| Soybean is a leguminous plant originating in China.It is loved by consumers all over the world because of its rich nutritional value and unique flavor.However,soybean also contains many anti-nutritional factors,such as phytic acid,lipid oxidase and trypsin inhibitors.The presence of these substances not only affects the absorption of soybean nutrients,but also affects the sensory quality of soybean products.Therefore,further improving the nutrition and taste of soybean products is an important issue in the processing of soybean products.In this study,soybean in Northeast China was used as raw material,and the traditional method of folk sprout bean processing was used to improve the nutrition of soybean by germination treatment.The dynamic changes of water absorption and germination,nutrient composition and anti-nutrient factors of soybean were studied to provide data support for the production of sprout soybean and its products with improved nutrition.The main research contents and results are as follows:1.Low field nuclear magnetic resonance(NMR)method was used to study soybean soaking germination.By changing the ratio of material to liquid and soaking temperature,the effects of soaking temperature on water absorption,germination rate and germination potential of soybean were compared.The distribution and migration of water during soaking and germination of soybean were detected by low field nuclear magnetic resonance,and the conditions needed for soybean germination and soaking were determined.The results showed that the optimum temperature for soaking and germination of soybean was 25 0C and the ratio of material to liquid was 1:2,soaking time is 6 h.2.The dynamic changes of main nutrients in germinated soybeans were determined.The trend was as follows:protein content of soybeans increased from 34.87%to 36.33%,36.72%and 37.32%at 20 ? 25?and 30 C during the 0-48 h germination process.The fat content of germinated soybean decreased by 4.54%(20 C),4.56%(25 C)and 3.73%(30 C).The fat content of germinated soybean decreased significantly from 0 to 32 h(p<0.05),but there was no significant change after 32 h(p>0.05).The reducing sugar of germinated soybean increased by 0.53%(20?),0.48%(25 C)and 0.37%(30 C).The dietary fiber content of germinated soybean increased significantly(p<0.05)by 2.99%(25 ?)and 4.05%(30 ?)at 25 ? and 30?.However,there was no significant change in dietary fiber content of germinated soybean at 20 ?(p>0.05).Moreover,under the same germination condition,the higher the temperature,the higher the dietary fiber content of germinated soybean.The higher the content,the higher the content of GABA in germinated soybean(p<0.05).3.The changes of anti nutritional factors during the germination of soybean were studied.The variation trend of anti-nutritional factors during germination was as follows:the content of trypsin inhibitors decreased during 0-48 h germination at 20 ?,25 ?and 30 ?.Trypsinase inhibitors decreased by 9.72%(20 ?),12.63%(25 ?)and 19.25%(30 0C),lipid oxidase content decreased by 21.9%(20 C),28.8%(25?),25.1%(30?),urease content decreased by 2.4%(20?),1.7%(25?)and 5.7%(30?),Phytic acid of soybean decreased by 3.3%(20?),5%(25?)and 5.5%(30?).4.Orthogonal experiment was designed according to the change trend of nutrition and anti-nutrition factors during soybean germination.The soybean germination technology was optimized by taking the quality,sensory,yield and water holding capacity of tofu as evaluation indexes.The optimum technological conditions for soybean germination were as follows:germination temperature was 25 ?,and germination time was 32 h.Under these conditions,compared with traditional tofu,the contents of phytic acid,trypsin inhibitor and urease in germinated soybean tofu were significantly lower than those in traditional tofu. |
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