Pub Date : 2022-01-26DOI: 10.1080/03610470.2021.2021766
Cécile Chenot, Guillaume Willemart, J. Gros, S. Collin
Abstract Following identification of the substantial pool of aromas represented by cysteinylated and glutathionylated precursors in hop, many studies have focused on developing methods for releasing volatile thiols based on chemical hydrolysis or yeast activity. The present work aimed to evaluate the release activity of either commercially available exogenous enzymes or endogenous wort enzymes (issued from hop or malt) on synthetic Cys- or G-precursors of 3SHol, 3SPol, 3SHptol, 3S4MPol and 4S4M2Pone. In a model medium at pH 7.7, both apotryptophanase and cystathionine β-lyase appeared very efficient on Cys-adducts (up to 77.9% release). Interestingly, a slight proportion of this release (up to 0.9%) appeared to result from chemical hydrolysis. In polyphenols rich media such as hop and beer, total release was much lower (under 0.2%). For release from G-adducts, a combination of γGT and apotryptophanase proved to be effective, highlighting for the first time the ability of β-lyase activity to release free PFTs also from CysGly-adducts. The best release rates (above 2% for all thiols) were obtained with a two-step incubation: 75 units γGT with synthetic glutathionylated precursors for 16 h at 37 °C in the presence of alanine followed by apotryptophanase for 7 h at room temperature. The alternative combination of γGT with S. cerevisiae was found to release free thiols more efficiently than yeast activity alone. Compared to commercially available enzymes, endogenous enzymes extracted from hop or malt displayed lower efficiency (below 0.3% for γGT activity and below 0.002% for β-lyase).
{"title":"Ability of Exogenous or Wort Endogenous Enzymes to Release Free Thiols from Hop Cysteinylated and Glutathionylated S-Conjugates","authors":"Cécile Chenot, Guillaume Willemart, J. Gros, S. Collin","doi":"10.1080/03610470.2021.2021766","DOIUrl":"https://doi.org/10.1080/03610470.2021.2021766","url":null,"abstract":"Abstract Following identification of the substantial pool of aromas represented by cysteinylated and glutathionylated precursors in hop, many studies have focused on developing methods for releasing volatile thiols based on chemical hydrolysis or yeast activity. The present work aimed to evaluate the release activity of either commercially available exogenous enzymes or endogenous wort enzymes (issued from hop or malt) on synthetic Cys- or G-precursors of 3SHol, 3SPol, 3SHptol, 3S4MPol and 4S4M2Pone. In a model medium at pH 7.7, both apotryptophanase and cystathionine β-lyase appeared very efficient on Cys-adducts (up to 77.9% release). Interestingly, a slight proportion of this release (up to 0.9%) appeared to result from chemical hydrolysis. In polyphenols rich media such as hop and beer, total release was much lower (under 0.2%). For release from G-adducts, a combination of γGT and apotryptophanase proved to be effective, highlighting for the first time the ability of β-lyase activity to release free PFTs also from CysGly-adducts. The best release rates (above 2% for all thiols) were obtained with a two-step incubation: 75 units γGT with synthetic glutathionylated precursors for 16 h at 37 °C in the presence of alanine followed by apotryptophanase for 7 h at room temperature. The alternative combination of γGT with S. cerevisiae was found to release free thiols more efficiently than yeast activity alone. Compared to commercially available enzymes, endogenous enzymes extracted from hop or malt displayed lower efficiency (below 0.3% for γGT activity and below 0.002% for β-lyase).","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"33 - 44"},"PeriodicalIF":2.0,"publicationDate":"2022-01-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45088573","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-14DOI: 10.1080/03610470.2021.2015560
Cécile Chenot, Sébastien Haest, R. Robiette, S. Collin
Abstract Cysteinylated and glutathionylated precursors of sulfanylalkyl alcohols have been extensively studied in hop and grape matrices, in contrast to those of sulfanylalkyl aldehydes and sulfanylalkyl acetates. Here, cysteinylated and glutathionylated adducts of 3-sulfanylpentanal (Cys-3SPal and G-3SPal), 3-sulfanylhexanal (Cys-3SHal and G-3SHal), 3-sulfanylpentyl acetate (only Cys-3SPA), and 3-sulfanylhexyl acetate (Cys-3SHA and G-3SHA) were first synthesized. Next, the occurrence of these compounds was studied by RP-HPLC-ESI(+)-MRM and apotryptophanase-GC-PFPD in a few dual hops and Belgian grape must samples. None of the Cys-adducts of 3-sulfanylalkyl aldehydes were detected in hop or grape extracts, while G-3SPal was identified for the first time in a natural matrix. Concentrations ranging from 3 to 15 mg/kg were found in several hop varieties, including Citra, Mandarina Bavaria, Mosaic, Nelson Sauvin, Polaris, and Saaz, whereas G-3SHal was detected (below the quantitation limit) only in the four latters. As for esters, Cys-3SPA was found in hop (4 mg/kg in Mosaic), while G-3SHA was detected only in grape extracts (Belgian Chardonnay and Johanniter). Besides the ubiquitous G-3SHol, G-3SPol was identified here for the first time in grape must (up to 7 mg/kg in Johanniter).
