promote the inactivation of undesirable enzymes and to maintain the food color.
Vacuum drying of rosehip leathers: Modelling of coupled moisture content and temperature curves as a function of time with simultaneous time-varying ascorbic acid retention J. Food Eng. (IF 3.099) Pub Date : 2018-03-30 Silvana M. Demarchi, R. Martín Torrez Irigoyen, Sergio A. Giner
Vacuum drying kinetics, thermal histories and quality kinetics of two rosehip leather formulations were determined, at tray temperatures between 40 and 70ºC. Data was simultaneously modelled as an ordinary differential equations system encompassing a transient water balance, a transient energy balance, and a variable-order quality kinetics equation, coupled to heat and mass transfer. A set of parameters was fitted for each formulation and satisfactory representations of the experimental data were obtained. Differences in drying rate compensated for the effect of the tray temperature on quality loss, so vacuum drying at 70 ºC was recommended for rosehip leathers due to the shorter drying time required. In particular, the reaction order for ascorbic acid degradation was found to be dependent on the tray temperature.
Mathematical model for the mass transport in multiple porous scales J. Food Eng. (IF 3.099) Pub Date : 2018-03-30 Jader Alean, Juan C. Maya, Farid Chejne
The transport of species in a vegetable matrix was modelled and studied based on a phenomenological model, in which a solid composed by the cells, pores and tissues was considered. The model is able to predict the multi-scale mass transport by defining only one effective diffusion coefficient, which made by proposing an inter-scale resistance constant. This parameter is a measure of the difficulty to the mass transport between two scales. The model was successfully validated with experimental data on the mass transport in both an organic and an inorganic matrix, which demonstrate the versatility of the model herein proposed.
Preparation and characterization of calcium alginate-chitosan complexes loaded with lysozyme J. Food Eng. (IF 3.099) Pub Date : 2018-03-30 Tiantian Wu, Yuan Li, Ni Shen, Yeshun Sun, Yaqin Hu
The objective of this study was to study the effect of calcium ions on the binding of lysozyme to chitosan (CS)/sodium alginate (SA) complexes (CS-SA-Ps), in order to develop a complex system for lysozyme delivery which might be of practical interest in the field of food preservatives. Result showed that with the increase of calcium ions (Ca2+) concentration, the value of Z-Ave decreased while the value of ζ-potential and LE increased, where the addition of 5.0 mM Ca2+ contributed to uniform distribution of the complexes. Sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) revealed that there was no significant difference of molecular integrity when lysozyme was released from CS-SA-Ps. The exothermic interaction between lysozyme and SA were proved by thermodynamic measurements, in which the binding stoichiometry showed a slight decrease in the presence of calcium chloride. Moreover, the release rate of lysozyme from CS-SA-Ps could be slowed by the increase of Ca2+ addition concentration.
Evidence for moderate losses of dissolved CO2 during aging on lees of a champagne prestige cuvee J. Food Eng. (IF 3.099) Pub Date : 2018-03-29 Gérard Liger-belair, Daniel Carvajal-perEZ, Clara Cilindre, Jérôme Facque, Marc Brevot, François Litoux-desrues, Vincent Chaperon, Richard Geoffroy
A misconception lingers in the minds of some wine consumers that Champagne wines should not age much after the minimum period of 15 months in contact with dead yeasts, known as maturation on lees. It is certainly a myth, as far as the best cuvees are concerned. Dissolved CO2 being responsible for bubble formation in sparkling wines, keeping it as efficiently as possible in the sealed bottles during aging is therefore a challenge of importance for old vintages likely to mature on lees for several decades. Measurements of dissolved CO2 were done on an outstanding vertical collection of successive vintages from a prestige cuvee, showing maturation on lees ranging from several months up to 35 years at a constant temperature of 12 °C. Progressive losses of dissolved CO2 during aging on lees were evidenced and discussed on the basis of a previously developed exponential-decay type model taking into account the main geometrical parameters of both the cork and bottle. The prestige cuvee (with a narrow bottleneck, and sealed with premium natural cork stoppers) was found to hold much more efficiently dissolved CO2 during aging than a batch of standard Champagne and sparkling wines bottles showing 3 mm wider bottlenecks. By fitting our data with the exponential-decay model, the diffusion coefficient of gas-phase CO2 through the cork stoppers used to seal this prestige cuvee was found to range between about and . Moreover, by extrapolating the data well beyond the measurement range, it was suggested that very long maturation on lees of the order of 76 ± 19 years should be needed to decrease the level of dissolved CO2 in the prestige cuvee below the critical concentration required for bubbling.
