Subcritical water treatment to modify insoluble dietary fibers from brewer’s spent grain for improved functionality and gut fermentability

• Published in: Food chemistry 2024-03, Vol.435, p.137654-137654, Article 137654
• Main Authors: Su, Xueqian, Jin, Qing, Xu, Yixiang, Wang, Hengjian, Huang, Haibo
• Format: Article
• Language: English
• Subjects: Brewer’s spent grain; Functional properties; In-vitro fermentation; Insoluble dietary fiber; Short-chain fatty acids; Subcritical water treatment
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2023.137654

•Hemicellulose in the IDF from BSG was significantly degraded after modification.•The modified IDF exhibited reduced particle sizes and more porous structures.•Improved functionalities were found in modified IDF samples.•The modified IDF showed slow in-vitro fermentation performance. Lactic acid (LA)-assisted subcritical water treatment (SWT) was applied to modify the insoluble dietary fiber (IDF) from brewer’s spent grain (BSG) for enhancing its functionality and gut fermentability. Modified IDFs were thoroughly characterized for their chemical and structural properties. The results revealed that increasing the treatment temperature and LA concentration reduced hemicellulose content in IDFs from 38.4 % to 0.7 %, alongside a decreased yield (84.8 %–51.4 %), reduced particle size (519.8–288.6 μm), and more porous structure of IDFs. These modifications were linked to improved functionalities, evidenced by the highest water and oil holding capacity increasing by 36 % and 67 %, respectively. Remarkably, the highest glucose adsorption capacity increased by 6.5 folds. Notably, modified IDFs exhibited slower in-vitro fermentation, elevated short-chain fatty acids (SCFAs) production, and a higher proportion of butyrate in SCFAs. These findings highlight the potential of LA-assisted SWT in transforming BSG-derived IDF into a valuable functional food ingredient.