Potential antidiabetic effect of muffins formulated with different protein hydrolysates: Role of bioactive peptides formed during digestion

This study aimed to evaluate whether the reformulation of a conventional muffin (CM) by incorporating hydrolysates of casein, soybean protein, pea protein, and rice protein at two concentrations as wheat flour replacement, affected the glycemic index (GI) and the release of bioactive peptides (BAPs) during the digestion in vitro. Compared to CM, muffins with hydrolyzed pea and rice proteins lowered GI by 15% and 5%, respectively, without a significant dose-dependent effect; moreover, during digestion they delivered BAPs, including some amylase-inhibitors. Conversely, the muffins incorporating casein hydrolysate at high concentration showed the highest GI and delivered highest amount of opioid and DPPIV-inhibitor BAPs. Soy protein hydrolysates did not significantly affect the GI or BAPs released. Findings suggested that reformulating a muffin with protein hydrolysates, besides a reduced GI, as in the case of pea and rice protein hydrolysates, may provide further biological effects through the release of BAPs during the digestion.