Unveiling the relationship between heat-resistant structure characteristics and inhibitory activity in colored highland barley proteinaceous α-amylase inhibitors.

Natural α-amylase inhibitors (α-AIs) serve as food processing additives, capable of mitigating postprandial blood glucose levels, but heat resistance limits their application in high-temperature processing. This study delved into the correlation between protein structural characteristics and heat-resistance of colored highland barley (CHB) α-AIs and evaluated the inhibitory activity during chemical modification and in vitro digestion. Results demonstrated that CHB α-AIs were glycoproteins, the inhibitory activity retention rate of black highland barley α-AI salted-out with 0-60 % (NH)SO (BK1 α-AI) was 56.23 % ± 0.64 %. The protein structure analysis revealed that the preservation of three-dimensional structure was attributed to hydrogen bonds and hydrophobic interactions, and disulfide bonds played a crucial role in maintaining protein folding and activity. Succinylation increased the content of disulfide bonds after heating, and the inhibitory activity retention rate of α-AI noodles increased from 37.72 % ± 2.49 % to 42.79 % ± 0.39 %. These findings provide a theoretical foundation for the application of α-AI in thermally processed foods.