Different oil-modified cross-linked starches: In vitro digestibility and its relationship with their structural and rheological characteristics

• Published in: Food chemistry 2023-08, Vol.418, p.135991-135991, Article 135991
• Main Authors: Zhao, Xiaoyun, Li, Xuxu, Guo, Ruotong, Wang, Xiaofen, Zeng, Lingjun, Wen, Xing, Huang, Qilin
• Format: Article
• Language: English
• Subjects: Amylopectin - chemistry; Amylose - chemistry; Hydrolysis; In vitro digestibility; Molecular Structure; Oil-modified cross-linked starch; Oils - chemistry; Rheological behavior; Starch - chemistry; Structure
• ISSN: 0308-8146; 1873-7072
• DOI: 10.1016/j.foodchem.2023.135991

[Display omitted] •Gelatinized oil-starch granules agglomerated into big lumps with oil on the surface.•Partial long B chains were degraded into short A chains after oil modification.•Oil-starch gels had higher apparent viscosity and G′ values than their counterparts.•Oil-starch had a lower digestion rate and higher RS content than their counterparts.•Oil as barrier on starch surface was the most critical contributor to low digestibility. This study investigated the structure, rheological behaviors and in vitro digestibility of oil-modified cross-linked starches (Oil-CTS). Gelatinized Oil-CTS were hard to be digested due to its intact granule shapes and the presence of surface-oil, which acted as physical barriers that inhibited the diffusion and penetration of enzymes to starch. Besides, the less amylose content in Oil-CTS (23.19–26.96%) than other starches (26.84–29.20%) contributed to its low digestibility because amylose with less α-1,6 linkages was more easily attacked by amyloglucosidase than amylopectin. Moreover, heat treatment during oil could shorten the amylopectin chain length and destroy the ordered structures, thus increasing enzymatic hydrolysis on starch. Pearson correlation analysis indicated rheological parameters were not significantly correlated with digestion parameters (p > 0.05). Overall, despite the damage caused by heat to molecular structures, physical barrier effect caused by surface-oil layers and integrity of swollen granules was the most critical contributor to the low digestibility of Oil-CTS.