产胞外多糖植物乳杆菌XN1904E发酵乳特性研究

为了研究植物乳杆菌XN1904E对乳的发酵特性,分别对复配组(直投式发酵剂和植物乳杆菌XN1904E复配)、发酵剂组(直投式发酵剂单独发酵)、XN1904E组(植物乳杆菌XN1904E单独发酵)的发酵乳发酵过程中的pH、滴定酸、黏度发酵特性进行测定;并且测定了发酵前后的风味成分和糖含量。结果表明:植物乳杆菌XN1904E单独发酵产酸慢,复配组与发酵剂组的酸度变化趋势接近;复配组黏度比发酵剂组黏度高3240.5 mPa·s,复配组发酵乳的多糖含量比发酵剂组发酵乳的多糖含量高128.746μg/mL,说明乳杆菌XN1904E产生的胞外多糖能改善发酵乳的黏稠度。在风味方面,复合组发酵乳的风味物质总共有35种,比发酵剂组和XN1904E组的风味物质种类分别多6种和4种;加入菌株XN1904E能显著改善乳的风味,与未加入菌株XN1904E相比,醛类物质相对含量减少了15.793%,酮类和醇类的相对含量分别增加了5.795%、6.119%。

Characteristics of Milk Fermented by Exopolysaccharide-Producing Lactobacillus Plantarum XN1904E

In order to study the fermentation characteristics of L.plantarum XN1904E on milk,fermented milk fermentation was carried out on the compounding group(direct injection of fermenting agent and L.plantarum XN1904E),the starter group,and the XN1904E group(L.plantarum XN1904E alone).The pH,titration acid,and viscosity fermentation characteristics in the process were measured;and the flavor component and sugar content before and after the fermentation were measured.The results showed that the titration acid and pH of fermented milk had little difference compared with the non-fermented group.L.plantarum XN1904E had little effect on the acidity of fermented milk;the viscosity of the compounding group was higher than that of the fermenting agent group 3240.5 MPa·s,the polysaccharide content of fermented milk in the compounding group was 128.746μg/mL higher than that in the fermented milk of the starter group,indicating that the extracellular polysaccharide produced by L.plantarum XN1904E can improve the viscosity of fermented milk.In terms of flavor,there are 35 kinds of flavor substances in the fermented milk of the composite group,which are 6 kinds and 4 kinds more than the flavor substances in the starter group and the XN1904E group.The addition of the strain XN1904E can significantly improve the flavor of the milk,and the strain XN1904E is not added.In comparison,the relative content of aldehydes decreased by 15.793%,and the relative contents of ketones and alcohols increased by 5.795%and 6.119%,respectively.