Hydrolysates from sorghum crude kafirin extract exhibit ice recrystallization inhibition activity

Authors: OLLIS, AVERY - University Of Tennessee; WANG, TONG - University Of Tennessee; Krishnan, Hari; DIA, VERMONT - University Of Tennessee

Submitted to: ACS Food Science and Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/28/2024
Publication Date: 9/5/2024
Citation: Ollis, A., Wang, T., Krishnan, H.B., Dia, V.P. 2024. Hydrolysates from sorghum crude kafirin extract exhibit ice recrystallization inhibition activity. ACS Food Science and Technology. https://doi.org/10.1021/acsfoodscitech.4c00312.
DOI: https://doi.org/10.1021/acsfoodscitech.4c00312

Interpretive Summary: Ice recrystallization is a process that lowers the quality of frozen foods over time. To develop new agents that can inhibit ice recrystallization and protect frozen foods, we need to understand the properties of ice recrystallization active agents. Most of these agents are animal proteins, but plant proteins, such as sorghum protein hydrolysates, could be a better alternative that would suit different types of frozen products, including vegan and vegetarian ones. In this study, we investigated the main factors that influence the ice recrystallization inhibition activity of hydrolyzed sorghum protein (kafirin). We found that sorghum protein can produce peptides that inhibit ice recrystallization and prevent the damage of frozen foods. Chemicals that modified the hydrophilicity of sorghum proteins increased ice recrystallization activity. The results of our study could benefit US farmers by increasing the demand for sorghum in the food industry.

Technical Abstract: Ice recrystallization can damage the microstructure of food products, and one potential solution is the use of molecules with demonstrated ice recrystallization inhibition (IRI) activity. The objective was to determine the IRI activity of sorghum kafirin hydrolysates as affected by succinylation and the dispersing medium. The IRI activity of the sorghum kafirin hydrolysates was analyzed by the splat assay in phosphate-buffered saline (PBS) and 10 mM NaCl. At 2% concentration, sorghum kafirin hydrolyzed by bromelain for 1 h resulted in 55% reduction in ice crystal size in 10 mM NaCl, while this was not observed when the dispersing medium is PBS. Succinylation at 0.25:1 molar ratio (succinic anhydride: amine group of the peptides) yielded modified hydrolysates that were slightly more IRI active in PBS, but the difference was not significant. The data showed the potential application of sorghum kafirin hydrolysates to act as antifreeze molecules to preserve the quality of frozen materials.