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  • Sustainability through Management of Water, Process and Product Hygiene on Food and Beverage Sites
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-12-18
    Elizabeth J. Lodolo

    Water is of major importance to all living organisms as a fundamental resource for life. Yet, competing demands for water resources may lead to an average gap of 40% between global demand and supply by 2030 based on the reality that in the 20th century the world population tripled, while water use multiplied six-fold. Additionally, freshwater constitutes only 2.5% of the total global water reserves. These freshwater reserves are not only threatened by the changes in weather patterns, but also by human activities, which tend to pollute water as it moves through the water cycle. The global water market caters to agriculture, households, municipal, and industrial sectors. Although this review touches on some of these aspects, the focus will be on the contribution of the food and beverage (F&B) sectors to water sustainability, whilst managing the risks. There is increased pressure on the Fast-Moving Consumable Goods (FMCG) companies, often high consumers of water, to optimize site water usage to counter the combined impacts of the growing world population and widening water scarcity. Firstly, through the prevention and reduction of waste such as improving efficiencies and focusing on asset care. Secondly, an opportunity presents itself for plants to optimize water consumption by implementing sound hygiene standards. Evidence is presented where projects were implemented to drive improved site hygiene as well as water savings. This review considers the main contributory risks and the practical approaches required to deliver sustainable water savings targets by optimizing water, process, and product hygiene at FMCG sites.

    更新日期:2020-01-08
  • Analysis of Selected Hop Aroma Compounds in Commercial Lager and Craft Beers Using HS-SPME-GC-MS/MS
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-11-18
    Johanna Dennenlöhr; Sarah Thörner; Aneta Manowski; Nils Rettberg

    In recent years, hop aroma emerged as a key quality characteristic of popular beer styles. Accordingly, the instrumental analysis of hop derived odorants in beer advanced as a must have analytical technique for research and quality control purposes. Still, the analysis of hop aroma compounds is challenging. Substance concentrations might strongly vary depending on the beer style, matrix effects might hinder reliable quantification, and SPME-GC-MS based protocols are suspected to lack (long-term) stability. The current paper describes the validation and application of a headspace solid-phase microextraction (HS-SPME) – gas chromatography (GC) – tandem mass spectrometry (MS/MS) method for analysis of 16 selected hop aroma compounds in beer. To enable rapid and reliable quantification of selected terpenes, terpenoids, and esters across a wide working range (1–1000 µg/L), instrumental parameters were optimized and three stable isotope labeled standards, namely d5-linalool, d2-myrcene, and d6-citronellol were synthesized and characterized by nuclear magnetic resonance (NMR) spectroscopy. Extensive method validation and routine application proves the excellent selectivity, sensitivity, and robustness of the method in all relevant matrices such as light hopped lagers and dry-hopped ales.

    更新日期:2020-01-08
  • A CZE-UV Method for Saturated and Unsaturated Fatty Acids Determination in Hops
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-11-21
    Lucas Mattos Duarte; Tatiane Lima Amorim; Luiz Henrique Cantarino Adriano; Marcone Augusto Leal de Oliveira

    Fatty acids (FA) are minor compounds in beer and its raw materials, but can develop important roles in brewing and require monitoring. The aim of this work was to show the potential of capillary electrophoresis for fast hop analysis and to propose a simple method for the determination of saturated and unsaturated FA in different hop varieties. Sample preparation was investigated and evaluated and validation procedures were carried out to determine palmitic, stearic, oleic and linolenic FA in hops. Low values of relative standard deviation for areas (< 5.32%) and good recoveries (85-110%) were achieved. Laborious extraction and derivatization reactions were not necessary and only a saponification reaction was employed in sample preparation. Also, specific columns were not required and analysis time was only 10 min. The proposed methodology appears promising for faster monitoring of FA in terms of hop quality control in the brewing industry.

