Impact of starch-lipid complexes on oil absorption of starch and its mechanism.

BACKGROUND: Worldwide, fried food has a huge demand and good development prospects. Low oil in foods is the standard that everyone is now pursuing for a healthy diet. RESULTS: The oil absorption behavior of rice starch during frying was investigated in the presence or absence of fatty acids or fatty acid esters with different carbon chain lengths. The complex formed between starch and fatty acids or fatty acid esters was dependent on lipid chain length, which was confirmed by X-ray diffraction and complexing index. The formation of starch-lipid complexes could significantly reduce the oil absorption of starch, and the complexes with higher complexing index had lower oil absorption. The starch-palmitic acid complex showed the lowest oil absorption after frying, which was 14.06 g per 100 g lower than that of gelatinized starch. This was attributed to the ability of the palmitic acid to increase the density of starch crystalline polymorphs as well as their ability to complex with the amylose spiral cavity. CONCLUSION: These results may be useful for development of healthier fried starch-based foods with reduced oil contents. © 2022 Society of Chemical Industry.

Influence of structural features and feruloylation on fermentability and ability to modulate gut microbiota of arabinoxylan in in vitro fermentation.

Introduction: Arabinoxylan (AX) is a versatile polysaccharide that shows various effects in modulating gut microbiota and health. The influence of arabinoxylan carbohydrate structural feature and feruloylation on fermentability and the effect of modulation of gut microbiota of AX was not clear. Methods: Arabinoxylans from rice bran and corn bran (RAX and CAX), and their deferulyolated counterpart dRAX and dCAX were fermented using an in vitro fermentation model. Structural information was determined based on monosaccharide composition. Gas production of fermentation products, SCFAs production, pH change, and microbiota change were measured. Results: RAX and dRAX posessed lower A/X ratio compared with CAX and dCAX. The gas and total SCFAs production were lower in RAX and dRAX, and the butyrate production were higher in RAX and dRAX compared with CAX and dCAX. Butyrate production was lower at dRAX compared to RAX. On the other hand, butyrate production was higher in dCAX than in CAX. The microbiota shift were different for the four fibers. Discussion: The AXs from rice have a higher A/X ratio than the AXs from maize, suggesting more branching and a more complex side chain. The structural difference was crucial for the difference in fermentation pattern. Different Bacteroides species are responsible for the utilization of rice AXs and corn AXs. Although feruloylation had a minor effect on the overall fermentation pattern, it significantly affected butyrate production and alpha diversity. dRAX promoted less butyrate than RAX, which is associated with a significantly lower amount of Faecalibacterium prausnitzi. dCAX promoted more butyrate than CAX, which may be associated with a lower amount of Bacteroides ovatus and a higher amount of Blautia in dCAX compared to CAX. The effects of feruloylation on the fermentation pattern and the resulted microbiota shift of AX varied depending on the carbohydrate structure.