Impact of UV-C pretreatment on fi-lactoglobulin hydrolysis by trypsin: Production and bioavailability of bioactive peptides

The effects of UV-C light irradiation and low-temperature long-time (LTLT) pasteurization on protein structural changes, degree of hydrolysis (DH) by trypsin, peptide profile of tryptic hydrolysates by MALDI-TOF/TOF-MS, and bioavailability of fi-lactoglobulin were compared. Compared with native or LTLT pasteurised samples, the hydrolysis rate constant of fi-lactoglobulin treated with UV-C increased significantly, implying that the protein backbone cleavage sites became more accessible, whereas ther-mal treatment produced aggregates that impede trypsin activity. Tryptic hydrolyses of UV-C light treated fi-lactoglobulin yielded more peptides and a more diverse peptide mass profile. Six bioactive peptides were revealed in fi-LG tryptic hydrolysates of UV-C-treated protein; transepithelial transport in Caco-2 cell monolayers showed intermediate in vivo transport and absorption for three (fi-LG f87-91, fi-LG f91-99, and fi-LG f158-164). The moderate allergen peptide LSFNPTQLEEQCHI fi-LG was absent after tryptic hydrolysis of UV-C-treated protein, indicating that UV-C photolysis may be a useful tool for allergenicity reduction. (c) 2023 Elsevier Ltd. All rights reserved.

Automated summary

This study compared the effects of UV-C light irradiation and low-temperature long-time (LTLT) pasteurization on protein structural changes, trypsin hydrolysis degree, peptide profile, and bioavailability of fi-lactoglobulin. UV-C treatment significantly increased the hydrolysis rate of fi-lactoglobulin, making protein cleavage sites more accessible. UV-C treatment also produced more peptides and a diverse peptide mass profile. Several bioactive peptides were found in the UV-C-treated fi-lactoglobulin hydrolysates, and some showed intermediate in vivo transport and absorption. UV-C photolysis may be useful for reducing allergenicity.