Pineapple peel polyphenols mitigate fructose-induced bovine lactoferrin glycation and aggregation: insights into enhanced digestibility and bioactivity of digests

Polyphenols alleviate fructose-induced lactoferrin glycation and restore its digestibility. • Ferulic acid increases lactoferrin's hydrolysis degree to 68.6% after gastrointestinal digestion. • Gallic acid and epicatechin promote production of small peptides (<3 kDa) from glycated lactoferrin. • Polyphenols protect lysine/arginine residues from glycation, preserving protease cleavage sites. • First structure-dependent comparison of three polyphenols in improving glycated protein digestion. This study addressed issues such as protein aggregation, reduced digestibility, decreased nutritional bioavailability, and the formation of harmful advanced glycation end products (AGEs) caused by fructose-induced glycation of bovine lactoferrin during thermal processing. We investigated the inhibitory effects of three pineapple peel polyphenols (gallic acid, epicatechin, and ferulic acid) on lactoferrin glycation, as well as their regulatory roles in the in vitro digestibility, antioxidant activity, and AGE formation of this protein. The results indicate that the three polyphenols inhibit lactoferrin glycation and aggregation in a structure-dependent manner, significantly improving its gastrointestinal digestibility (ferulic acid increased the degree of hydrolysis at the end of digestion to 68.6%), enhancing the antioxidant capacity of the digestion products, and effectively suppressing AGE formation during digestion. This study provides theoretical support for the application of representative pineapple peel polyphenols as glycation inhibitors to improve the nutritional utilization of milk proteins. Download: Download high-res image (165KB) Download: Download full-size image