Inhibition of ice crystal growth by protein hydrolysates from different plant-and animal-based proteins

Due to the quality deterioration and the corresponding waste of frozen foods,there is a constant need for an effective,consumer and environmentally friendly,and sustainable anti-freezing ingredient.In this study,enzymatic hydrolysis and food grade chemical modification(succinylation)were evaluated to produce ice re-crystallization inhibition(IRI)active peptide-based ingredients.Six different types of plant-and animal-based proteins were evaluated.Soy protein isolate(SPI),after 15-and 60-min alcalase hydrolysis,demonstrated a significant IRI activity compared to polyethylene glycol(PEG;as negative control)resulting in a two-third reduction of ice crystal size annealed at−8℃.Annealing temperature and peptide concentration also affected the IRI activity of SPI hydrolysate where decreased temperature and increased concentration resulted in a higher IRI activity.Increased hydrolysis time decreased the IRI activity of SPI hydrolysates but increased the IRI activity of sodium caseinate(SC)and pea protein isolate(PPI)hydrolysates.SPI-60 was less temperature resistant compared to SPI-15 which inhibited the growth of ice crystals(smaller than 23μm).Moreover,chemical modification via succinylation reaction with octenyl succinic anhydride(OSA)enhanced the IRI activity of the PPI and SPI hydrolysates leading to a 55.3%and 60.6%reduction in the size of ice crystals,respectively.Overall,this study demonstrates a great potential in the utilization of common food proteins for the production of value-added natural anti-freezing ingredients which could benefit the food industry by enhancing frozen foods'shelf-life and reducing waste.