{"title":"Thiol S-Conjugate Profiles: A Comparative Investigation on Dual Hop and Grape Must with Focus on Sulfanylalkyl Aldehydes and Acetates Adducts","authors":"Cécile Chenot, Sébastien Haest, R. Robiette, S. Collin","doi":"10.1080/03610470.2021.2015560","DOIUrl":"https://doi.org/10.1080/03610470.2021.2015560","url":null,"abstract":"Abstract Cysteinylated and glutathionylated precursors of sulfanylalkyl alcohols have been extensively studied in hop and grape matrices, in contrast to those of sulfanylalkyl aldehydes and sulfanylalkyl acetates. Here, cysteinylated and glutathionylated adducts of 3-sulfanylpentanal (Cys-3SPal and G-3SPal), 3-sulfanylhexanal (Cys-3SHal and G-3SHal), 3-sulfanylpentyl acetate (only Cys-3SPA), and 3-sulfanylhexyl acetate (Cys-3SHA and G-3SHA) were first synthesized. Next, the occurrence of these compounds was studied by RP-HPLC-ESI(+)-MRM and apotryptophanase-GC-PFPD in a few dual hops and Belgian grape must samples. None of the Cys-adducts of 3-sulfanylalkyl aldehydes were detected in hop or grape extracts, while G-3SPal was identified for the first time in a natural matrix. Concentrations ranging from 3 to 15 mg/kg were found in several hop varieties, including Citra, Mandarina Bavaria, Mosaic, Nelson Sauvin, Polaris, and Saaz, whereas G-3SHal was detected (below the quantitation limit) only in the four latters. As for esters, Cys-3SPA was found in hop (4 mg/kg in Mosaic), while G-3SHA was detected only in grape extracts (Belgian Chardonnay and Johanniter). Besides the ubiquitous G-3SHol, G-3SPol was identified here for the first time in grape must (up to 7 mg/kg in Johanniter).","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"23 - 32"},"PeriodicalIF":2.0,"publicationDate":"2022-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42819811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-12DOI: 10.1080/03610470.2021.2012747
Yvonne Methner, M. Hutzler, M. Zarnkow, A. Prowald, F. Endres, F. Jacob
Abstract Non-alcoholic beers have seen steady growth in recent years and are attracting customer interest. At the same time, consumer demand for non-alcoholic beers is rising. While wort-like flavors are often criticized in beer and also regarded as off-flavors, there is growing demand for beer flavor diversification. The latest research results prove that certain non-Saccharomyces yeast species can produce distinctive fruity flavor profiles during wort fermentation. In this study, 15 different yeast strains were evaluated for their suitability to produce novel flavor profiles during fermentation in wort from malt extract while being tested for their ability to produce less than 0.5% (v/v) ethanol. The yeast strains were therefore analyzed for their sugar utilization and were compared with the maltose-negative reference yeast strain Saccharomycodes ludwigii TUM SL17. Following the fermentation experiments, the beers were analyzed for secondary metabolites and ethanol content before being tasted by trained assessors. The results reveal that all 15 yeasts are suitable for the production of non-alcoholic beers based on their sugar utilization. Particularly promising flavors were produced by three yeast strains of the species Cyberlindnera saturnus, which were reminiscent of cool mint sweets, pear, and banana. Two further yeasts of the species Kluyveromyces marxianus and Saccharomycopsis fibuligera also produced a wide range of pleasant fruity flavors. Although the secondary metabolites were mostly below the odor thresholds based on regular alcoholic beers, this study reveals that the thresholds in non-alcoholic beers can be classified as significantly lower. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2021.2012747 .
