Facile construction of fruit protein based natural hydrogel via intra/inter molecular cross-linking

Abstract

The current study focused on the possible beneficial action of microbial transglutaminase (MTG) modification on techno-functional and hydrogel characteristics of sour cherry seed protein (SCSP). Firstly, the occurred variations in the oil holding capacity (OHC) and emulsifying activity index (EAI) of SCSP depending on MTG/substrate ratio and process time were explored to detect plausible cross-linking conditions. The accuracy of the modification in MTG-induced SCSP (MTG-SCSP) was assigned by FTIR and SDS analyses. The upward trend was observed in the techno-functional features including wettability (4.01 s for SCSP and 46.50 s for MTG-SCSP), OHC (1.53 g/g for SCSP and 8.48 g/g for MTG-SCSP), EAI (45.30 m 2 /g for SCSP and 65.82 m 2 /g for MTG-SCSP) and emulsifying stability index (ESI) (15.10 min for SCSP and 26.19 min for MTG-SCSP) behavior after cross-linking process. MTG-SCSP was also incorporated into hydrogels models. Hydrogels with 3 different contents namely SCSP alone, SCSP and pectin mixture, and MTG-SCSP and pectin mixture as control groups were prepared. The microstructure of hydrogels was characterized by SEM images. The coexistence of MTG-SCSP and pectin displayed a noteworthy synergistic impact on the functional properties (water holding capacity (WHC), swelling ratio, and volume gel index (VGI)) of gels. A similar pattern with these results was obtained in the textural and rheological behavior. • Suitable cross-linking conditions for protein modification were determined. • FTIR spectrum and SDS pattern were used to reveal enzyme action contraptions. • Functional attributes of proteins were improved with enzyme modification. • Hydrogel formation ability of fruit based-proteins was enhanced by cross-linking. • Modified protein resulted in gels with superior functional and mechanical features.