به‌كارگيري روش تغيير pH و اصلاح پروتئين-پروتئين براي ايجاد بافت در مخلوط ايزوله پروتئين سويا و گلوتن

Current agrifood research is intensely focused on developing next-generation food products to replace conventional meat. Plant-based meat analogues (PBMA) have garnered significant interest as viable substitutes for animal protein. This study investigated the feasibility of texture formation (texturization) in a blend of Soy Protein Isolate (SPI) an‎d Wheat Gluten (G) through chemical modification by adjusting the pH to a highly alkaline environment (pH 10 an‎d 12). The investigation was carried out across three distinct SPI:G ratios (100:0, 95:5, an‎d 90:10). The impact of varying pH levels an‎d SPI/G ratios on the protein system was comprehensively assessed using a suite of analytical techniques, including electrophoretic mobility profiles, Fourier-Transform Infrared (FT-IR) spectroscopy, intrinsic fluorescence spectroscopy, surface hydro‎phobicity (H0), solubility index, free sulfhydryl (SH) content, water holding capacity (WHC), free moisture content, color analysis, emulsifying/foaming characteristics, microstructural analysis, texturometry, an‎d rheology. Results demonstrated that pH adjustment an‎d changes in the SPI/G ratio significantly altered the electrophoretic molecular weight profile, confirming inter-protein molecular interactions. FT-IR spectroscopy corroborated these findings by revealing a marked change in the protein secondary structure. Intrinsic fluorescence data further indicated tertiary structure perturbation an‎d enhanced dityrosine residue migration toward the polar phase, signifying protein unfolding an‎d cross-linking. Elevating the pH an‎d increasing the G ratio in the resulting gels led to notable improvements in H0, WHC, emulsifying activity index (EAI), emulsion stability index (ESI), an‎d foam stability, concurrently causing a reduction in free moisture an‎d lightness (L∗). Conversely, the combination of increased pH an‎d a lower G ratio enhanced the solubility of the protein matrix, foaming capacity, an‎d SH content. Scanning Electron Microscopy (SEM) images revealed the inherent porous structure of pure SPI gels, which transformed into a noticeably fibrous an‎d continuous structure upon the incorporation of G. Textural Profile Analysis (TPA) confirmed a synergistic effect between increased pH an‎d G content, leading to the development of a robust gel network an‎d ultimately enhancing the mechanical properties of the SPI/G composite gel. Dynamic rheological measurements (viscoelastic modulus vs. frequency an‎d tanδ vs. strain) substantiated the formation of a continuous three-dimensional network structure exhibiting typical elastic quasi-solid behavior. In conclusion, the findings strongly support that chemical modification via strong alkaline pH treatment applied to the SPI/G composite (10:90 ratio) represents a strategic an‎d promising approach for the development of highly texturized, plant-based meat analogues.

نفيسه سلطاني زاده

اسماعيل مهريار , حسين رضوي زادگان جهرمي