Effect of Ultraviolet-Induced Protein Modification on Techno-Functional, Antioxidant, and Cytotoxic Properties of Caulerpa prolifera Proteins

Abstract This is the first study to investigate protein modification using ultraviolet radiation (UVR) for improving techno-functional properties and antioxidant activity (AOA) of protein extracts from Caulerpa prolifera. In this study, UVR conditions were treatment time of 1, 5, 10, 15, and 20 min with two different distances between sample and ultraviolet light source of 25 and 50 cm. The effect of these conditions was investigated on water absorption capacity (WAC) and oil absorption capacity (OAC), sulfhydryl group (SH) content, and protein solubility (PS), antioxidant activity (AOA), and cytotoxic effect of proteins extracts and functional groups, microstructure, and color properties of the modified proteins. According to results, protein extracts modified under UVR conditions with treatment time of 15 min and distance of 25 cm, which provided the best results, WAC, OAC, SH content, PS, AOACUPRAC, and AOADPPH were determined as 316.98±4.97%, 610.51±32.12%, 12.04±0.11%, 58.95±3.15 μmol/g, 11.77±0.52 mg Trolox equivalent (TE)/g, and 8.11±0.71 mg TE/g, respectively. According to the results of FT-IR analysis, UVR lead to an increase in β-sheet and a decrease in 310-helix content and β-turn structure. UVR provided an increase in WAC, OAC, SH, PS, and AOA of proteins compared to untreated protein extracts.