生浆豆渣混菌发酵过程中的营养品质和功能特性变化规律

Changes in nutritional quality and functional characteristics of raw pulp okara during mixed fermentation

采用雅致放射毛霉联合运动发酵单胞菌对生浆豆渣进行发酵,研究0~72 h发酵过程中豆渣的营养品质和功能特性变化规律,并利用酶活力变化分析了原因。结果表明,豆渣的粗蛋白含量逐渐下降,蛋白分子质量逐渐降低。可溶性蛋白含量先升后降,在发酵60 h达到峰值11.01 mg/g[以牛血清白蛋白(bovine albumn,BSA)当量表示]。氨基酸态氮含量逐渐上升,在发酵72 h达到0.31 g/100g。粗脂肪含量在发酵0~48 h逐渐下降,然后维持在7%左右。不溶性膳食纤维逐渐向可溶性膳食纤维转化,均在发酵48 h后趋于稳定,此时含量分别为54.74%和7.07%。可溶性总糖和还原糖含量先降后升,在发酵72 h分别达到80.26 mg葡萄糖/g和7.55 mg葡萄糖/g。持水性、持油性均在发酵48 h时达到峰值,分别为10.36 g/g和6.04 g/g。水溶性和膨胀性逐渐上升,在发酵72 h时分别达到了21.36%和8.82 mL/g。酶活力测定发现,微生物可以在发酵过程中产生活力逐渐变强的蛋白酶、脂肪酶、纤维素酶,由此解释了生浆豆渣营养品质和功能特性的变化规律。该研究结果为生浆渣的微生物改性、工艺优化以及产品开发提供一定理论和技术支撑。

The changes in nutritional quality and functional properties of raw pulp okara were studied during 0-72 h fermentation by using Actinomucor elegans in combination with Zymomonas mobilis,which were analyzed according to the changes in enzyme activity.The results showed that crude protein content and protein molecular weight of okara declined gradually.Soluble protein content increased first and then decreased,reaching the peak of 11.01 mg BSA/g at 60 h.Amino acid nitrogen content increased gradually and reached 0.31 g/100g at 72 h.The crude fat content gradually decreased from 0 h to 48 h of fermentation,and then remained at about 7%.The insoluble dietary fiber was gradually converted to soluble dietary fiber,and both stabilized after fermentation for 48 h,when the contents were 54.74%and 7.07%,respectively.The soluble total sugars content and reducing sugars content showed a decrease and then an increase,reaching 80.26 mg glucose/g and 7.55 mg glucose/g,respectively,at 72 h.The water holding capacity and oil holding capacity reached their peaks at 48 h of fermentation with 10.36 g/g and 6.04 g/g,separately.Water solubility and swelling capacity improved gradually,reaching 21.36%and 8.82 mL/g at 72 h of fermentation,respectively.The determination of enzyme activity revealed that microorganisms can produce proteases,lipases,and cellulases with gradually growing activity during the fermentation process,explaining the changes in nutritional quality and functional characteristics of raw pulp okara.The results of this research provide some theoretical and technical support for the microbial modification,process optimization,and product development of raw pulp okara.