降胆固醇双歧杆菌的研究进展

双歧杆菌是人体中最有益的益生菌,尤其是降胆固醇双歧杆菌对降低心脑血管疾病具有重要意义。所以综述了降胆固醇双歧杆菌的研究进展。重点探讨了如何有效筛选到降胆固醇双歧杆菌,如何获得耐氧的双歧杆菌,如何对双歧杆菌进行高密度发酵,以及双歧杆菌如何降胆固醇,以期能给从事这方面研究的学者有所启示。可以通过选择合适样品后利用选择性培养基进行培养并结合双歧杆菌形态学特征和降胆固醇试验筛选到降胆固醇双歧杆菌。对于筛选到的降胆固醇双歧杆菌可通过耐氧驯化、微胶囊化技术和双层包埋技术而获得耐氧双歧杆菌。而且,可通过培养基优化和发酵方式控制来获得高浓度的降胆固醇双歧杆菌。关于双歧杆菌的降胆固醇机制主要有共沉淀作用、吸附与结合作用和同化作用等。     

Effects of Potato Fiber and Potato‐Resistant Starch on Biomarkers of Colonic Health in Rats Fed Diets Containing Red Meat

Abstract: The effects of red meat consumption with and without fermentable carbohydrates on indices of large bowel health in rats were examined. Sprague‐Dawley rats were fed cellulose, potato fiber, or potato‐resistant starch diets containing 12% casein for 2 wk, then similar diets containing 25% cooked beef for 6 wk. After week 8, cecal and colonic microbiota composition, fermentation end‐products, colon structure, and colonocyte DNA damage were analyzed. Rats fed potato fiber had lower Bacteroides‐Prevotella‐Porphyromonas group compared to other diet groups. Colonic Bifidobacterium spp. and/or Lactobacillus spp. were higher in potato fiber and potato‐resistant starch diets than in the cellulose diet. Beneficial changes were observed in short‐chain fatty acid concentrations (acetic, butyric, and propionic acids) in rats fed potato fiber compared with rats fed cellulose. Phenol and p‐cresol concentrations were lower in the cecum and colon of rats fed potato fiber. An increase in goblet cells per crypt and longer crypts were found in the colon of rats fed potato fiber and potato‐resistant starch diets. Fermentable carbohydrates had no effect on colonic DNA damage. Dietary combinations of red meat with potato fiber or potato‐resistant starch have distinctive effects in the large bowel. Future studies are essential to examine the efficacy of different types of nondigestible carbohydrates in maintaining colonic health during long‐term consumption of high‐protein diets. Practical Application: Improved understanding of interactions between the food consumed and gut microbiota provides knowledge needed to make healthier food choices for large bowel health. The impact of red meat on large bowel health may be ameliorated by consuming with fermentable dietary fiber, a colonic energy source that produces less harmful by‐products than the microbial breakdown of colonic protein for energy. Developing functional red meat products with fermentable dietary fiber could be one way to promote a healthy and balanced macronutrient diet.     

新型糖源——低聚异麦芽糖

介绍了一种新型糖源低聚异麦芽糖。它具有低甜度、低热量、不蛀牙的特性。是人体肠道内双歧杆菌的增殖因子,能促进有益菌群在肠道中的繁殖。它是一种具有特殊功能的食品及食品配料。鉴于它的特殊功效,被广泛地应用于医药、保健、食品等领域。     

均匀设计法改良双歧杆菌大豆酸奶发酵工艺

采用变温发酵工艺提高利用乳酸菌系和双歧杆菌发酵大豆所制备的酸奶中的活菌数量。采用平行试验法确定大豆干粉和果葡糖浆的用量,利用计算机分析,考察程序变温和发酵时间对大豆酸奶活菌数的影响,并用均匀设计法,对发酵工艺进行优化,得到最佳工艺条件为大豆干粉5.3%,果葡糖浆4%,乳酸菌系(保加利亚乳杆菌∶嗜热链球菌=1∶1)接种量0.03%(以菌种干粉/总固形物计),双歧杆菌接种量0.15%(以菌种干粉/总固形物计),第1阶段发酵为温度42℃,发酵2.5 h,第2阶段为温度36℃,发酵3 h,终产品中活菌数达到6.5×106个/mL以上。     

