Structure, physicochemical and functional properties of plant-based SPI films from different soybean varieties deficient in β-conglycinin subunits

Abstract

This study discusses the effects of different β-conglycinin subunit compositions on the processing properties of plant-based soy protein isolate (SPI) films. SPI from different soybean varieties, deficient in different β-conglycinin subunits (Wild, α'-lack, α-lack, and (α + α')-lack) were studied. The effects of α and α′ subunits on the structure and properties of SPI films were analyzed by circular dichroism, intrinsic emission fluorescence, and surface properties. α′-lack films had the lowest water solubility and water vapor transmission coefficient, as well as the best thermal stability and optical properties. This study demonstrates that eliminating the α′ subunit affects microstructure and rheological properties of SPI films by changing the internal structural conformation of the protein. This study also provides a theoretical basis for targeted improvements in the mechanical properties, water resistance, and thermal stability of the films.