    更新日期:2020-01-08
  • Protective Roles of Hop Proanthocyanidins on Alcohol-Induced SH-SY5Y Cell Damage
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-12-19
    Xiaolei Dong; Xiaoyong Zhang; Wenjuan Zhao; Cong Nie; Yan Li; Zhihui Li; Naiming Zhai; Wei Zhang; Fei Mao; Patrick L. Ting; Yang Song

    The present study examined whether hop proanthocyanidins (PACs) or polyphenols could effectively protect alcohol-induced toxicity in human neuroblastoma SH-SY5Y cells. An in-vitro experiment indicated that alcohol could damage the SH-SY5Y cells. The degree of damage was correlated with the alcohol concentration. Cell damage was measured by cell viability, using the MTT assay, and cell apoptosis (programmed cell death) using the TUNEL assay. The results showed that 4 g/L alcohol in-vitro reduced cell viability to 71.7% and caused 34.7% cell apoptosis. Using this model, pre-treatments with 50-75 mg/L hop PACs retained 91% cell viability and inhibited cell apoptosis to below 15%. In addition, it was speculated that the mechanism underlying this neuroprotective effect of PACs might be closely associated with intracellular reactive oxygen species (ROS) levels. This in-vitro experiment demonstrated that the addition of 50-75 mg/L of PACs protected the nerve cells from the damage caused by 4 g/L of alcohol. To date, the impacts of PACs in the brains of humans are not known, however, if blood alcohol concentrations reach 4-5 g/L, severe central nervous system depression, coma, and possibly death can result. Responses of the SH-SY5Y cells might lend an indication of potential neuroprotective effects of hop PACs in alcohol-induced neurotoxicity.

    更新日期:2020-01-08
  • Predicting Malt Fermentability in Malting Barley Breeding Lines
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-11-21
    Ramon Huerta-Zurita; John Barr; Richard D. Horsley; Paul B. Schwarz

    Malt fermentability, along with malt extract, helps determine the amount of malt needed for beer production. While diastatic power (DP) was initially associated with fermentability, it was later demonstrated that variation in fermentability is poorly explained by DP alone. Several studies have suggested that β-amylase and its thermostability, as well as some malt modification parameters, can considerably improve fermentability estimations, especially with commercial malts. However, few experiments have measured variation in fermentability within barley breeding lines, where variation in quality parameters can be wider. The objective of this study was to determine the effect of standard and nonstandard malt quality parameters on the fermentability of 90 barley genotypes, grown at different locations and years in North Dakota, and to then select the best multi-linear regression equation for predicting this trait. Our results showed that, unlike the results of previous studies, β-amylase and its thermostability were not highly associated with fermentability. Rather, wort fermentable sugars, limit-dextrinase, free amino nitrogen, soluble protein, and α-amylase were found to be most closely associated with fermentability. Overall, the results of the current experiment further demonstrate that fermentability results are very population dependent, and that the development of a universal equation is unlikely.

    更新日期:2020-01-08
  • Modeling Yeast in Suspension during Laboratory and Commercial Fermentations to Detect Aberrant Fermentation Processes
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-12-06
    Arthur Rudolph; Andrew J. MacIntosh; R. Alex Speers; Colette St. Mary

    Understanding yeast dynamics during fermentation is important for quality control, whether monitoring fermentation consistency or identifying aberrant events, such as premature yeast flocculation (PYF). Previous models of fermentation dynamics tend to be parameter rich and require large time series, which are rare in industry. This research investigates five simpler models to 1) describe fermentation dynamics, 2) refine quality control sampling regimes to improve model fit, and 3) identify PYF fermentations. The ability of these models to describe yeast dynamics was evaluated using model fitting with time series data and Akaike Information Criterion (AIC) model selection. Data simulated from large time series was used with this model fitting approach to improve sampling schedules without increasing sampling effort. Lastly, PYF was identified in fermentations of fungal-contaminated malt using linear discriminant analysis (LDA). For large data sets, a four-parameter extension of the normal curve performed best while smaller data sets were better described by the 2-parameter gamma model. Moving sampling effort nearer the population peak improved model fits. Lastly, all models detected PYF, however the two-parameter gamma model provided a simple metric for distinguishing PYF. This research provides guidelines on appropriate model use, improving sampling regimes, and identifying PYF.

