Effects of lysine on the physiochemical properties of plant-protein high-moisture extrudates

This study investigated the effects of lysine addition (0 g/100g, 0.25 g/100g, 0.50 g/100g, 0.75 g/100g, 1.00 g/ 100g, 1.25 g/100g) on the physiochemical properties of a soy protein-wheat gluten mixture subjected to highmoisture extrusion. Extrudates were evaluated in terms of color, degree of texturization, textural properties, microstructure, water distribution, rheological properties, protein solubility and protein secondary structure. The results showed that the addition of lysine deepened the color of the extrudates and increased the degree of texturization (2.00-2.73) and chewiness of the extrudates. Adding lysine enhanced hydrogen bond formation and hydrophobic interactions, which ultimately generated a more compact, fibrous structure. The increase of storage modulus indicated that the addition of lysine promoted the aggregation of protein in extrudates. The bound water content, & alpha;-helix and & beta;-sheet content of the extrudates increased with the addition of lysine. In total, this study provides a reference for improving the quality of plant-protein extrudates.

Automated summary

This study investigated the effects of lysine addition on the physiochemical properties of a soy protein-wheat gluten mixture subjected to high-moisture extrusion. The results showed that lysine addition deepened the color and increased the degree of texturization and chewiness of the extrudates. Lysine also enhanced hydrogen bond formation, hydrophobic interactions, protein aggregation, and the content of bound water, α-helix, and β-sheet in the extrudates.