67B-16 |
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K. Y. WONG, The Department of Biology, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong SAR, China and P. C. K. Cheung, Food and Nutritional Sciences Programme, The Chinese University of Hong Kong, Shatin, New Territories, HongKong, China. The physiological effect associated with the fermentation of dietary fiber (DF) by colonic bacteria is found to promote colonic health, mainly by producing beneficial Short Chain Fatty Acids (SCFAs) and stimulating the growth of particular types of colonic microflora. Mushroom sclerotia have a high DF content (over 80%) which can serve as a potential source of novel prebiotics. The objective of this study was to compare the in vitro fermentability of DF isolated from three mushroom sclerotia by using human fecal microflora in order to evaluate their potential as prebiotics. In this study, DF was prepared from three mushroom sclerotia, Pleurotus tuber-regium (PTR), Polyporous rhinoceros (PR) and Poria cocos (PC) according to AOAC enzymatic and gravimetric method. In vitro fermentability of the sclerotial DF were assessed using human fecal microflora and was compared with that of a commercial barley DF based on dry matter disappearance (DMD), organic matter disappearance (OMD), individual as well as total SCFAs (including acetate, propionate and butyrate), which were determined by gas chromatography. When compared with the barley DF, the in vitro fermentability of the three sclerotial DF varied in terms of SCFA profiles as well as SCFA molar ratios. However, except propionate, PC dietary fiber exhibited the highest (p < 0.05) values of DMD, OMD, total SCFAs, acetate and butyrate. Acetate, butyrate and total SCFA production by sclerotial DF (mmol/g substrate organic matter) were highly correlated to their OMD (r=0.96, r=0.99 & r=0.99, respectively; n=8). In conclusion, PC dietary fiber possessing the highest in vitro fermentability may be a potent prebiotic agent that promotes colonic health in humans. Further investigation on its proliferative effect on beneficial bacteria species, mainly Lactobacillus and Bifidobacteria is underway.
Session 67B, Food Chemistry: Antioxidants and bioactive agents
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