Effect of Low Moisture Extrusion on the Physicochemical Properties of Mixtures of Β-Glucan/Soybean Protein Isolate

Abstract

In this study, β-glucan(BG) was added into soybean protein isolate (SPI) at 0%, 1%, 2%, 3%, 4% and 5% respectively, and the BG-SPI blends were subjected to low moisture extrusion (36%). The apparent properties, functional properties, and structural properties of BG-SPI extrudates were investigated. The results showed that the hardness decreased and then increased with the increase of BG addition, which was mainly influenced by the enhancement of H-S-Q (interactions between hydrogen bonds, hydrophobic interactions, and disulfide bonds). The addition of 5% BG promoted the formation of disulfide bonds (S) and hydrogen bonds (H), and thus improved the oil holding capacity (OHC) and cooking yield (CY) of BG-SPI extrudates. It also promoted the formation of H and disrupted Q-S (interactions between hydrophobic interactions and disulfide bonds) to improve nutrient retention during subsequent processing. In addition, BG and SPI in the extruder formed a compound with a large molecular weight, and the main forces that maintain this compound were S and H.

Keywords: β-Glucan, Soybean protein isolate, Low moisture extrusion, Glycosylation reaction, Texturized vegetable protein