近年来，无酒精啤酒的销量稳步增长，并吸引了消费者的兴趣。与此同时，消费者对无酒精啤酒的需求正在上升。虽然麦汁口味在啤酒中经常受到批评，也被认为是异味，但人们对啤酒口味多样化的需求越来越大。最新的研究结果证明，某些非酵母菌种在麦汁发酵过程中可以产生独特的水果风味。在这项研究中，研究人员评估了15种不同的酵母菌株在麦芽汁发酵过程中产生新风味的适用性，同时测试了它们产生低于0.5% (v/v)乙醇的能力。因此，分析了酵母菌的糖利用情况，并与麦芽糖阴性的参考酵母菌Saccharomycodes ludwigii TUM SL17进行了比较。在发酵实验之后，在由训练有素的评估人员品尝之前，对啤酒进行了次级代谢物和乙醇含量的分析。结果表明，15种酵母的糖利用率均适合生产无酒精啤酒。特别有希望的味道是由三种名为Cyberlindnera saturnus的酵母菌株产生的，它们让人想起清凉的薄荷糖、梨和香蕉。另外两种酵母——马氏克卢维酵母和纤维酵母菌也能产生各种各样令人愉快的果味。虽然次生代谢物大多低于基于普通酒精啤酒的气味阈值，但本研究表明，非酒精啤酒的阈值可以归类为明显更低。本文的补充数据可在https://doi.org/10.1080/03610470.2021.2012747上在线获得。
{"title":"Investigation of Non-Saccharomyces Yeast Strains for Their Suitability for the Production of Non-Alcoholic Beers with Novel Flavor Profiles","authors":"Yvonne Methner, M. Hutzler, M. Zarnkow, A. Prowald, F. Endres, F. Jacob","doi":"10.1080/03610470.2021.2012747","DOIUrl":"https://doi.org/10.1080/03610470.2021.2012747","url":null,"abstract":"Abstract Non-alcoholic beers have seen steady growth in recent years and are attracting customer interest. At the same time, consumer demand for non-alcoholic beers is rising. While wort-like flavors are often criticized in beer and also regarded as off-flavors, there is growing demand for beer flavor diversification. The latest research results prove that certain non-Saccharomyces yeast species can produce distinctive fruity flavor profiles during wort fermentation. In this study, 15 different yeast strains were evaluated for their suitability to produce novel flavor profiles during fermentation in wort from malt extract while being tested for their ability to produce less than 0.5% (v/v) ethanol. The yeast strains were therefore analyzed for their sugar utilization and were compared with the maltose-negative reference yeast strain Saccharomycodes ludwigii TUM SL17. Following the fermentation experiments, the beers were analyzed for secondary metabolites and ethanol content before being tasted by trained assessors. The results reveal that all 15 yeasts are suitable for the production of non-alcoholic beers based on their sugar utilization. Particularly promising flavors were produced by three yeast strains of the species Cyberlindnera saturnus, which were reminiscent of cool mint sweets, pear, and banana. Two further yeasts of the species Kluyveromyces marxianus and Saccharomycopsis fibuligera also produced a wide range of pleasant fruity flavors. Although the secondary metabolites were mostly below the odor thresholds based on regular alcoholic beers, this study reveals that the thresholds in non-alcoholic beers can be classified as significantly lower. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2021.2012747 .","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"80 1","pages":"341 - 355"},"PeriodicalIF":2.0,"publicationDate":"2022-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46982645","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-04DOI: 10.1080/03610470.2021.2008221
Ting Sun, Xinjun Hu, Jianping Tian, Q. Gu, Dan Huang, Huibo Luo, Dan Huang
Abstract The moisture content and distribution of Daqu significantly influences the quality of Daqu products. This work presents the visualization of the moisture content in Daqu using a combination of spectral and spatial information from hyperspectral imaging. The least squares support vector machine (LS-SVM) and partial least squares regression (PLSR) methods were adopted to establish the predictive models based on the full wavelengths and the 29 feature wavelengths combined with color features, respectively. The best prediction model was PLSR ( , ) based on feature wavelengths. The results showed that the combination of spectral and spatial information of hyperspectral imaging can accurately predict the moisture content in Daqu during different fermentation processes, and the visualization of the distribution map of moisture content in Daqu provided a more convenient and understandable assessment of moisture content. This work presents a novel, rapid, and nondestructive approach for moisture content detection in Daqu, and provides theoretical support and basis for intelligent adjustment of temperature, humidity and other environmental parameters of Daqu fermentation.
