产乳化活性多糖乳酸菌的筛选及其发酵荞麦酸面团、面包的特性

Screening of Lactic Acid Bacteria Producing Emulsifying Active Exopolysaccharide and Properties of Its Fermented Buckwheat Sourdough and Bread

本研究从不同来源的原料中分离得到18株具有产胞外多糖(EPS)能力的乳酸菌,通过对比发酵液及乳酸菌荞麦酸面团的乳化活性,获得一株产EPS且乳化活性较高的乳酸菌,并应用于荞麦酸面团的制作。采用动态流变测定、激光共聚焦观察、质构分析等手段,研究其对荞麦酸面团面包烘焙学特性的影响。结果表明:优选产乳化性多糖的乳酸菌YC'-22经鉴定为发酵乳杆菌(Lactobacillus fermentum strain HBUAS54017),且同源性为100%,EPS产量为1.63g/L。通过添加乳酸菌荞麦酸面团,使面包面团的面筋网络结构得到强化。相比空白面包(CB),添加1.0%阿拉伯胶的荞麦面包(AGB)、荞麦酸面团面包(SDB)的比容分别增加了12.42%和14.08%,硬度分别降低了13.90%和22.87%;其中SDB面包整体可接受度最高,改善效果最明显。因此,产乳化性多糖的乳酸菌发酵的荞麦酸面团可以作为一种天然的面包功能配料。

In this study,18 strains of exopolysaccharides( EPS) producing lactic acid bacteria( LAB) were isolated from raw materials from different sources.By comparing the emulsifying activity of the fermentation broth and buckwheat sourdough fermented by LAB,a LAB with EPS and high emulsifying activity was obtained and used as starter in buckwheat sourdough fermentation.The effects of starter used on the baking characteristics of buckwheat sourdough bread were investigated using methods of means of rotational rheometer,laser confocal and texture analysis.The results revealed that EPS producing LAB YC'-22 strain with high emulsifying properties was identified as Lactobacillus fermentumstrain HBUAS54017 with a homology of 100%.The EPS yield of this strain was 1.63 g /L.The gluten network structure ofbread dough was strengthened after adding buckwheat sourdough fermented by LAB.Compared to control bread( CB),the specific volume of buckwheat bread added 1.0% arabic gum( AGB) and buckwheat sourdough bread( SDB) increased by 12.42% and 14.08%,respectively,while the hardness decreased by 13.90% and 22.87%,respectively.SDB bread had the highest overall acceptability and the most obvious improvement effect.Therefore,the buckwheat sourdough fermented by LAB strains with emulsifying EPS can be used as a natural bread functional ingredient.