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

Abstract

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. Hence, in this study, enzymatic hydrolysis and food grade chemical modification (succinylation) were evaluated to produce ice recrystallization 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 ºC. 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 23 µm). Moreover, chemical modification via succinylation reaction with 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.