咖啡饮料是由阿拉伯半乳聚糖组成的膳食纤维的来源，阿拉伯半乳聚糖也可与蛋白质和酚类化合物结合，产生类黑素。对咖啡组分进行人结肠体外发酵，其中一种富含类黑素 (Mel)，另一种富含其亲本多糖阿拉伯半乳聚糖 (AG)，以评估微生物群产生的代谢物，即短链脂肪酸 (SCFA)，酚类化合物和胆汁酸。发酵 48 小时后，观察到 AG 碳水化合物部分（62%）的发酵能力高于 Mel（27%），导致 SCFA 含量分别为 63mM 和 22mM。补充 AG 和 Mel 组分可将乙酸：丙酸比例从 4.7（不存在咖啡组分时）分别降低至 2.5 和 3.5，表明对 HMG-CoA 还原酶（胆固醇合成的限速酶）有潜在的抑制作用。咖啡馏分的发酵产生二氢阿魏酸和二氢咖啡酸，已知它们具有抗氧化特性。在梅尔存在的情况下，观察到次级胆汁酸的产生减少（从 0.25 至 0.16 毫克/毫升），次级胆汁酸的高含量与多种疾病的发生有关，如结直肠癌、神经退行性疾病和心血管疾病。版权© 2024。由 Elsevier B.V. 出版

Coffee beverage is a source of dietary fiber composed by arabinogalactans, which can also be associated to proteins and phenolic compounds, originating melanoidins. Human colonic in vitro fermentations of coffee fractions, one rich in melanoidins (Mel) and the other in its parental polysaccharide arabinogalactans (AG), were performed in order to evaluate the metabolites produced by microbiota, namely short-chain fatty acids (SCFA), phenolic compounds, and bile acids. After 48 h of fermentation, a higher fermentability of the carbohydrate fraction of AG (62 %) than that of Mel (27 %) was observed, resulting in a SCFA content of 63 mM and 22 mM, respectively. Supplementation with AG and Mel fractions decreased the acetate:propionate ratio from 4.7 (in the absence of coffee fractions) to 2.5 and 3.5, respectively, suggesting a potential inhibition of HMG-CoA reductase, a rate-limiting enzyme for cholesterol synthesis. The fermentation of coffee fractions yielded dihydroferulic and dihydrocaffeic acids, known to have antioxidant properties. In the presence of Mel, it was observed a decrease (from 0.25 to 0.16 mg/mL) in the production of secondary bile acids, whose high content is associated to the development of several diseases, such as colorectal cancer, neurodegenerative and cardiovascular.Copyright © 2024. Published by Elsevier B.V.