Cross-feeding between bifidobacteria and butyrate-producing colon bacteria explains bifdobacterial competitiveness, butyrate production, and gas production

Inulin-type fructans are not digested and reach the human colon intact, where they are selectively fermented by the colon microbiota, in particular bifidobacteria. As a result, they are converted, directly or indirectly, to short-chain fatty acids and other organic acids, as well as gases, and lead to both bifidogenic and butyrogenic health-promoting effects. Bifidobacteria display phenotypic variation on strain level as to their capacity to degrade inulin-type fructans. Also, different chain lengths of inulin-type fructans may stimulate different subgroups within the bifidobacterial population. The end-metabolites of inulin-type fructan degradation by bifidobacteria reflect their growth rates on these polymers. Other colon bacteria are also able to degrade inulin-type fructans, as is the case for lactobacilli, Bacteroides, certain enterobacteria, and butyrate producers. Bacterial cross-feeding mechanisms in the colon lay at the basis of overall butyrate production, a functional characteristic of several colon bacteria that is always accompanied by gas production. Finally, specificity of polysaccharide use by the colon microbiota may determine diet-induced alterations in the microbiota and consequent metabolic effects.     

菊粉研究的回顾与展望

菊粉作为一种天然功能性食品配料,已在欧美国家得到了广泛应用。近几年,中国的菊粉市场逐渐兴起。文中综述了菊粉的来源、理化性质和生理功能;介绍了菊粉在食品工业中的应用情况及其安全性评价;对比分析了菊粉在国内国外的生产加工情况;展望了菊粉的发展前景。     

The Metabolism of Fructooligosaccharides and Fructooligosaccharide-Related Compounds in Plants

Fructooligosaccharides are the most studied prebiotics. They are fructose oligomers linked to glucose and/or fructose molecules that contain up to ten sugar moieties. Fructooligosaccharides have both functional (physiologically beneficial to health) and technological properties. The aim of this article is to review published plant sources of different fructooligosaccharide types and production mechanisms, since the properties depend on the molecular structure. Fructooligosaccharide metabolizing enzymes, sources of specific fructooligosaccharide isomers and factors affecting their profiles reported in the plant species are also included.     

Effects of refrigeration,freezing and replacement of milk fat by inulin and whey protein concentrate on texture profile and sensory acceptance of synbiotic guava mousses

The effects of refrigeration, freezing and substitution of milk fat by inulin and whey protein concentrate (WPC) on the texture and sensory features of synbiotic guava mousses supplemented with the probiotic, Lactobacillus acidophilus La-5, and the prebiotic fibre oligofructose, were studied. The frozen storage (−18 ± 1 °C), followed by thawing at 4 °C before the analyses, and the complete replacement of the milk fat by inulin plus WPC, led to significant differences in the instrumental texture parameters of mousses (P < 0.05). Nonetheless, these changes did not affect the sensory acceptability of the products studied. The frozen storage may be employed to extend the shelf-life of synbiotic guava mousses. Additionally, to obtain a texture profile similar to the traditional product, the simultaneous addition of inulin and WPC is recommended only for the partial replacement of milk fat in refrigerated and frozen mousses, and the total proportion of both ingredients together should not exceed 2.6%.     

运动员肠道微生物组与营养干预研究进展

运动员日常管理的目标是优化比赛过程中的表现并提高训练期间的恢复效率。研究表明,运动员的肠道微生物组成与运动表现密切相关。本文综述运动员群体的肠道微生物组特征及其对运动表现的提升机制,包括肠道微生物促进乳酸代谢以及短链脂肪酸等肠道微生物代谢物在调节糖原储存和肠道屏障功能方面的重要性,总结目前以肠道微生物组为靶点,通过益生菌、益生元和促进肌肉合成的膳食补充剂等营养干预提高运动表现的研究进展。此外,提出未来通过调节肠道微生物组提高耐力和运动能力这一重要的研究方向和应用领域。     

