Influence of transglutaminase treatment on the digestibility of pork longissimus dorsi proteins

Abstract

This work aimed to investigate effect of TG treatment on the in vitro digestibility of pork longissimus dorsi proteins. Based on measurement of liberated –NH2, TGase treatment promoted the release of –NH2 by 9.6–30.2% after the gastric digestion, due to changes in advanced structure of protein. However, the released –NH2 was reduced by 19.4–28.0% and 10.2–24.5% in the initial 15 min of gastric and intestinal digestion respectively by TGase treatment due to the formation of Lys-Gln crosslinked structures and loss of Lys residues. Compared with controls, more undigested bands in the molecular range of 5–15 kDa were found in the digests of sample treated with 20 U TGase. Peptidomics analysis indicated that the changes in peptide composition of the digests of TGase-treated samples were largely related to the loss of Lys and Gln residues during TGase treatment. The relative abundances of potential bioactive peptides, including VDDLEGSLEQEK, EDQVFPMNPPK, LFDKPVSPL and HVFGESDELIGQK, were elevated in the TGase-treated samples. This study helps to uncover the effect of TGase treatment on meat nutrition, which will provide guidance for the TGase application in meat industry.