Effects of prebiotics on the fermentation of traditional suancai of Northeast China

Suancai is a traditional fermented vegetable widely consumed in Northeast China.In this study,different prebiotics were used to improve the quality of suancai.Four prebiotics(inulin(INU),xylooligosaccharide(XO S),galactooligosaccharide(GOS),and stachyose(STA))were shown to reduce the pH value and increase the content of total titratable acidity(TTA)in suancai,while the contents of most organic acids were also increased.The addition of prebiotics had significant effects on the bacterial microbiota during the suancai fermentation process.All prebiotics were shown to contribute to the growth of Lactobacillus.The suancai sample with fructooligosaccharides(FOS)had the highest relative abundance of Lactobacillus.Besides,INU and XOS could increase the abundance of Weissella.To evaluate the quality of suancai fermented with prebiotics,profiles of volatile flavor compounds(VOCs)and free amino acids(FAA)were analyzed.The prebiotics affected the VOCs and FAA profiles via transforming the bacterial microbiota.In addition,the addition of prebiotics also changed the taste profiles of the suancai samples.This study is among the first attempts to reveal the effects of different prebiotics on suancai fermentation,and the findings provide a foundation to develop new ways for improving the quality of suancai.

Effects of salt and rice flour concentration on microbial diversity and the quality of sour meat,a Chinese traditional meat

This study investigated the effects of salt(3%and 6%,m/m)and rice flour(10%and 20%,m/m)addition in sour meat,a traditional Chinese fermented meat.It was found that salt has greater effect than rice flour addition in spontaneous fermentation.Low-salt groups had lower pH and higher titratable total acid.In the low-salt groups,the dominant genera were Lactobacillus and Lactococcus,whereas Staphylococcus,Weissella,and Tetragenococcus were dominant in the high-salt groups.Higher total free amino acids and essential amino acids,organic acids,hexanoic acid ethyl ester and octanoic acid ethyl ester were found in the low-salt groups.The RDA analysis revealed that Lactococcus was closely related to product quality,with the S3F10(3%salt and 10%rice f lour)group outperforming the others in the sensory evaluation.Therefore,3%salt and 10%rice flour were considered more appropriate for the production of healthy and tasty fermented sour meats.

Moderate papain addition improves the physicochemical,microbiological,flavor and sensorial properties of Chouguiyu,traditional Chinese fermented fish

The objective of this study was to investigate the effect of papain on the physicochemical and microbiological properties,volatile compound profiles,and sensorial attributes of Chouguiyu.Papain was applied at a dose of 10,50,200,400 U/g fish.Results showed that papain addition improved the release of free amino acids,essential amino acids,eicosapentaenoi acid(EPA,C20:5n3),and docosapentenoic acid(DPA,C22:5n6),respectively.Lower biogenic amines content,higher the volatile compound concentrations and relative abundance of Lactobacillales were also observed.Further results showed that the papain dose group decreased the fermentation time from 10 to 7 days while good organoleptic quality was remained,especially in the 200 U/g dose group.The redundancy analysis(RDA)showed a high correlation between Lactobacillus and the key volatile compounds in the 200 U/g and 400 U/g groups,which indicated that Lactobacillus could contribute to the fatty flavor.In summary,proper papain addition(i.e.200 U/g or 400 U/g)could reduce biogenic amines contents and maintain acceptable sensorial properties of Chouguiyu in a shorter fermentation time.