| Brewed soy sauce,originated in China and is now spread all over the world,is an essential dietary condiment in daily life.In recent years,scholars have devoted themselves to the research of soy sauce,new categories of nutritious and healthy soy sauce have emerged,and the market demand has been expanding.Soy sauce is brewed with soybean and wheat bran as protein raw materials and starch raw materials after pretreatment,inoculation,koji making,fermentation and other processes.On the basis of replacing soybean with peony seed meal as protein raw material,this paper explores the koji making process and fermentation process of low salt solid fermented soy sauce of peony seed meal,and the antioxidant capacity of soy sauce was analyzed.The electronic nose and GC-MS technology were used to explore the fermentation process.The main experimental results are as follows:1 Optimization of koji making process of peony seed meal soy sauce.The indexes of proteinase enzyme activity and saccharifying enzyme activity were as follows,the optimal conditions for the koji production process of peony seed meal soy sauce are: the ratio of raw materials(wheat bran: peony seed meal)is 2: 8,and the amount of water is 100%.The material time is 30 min and the song making time is 46 h.Under these conditions,the protease activity in Chengqu was 1339.10 U / g;the saccharifying enzyme activity value was 63.19 U / g.2 The fermentation conditions were optimized by means of response surface.The best fermentation conditions under single factor experiment were as follows: fermentation time 20 d,salinity 11%,and fermentation temperature 45 °C,the total nitrogen and soluble non-salt solids content also reached the maximum values of 1.05 g / 100 ml and 15.83 g / 100 ml,At this time,the contents of total nitrogen and soluble non-salt solids also reached the maximum values of 1.05 g / 100 ml and 15.83 g / 100 ml.The contents of reducing sugar,Na Cl and total acid are all within the standard range.The Box-Behnken method optimized the fermentation process conditions for fermentation temperature of 45.5 ℃,fermentation time of 18 days,and salinity of 12%.Under this condition,the amino nitrogen content of raw soy sauce was 0.616 g / 100 ml,and the amino nitrogen content increased by 2.33%.3 GC-MS and electronic nose were used to analyze peony seed meal soy sauce with different fermentation time,two analytical methods of PCA and LDA were used for demonstration,and finally PLS(Partial Least Squares)was used to establish the electronic nose sensor data and the content of amino nitrogen Correlation.The results show that the main volatile aroma substances of soy sauce are alcohols,aldehydes,acids,esters,phenols,ketones and heterocycles,and the types of soy sauce with different fermentation time are different,and the volatile aroma compounds are different.PCA and LDA analysis can also distinguish peony seed meal soy sauce with different fermentation times;in PLS analysis,R20.979,electronic nose data and amino nitrogen content have a high correlation in identifying soy sauce with different fermentation times.4 To study the antioxidant activity of peony seed meal soy sauce.First,different sterilization processes were used to sterilize peony seed meal soy sauce,and then the antioxidant activity of low salt solid fermented soy sauce of penoy seed meal was analyzed by three methods: DPPH,ABTS free radical scavenging ability and iron ion reducing force.And the antioxidant ability was compared with the market soy sauce of two brands.The results show that: Peony seed meal soy sauce has good antioxidant capacity.The DPPH free radical scavenging ability,iron ion reducing power and ABTS free radical scavenging ability of the high-temperature and high-pressure sterilized peony seed meal soy sauce are higher than the commercially available S1 soy sauce.And the DPPH free radical scavenging ability of the high-temperature and high-pressure sterilized peony seed meal soy sauce is higher than that of the commercially available S2 soy sauce. |
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