{"title":"Combination of Spectral and Spatial Information of Hyperspectral Imaging for the Prediction of the Moisture Content and Visualizing Distribution in Daqu","authors":"Ting Sun, Xinjun Hu, Jianping Tian, Q. Gu, Dan Huang, Huibo Luo, Dan Huang","doi":"10.1080/03610470.2021.2008221","DOIUrl":"https://doi.org/10.1080/03610470.2021.2008221","url":null,"abstract":"Abstract The moisture content and distribution of Daqu significantly influences the quality of Daqu products. This work presents the visualization of the moisture content in Daqu using a combination of spectral and spatial information from hyperspectral imaging. The least squares support vector machine (LS-SVM) and partial least squares regression (PLSR) methods were adopted to establish the predictive models based on the full wavelengths and the 29 feature wavelengths combined with color features, respectively. The best prediction model was PLSR ( , ) based on feature wavelengths. The results showed that the combination of spectral and spatial information of hyperspectral imaging can accurately predict the moisture content in Daqu during different fermentation processes, and the visualization of the distribution map of moisture content in Daqu provided a more convenient and understandable assessment of moisture content. This work presents a novel, rapid, and nondestructive approach for moisture content detection in Daqu, and provides theoretical support and basis for intelligent adjustment of temperature, humidity and other environmental parameters of Daqu fermentation.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"181 - 189"},"PeriodicalIF":2.0,"publicationDate":"2022-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46724127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-04DOI: 10.1080/03610470.2021.2013645
Josephine L. Hinkley, Matthew T. Bingman, Joslynn S. Lee, Colin P. Bradley, C. Cole
Abstract The volatile organic compounds (VOCs) produced during cider fermentation, maturation, and dry hopping greatly impact enjoyment of the final product. To investigate the effect of apple variety on VOC development in cider, five apple varieties were picked from two orchards in southwest Colorado. Each apple variety was juiced, fermented with Lalvin QA23 Saccharomyces cerevisiae, dry-hopped with Citra hops, and analyzed separately alongside non-dry hopped controls. The aroma attributes of these historical southwest Colorado apples have never been explored, and few studies have chemically profiled the aromas of dry-hopped cider. A total of 73 VOCs were identified using headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) from fruit juice to cider. Ethyl esters, acetate esters, higher alcohols, and terpenes were the major aroma contributors observed in dry-hopped cider. The identity and concentrations of VOCs varied greatly between apple varieties, with only 24 common VOCs detected in all samples studied. This indicates the importance of apple variety choice in tuning the aroma profile of the finished cider. This method can be used to more effectively evaluate orchard or cider production treatments on cider quality. This case study also provides practical information for cider makers seeking to improve the quality of their products through consideration of fruit variety and dry hopping. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2021.2013645 .