    更新日期:2020-01-08
  • Mutation and Deletion of PAD1 and/or FDC1 and Absence of Phenolic Off-Flavor Production in Top- and Bottom-Fermenting Yeasts
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-11-21
    Tomoo Ogata; Ryusuke Yamada; Ryo Ayuzawa; Kensuke Nakamura

    To convert ferulic acid into 4-vinylguaiacol (4-VG), Saccharomyces cerevisiae must have intact PAD1 and FDC1 genes. British-type top-fermenting yeast strains have nonsense mutations in both of these genes; whereas, bottom-fermenting yeast strains have a nonsense mutation in their S. cerevisiae-type FDC1, and have lost their S. eubayanus-type FDC1 and PAD1 genes. Here, top-fermenting yeast transformants in which wild-type PAD1 and FDC1 derived from the laboratory yeast S. cerevisiae S288C were inserted in the genome, exhibited ferulic acid decarboxylation activity. Similarly, bottom-fermenting yeast transformants expressing wild-type S. cerevisiae-type FDC1 or S. eubayanus-type FDC1 also exhibited ferulic acid decarboxylation activity. Thus, the lack of ferulic acid decarboxylation activity in bottom-fermenting yeast is due to mutation of the S. cerevisiae-type FDC1 gene, coupled with absence of the S. eubayanus-type FDC1 gene.

    更新日期:2020-01-08
  • Low Carbohydrate Beers Produced by a Selected Yeast Strain from an Alternative Source
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-11-25
    Antonio Troilo; Giovanni De Francesco; Ombretta Marconi; Valeria Sileoni; Benedetta Turchetti; Giuseppe Perretti

    Recently, the brewing industry has invested significant resources into the development of new specialty beers, in response to increased consumer demand. Low carbohydrate and novel flavored beers have resulted and these are particularly attractive for consumers, even if technologically challenging to produce. The aim of this work was to produce a low carbohydrate and novel flavored beer in a traditional manner. A Saccharomyces cerevisiae strain isolated from an alternative source (i.e., yeast strain DBVPG 6580 was used in a Brazilian bioethanol production facility) was selected because of its starch degrading character and this yeast was employed in a traditional brewery plant to achieve this goal. The strain DBVPG 6580 was used to ferment worts of different densities (12 and 20°P) and at different fermentation temperatures (18 and 25 °C), to explore possible technological applications. The results demonstrated that yeast DBVPG 6580 was able to degrade dextrins to fermentable sugars, giving an apparent attenuation above 100% and allowing for the production of a low carbohydrate beer by traditional methods. Moreover, strain DBVPG 6580 produced novel flavored beers, rich in fruity, floral, banana and pear flavors. This yeast strain demonstrated that under optimal conditions, it possessed the ability to ferment a high density wort, which could lead to important economic advantages for the producer.

    更新日期:2020-01-08
  • The Relationship Between Wort Sugar Concentration and Yeast Carbon Partitioning During Brewing Fermentations
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-10-07
    Shiwen Zhuang, Katherine Smart, Chris D. Powell

    High gravity (HG) and very high gravity (VHG) fermentations are increasingly attractive within the brewing industry as a means of optimizing process efficiency and energy-saving. However, the use of highly concentrated worts is concomitant with a number of biological stress factors that can impact on yeast quality and fermentation performance. In order to eliminate or reduce potentially detrimental effects, brewing yeast respond to their environment by shunting carbon into different metabolic end products, which assist in the protection of cells, but also impact on final ethanol yield. The purpose of this research was to investigate the impact of substrate sugar concentration on carbon partitioning in brewing fermentations. This was conducted using a series of laboratory-scale fermentations with worts of 13°P, 18°P and 24°P, pitched using lager and ale yeast strains. Fermentation performance was assessed with respect to the uptake of wort sugars and the production of key carbon-based metabolites, leading to a calculation of yeast central carbon flux. Analysis of carbon assimilation and dissimilation revealed that changes in intracellular trehalose, glycogen, higher alcohols and esters were observed, however the production of yeast biomass acted as the major trade-off with ethanol production. The data presented here shows for the first time the requirements of yeast populations during HG and VHG conditions and the factors that have a major impact on key performance indicators. This data has major significance for fermentation-based industries globally and is especially important for those sectors seeking to maximize yield from existing resources through high gravity fermentations.

