Extraction of protein from sesame meal: Impact of deep eutectic solvents on protein structure and functionality

Abstract

There is an increasing need for sustainable sources of dietary protein. Sesame meal is a protein-rich waste from the industrial production of sesame oil. It could help meet this need if high quality protein could be extracted from the meal in an environmentally friendly way. The traditional alkali-soluble acid precipitation extraction process produces proteins with poor functionality and harmful to the environment. Deep eutectic solvents (DESs) offer a novel, sustainable approach to protein extraction. In this study, four DES systems (choline chloride-glycerol, choline chloride-ethylene glycol, choline chloride-oxalic acid, and choline chloride-glycolic acid) were designed and tested in 3 M ratios (10 sample solutions). Extracted proteins were compared with protein extracted by traditional alkali-soluble acid precipitation in terms of structure and function. The choline chloride-ethylene glycol system extracted protein with a purity of 93.3%. The choline chloride-oxalic acid system performed well in terms of solubility, emulsification, foaming and thermal stability. These results indicate that deep eutectic solvents can effectively extract sesame protein with characteristics appropriate for use in the food industry. This research lays the groundwork for high-value utilization of sesame meal, which is currently discarded as waste.