发酵前后枣小分子糖分析及对细菌生长影响

Analysis of low-molecule-weight sugars before and after fermentation of jujube and their effect on bacterial growth

研究发酵前后乐陵小枣中小分子糖含量的变化及小分子糖对双歧杆菌和大肠杆菌生长的影响。以乐陵小枣为原料经水提醇沉、浓缩后一部分直接干燥处理得枣小分子糖(LMS),另一部分经酵母发酵后干燥得发酵枣小分子糖(FLMS)。LMS、FLMS分别经超滤和DEAE-52纤维素分离纯化,HPLC检测小分子糖含量变化。FLMS与LMS相比,葡萄糖和果糖混合物含量减少了2.98%,蔗糖含量减少了11.4%,蔗果三糖含量增加了24.6%。将FLMS、LMS按不同添加量添加到基础培养基,在最佳观测时间测定OD值,结果表明一定剂量的FLMS、LMS对双歧杆菌的生长有促进作用(P<0.05),对大肠杆菌的生长有抑制作用(P<0.05)。结论:发酵能够在降低枣中单糖和蔗糖的含量同时提高了功能性糖蔗果三糖的含量,剂量为0.1%的枣小分子糖对双歧杆菌有促进作用,对大肠杆菌有抑制作用。

The purpose of this work is to study the effect of fermentation on low-molecular-weight sugars in Laoling Zizyphus jujuba and influence of these sugars on the growth of bifidobacteria and E. coli. After water extraction, alcohol precipitation, and concentration, one part of samples were dried directly in order to get low-molecular-weight sugars（LMS）, while another part of samples were further fermented with yeast and then dried in order to get fermented low-molecular-weight sugars（FLMS）. LMS and FLMS were isolated and purified by ultrafiltration and DEAE-52 cellulose. HPLC was used to detect the changes of small sugar content. Compared with those in LMS, content of glucose and fructose decreased by 2.98%, sucrose decreased by 11.4%, while kestose increased by 24.6% in FLMS. Different amount of LMS and FLMS were added in the basic medium and OD value was measured at time suitable for observation. Our results show that a certain dose of FLMS and LMS have promoting effects on the growth of bifidobacterium（p〈0.05）, and have inhibitory effects on the growth of E. coli（p〈0.05）. Conclusion： Fermentation of jujube can reduce the content of monosaccharide and sucrose, while increase the content of kestose. 0.1% dosage of jujube low-molecule-weight sugars can stimulate the growth of bifidobacterium, while inhibit the growth of Escherichia coli.