低聚果糖对C57BL/6小鼠肥胖预防及其肠道菌群的调节作用

为探究低聚果糖（fructooligosaccharides,FOS）对C57BL/6小鼠肥胖预防及其肠道菌群的调节作用,将50只雄性5周龄C57BL/6小鼠随机分为5组,正常组食用正常饲料,其他组通过食用高脂饲料构建肥胖模型,正常组、模型组灌胃给予生理盐水,实验组灌胃给予高、低剂量的FOS,阳性对照组灌胃给予奥利司他,实验进行6周。采用高通量16S rRNA基因扩增测序、酶联免疫吸附测试等方法,分析FOS对C57BL/6小鼠的肥胖预防及肠道菌群的调节作用。结果表明,高、低剂量FOS都显著降低了肥胖模型小鼠的Lee’s指数、附睾脂肪指数（P<0.05）,并显著升高了肥胖模型小鼠血清高密度脂蛋白胆固醇（high density lipoprotein cholesterol,HDL-C）浓度（P<0.05）;高剂量FOS显著降低了肥胖模型小鼠的体质量增量及血清低密度脂蛋白胆固醇（low density lipoprotein cholesterol,LDL-C）、肿瘤坏死因子α(tumor necrosis factor α,TNF-α)、脂多糖（lipopolysaccha...     

食品中益生元的研发和应用研究进展

益生元的定义目前被更新为\"能被宿主微生物选择性利用并产生健康益处的底物\".根据最新的定义,益生元种类扩展到碳水化合物以外的物质,例如共轭亚油酸和植物多酚等;益生元作用部位不再局限于胃肠道,应用范围也不局限于食品.针对益生元具有缓解便秘、促进骨骼健康、缓解肥胖、抑制致病菌、减少炎症、免疫调节等多种健康促进效应,深入阐述了益生元促进宿主健康的作用机制.其机制主要体现为两个方面,一是益生元被宿主的有益微生物直接或间接性利用,从而起到菌群调节作用;二是益生元被菌群代谢后产生有益于宿主健康的代谢产物.此外,某些低聚糖类和多糖类的益生元还具有很好的加工特性,对于食品的质构特性和风味有积极的作用.因此,益生元在固体饮料、糖果、乳制品和烘焙制品等食品中广泛应用.然而,益生元的功效评价及应用中,仍存在一些问题亟待解决.不同生理状态下人体的肠道菌群是不同的,菌群结构的差异必然导致同种益生元在不同人群中利用情况的差异.益生元的单糖结构、聚合程度、分支以及官能团等结构差异会影响其被肠道微生物的利用.总之,针对不同人群的生理状态靶向应用益生元和对益生元进行特定结构的优化或修饰,将是未来益生元精准化应用的关键.     

天然产物多糖对胃肠道功能的影响

研究证明许多天然产物多糖具有良好的生物活性,可被用于多种疾病的辅助治疗。本文综述了多糖与胃肠道功能的相互作用,包括:多糖在胃肠道的消化行为及对胃肠动力的影响;多糖对胃黏膜的保护作用;多糖与肠道菌群的相互影响以及多糖与肠道黏膜免疫系统的相互作用。希望为多糖生物活性机制的深入研究提供参考。     

藤茶多酚对小鼠衰老过程中骨质代谢及肠道菌群的影响

肠道菌群对于宿主健康起着至关重要的作用,与衰老过程中骨质代谢紊乱息息相关。作者旨在研究以长寿特性而闻名的巴马藤茶对小鼠衰老进程中骨质代谢的影响,以评估藤茶多酚改善衰老小鼠肠道菌群结构的潜力。结果表明,藤茶多酚可以上调小鼠肝脏中的超氧化物歧化酶、谷胱甘肽和总抗氧化力水平,下调丙二醛水平。同时,藤茶多酚能够通过改善小鼠衰老过程中的骨质代谢,上调Osterix基因的表达,降低Acp5的表达,从而促进骨形成、减少骨吸收。此外,藤茶多酚可以调节衰老小鼠的肠道菌群组成,促进粪便中乙酸、丙酸和丁酸的产生。总之,藤茶多酚可以作为一种益生元,减少衰老过程中的骨质流失并调节肠道菌群,从而达到延缓衰老的目的。