Ethanol pre-treatment improves vegetable drying and rehydration: kinetics, mechanisms and impact on viscoelastic properties J. Food Eng. (IF 3.099) Pub Date : 2018-03-29 Meliza Lindsay Rojas, Pedro E.D. Augusto
Drying is a complex process widely applied in food processing. There is still an increasing interest to enhance the process, as well as the product quality and properties. In this work, ethanol was used to enhance drying of pumpkin, which has been considered as a structurally representative material of plant foods. The effect of ethanol treatment on microstructure, convective drying kinetics (Page model), rehydration kinetics (Peleg model) and viscoelastic properties (generalized Maxwell model) was evaluated. The pre-treatment was conducted by immersing pumpkin cylinders in ethanol before convective drying. The ethanol treatment accelerated both drying and rehydration processes. Microstructure modifications were observed after the ethanol treatment, drying and rehydration. The rehydrated samples (control and ethanol treated) showed different viscoelastic properties compared with those in natura, which presented low stress decay and more residual elasticity. A possible mechanism was proposed. In conclusion, the ethanol improved both drying and rehydration processes, without negatively impacting on the microstructure and viscoelastic properties of pumpkin cylinders.
Assessment of liquid−liquid phase separation in the composition and oxidation stability of partially hydrolyzed olive oil J. Food Eng. (IF 3.099) Pub Date : 2018-03-29 Paloma S. Cabral, Marcos L. Corazza, Guilherme L. Sassaki, Maria A. Grompone, Bruno A. Irigaray, Fernando A.P. Voll
Process optimization for producing diacylglycerol-enriched oils has received great attention due the importance of these products for healthier and more balanced diets. This work reports experimental data of liquid-liquid phase equilibrium of hydrolyzed olive oil (which comprises on its composition triacylglycerols, diacylglycerols, monoacylglycerols and free fatty acids) with ethanol and water, and subsequent analysis of oxidative stability of the oil obtained from the liquid phases. Liquid-liquid equilibrium experimental data obtained were modeled using the UNIQUAC thermodynamic model, which was well fitted to experimental data with a root mean square deviation of 1.76 wt%. The results obtained demonstrated the potentiality of liquid-liquid extraction as a suitable procedure for olive oil enrichment in diacylglycerol, after a hydrolysis procedure. It was also observed that liquid-liquid phase separation has a significant effect on the content of important antioxidants present in the olive oil, what affects the oxidative stability of the samples submitted to the liquid phase extraction. From the results obtained in this study, it has been also noticed that the acylglycerols and free fatty acids profile in of the oil samples presented a major rule on their stabilities.
Characterization of dough baked via blue laser J. Food Eng. (IF 3.099) Pub Date : 2018-03-28 Jonathan Blutinger, Yorán Meijers, Peter Yichen Chen, Changxi Zheng, Eitan Grinspun, Hod Lipson
Depth of heat penetration and temperature must be precisely controlled to optimize nutritional value, appearance, and taste of food products. These objectives can be achieved with the use of a high-resolution blue diode laser—which operates at 445 nm—by adjusting the water content of the dough and the exposure pattern of the laser. Using our laser, we successfully cooked a 1 mm thick dough sample with a 5 mm diameter ring-shaped cooking pattern, 120 repetitions, 4000 mm min−1 speed, and 2 W laser power. Heat penetration in dough products with a blue laser is significantly higher compared to with an infrared laser. The use of a blue laser coupled with an infrared laser yields most optimal cooking conditions for food layered manufacture.