{"title":"Volatile Profile Survey of Five Apple Varieties Grown in Southwest Colorado from Juice to Finished, Dry-Hopped Cider","authors":"Josephine L. Hinkley, Matthew T. Bingman, Joslynn S. Lee, Colin P. Bradley, C. Cole","doi":"10.1080/03610470.2021.2013645","DOIUrl":"https://doi.org/10.1080/03610470.2021.2013645","url":null,"abstract":"Abstract The volatile organic compounds (VOCs) produced during cider fermentation, maturation, and dry hopping greatly impact enjoyment of the final product. To investigate the effect of apple variety on VOC development in cider, five apple varieties were picked from two orchards in southwest Colorado. Each apple variety was juiced, fermented with Lalvin QA23 Saccharomyces cerevisiae, dry-hopped with Citra hops, and analyzed separately alongside non-dry hopped controls. The aroma attributes of these historical southwest Colorado apples have never been explored, and few studies have chemically profiled the aromas of dry-hopped cider. A total of 73 VOCs were identified using headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) from fruit juice to cider. Ethyl esters, acetate esters, higher alcohols, and terpenes were the major aroma contributors observed in dry-hopped cider. The identity and concentrations of VOCs varied greatly between apple varieties, with only 24 common VOCs detected in all samples studied. This indicates the importance of apple variety choice in tuning the aroma profile of the finished cider. This method can be used to more effectively evaluate orchard or cider production treatments on cider quality. This case study also provides practical information for cider makers seeking to improve the quality of their products through consideration of fruit variety and dry hopping. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2021.2013645 .","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"131 - 140"},"PeriodicalIF":2.0,"publicationDate":"2022-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41693996","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-16DOI: 10.1080/03610470.2021.1994814
C. Schubert, Sarah Thörner, L. Knoke, Nils Rettberg
Abstract Hop-derived esters contribute to beer flavor and changes in the ester spectrum are believed to be an important driver in the flavor–instability of hoppy beers. To date, there exists no published method that enables reliable quantification of hop-derived esters in beer. As the availability of such a method is vital to enlarge the understanding of beer flavor stability, the current article is concerned with the development, validation, and application of a headspace solid phase microextraction gas chromatography selected ion monitoring mass spectrometry (HS-SPME-GC-SIM-MS) based methodology for quantification of 16 hop-derived esters in beer. The validation data shows that choosing suitable HS-SPME-GC-SIM-MS conditions enabled reliable quantification of esters across a range of 1–200 µg/L, with calculated limits of quantification being well below 1 µg/L. Spiking experiments using terpenes and terpenoids evidenced method robustness, most importantly when two commercially available stable isotope labeled internal standards (d6-geranyl acetate and 13C-methyl octanoate) were used. Application to beer samples indicated that beers brewed with different qualities/quantities of hops and differing in freshness could be well differentiated by HS-SPME-GC-SIM-MS analysis of their ester profile. Supplemental data for this article is available online at at https://doi.org/10.1080/03610470.2021.1994814 .
{"title":"Development and Validation of a HS-SPME-GC-SIM-MS Multi-Method Targeting Hop-Derived Esters in Beer","authors":"C. Schubert, Sarah Thörner, L. Knoke, Nils Rettberg","doi":"10.1080/03610470.2021.1994814","DOIUrl":"https://doi.org/10.1080/03610470.2021.1994814","url":null,"abstract":"Abstract Hop-derived esters contribute to beer flavor and changes in the ester spectrum are believed to be an important driver in the flavor–instability of hoppy beers. To date, there exists no published method that enables reliable quantification of hop-derived esters in beer. As the availability of such a method is vital to enlarge the understanding of beer flavor stability, the current article is concerned with the development, validation, and application of a headspace solid phase microextraction gas chromatography selected ion monitoring mass spectrometry (HS-SPME-GC-SIM-MS) based methodology for quantification of 16 hop-derived esters in beer. The validation data shows that choosing suitable HS-SPME-GC-SIM-MS conditions enabled reliable quantification of esters across a range of 1–200 µg/L, with calculated limits of quantification being well below 1 µg/L. Spiking experiments using terpenes and terpenoids evidenced method robustness, most importantly when two commercially available stable isotope labeled internal standards (d6-geranyl acetate and 13C-methyl octanoate) were used. Application to beer samples indicated that beers brewed with different qualities/quantities of hops and differing in freshness could be well differentiated by HS-SPME-GC-SIM-MS analysis of their ester profile. Supplemental data for this article is available online at at https://doi.org/10.1080/03610470.2021.1994814 .","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"12 - 22"},"PeriodicalIF":2.0,"publicationDate":"2021-12-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49235472","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-13DOI: 10.1080/03610470.2021.2003669
Hebe Parr, I. Bolat, D. Cook
Abstract We report for the first time the application of HS-SPME-GC coupled with sulfur-specific pulsed flame photometric detection to sensitively analyze the volatile sulfur compounds (VSC’s) present in drum roasted malt and barley samples typically used in brewing. Twenty-five VSC’s were identified across a range of 9 roasted products produced from barley/malt. Thiophenes (n = 10) were a major class of heterocyclic sulfur compounds identified, along with thiazoles (n = 4), and thiofurans (n = 2). Quantitative (n = 18) and semi-quantitative (n = 6) data are reported for VSC’s across this product range. Principal Component Analysis (PCA) of data clearly identified (PC1) that heterocyclic sulfur compounds were formed in products processed at high temperatures (>170 °C) under dry conditions (roasted barley, chocolate and black malts). Whereas compounds such as methyl dithiolane and methyl propyl sulfide were associated primarily with lower temperature finished products (crystal, amber and cara malts). Pathways for the generation of observed VSC’s are considered alongside typical roasting conditions employed in the manufacture of these products. Concentrations of VSC’s identified will certainly contribute characteristic aromas to the roasted products themselves. The transfer of VSC’s from the grist into finished beer, and their sensory impact in a range of beer styles, remains to be determined. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2021.2003669 .
