Corn silk as an underutilized sustainable source of plant proteins: Extraction, fractionation, structure, and techno-functional properties

Abstract

Plant proteins extracted from agro-industrial waste are gaining importance in the food industry due to environmental, sustainability, and economic reasons. These proteins can be extracted and then converted into high-value ingredients, thereby promoting a circular economy. Corn silk, often regarded as an underutilized waste stream, currently has limited applications beyond its uses as a traditional medicine in some regions of the world. The present study characterized the structural, physicochemical, thermal, techno-functional, and in vitro digestibility properties of corn silk protein (CSP) and its three major fractions (albumin, globulin, and glutelin). Glutelin (67.5%) was the major protein fraction of CSP, followed by albumin (23.2%) and globulin (9.2%). A purity greater than 60% could be achieved for all fractions. The structural and techno-functional properties of the different protein fractions were impacted by their composition. The glutelin fractions had higher foaming and thermal properties but lower emulsification properties than the other fractions. However, the albumin fraction had higher in vitro digestibility and better nutritional quality. Nevertheless, the CSPs did have lysine levels below the recommended values. These findings extend the current understanding of the structural and functional properties of corn silk protein and its fractions, thereby expanding their potential applications in the food and other industries. • Glutelin was the major protein fraction of CSP, followed by albumin and globulin. • A purity for albumin, globulin, and glutelin reached over 50%. • Albumin fraction had better in vitro digestibility and better nutritional quality. • The glutelin fractions had better foaming and thermal properties.