Impact of cold chain and product variability on quality attributes of modified atmosphere packed mushrooms (Agaricus bisporus) throughout distribution J. Food Eng. (IF 3.099) Pub Date : 2018-03-26 Kompal Joshi, Jenna Warby, Juan Valverde, Brijesh Tiwari, Patrick J. Cullen, Jesus M. Frias
Study on the Water State and Distribution of Chinese Dried Noodles during the Drying Process J. Food Eng. (IF 3.099) Pub Date : 2018-03-26 Yu Xiaolei, Wang Zhenhua, Zhang Yingquan, Syed Abdul Wadood, Wei Yimin
In this study, the water state and distribution of Chinese dried noodles during drying process was investigated by low-field nuclear magnetic resonance (LF-NMR). Transverse relaxation times (T2) were achieved by LF-NMR coupled with a 0.5 T permanent magnet equivalent to a proton resonance frequency of 21 MHz at 32 °C. Three populations of water state can be distinguished: strongly bound water (T21, 0.04-0.40ms; A21, 0.25-19.08%), weakly bound water (T22, 0.96-5.34; A22, 80.81-98.44%), and free water (T23, 74.50-266.47 ms; A23, 0.11-1.61%). During the drying process, the transverse relaxation time of all water states followed decreasing trend. Initially, the moisture content decreased faster from the edges; however, moisture migrated rapidly from the central part during 90-180min. The moisture gradient disappeared after drying for 240min. Besides, a special method as "Oil immersion method" was introduced to address poor signal to noise ratio in samples when moisture content was low during the drying process. High signal to noise ratio was successfully achieved by this method.
Characterization of barley grains in different levels of pearling process J. Food Eng. (IF 3.099) Pub Date : 2018-03-22 M.P. Felizardo, J.T. Freire
It has been shown recently that addition of barley grains to human nutrition translates into many benefits to the health. Therefore the purpose of this paper was to characterize the barley grains through the pearling process. The barley grains were dehulled on the rotatory drum with abrasive wall. The measured properties evaluated the physical, flow and fluid dynamic characteristics of barley grains at different levels of the pearling process. A maximum of (49.08 ± 5.25)% mass-fraction removal was achieved, this meaning that all four commercial levels of pearling, ranging from 11% to 34%, could be sampled. This range of pearling process caused about 40% of reduction in thickness, 25% of reduction in the bulk porosity, 30% reduction in permeability and 17% reduction in the angle of repose. Barley grains were influenced in the pearling process kinetics and consequently in the physical properties and altering the particle-particle and fluid-particle interactions.
Structured-Illumination Reflectance Imaging Coupled with Phase Analysis Techniques for Surface Profiling of Apples1 ☆ J. Food Eng. (IF 3.099) Pub Date : 2018-03-21 Yuzhen Lu, Renfu Lu
Three-dimensional (3-D) geometry information is valuable for fruit quality evaluation. This study was aimed at exploring an emerging structured-illumination reflectance imaging (SIRI) system, coupled with phase analysis, for reconstructing surface profiles of fruit. Phase-shifted sinusoidal patterns, distorted by the fruit geometry, were acquired and processed through phase demodulation, phase unwrapping and other post-processing procedures to obtain phase difference maps relative to the phase of a reference plane. The phase maps were then transformed into height profiles based on phase-to-height calibrations. A reference plane-based approach, in conjunction with the curve fitting technique using polynomials of order 3 or higher, was utilized for phase-to-height calibrations, which achieved superior accuracies with the root-mean-squared errors (RMSEs) of 0.027-0.033 mm for a height measurement range of 0-91 mm. The 3rd-order polynomial curve fitting technique was further tested on two reference blocks with known heights, resulting in relative errors of 3.75% and 4.16%. Tests of the calibrated system for reconstructing the surface of apple samples showed that surface concavities (i.e., stem/calyx regions) could be readily discriminated from bruising defects from both the phase difference images and reconstructed height profiles. This study has laid a foundation for using SIRI for reconstructing the 3-D geometry, and thus expanded the capability of the technique for quality evaluation of horticultural products. Further research is needed to utilize the phase analysis techniques for detecting surface concavities of apples, and optimize the phase demodulation and unwrapping algorithms for faster and more reliable detection.
