产单宁酶乳酸菌发酵红豆、扁豆酸面团的生化特性及其对馒头体外消化的影响

本研究利用一株本课题组前期从自然发酵的豆粉中筛选出的高产单宁酶的发酵乳杆菌D23,来分别发酵红豆、扁豆两种豆类酸面团并制作成馒头,通过测定酸面团发酵前后缩合单宁等抗营养因子含量、多肽分子量分布、游离总酚、游离氨基酸含量,以及馒头淀粉、蛋白质体外消化率,对酸面团的生化特性及馒头的体外消化进行了对比研究。结果表明:通过菌株D23的发酵作用,两种豆类酸面团中缩合单宁含量显著下降(P<0.05),在红豆、扁豆酸面团中分别降低了57.87%、53.54%;大分子量肽含量降低,小分子肽含量升高;游离总酚含量分别升高了75.74%、65.94%;必需氨基酸含量增加了429.31%、358.20%;同时相比普通馒头,酸面团馒头最终消化液中的还原糖含量分别增加了3.27%、5.55%,淀粉的体外消化率得到了提升;蛋白质的最终体外消化率也分别由67.68%、70.21%增加为73.21%、76.97%。因此,该株具有高单宁酶活力的发酵乳杆菌D23可以通过酸面团的发酵作用有效降低豆类基质中缩合单宁等抗营养因子带来的不利影响,并增强最终馒头产品的营养价值,在发酵豆类制品中拥有良好的应用潜力。

Biochemical Characteristics of Tannase-Producing LAB Fermented Red Beans and Lentils Sourdough and Its Effects on in Vitro Digestibility of Steamed Bread

In this study,a strain of Lactobacillus fermentum D23 with high yield of tannase,which was selected from the naturally fermented legume flour in the previous research of this group,was used to make red beans and lentils sourdough and steamed bread. By determining the content of anti-nutritional factors such as condensed tannin,peptide molecular weight distribution,content of free total phenols and free amino acids before and after sourdough fermentation,and the in vitro digestibility of starch and protein in steamed bread,the biochemical characteristics of sourdough and in vitro digestibility of steamed bread were studied to make a comparative research. The results showed that through the fermentation of D23,the content of condensed tannin in these two kinds of legume sourdough decreased significantly(P<0.05),by 57.87% and 53.54% in red beans and lentils sourdough,respectively. The content of large molecular weight peptides decreased,and the content of small molecular peptides increased.The content of free total phenols increased by 75.74% and 65.94%,respectively. The essential amino acid content increased by 429.31% and 358.20%,respectively. The content of reducing sugar in the final digestive juice of sourdough steamed bread increased by 3.27% and 5.55%,respectively.Compared with the unfermented group,the in vitro digestibility of starch was improved,and the final in vitro digestibility of protein also increased from 67.68%,70.21% to 73.21%,76.97% respectively. Therefore,the strain D23 with high tannase activity can effectively reduce the adverse effects of anti-nutritional factors such as condensed tannins in legume matrix,and enhance the nutritional value of final steamed bread products through the process of sourdough fermentation,which gives the strain a good application potential in fermented legume products.