    更新日期:2019-11-14
  • Rapid Beer Fermentation: The Effect of Vacuum Pressure on a Pilot Scale Lager Fermentation
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-10-24
    Mario Guadalupe-Daqui, Andrew J. MacIntosh

    Changes to industrial fermentation processes are rare, largely due to the impact on viability for Saccharomyces spp., related to environmental stresses during the process such as: osmotic pressure, ethanol concentration, dissolved CO2. This research studied yeast behavior during a High Gravity (HG) fermentation under partial vacuum pressure during standard brewing operations. This was accomplished by controlling the temperature and pressure of 30 L pilot fermentations. An experimental lager wort recipe with “Diamond” lager yeast (Saccharomyces pastorianus) was used in this study. The modified process conducted at 24.1 kPa of pressure in the headspace was compared to a control process at standard atmospheric pressure (101.3 kPa). This research showed that at 15 °C, lager fermentations (14–15°P) fermented up to 30% faster under vacuum, with an increase in the number of yeast cells in suspension of up to 100%. The rate of sugar consumption under vacuum was greater compared to the control, thus increasing the rate of ethanol production. The removal of volatile CO2 is one hypothesized mechanism for these results. The total ethanol production, pH and yeast viability did not differ significantly between the control and modified process. The application of vacuum during brewing resulted in an increased fermentation rate and number of yeast cells in suspension during fermentation.

    更新日期:2019-11-14
  • Characterization of Microbial Communities Populating the Inflorescences of Humulus lupulus L.
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-10-07
    Mary E. Allen, Andrew J. Piefer, Sean N. Cole, Jeffrey J. Werner, Peter T. Benziger, Laura Grieneisen, Scott J. Britton

    The aerial portion of plants (phyllosphere) harbors complex and diverse microbial communities that have been shown to influence host growth and fitness, tolerance to environmental stressors, disease susceptibility, and the productivity of economically significant crops. However, despite its reproductive importance to the host and economic value, the microbial ecology of anatomical flowers (anthosphere) remains largely uninvestigated. Here a culture-independent assessment of bacterial communities on freshly harvested and dried inflorescences of eight hop varieties (Humulus lupulus L.), using Illumina MiSeq 16S platform-based rRNA gene sequence analysis, is reported. The results reveal the hops anthosphere is dominated by a single taxonomic phylum, the Proteobacteria, where at least 60% of the sequences are attributed across two genera, Pseudomonas (Gammaproteobacteria) and Sphingomonas (Alphaproteobacteria). Chao1 diversity analysis indicated the presence of many very rare taxa across all varieties. Beta-diversity analysis resolved, from the comparison of unweighted and weighted UniFrac distances, the absence of distinct clustering between freshly harvested and dried hops or between hop varieties. The prevalence of Proteobacteria associated with hop inflorescences is consistent with other anthosphere microbiomes; however, presently the predominance of Gammaproteobacteria in the phyllosphere appears to be a distinct characteristic of the hops microbiome.

    更新日期:2019-11-14
  • A Comparison of Single-Stage and Two-Stage Dry-Hopping Regimes
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-10-24
    Dean G. Hauser, Karli R. Van Simaeys, Scott R. Lafontaine, Thomas H. Shellhammer

    Multi-stage dry-hopping is a technique that is widely used by brewers to achieve intense hop aroma in beer. However, a thorough analysis of its efficacy does not exist in the published literature. The goal of this study was to compare the properties of beers produced by single or two-stage dry-hopping at the same cumulative rate. On the pilot scale (80–100 L), an un-hopped base beer was subjected alternately to single- or two-stage dry-hop additions at 386, 772, and 1544 g/hL using Centennial hops. Separately commercial beers (∼350 hL batch size) were dry-hopped at 733 g/hL in single or two-stage additions using a combination of Amarillo, Simcoe, Cascade, Citra, and CTZ pellets. Pilot scale dry-hopped beers showed increases in residual extract, pH, bitterness units, humulinones, and total polyphenols, accompanied by a decrease in iso-α-acids with increasing hop dose. Changes in bitterness units, humulinones, and iso-α-acids all appeared to be more pronounced in the two-stage dry-hopped beers. In contrast, commercial beers were nearly identical in terms of chemical composition. Significant increases in six aroma attributes scaled by a trained panel were observed as a result of two-stage dry-hopping in the pilot scale treatments. Slight increases in aroma potential were observed for the commercial beer made with two-stage additions, although these differences were not statistically significant. These results illustrate the impact multi-stage dry-hop additions have on beer aroma, and provide direction to brewers to consider whether multi-stage dry-hopping may yield desirable results while potentially using less hop material.

