Thermal Stability of Anisoyl Kaempferol Glycosides in Jack Bean (Canavalia ensiformis (L.) DC) and Their Effect on α-Glucosidase Inhibition

Kaempferol glycosides are functional components of jack bean. The chemical stability of kaempferol glycosides under simulated food processing conditions was evaluated in this study by subjecting the methanol extract and each compound to heat treatment. During the heat treatment, rearrangement of the anisoyl group on the rhamnose moiety of the kaempferol glycoside was observed, followed by hydrolysis upon long-term heat treatment. One of the two regioisomers produced under heating conditions showed higher alpha-glucosidase inhibitory activity than the dominant anisoyl kaempferol glycoside. This rearrangement reaction was also observed upon the heat treatment of methyl-3-O-anisoyl-rhamnose, with the rearrangement from the 3-position to the 2-position occurring preferentially. The approach adopted in this study can be used to design appropriate food processing conditions, which, in turn, will increase the functional value of foods.

Automated summary

This study evaluated the chemical stability of kaempferol glycosides under simulated food processing conditions and found that rearrangement and hydrolysis reactions occurred during heat treatment. One of the rearrangement products showed higher enzymatic inhibitory activity. These findings can be used to design food processing conditions that increase the functional value of foods.