Ice recrystallization inhibition activity of soy protein hydrolysates

Authors: FOMICH, MADISON - University Of Tennessee; DIA, VERMONT - University Of Tennessee; PREMADASA, UVINDUNI - Oak Ridge National Laboratory; DOUGHTY, BENJAMIN - Oak Ridge National Laboratory; Krishnan, Hari; WANG, TONG - University Of Tennessee

Submitted to: Journal of Agricultural and Food Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/15/2023
Publication Date: 8/2/2023
Citation: Fomich, M., Dia, V., Premadasa, U., Doughty, B., Krishnan, H.B., Wang, T. 2023. Ice recrystallization inhibition activity of soy protein hydrolysates. Journal of Agricultural and Food Chemistry. 71(30):11587-11598. https://doi.org/10.1021/acs.jafc.2c08701.
DOI: https://doi.org/10.1021/acs.jafc.2c08701

Interpretive Summary: Ice recrystallization is a phenomenon that can deteriorate the quality of frozen foods over time. Uncovering important characteristics of ice recrystallization active agents could lead to the development of new ice recrystallization inhibition agents which could then be used to prevent damage to frozen foods. Mostly various animal proteins have been used to evaluate ice recrystallization inhibition active peptides. However, the utilization of an alternative plant-protein, such as soy protein isolate, would present a more abundant option that would be allowed in a variety of frozen products including vegan and vegetarian options. In this study, we have examined the key factors contributing to the ice recrystallization inhibition activity of soy protein isolate hydrolysates. Our results show that recrystallization inhibition active peptides can be produced from soy protein isolate which can be used to prevent the deterioration of frozen foods. Our study should benefit US farmers by promoting wider use of soybean in food industry.

Technical Abstract: Identifying and developing ice recrystallization inhibitors from sustainable food proteins such as soy protein isolate (SPI) can lead to practical applications in both pharmaceutical and food industries. The objective of this study was to investigate the ice recrystallization inhibition (IRI) activity of SPI hydrolysates, and this was achieved by using an IRI activity-guided fractionation approach and relating IRI activity to interfacial molecular activity measured by vibrational sum frequency generation (VSFG). In addition, the impact of molecular weight (MW) and enzyme specificity was analyzed using three different proteases (Alcalase, trypsin, and pancreatin) and varying hydrolysis times. Using preparative chromatography, hydrolysates from each enzyme treatment were fractionated into five different MW fractions (F1–F5), which were then characterized by high-performance liquid chromatography (HPLC). All SPI hydrolysates had IRI activity, resulting in a 57–29% ice crystal diameter reduction when compared to native SPI. The F1 fraction (of 4–14 kDa) was most effective among all tested hydrolysates, while the lower MW peptide fractions lacked activity. One sample (SPI-ALC 20-F1) had a 52% reduction of ice crystal size at a lower concentration of 2% compared to the typical 4% used. SFG showed a difference in H-bonding and hydrophobic interactions of the molecules on the water/air interface, which may be linked to IRI activity. This study demonstrates for the first time the ability of SPI hydrolysates to inhibit ice crystal growth and the potential application of SFG to study molecular interaction at the interface that may help illustrate the mechanism of action.