    更新日期:2019-11-14
  • Brewing of a Porter Craft Beer Enriched with the Plant Parastrephia lucida: A Promising Source of Antioxidant Compounds
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-09-03
    Luis Bustos, Emilio Soto, Felipe Parra, Carlos Echiburu-Chau, Claudio Parra

    Beer is a fermented beverage rich in polyphenols, with approximately 30% derived from hops and 70–80% originating from the malt. In a previous study, a native plant called Parastrephia lucida was reported as a new natural source of antioxidant compounds. Thus, this study aimed to produce a Porter-style craft beer enriched with P. lucida, for a higher antioxidant capacity. The addition of P. lucida was shown to increase linearly relative to the concentration of bioactive compounds and antioxidant activity compared with the control beer. In conclusion, an enriched Porter-style beer was brewed with a native plant, as a source of bioactive compounds, which allowed for the production of a beer with high antioxidant activity, while maintaining the characteristics of the beer.

    更新日期:2019-11-14
  • Effect of Steeping Regime on Barley Malt Quality and Its Impacts on Breeding Program Selection
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-07-30
    Hannah M. Turner, Liz Elmore, Jason Walling, Jennifer Lachowiec, Dylan Mangel, Andreas Fischer, Jamie Sherman

    When making malt, the endosperm is hydrated during steeping to make stored starch available for extraction. Differences in steep regime impact malt quality. Differences in malt quality results between the United States Department of Agriculture-Agricultural Research Service (USDA-ARS) and Montana State University (MSU) malt quality laboratories are primarily due to differences in steep regime and are reported herein. Evidence suggests that differences in steep regime in this study were primarily due to length of water immersion versus air rests, rather than other differences (e.g., temperature of steep, sorting of seed, or length of germination). The difference in steep regime caused a difference in the level of endosperm modification. To confirm this finding, three different steep regimes on seven different lines were tested and it was found that the impact on quality varied depending on the trait and in some cases on the genotype. The steep regime was found to have affected both moisture uptake and quality of hydration. Finally, the implications of these findings on malt quality analysis and breeding for malt quality are discussed.

    更新日期:2019-11-14
  • Potential of Triticale (X Triticosecale Wittmack) Malts for Beer Wort Production
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-10-24
    Tania N. Ambriz-Vidal, Maria D. Mariezcurrena-Berasain, Erick Heredia-Olea, Dora L. Pinzon Martinez, Ana T. Gutierrez-Ibañez

    Triticale grain, a wheat-rye hybrid mostly used for animal feed, has been recently reported to exhibit different trends when used as unmalted or malted grain in the brewing industry. The aim of this study was to evaluate the potential of four different triticale lines to evaluate their potential for malt production. The four studied triticale malts PM-1, PM-3, PM-6, and PM-8 lines yielded an extract content higher than 100% and a diastatic power similar to some barley malts (86.19–190.19°L). The produced worts showed a higher percentage of soluble protein, between 4.56% and 5.66%, with a large viscosity value (∼2.055 cP) reported for this raw material. Two triticale malts were selected based on their performance, PM-1 and PM-3, and fermented at different percentage combinations with barley malt (0, 30, 50, 70, and 100%). The results revealed that the use of 100% triticale malt yielded an acceptable fermentation, with an Apparent Attenuation Limit (AAL) of 72%. The optimal triticale-barley malt ratio was 30/70, where supplementing triticale malt enriched the extract, enhancing the fermentation. These results support the suitability and possible establishment of triticale grain as a brewing crop.

    更新日期:2019-11-14
  • Dynamic Analysis of Physicochemical and Biochemical Indices and Microbial Communities of Light-Flavor Daqu during Storage
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-07-29
    Penghui Liu, Lihong Zhang, Xiaowei Du, Jinglong Zhao, Gang Gao, Xiuhong Zhang

    To understand the influence of storage period on the quality of light-flavor Daqu, physicochemical and biochemical indices, as well as microbial communities of Daqu were analyzed by traditional and metagenomics methods. The results suggest that the moisture content of the Daqu samples are essentially invariant during the storage period; the acidity ascended slowly during the first 3 months, then descended; the saccharifying power of some samples began to decrease during the first 3 months. The diversity of the bacterial and fungal communities of some of the Daqu samples was found to decline to a minimum after storage for 3 months. On the basis of the variations in primary indices of the Daqu samples, it was deemed acceptable to store samples for 3 months before use for light-flavor Daqu. This is the first report of Daqu quality being estimated during storage by physicochemical, biochemical, and microbial indices, and it provides a theoretical foundation for the quality evaluation of Daqu during storage and use.