{"title":"Identification and Categorization of Volatile Sulfur Flavor Compounds in Roasted Malts and Barley","authors":"Hebe Parr, I. Bolat, D. Cook","doi":"10.1080/03610470.2021.2003669","DOIUrl":"https://doi.org/10.1080/03610470.2021.2003669","url":null,"abstract":"Abstract We report for the first time the application of HS-SPME-GC coupled with sulfur-specific pulsed flame photometric detection to sensitively analyze the volatile sulfur compounds (VSC’s) present in drum roasted malt and barley samples typically used in brewing. Twenty-five VSC’s were identified across a range of 9 roasted products produced from barley/malt. Thiophenes (n = 10) were a major class of heterocyclic sulfur compounds identified, along with thiazoles (n = 4), and thiofurans (n = 2). Quantitative (n = 18) and semi-quantitative (n = 6) data are reported for VSC’s across this product range. Principal Component Analysis (PCA) of data clearly identified (PC1) that heterocyclic sulfur compounds were formed in products processed at high temperatures (>170 °C) under dry conditions (roasted barley, chocolate and black malts). Whereas compounds such as methyl dithiolane and methyl propyl sulfide were associated primarily with lower temperature finished products (crystal, amber and cara malts). Pathways for the generation of observed VSC’s are considered alongside typical roasting conditions employed in the manufacture of these products. Concentrations of VSC’s identified will certainly contribute characteristic aromas to the roasted products themselves. The transfer of VSC’s from the grist into finished beer, and their sensory impact in a range of beer styles, remains to be determined. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2021.2003669 .","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"76 - 87"},"PeriodicalIF":2.0,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44514617","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-13DOI: 10.1080/03610470.2021.2006559
M. Shimokawa, Koji Suzuki, Y. Motoyama
Abstract In microbiological quality control of final beer products, 100–400 ml beer samples are traditionally filtered on a membrane filter, followed by a lengthy culturing process in/on a laboratory medium that usually requires 3–14 days. This study aims to detect beer spoilage lactic acid bacteria (LAB) in a culture-independent fashion, using a direct polymerase chain reaction (PCR) approach. In order to detect a trace level of spoilage LAB in beer products, pressure cycling technology was evaluated to determine if this technology could improve the direct recovery of DNA from membrane filters for PCR detection. In this study, a mixed cellulose ester filter was adopted to allow a larger volume of beer to be filtrated. As a result of the optimization of the DNA extraction process that minimizes the loss of DNA and the effect of PCR inhibitors, 100 (1–10) cells/300 ml beer were successfully detected for beer spoilage LAB. Furthermore, a challenge test using 3,000 ml beer showed that 100 cells of Levilactobacillus (Lactobacillus) brevis were detectable without the negative effects of beer-originated PCR inhibitors, indicating that a trace level of contamination, corresponding to 1 cell in 300 ml of beer products, is detectable. It was also shown that the test was completed in approximately 8 hours. Therefore, this newly developed method is considered to be useful for the culture-independent direct detection of an extremely low level of beer spoilage LAB without a traditional culturing process. Supplemental data for this article is available online at at.
