| Yogurt has led the world's fermented dairy industry,not only because of its flavor,but also because it's an excellent carrier for bringing probiotics into the body.With the deepening of people's understanding of intestinal microecology and the gradual deepening of the concept of big health,how to improve the number of probiotics in yogurt,especially the number of probiotics to reach the gut has become a research hotspot.However,some probiotics(such as bifidobacterium breve used in this study)have poor resistance to gastric acid and bile salts,and embedding and protecting these probiotics into yogurt is one of the important ways to improve the probiotic function of yogurt.Therefore,the aim of this study was to develop a particle size smaller(less than1 mm)of low methoxyl pectin microcapsule,the microcapsule used for embedding bifidobacterium breve,and select the appropriate at a specific time point to add to the preparation of milk fermentation yogurt,improve bifidobacterium breve in yogurt stores and into the body at the same time,the number of living bacterium after minimizing microcapsule particle influence on yogurt quality(especially the taste),evaluation of adding bifidobacterium breve microcapsule yogurt on the mice immune enhancement effect,and pectin as prebiotics synergy.Firstly,low methoxy pectin was used as the embedding material to prepare bifidobacterium breve microcapsules by ion cross-linking method,and the embedding rate of microcapsules and the survival rate after simulated gastrointestinal digestion were measured in vitro.The results showed that the diameter of bifidobacterium breve microcapsules was 0.57±0.02 mm and the embedding rate was 99.9%.The survival rate of embedded and unembedded bifidobacterium breve microcapsules was 62.84% and32.47%,respectively.Secondly,the yogurt was prepared with commercially available starter,and the embedded or unembedded bifidobacterium breve was added to the yogurt as a probiotic supplement before or in the middle and late stage of fermentation.Based on the qualitative structure,electronic nose and electronic tongue detection system,the influence of the microcapsule on the yogurt quality was analyzed.The results showed that adding the microcapsule in the middle and late stage of fermentationhad little effect on the original quality and flavor of yogurt.Finally,in the middle and late stage of fermentation,bifidobacterium breve and pectin were added to prepare yogurt,and 72 KM mice,half male and half female,were gavaged.The experiment was divided into six groups,namely,group C was fed with normal diet and gavaged with normal saline(0.2 m L/d).Y group was fed with normal feed and received gastric yoghurt(0.2 m L/d.Group M was treated with normal feed,gavage drinking water and empty microcapsule(0.2 m L/d).The YM group was fed with normal diet,with gastric yoghurt and empty microcapsule(0.2 m L/d).YB group was fed with normal diet,gastric yoghurt and bifidobacterium breve liquid(0.2 m L/d).The YBM group was fed with normal diet,gastric yoghurt and bifidobacterium breve microcapsule(0.2 m L/d).Supplement the participants after 8 weeks,through the type of body weight,viscera index,fecal content of short chain fatty acids(acetic acid,propionic acid,butyric acid),serum immune factors in(SIg A,IFN-?,TNF-?,IL-1?,IL-10,IL-17A),liver tissue antioxidant capacity(MDA,SOD,T-AOC,GSH,GSH-Px),spleen lymphocytes CD11 c and the expression of CD80,small intestinal villus height and crypt depth and the intestinal micro ecology index functional evaluation.Results showed that feeding normal feed mice weight was 60.94±8.35 g in 8 weeks,significantly higher than the added pectin mice weight level 52.27±4.98 g(P<0.01),and also higher than adding bifidobacterium breve microcapsule weight 55.25±9.37 g mice(P<0.05),illustrate as prebiotics low methoxyl pectin,can not only provide protection for the bacteria,also with probiotics synergy in the body.Compared with mice fed normal diet,mice with microcapsules supplemented with bifidobacterium breve had higher content of short-chain fatty acids in feces,and the acetic acid content was 10.84 ?g/m L different.The concentrations of SIg A,IFN-?,IL-1? and IL-10 were significantly different in each group.Compared with mice fed normal diet,the concentrations of the above indexes were 4.47 ?g/m L,5.74 pg/m L,11.53 pg/m L and 38.49 pg/m L,respectively.Compared with mice fed normal diet,mice supplemented with bifidobacterium breve microcapsules showed lower MDA concentration(1.28 nmol/mgprot)and higher GSH concentration(51.58 ?mol/gprot),and lower CD11 c expression rate in spleen lymphocytes(3.66%).In the intestinal microbial community structure of the mice ineach group,the mice fed bifidobacterium breve microcapsule had a higher proportion of Odoribacter bacteria in the intestinal microbial community and a lower proportion of Akkermansia bacteria.The intake of prebiotic pectin and yogurt showed a strong synergistic effect,mainly reflected in the effect on the proliferation of bacteria.The microcapsules of bifidobacterium breve showed good stability in vitro and the number of viable bacteria was also significantly increased after the treatment of digestive fluids.Meanwhile,the microcapsules of bifidobacterium breve prepared with prebiotic low-methoxy-pectin as wall material also showed good compatibility with yogurt,which had little effect on the quality of yogurt.Microencapsulation can not only protect the bacteria and effectively play a probiotic role in the intestinal tract,but also promote the improvement of the intestinal microecological balance of the host,enhance the immune tolerance,enhance the antioxidant capacity and intestinal barrier function of the body.Will probiotics microcapsule added to yogurt,not only improve the application value of yogurt as probiotics carrier,also expand the application range of pectin,make its protective carrier with probiotics and prebiotics double function,which will strengthen the intestinal micro ecology and probiotics yogurt organic combination,and further enrich the concepts of health research. |
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