    更新日期:2019-11-14
  • Quantitative Comparison of Volatiles in Vapor Infused Gin versus Steep Infused Gin Distillates
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-07-22
    Jan Hodel, Matthew Pauley, Maarten C. J. K. Gorseling, Annie E. Hill

    The impacts of infusion methods used in the production of gin were investigated by analyzing the concentrations of terpene flavor compounds in two laboratory distilled gins and six commercial gins using Gas Chromatography–Mass Spectrometry (GC–MS). The technique quantified 10 volatile terpenes that are common flavor-active constituents of botanicals used in gin recipes. Differences between the individual commercial gins in terms of production method are discernible. Discrepancies between infusion methods were enhanced in the comparison of laboratory extractions using a known botanical ratio. Comparison of extraction using vapor infusion or steep infusion methods revealed that 9 of the 10 compounds analyzed were found in higher concentration in distillates produced by vapor infusion; only linalool was found to be in higher concentration in steep than it was in vapor infusion. The linalool concentration in the distillate from steep infusion was 1.7 times as high as that from vapor infusion. The method of analysis used enables a comparison of gin distillates from different categories and styles of gin.

    更新日期:2019-11-04
  • Investigation into the Potential of Lachancea fermentati Strain KBI 12.1 for Low Alcohol Beer Brewing
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-07-18
    Konstantin Bellut, Maximilian Michel, Mathias Hutzler, Martin Zarnkow, Fritz Jacob, David P. De Schutter, Luk Daenen, Kieran M. Lynch, Emanuele Zannini, Elke K. Arendt

    In brewing research, non-Saccharomyces yeasts have gained attention in recent years, owing to their potential to influence the characteristics and flavor of beer. The Lachancea genus possesses an uncommon trait, the production of significant amounts of lactic acid during alcoholic fermentation. This trait could potentially be harnessed for brewing purposes, particularly for the production of low alcohol beer. In this study, the potential of Lachancea fermentati strain KBI 12.1 was investigated for the production of low alcohol beer in low gravity wort. KBI 12.1 was characterized for sugar utilization, hop sensitivity, phenolic off-flavor (POF) production, and propagation performance. Lab scale fermentation trials in diluted wort (6.6°P) were conducted and compared to a brewers’ yeast, Saccharomyces cerevisiae WLP001. Fermentations were monitored for lactic acid and ethanol production, pH drop, and sugar consumption. In the final beers, amino acid and free amino nitrogen (FAN) content were determined and secondary metabolites were quantified. Lachancea fermentati KBI 12.1 showed to be unable to utilize maltotriose. The strain exhibited no POF production, minor hop sensitivity, and excellent propagation performance. Amino acid and FAN consumption were much lower compared to that of the brewers’ yeast. In the final beer fermented with KBI 12.1, the lactic acid concentration reached 1.3 g/L, giving the beer a sour taste. During sensory analysis, the beer was additionally described to have a fruity character. In conclusion, Lachancea fermentati KBI 12.1 proved to be a suitable strain for brewing purposes, with promising traits with regard to nonalcoholic and low alcohol beer brewing.

    更新日期:2019-11-04
  • Influence of Top Pressure on the Flavor and Sensorial Characteristics of Lager Beer
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-05-10
    Dongsheng Yang

    The top pressure of CO2 has been studied in the brewing industry as a method for improving the quality of beer. This study focused on the influence of top pressure on the flavor of lager beers by measuring different physicochemical and flavor parameters during primary fermentation and maturation. Sensorial analyses were also conducted to reveal the relationship between the instrumental data and the sensory results. Based on a detailed evaluation of the parameters and multivariate data analysis, it was demonstrated that the top pressure influenced the sensorial characteristics of lager beer by balancing the flavor in lager beers. The flavor quality was improved by altering the relative contents of the volatile compounds produced and improving the organoleptic properties of beer. On the other hand, the increased CO2 pressure slightly reduced the rate of fermentation, but its effects on the acetaldehyde and DMS content were minimal. A study on consumer preferences was also carried out to determine the possible impact of top pressure and wort gravity on the flavor quality of beers and market preferences. The maturation characteristics appeared to be improved by using a top pressure of 1.5 bar for 8°P and 0.5 bar for 12°P.

