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

• Published in: Food science & technology 2023-01, Vol.173, p.114410, Article 114410
• Main Authors: Dai, Hui-Hui, An, Hong-Zhou, Ma, Yu-Xiang, Guo, Yi-Ting, Du, Yan, Zhu, Xue-Qing, Luo, Qiong
• Format: Article
• Language: English
• Subjects: Degree of texturization; Fibrous structure; High-moisture extrusion; Lysine; Plant-protein
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1016/j.lwt.2022.114410

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 high-moisture 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, α-helix and β-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. •Lysine was added to improve the quality of high moisture extrudates.•Adding lysine increased the degree of texturization of the extrudates.•Lysine promoted the formation of fiber structure by forming hydrogen bond.•The addition of lysine increased of the bound water content of the extrudates.•Adding lysine increased the elasticity of the extrudates dispersion.