{"title":"Development of Culture-Independent Detection Method for Beer Spoilage Lactic Acid Bacteria","authors":"M. Shimokawa, Koji Suzuki, Y. Motoyama","doi":"10.1080/03610470.2021.2006559","DOIUrl":"https://doi.org/10.1080/03610470.2021.2006559","url":null,"abstract":"Abstract In microbiological quality control of final beer products, 100–400 ml beer samples are traditionally filtered on a membrane filter, followed by a lengthy culturing process in/on a laboratory medium that usually requires 3–14 days. This study aims to detect beer spoilage lactic acid bacteria (LAB) in a culture-independent fashion, using a direct polymerase chain reaction (PCR) approach. In order to detect a trace level of spoilage LAB in beer products, pressure cycling technology was evaluated to determine if this technology could improve the direct recovery of DNA from membrane filters for PCR detection. In this study, a mixed cellulose ester filter was adopted to allow a larger volume of beer to be filtrated. As a result of the optimization of the DNA extraction process that minimizes the loss of DNA and the effect of PCR inhibitors, 100 (1–10) cells/300 ml beer were successfully detected for beer spoilage LAB. Furthermore, a challenge test using 3,000 ml beer showed that 100 cells of Levilactobacillus (Lactobacillus) brevis were detectable without the negative effects of beer-originated PCR inhibitors, indicating that a trace level of contamination, corresponding to 1 cell in 300 ml of beer products, is detectable. It was also shown that the test was completed in approximately 8 hours. Therefore, this newly developed method is considered to be useful for the culture-independent direct detection of an extremely low level of beer spoilage LAB without a traditional culturing process. Supplemental data for this article is available online at at.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"155 - 161"},"PeriodicalIF":2.0,"publicationDate":"2021-12-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49369500","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-07DOI: 10.1080/03610470.2021.2000328
G. Donadini, G. Spigno
Abstract This study presents a brief history of beer in Namibia and explores the Namibian beer market by investigating the sensory characteristics of the beers readily available on the off-premises segment of the drink market. Twenty-two beers were sampled, and their characteristics were quantified using Descriptive Analysis and trained assessors. The results showed that the beers under study included a small range of products in terms of beer styles, most of the beers brewed in or imported to Namibia being bottom-fermented blond lagers of low to moderate alcohol content. These beers were not typically complex and divided into samples brewed in accordance with the Reinheitsgebot standards and into samples brewed in accordance to brewing protocols not compliant with the Germany purity law. Although sameness seemed to be the keyword, subtle significant differences existed among these beers. Some samples, the most flavorsome overall, were perceived as being significantly more alcoholic, bodied, carbonated, bitter, astringent, malty, and richer in solvent-like and vinous impressions. Other samples were perceived as having a thinner mouthfeel and being richer in caramel-like and cooked vegetable notes. Other blond beers included lite beers and were identified as thinner, whereas alcohol-free beers were identified as watery, rich in wort and cooked vegetable-like notes, and low in bitterness and perceived levels of carbonation. IPA and Doppelbock stood out from the others due to maltiness, bitterness, fruitiness, and a full body. Nearly all the samples were free from faults, and this attested to the high-quality standards of Namibian beers. In terms of brewing styles, unfilled gaps in the market exist and offer untapped opportunities for brewers.
{"title":"Beer Brewing in Namibia and Sensory Profile of Beer on Sale in the Namibian Market","authors":"G. Donadini, G. Spigno","doi":"10.1080/03610470.2021.2000328","DOIUrl":"https://doi.org/10.1080/03610470.2021.2000328","url":null,"abstract":"Abstract This study presents a brief history of beer in Namibia and explores the Namibian beer market by investigating the sensory characteristics of the beers readily available on the off-premises segment of the drink market. Twenty-two beers were sampled, and their characteristics were quantified using Descriptive Analysis and trained assessors. The results showed that the beers under study included a small range of products in terms of beer styles, most of the beers brewed in or imported to Namibia being bottom-fermented blond lagers of low to moderate alcohol content. These beers were not typically complex and divided into samples brewed in accordance with the Reinheitsgebot standards and into samples brewed in accordance to brewing protocols not compliant with the Germany purity law. Although sameness seemed to be the keyword, subtle significant differences existed among these beers. Some samples, the most flavorsome overall, were perceived as being significantly more alcoholic, bodied, carbonated, bitter, astringent, malty, and richer in solvent-like and vinous impressions. Other samples were perceived as