Microwave vacuum drying and multi-flash drying of pumpkin slices J. Food Eng. (IF 3.099) Pub Date : 2018-03-21 Ricardo L. Monteiro, Jade V. Link, Giustino Tribuzi, Bruno A.M. Carciofi, João B. Laurindo
In this study, the effect of different drying methods on the drying kinetics, product structures, rehydration kinetics and rehydration indices of dehydrated pumpkin slices was evaluated. For that, pumpkin slices were dehydrated by five different methods: i) Microwave multi-flash drying (MWMFD), ii) Microwave vacuum drying (MWVD), iii) Conductive multi-flash drying (KMFD), iv) Freeze-drying (FD), and v) Air-drying (AD). For reaching a moisture content of 0.022 g g-1 (dry basis, db) and water activity of 0.438, the drying times were 1.28 h for MWVD, 1.32 h for MWMFD, 3.50 h for KMFD, 16.33 h for AD and 16.67 h for FD. All the drying methods presented a constant drying rate period and a falling rate period. The highest constant drying rate was observed for MWVD, which was 1.3, 8, 22 and 53 times higher than the observed for MWMFD, KMFD, AD, and FD, respectively. Stereo micrographs of samples from multi-flash drying processes (KMFD and MWMFD) and from MWVD showed large pores in a highly porous structure. Rehydration of dried pumpkin slices was studied at 25°C and 80°C. Water temperature influenced samples rehydration ratio (RR = mass of rehydrated sample/mass of dried sample). RR up to 15 was observed at 25°C, while RR up to 12 was observed at 80°C. Samples from MWMFD and MWVD, rehydrated at 25°C presented higher moisture after rehydration than those observed from AD, FD and KMFD samples. At 80°C, FD samples showed the highest RR. From the whole results, one can conclude that MWVD and MWMFD are the suitable processes for producing dehydrated pumpkin slices in very short drying times.
“Effect of Water Content on the Dynamic Measurement of Dielectric Properties of Food Snack Pellets during Microwave Expansion” J. Food Eng. (IF 3.099) Pub Date : 2018-03-21 José D. Gutiérrez-Cano, Ian E. Hamilton, José M. Catalá-Civera, John Bows, Felipe L. Peñaranda-Foix
The evolution of dielectric properties of starch-based food pellets with different moisture contents was measured during microwave expansion to determine the effect of water content on the expansion dynamics. Dynamic dielectric measurements were found to be an excellent procedure to in situ monitor and characterize the different stages in the material transformation of food pellets during microwave expansion. Although the maximum bulk expansion of pellets was achieved at a moisture content of approximately 8% (wet basis), comparative analysis showed that a moisture content 10–11% produced the best results considering the tradeoff between the foaming and expansion temperature. This was due to the high expansion index and an expansion temperature that was sufficiently lower than the onset temperature for pellet scorching, which provides an operating window to maximize expansion and minimize the likelihood of burning. Dielectric measurements during microwave heating in short on/off cycles prior to pellet expansion suggested that the water was not as dielectrically bound for high moisture content pellets
In-situ Single Mode Dielectric Measurements of microwaveable snack pellets J. Food Eng. (IF 3.099) Pub Date : 2018-03-20 Erik Esveld, John Bows, Martijntje Vollebregt, Ruud van der Sman
The dielectric properties of starch based snack pellets have been measured in situ during microwave heating and expansion. The microwave setup consists of a single mode shorted waveguide, equipped with a six-port impedance analyser which measures the absorbed power and complex reflection coefficient during heating. The pellet is suspended in the electric field maximum, with an optic temperature sensor inserted in the centre. The dielectric properties of the pellet during heating and after expansion are obtained via an inverse mapping of the recorded reflection coefficient to dielectric properties, which are pre-computed via finite elements simulations. Experiments show that the dielectric properties of the starch pellets change significantly during heating, expansion and subsequent drying. The dielectric properties increase with increasing temperature up to the moment that the pellet starts expanding. Subsequently, the power absorption shows a sudden decline, which is mainly due to the sudden change in porosity. Addition of salt (2.5%) to the starch pellet composition results in a slight decrease of the dielectric constant and loss factor, as it apparently lowers the effective mobility of the dipoles. The dielectric properties as function of temperature and moisture content were fitted with a polynomial model. The strong effect of porosity for the dielectric properties of the expanded snack is well predicted with the effective medium mixing rule.