    更新日期:2019-11-04
  • Evaluating the Impact of Dissolved Oxygen and Aging on Dry-Hopped Aroma Stability in Beer
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-05-20
    Bradley M. Barnette, Thomas H. Shellhammer

    It is generally recognized within the brewing industry that hop aroma and flavor in beer changes as beer ages post-packaging. Lager beer staling has been studied extensively, while dry-hopped beer has received limited attention. This study evaluated the impact of dissolved oxygen on the sensory and hop volatile profiles of dry-hopped beer during storage. Commercially-brewed dry-hopped beer was dosed with oxygen in a controlled fashion to create beers with a range of dissolved oxygen concentrations from approximately 40 to 250 μg/L 40 to 250 µg/L and then stored under chilled (3 °C) or accelerated (30 °C) storage conditions. Projective Mapping (Napping®) generated unique Euclidian configurations for each panelist, and ultra-flash profiling enriched the configurations with sensory descriptors. Sensory results identified storage temperature, used as a proxy for aging duration, as having the greatest effect on aroma during storage. Dissolved oxygen concentration was observed to have a lesser, but significant, impact at both high and low storage temperatures after only two weeks of aging. Higher temperature and dissolved oxygen concentrations resulted in decreased tropical, citrus, and hoppy characteristics and the expression of malty, dried fruit, and cardboard aromas. Hop derived monoterpenes were not significantly affected by treatment temperature or dissolved oxygen, suggesting stale character expression from alternate sources such as lipid oxidation or Strecker aldehydes formation.

    更新日期:2019-11-04
  • Extraction Efficiency of Dry-Hopping
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-06-18
    Dean G. Hauser, Scott R. Lafontaine, Thomas H. Shellhammer

    Dry-hopping, which is the cold, aqueous extraction of hops into beer, has gained popularity in recent years as a method for achieving intense hop aroma and flavor in beer. With some brewers dry-hopping at rates up to 2 kg/hL (∼5 lb/barrel), considerable waste is generated in terms of both beer loss and spent hops. The retention of valuable volatile and non-volatile hop components within spent hops, as well as their extraction into beer, was investigated on both a pilot and industrial scale. On the pilot scale (80 L), an unhopped pale ale was statically dry-hopped with differing lots of whole cone Amarillo®, Centennial, and Cascade at a rate of 386 g/hL (1 lb/bbl) for 24 h at 13 °C (55 °F). Spent hop material was also collected from a local brewery that dry-hopped ∼60 hL (50 bbl) of beer at a rate of 1,592 g/hL (4.125 lb/bbl). Approximately one-third of the dry-matter composition of hops was lost during dry-hopping regardless of hop variety; however, there was high retention of both α-acids (77% pilot scale, 52% industrial) and hop essential oil (51% pilot scale, 33% industrial). The oil remaining in the spent hops was enriched in hydrocarbon compounds and depleted in oxygenated compounds. These results indicate that spent dry-hops contain considerable brewing value and have the potential for re-use.

    更新日期:2019-11-04
  • Influence of Nitrogen Fertility Practices on Hop Cone Quality
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-06-11
    Anne E. Iskra, Scott R. Lafontaine, Kristin M. Trippe, Stephen T. Massie, Claire L. Phillips, Megan C. Twomey, Thomas H. Shellhammer, David H. Gent

    Abstract A multi-year field study was conducted in Oregon and Washington to evaluate the influence of nitrogen fertilization rate and timing on cone quality and nitrate accumulation in cones. The impact of nitrogen rate on cone yield, levels of hop acids, total oil content, color, and nitrate level were year dependent. However, when data were aggregated over years and analyzed using a mixed effect model, α-acids, β-acids, and total oil volume decreased linearly with increasing nitrogen rate; while cone color, expressed as the degree of greenness of cones, and nitrate content of cones increased linearly with nitrogen rate. Yield was not improved with the highest nitrogen rate. In one of four studies, panelists used triangle tests to evaluate hop aroma of ground hop cones and detected a difference among treatments. The α- and β-acids decreased and nitrate concentration increased when nitrogen was applied after bloom. One harvest showed that fertilizer timing led to differences in the aroma of the hop cones although this difference was within the standard aroma variation for the variety. Overall, this research indicates that applying the lowest feasible nitrogen rate and ceasing nitrogen applications before or at bloom may optimize certain cone quality factors while minimizing nitrate accumulation.