having a thinner mouthfeel and being richer in caramel-like and cooked vegetable notes. Other blond beers included lite beers and were identified as thinner, whereas alcohol-free beers were identified as watery, rich in wort and cooked vegetable-like notes, and low in bitterness and perceived levels of carbonation. IPA and Doppelbock stood out from the others due to maltiness, bitterness, fruitiness, and a full body. Nearly all the samples were free from faults, and this attested to the high-quality standards of Namibian beers. In terms of brewing styles, unfilled gaps in the market exist and offer untapped opportunities for brewers.","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"118 - 130"},"PeriodicalIF":2.0,"publicationDate":"2021-12-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47837204","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-12-01DOI: 10.1080/03610470.2021.1997280
C. Luan, Weihua Cao, Na Luo, Jingxia Tu, Jian-shu Hao, Y. Bao, Feike Hao, Deliang Wang, Xin Jiang
Abstract A novel beer-spoilage bacterium, Lactobacillus acetotolerans, has frequently been encountered in south China beer breweries, imparting an undesirable and unpalatable “buttery” taste and oily mouthfeel to beer. Understanding the genetic basis of spoilage bacterial adaptability to the beer microenvironment is crucial for the proper control of bacteria such as L. acetotolerans CN247 at an industrial scale. In this study, the complete genome of L. acetotolerans CN247 was sequenced using the PacBio and Illumina Miseq high-throughput sequencing technologies, and the relationship between genetic and physicochemical properties was analyzed. The genome size of L. acetotolerans CN247 was found to be 1.677 Mb, with a GC content of 37.55%. A total of 1,636 protein-coding genes were predicted, accounting for 88.96% of the genome. The average length of coding sequences was 912 bp. The L. acetotolerans CN247 strain was tolerant to high concentrations of acetic acid (6%) and showed varying degrees of preference for different beer components (i.e., sugars such as maltose, ribose, cellobiose, and mannitol). This strain also had a high tolerance for ethanol (14%) in the beer and was resistant to streptomycin, at a minimum inhibitory concentration of 256 μg/mL. Finally, genes associated with viable but non-culturable (VBNC) bacteria were found in the genome of L. acetotolerans CN247. This is the first study reporting the complete genome sequence of L. acetotolerans as a beer spoilage bacteria. These findings will contribute to the understanding of this bacterium’s life cycle and help in the improvement of industrial contamination prevention practices. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2021.1997280 .
{"title":"Genomic Insights into the Adaptability of the Spoilage Bacterium Lactobacillus acetotolerans CN247 to the Beer Microenvironment","authors":"C. Luan, Weihua Cao, Na Luo, Jingxia Tu, Jian-shu Hao, Y. Bao, Feike Hao, Deliang Wang, Xin Jiang","doi":"10.1080/03610470.2021.1997280","DOIUrl":"https://doi.org/10.1080/03610470.2021.1997280","url":null,"abstract":"Abstract A novel beer-spoilage bacterium, Lactobacillus acetotolerans, has frequently been encountered in south China beer breweries, imparting an undesirable and unpalatable “buttery” taste and oily mouthfeel to beer. Understanding the genetic basis of spoilage bacterial adaptability to the beer microenvironment is crucial for the proper control of bacteria such as L. acetotolerans CN247 at an industrial scale. In this study, the complete genome of L. acetotolerans CN247 was sequenced using the PacBio and Illumina Miseq high-throughput sequencing technologies, and the relationship between genetic and physicochemical properties was analyzed. The genome size of L. acetotolerans CN247 was found to be 1.677 Mb, with a GC content of 37.55%. A total of 1,636 protein-coding genes were predicted, accounting for 88.96% of the genome. The average length of coding sequences was 912 bp. The L. acetotolerans CN247 strain was tolerant to high concentrations of acetic acid (6%) and showed varying degrees of preference for different beer components (i.e., sugars such as maltose, ribose, cellobiose, and mannitol). This strain also had a high tolerance for ethanol (14%) in the beer and was resistant to streptomycin, at a minimum inhibitory concentration of 256 μg/mL. Finally, genes associated with viable but non-culturable (VBNC) bacteria were found in the genome of L. acetotolerans CN247. This is the first study reporting the complete genome sequence of L. acetotolerans as a beer spoilage bacteria. These findings will contribute to the understanding of this bacterium’s life cycle and help in the improvement of industrial contamination prevention practices. Supplemental data for this article is available online at https://doi.org/10.1080/03610470.2021.1997280 .","PeriodicalId":17225,"journal":{"name":"Journal of the American Society of Brewing Chemists","volume":"81 1","pages":"171 - 180"},"PeriodicalIF":2.0,"publicationDate":"2021-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41518191","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"农林科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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