Application of Osmotic Dehydration to Improve the Quality of Dried Goji Berry J. Food Eng. (IF 3.099) Pub Date : 2018-03-15 E. Dermesonlouoglou, A. Chalkia, P. Taoukis
Quality and preservation of dried goji berry can be improved with the application of osmotic dehydration (OD) as a pre-treatment step. The aim was to optimize OD conditions based on water loss, solid gain, water activity decrease and quality (color, antioxidant capacity, total phenolics, sensory properties) during processing and post-processing, to develop and produce a dried goji berry product of improved quality and with reduced energy requirements. Goji berries were treated in concentrated solution of glycerol, maltodextrin, ascorbic acid, sodium chloride for 60 min at 55°C, and air-dried for 300 min at 60°C (target aw 0.50-0.55). Combining OD and air-drying led to drying time decrease by 120 min, bright red color close to the fresh berry color, improved texture characteristics, higher antioxidant capacity and total phenolic content of the final dried product. Quality of OD-treated and non-treated air-dried samples was monitored during storage at 25-35-45°C. Shelf life was significantly prolonged for OD-treated goji berries: 206 days at 25⁰C compared to 99 days for the non-treated.
Model-based design and validation of food texture of 3D printed pectin-based food simulants J. Food Eng. (IF 3.099) Pub Date : 2018-03-14 Valérie Vancauwenberghe, Mulugeta Admasu Delele, Jeroen Vanbiervliet, Wondwosen Aregawi, Pieter Verboven, Jeroen Lammertyn, Bart Nicolaï
A prime interest in 3D food printing consists of controlling the texture of food products by means of structure design. Analytical and finite element models were used to predict the texture properties of printed honeycomb structures. Structures with varying cell size were 3D printed using food-inks composed of three different pectin concentrations and characterized with micro-CT and compression analysis. Porosity and average wall thickness of the samples appeared independent of food-ink composition but structure deviations could be distinguished between actual printed structures and CAD designs. The comparison between the texture properties of printed structures and those predicted by analytical and FE modelling in function of porosity showed that both predicted and actual texture properties matched to the same decreasing trend with increasing porosity. Finally, a good fit of the analytical model to the measured Young's modulus was obtained by using the actual porosity of the printed structures, while the validated finite element model provides a means to design more complex structures. The results emphasize the importance of structure correspondence for reliable design of texture properties of printed food structures.
Thermal degradation kinetics of L-carnitine J. Food Eng. (IF 3.099) Pub Date : 2018-03-14 Athanasia M. Goula, Polyvios Prokopiou, Nikolaos G. Stoforos
The objectives of this work were to study the thermal degradation kinetics of L-carnitine and to develop a procedure for thermal inactivation kinetics determination from dynamic temperature profile experiments. Experiments were conducted at isothermal conditions in a temperature range from 80 to 130 °C. Remaining L-carnitine concentration was measured at predescribed time intervals at each temperature tested. The kinetic parameters DTref and z were determined after the first order kinetic behavior of L-carnitine thermal inactivation was verified. Furthermore, L-carnitine concentration data were collected during a non-isothermal experiment and the DTref and z values were determined through appropriate methodology. From the isothermal experiments, the parameters D120°C and z were calculated equal to 50.4 min and 30.8 °C, respectively. Similar values (D120 °C = 52.0 min and z = 31.8 °C) were obtained from the measurements during the dynamic temperature profile experiment. Based on the agreement between the parameters estimated using isothermal and non-isothermal temperature profiles, and given the reduced number of experimental data required by the latter approach, kinetic parameter estimation from experiments at dynamic conditions is recommended.
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