    更新日期:2019-11-04
  • Analysis of the Microbial Community Structure during Brewing of Sichuan Xiaoqu Baijiu
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-05-10
    Ming-Yao Wang, Qing-Song Zhao, Chang Su, Jian-Gang Yang

    Chinese baijiu is produced using a unique brewing method, and few studies have examined changes in microbial communities during baijiu fermentation. In this study, changes were evaluated in the microbial communities of Sichuan Xiaoqu baijiu fermented grains using high-throughput sequencing. The bacterial community mainly consisted of Enhydrobacter, Acinetobacter, Leuconostoc, Escherichia-Shigella, Weissella, and Klebsiella. Klebsiella was the dominant microorganism, accounting for >75% of the bacteria on days 1, 3, 5, and 7 of fermentation. Fungal communities consisted mainly of Saccharomycetales and Rhizopus oryzae. The abundance of R. oryzae was 88% on day 1 but decreased rapidly to 4% on day 5, with 0% R. oryzae on day 7. In contrast, Saccharomycetales abundance was only 10% on day 1 but was much higher on days 5 and 7 at 99% and 100%, respectively. Acidity increased, and pH decreased during fermentation. Additionally, the temperature and reducing sugar content first increased and then decreased, whereas the ethanol and water content increased. Finally, Saccharomycetales was strongly correlated with reducing sugars, suggesting it may be a functional microorganism during fermentation. These data provide some insights into the functional microorganisms involved in the fermentation process, enabling a deeper understanding of Xiaoqu liquor.

    更新日期:2019-11-04
  • Validating the Sensitivity of the Beer Tetrad Test as Compared with the Beer Triangle Test: An American Society of Brewing Chemists Technical Committee Report
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-06-21
    D. Bissmeyer, ASBC Technical Committee

    This subcommittee was formed based on the recommendation of the American Society of Brewing Chemists (ASBC) sensory subcommittee. Its purpose was to determine if the Tetrad Test is as sensitive as the Triangle Test for beer sensory testing. To accomplish this task, 11 sensory panels participated in Tetrad and Triangle testing of two commercially available beers. Half of the samples were stored at 4 °C and the other half were stored at 24 °C. Samples, detailed instructions, and ballots were shipped to each of the participating panels. Each panel returned their results to the Wolf Group for data analysis. The Tetrad Test was found to be a suitable replacement for the Triangle Test. The Tetrad Test had a higher percentage of correct responses at more panel sites than did the Triangle Test. At a confidence level of 95%, no significant differences were observed in the aggregate proportion of correct answers for the Triangle Test versus the Tetrad Test. The reduction of Effect Size (d′) for the Tetrad was less than the theoretical reduction of 1/3, indicating that the Tetrad Test is slightly more powerful than the Triangle Test. The lower standard deviation of the Tetrad Effect Size indicates that it is more precise than that of the Triangle Test. The subcommittee recommended that the Tetrad Test Method be published in the ASBC Methods of Analysis as a suitable alternative to the Triangle Test. The subcommittee also recommended that further testing be conducted to test the tolerances of the Effect Size (d′).

    更新日期:2019-11-04
  • Validating the Sensitivity of the Beer Tetrad Test as Compared with the Beer Triangle Test (A Follow-Up Study): An American Society of Brewing Chemists Technical Committee Report
    J. Am. Soc. Brew. Chem. (IF 0.792) Pub Date : 2019-06-21
    D. Bissmeyer, ASBC Technical Committee

    Previous testing by the sensory subcommittee confirmed that the Tetrad Test was more sensitive than the Triangle Test on beer samples with higher Effect Sizes. The subcommittee also wanted to confirm that the Tetrad Test was equally effective for samples with lower Effect Sizes; therefore, a new study was designed to validate the sensitivity of the Tetrad Test for smaller d’ values. The results of the second study show that for samples with smaller d’ values, the Tetrad Test resulted in a 15% reduction in d’ compared with the Triangle Test. This is less than the theoretical 1/3 reduction, indicating that the Tetrad Test is more sensitive. The Tetrad Test also resulted in a higher proportion of correct responses, though the difference was not significant at the 95% confidence interval. The subcommittee recommended that the Tetrad Test method be included in the ASBC Methods of Analysis.

    更新日期:2019-11-04
Contents have been reproduced by permission of the publishers.
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