Abstract：
BACKGROUND: Wheat bran is rich in dietary fiber (DF), particularly insoluble dietary fiber (IDF). Although the benefits for human health following the consumption of these DFs have been documented, the lower water retention capacity (WRC) and other properties still limit the applications of DF. Therefore, the current research investigated the impact of acetylation on the changes in the corresponding physicochemical and functional properties of DF.
RESULTS: The current results indicated the acetylated group restricted the alignment of the molecular chains, which led to an increased amorphous phase in the fiber structure, followed by an enhanced thermal sensitivity and a reduced crystallinity as evidenced by X-ray diffraction (XRD). Moreover, the acetylation of the IDFs enhanced the cholesterol absorption capacity, but the corresponding antioxidant capacity and cation exchange capacity were reduced, which might be due to the partial loss of the phenolic compounds onto the polysaccharides during the modification. Interestingly, a lower degree of substitution (DS) of the IDF achieved from water-acetic anhydride modification led to a higher WRC and water swelling capacity (WSC). In contrast, a higher DS from acetic anhydride modification demonstrated a greatly improved in vitro hypoglycemic performance of the IDF, including α-amylase inhibitory activity and glucose dialysis retardation index (GDRI), compared to the other samples.
CONCLUSIONS: This study highlights a new approach to modify the functionality of IDFs via acetylation and the design of a novel IDF with hypoglycemic activity. © 2023 Society of Chemical Industry.
RESULTS: The current results indicated the acetylated group restricted the alignment of the molecular chains, which led to an increased amorphous phase in the fiber structure, followed by an enhanced thermal sensitivity and a reduced crystallinity as evidenced by X-ray diffraction (XRD). Moreover, the acetylation of the IDFs enhanced the cholesterol absorption capacity, but the corresponding antioxidant capacity and cation exchange capacity were reduced, which might be due to the partial loss of the phenolic compounds onto the polysaccharides during the modification. Interestingly, a lower degree of substitution (DS) of the IDF achieved from water-acetic anhydride modification led to a higher WRC and water swelling capacity (WSC). In contrast, a higher DS from acetic anhydride modification demonstrated a greatly improved in vitro hypoglycemic performance of the IDF, including α-amylase inhibitory activity and glucose dialysis retardation index (GDRI), compared to the other samples.
CONCLUSIONS: This study highlights a new approach to modify the functionality of IDFs via acetylation and the design of a novel IDF with hypoglycemic activity. © 2023 Society of Chemical Industry.
摘要：
背景：麦麸富含膳食纤维（DF），特别是不溶性膳食纤维(IDF)。尽管已经记录了食用这些DFs后对人类健康的益处，较低的保水能力（WRC）和其他性能仍然限制了DF的应用。因此,目前的研究调查了乙酰化对DF相应的物理化学和功能性质变化的影响。
结果：当前结果表明乙酰化基团限制了分子链的排列，这导致纤维结构中非晶相增加，随后是增强的热敏感性和降低的结晶度,如通过X射线衍射(XRD)所证明的。此外，IDF的乙酰化增强了胆固醇的吸收能力，但相应的抗氧化能力和阳离子交换能力降低，这可能是由于在改性过程中酚类化合物在多糖上的部分损失。有趣的是,由水-乙酸酐改性获得的IDF的较低取代度(DS)导致较高的WRC和水溶胀能力(WSC)。相比之下,来自乙酸酐修饰的较高DS表明IDF的体外降血糖性能大大提高，包括α-淀粉酶抑制活性和葡萄糖透析阻滞指数（GDRI），与其他样品相比。
结论：本研究强调了一种通过乙酰化修饰IDF功能的新方法，以及一种具有降血糖活性的新型IDF的设计。©2023化学工业学会。
结果：当前结果表明乙酰化基团限制了分子链的排列，这导致纤维结构中非晶相增加，随后是增强的热敏感性和降低的结晶度,如通过X射线衍射(XRD)所证明的。此外，IDF的乙酰化增强了胆固醇的吸收能力，但相应的抗氧化能力和阳离子交换能力降低，这可能是由于在改性过程中酚类化合物在多糖上的部分损失。有趣的是,由水-乙酸酐改性获得的IDF的较低取代度(DS)导致较高的WRC和水溶胀能力(WSC)。相比之下,来自乙酸酐修饰的较高DS表明IDF的体外降血糖性能大大提高，包括α-淀粉酶抑制活性和葡萄糖透析阻滞指数（GDRI），与其他样品相比。
结论：本研究强调了一种通过乙酰化修饰IDF功能的新方法，以及一种具有降血糖活性的新型IDF的设计。©2023化学工业学会。
