Yong Xie,Qingqing Liu,Haibo Liu,Zhiping Fan,Jia Shi,Xiong Liu
The favorable prebiotic effect of cereal β-glucans is associated with its structure characteristic, which may be influenced by thermal processing. This study aimed to evaluate the structure and in vitro fermentation characteristics of β-glucan isolated from hulless barley preprocessed with flaking-roasting (FR), stir-frying (SF), steam-flash explosion (SFE) and popping expansion (PE). The results showed that all thermal processing had no impact on the type of chemical groups. Compared with the native β-glucan, the molecular weight of PE-β-glucan increased from 147.36 × 10 3 Da to 5, 243.60 × 10 3 Da, whereas its crystallinity index decreasing from 52.9 ± 0.7% to 41.5 ± 1.1%. Furthermore, the PE-β-glucan exhibited a porous structure like that in native β-glucan, while the SFE-β-glucan displayed a compacted structure with the lowest molecular weight (89.90 × 10 3 Da). Expectedly, PE-β-glucan exerted the highest availability and increased the relative abundance of Bifidobacterium , while FR-, SF-, and SFE-β-glucan tended to promote the growth of Megasphaera and Lactobacillus . Additionally, the level of total SCFAs, acetate, propionate , and butyrate in PE-β-glucan were dramatically higher than those in other β-glucan. Overall, the chain conformation of β-glucan played a pivotal role in determining its bioavailability and probiotic characteristic, which could be improved evidently by PE processing.
Plant polysaccharides possess many health-promoting properties, which are closely related to the digestion, absorption and utilization of polysaccharides in the host. The characteristic changes in Chinese yam polysaccharide (CYP) during simulated gastrointestinal digestion and faecal fermentation, as well as the intestinal anti-inflammatory effects of CYP and fermented CYP, were studied. The molecular weight of CYP remained unchanged during gastrointestinal digestion. After 24 h of faecal fermentation, free glucose and mannose released from CYP were utilized by gut microbiota, and the production of short-chain fatty acids increased. Simultaneously, CYP improved the growth of Bifidobacterium and Megasphaera. Compared with CYP, faecal fermented CYP exhibited greater suppression of anti-inflammatory mediators and increased intestinal tight junction expression in LPS-stimulated coculture Caco-2/Raw264.7 cells. The obtained results reveal that the role of CYP in promoting gut health is closely related to the interactions between CYP and gut microbes, and CYP has potential as an anti-inflammatory adjuvant in enteritis therapy.
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