双歧杆菌的检测与鉴定研究进展

总结和回顾了双歧杆菌的常规和分子生物学方面与鉴定方面的研究进展,重点介绍了分子生物学在双歧杆菌检测和鉴定方面的应用,如各种特异性核酸前体或探针直接检测技术、分子标记技术、PCR相关技术等。对各种技术的优缺点进行了比较,并展望了各种检测技术的发展前景。     

Enzymic Transformation of Isoflavone Phytoestrogens in Soymilk by β-Glucosidase-Producing Bifidobacteria

ABSTRACT: Five strains of bifidobacteria were screened for β-glucosidase activity using p-nitrophenyl-β-D-glucopyranoside as the substrate, and selected strains were used to ferment soymilk. Enumeration of viable bifidobacteria and quantification of isoflavones using HPLC were performed at 0, 12, 24, 36, and 48 h of incubation. Four strains produced β-glucosidase. B. pseudolongum and B. longum -a displayed the best growth in soymilk, with an increase of 1.3 log₁₀ CFU/mL after 12 h. B. animalis, B. longum -a, and B. pseudolongum caused hydrolysis of isoflavone malonyl-, acetyl- and β-glucosides to form aglycones, and transformed daidzein to equol in soymilk. Fermentation of soymilk with Bifidobacterium sp. resulted in a significant increase (p < 0.05) in the concentration of aglycones.     

双歧营养片

采用现代生物工程技术研制,具有国际先进水平的生物工程食品。富含双歧活性杆菌、乳酸活性杆菌、双歧因子,采用高科技特殊保护,使双歧杆菌隔氧和在酸作用下不易失活,并且携带、食用方便     

Growth-promoting factors for Bifidobacterium longum

The ability of various biological materials to promote growth of Bifidobacterium Iongum (ATCC 15708) was tested using Bacto B₁₂ assay medium (Difco Corp.). Supplements included yeast extract, beef extract, malt extract, α-lactalbumin, β-lactoglobulin, trypticase soy broth, phytone-peptone and unknown factors from Escherichia coli spent broth. Growth of B. longum 15708 was monitored by measuring turbidity and pH. Yeast extract, α-lactalbumin and β-lactoglobulin were the best growth promoters. Growth in the presence of E. coli spent broth was maximal; however, fresh enzymatically hydrolyzed E. coli broth was as effective. Beef extract and trypticase soy broth were effective to some extent. Malt extract and phytone-peptone did not significantly enhance growth. All materials lost growth promoting activity when their disulfide bonds were reduced-alkylated.     

添加双歧杆菌的干酪

双歧杆菌是对人体有益的微生物,干酪的环境有利于双歧杆菌的长期存活;着重介绍了将双歧杆菌加入到干酪方面的研究进展以及干酪中双歧杆菌的精确计数方法。     

乳清蛋白冷凝胶对双歧杆菌的保护

以CaCl_2和葡萄糖酸-δ-内酯(glucono-δ-lactone,GDL)作为凝胶剂,采用酸耐受性实验为评价指标,确定乳清蛋白冷凝胶工艺参数,并借助扫描电子显微镜观察凝胶结构,探讨采用盐和酸诱导乳清分离蛋白(whey protein isolate,WPI)所形成的包含双歧杆菌冷凝胶对双歧杆菌的保护作用。结果显示,0.30%的GDL诱导5%WPI和6%WPI形成的颗粒状冷凝胶,在pH1.5的酸环境下对双歧杆菌的保护性最好,作用120 min后菌落数下降2个数量级,菌体存活率分别达到1.7%和2.1%。制各出的乳清蛋白冷凝胶对双歧杆菌有良好的保护性,为益生菌产品的开发和扩展应用提供了参考。