A Comparative Study on Physiological Activities of Lager and Ale Brewing Yeasts under Different Gravity Conditions

Zhimin Yu,Mou-Ming Zhao,Huiping Li,Hai-Feng Zhao,Qingli Zhang,Chunyan Wan,Huipin Li 한국생물공학회 2012 Biotechnology and Bioprocess Engineering Vol.17 No.4

High gravity (HG) or very high gravity (VHG)brewing has become popular in modern breweries due to its economic and product quality advantages. However,there are the negative impacts such as the fermentation performance of brewer’s yeast in HG or VHG wort, which are closely related to changes in cell physiological activity. In the present study, 3 kinds of worts, with different gravities, were used to examine the systematic effects on fermentation performance and physiological activity of lager yeast FBY009505 (Saccharomyces pastorianus) and ale yeast FBY0099 (Saccharomyces cerevisiae), as well as the resulting beer flavor. Results showed that the responses of FBY009505 and FBY0099 to the HG or VHG worts were similar. The specific fermentation rate and viability of cropped yeast of FBY009505 and FBY0099 were decreased with increasing wort gravity. The increased wort gravity resulted in the increase of energy charge and the decrease of α-glucosides transport rate and glycolytic enzyme activities. Moreover, the environmental stresses in the HG or VHG wort showed a higher inhibitory activity against α-glucoside transport than glycolytic enzymes. The content of intracellular trehalose and glycerol of FBY009505 and FBY0099 increased with the increase in wort gravity. The results from this study provided a potential means to systematically understand the physiology of brewer’s yeast under HG or VHG conditions. High gravity (HG) or very high gravity (VHG)brewing has become popular in modern breweries due to its economic and product quality advantages. However,there are the negative impacts such as the fermentation performance of brewer’s yeast in HG or VHG wort, which are closely related to changes in cell physiological activity. In the present study, 3 kinds of worts, with different gravities, were used to examine the systematic effects on fermentation performance and physiological activity of lager yeast FBY009505 (Saccharomyces pastorianus) and ale yeast FBY0099 (Saccharomyces cerevisiae), as well as the resulting beer flavor. Results showed that the responses of FBY009505 and FBY0099 to the HG or VHG worts were similar. The specific fermentation rate and viability of cropped yeast of FBY009505 and FBY0099 were decreased with increasing wort gravity. The increased wort gravity resulted in the increase of energy charge and the decrease of α-glucosides transport rate and glycolytic enzyme activities. Moreover, the environmental stresses in the HG or VHG wort showed a higher inhibitory activity against α-glucoside transport than glycolytic enzymes. The content of intracellular trehalose and glycerol of FBY009505 and FBY0099 increased with the increase in wort gravity. The results from this study provided a potential means to systematically understand the physiology of brewer’s yeast under HG or VHG conditions.

Changes in Volatile Aroma Compounds of Traditional Chinese-type Soy Sauce During Moromi Fermentation and Heat Treatment

Xian-Li Gao,Chun Cui,Hai-Feng Zhao,Mou-Ming Zhao,Lan Yang,Jiao-Yan Ren 한국식품과학회 2010 Food Science and Biotechnology Vol.19 No.4

Considering the important influence of longtime (150 day) moromi fermentation and heat treatment on the aroma formation of traditional Chinese-type soy sauce (TCSS), volatile compounds in samples taken from different stages of moromi fermentation and heat treatment were analyzed by solid phase microextraction coupled with gas chromatography-mass spectrometry. Results showed that a total of 76 volatile compounds were identified in all the samples, and most of the volatile compounds were common. During 150 day of moromi fermentation, relative contents of acids, alcohols, aldehydes and ketones, esters,and furan(one)s along with all the sensory attributes of acidic, alcoholic, fruity, caramel-like, smoky, and malty changed greatly. Notably, relative contents of alcohols,aldehydes and ketones along with the sensory intensities of alcoholic, caramel-like, and smoky of heated sample (80℃/60 min) decreased markedly, whereas there were slight increases in relative contents of furan(one)s, phenols,and sulfur-containing compounds of it. Long-time moromi fermentation and heat treatment have significant influence on the formation and relative contents of volatile compounds in TCSS, whereas changes in volatile compounds and their relative contents of the samples were responsible for the differences in sensory attributes.

Comparative Study on Volatile Flavor Compounds of Traditional Chinese-type Soy Sauces Prepared with Soybean and Defatted Soy Meal

Xian-Li Gao,Hai-Feng Zhao,Mou-Ming Zhao,Chun Cui,Jiao-Yan Ren 한국식품과학회 2009 Food Science and Biotechnology Vol.18 No.6

Volatile extracts obtained from traditional Chinese-type soy sauces prepared with soybean (SSSB) and defatted soy meal (SSDSM) by solid phase microextraction (SPME) and direct solvent extraction (DSE) were analyzed by gas chromatography-mass spectrometry (GC-MS). The volatile flavor compounds and relative contents of different chemical classes detected in SSSB and SSDSM were compared for their differences. Results showed that significant differences in both constituents of volatile flavor compounds and relative contents of different chemical classes were observed for both kinds of soy sauces. A total of 152 and 131 compounds were identified in SSSB and SSDSM, respectively, and 102 volatile flavor compounds were common in both kinds of soy sauces. Moreover, relative contents of acids, aldehydes, esters, furan(one)s, miscellaneous compounds, phenols, pyrazines, pyrrol(idinon)es, and sulfur-containing compounds in both kinds of soy sauces were all significantly different.

Gut Microbiota Community and Its Assembly Associated with Age and Diet in Chinese Centenarians

( Fang Wang ),( Ting Yu ),( Guo Hong Huang ),( Da Cai ),( Xiaolin Liang ),( Hai Yan Su ),( Zhenjun Zhu ),( Danlei Li ),( Yang Yang ),( Pei Hong Shen ),( Rui Feng Mao ),( Lian Yu ),( Mou Ming Zhao ),( 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.8

Increasing evidence suggests that gut microbiota underpin the development of health and longevity. However, our understanding of what influences the composition of this community of the longevous has not been adequately described. Therefore, illumina sequencing analysis was performed on the gut microbiota of centenarians (aged 100-108 years; RC) and younger elderlies (aged 85-99 years; RE) living in Bama County, Guangxi, China and the elderlies (aged 80-92 years; CE) living in Nanning City, Guangxi, China. In addition, their diet was monitored using a semiquantitative dietary questionary (FFQ 23). The results revealed the abundance of Roseburia and Escherichia was significantly greater, whereas that of Lactobacillus, Faecalibacterium, Parabacteroides, Butyricimonas, Coprococcus, Megamonas, Mitsuokella, Sutterella, and Akkermansia was significantly less in centenarians at the genus level. Both clustering analysis and UniFraq distance analysis showed structural segregation with age and diet among the three populations. Using partial least square discriminate analysis and redundancy analysis, we identified 33 and 34 operational taxonomic units (OTUs) as key OTUs that were significantly associated with age and diet, respectively. Age-related OTUs were characterized as Ruminococcaceae, Clostridiaceae, and Lachnospiraceae, and the former two were increased in the centenarians; diet-related OTUs were classified as Bacteroidales, Lachnospiraceae, and Ruminococcaceae. The former two were deceased, whereas the later one was increased, in the high-fiber diet. The age and high-fiber diet were concomitant with changes in the gut microbiota of centenarians, suggesting that age and high-fiber diet can establish a new structurally balanced architecture of gut microbiota that may benefit the health of centenarians.