ULTRASONICATION-ENHANCED MICROBIAL TRANSGLUTAMINASE CROSSLINKING OF BOTANICAL AND FOREIGN PROTEIN FOR SUSTAINABLE HIGH-MOISTURE EXTRUDED MEAT ANALOGUE: A COMPREHENSIVE MULTIDIMENSIONAL CHARACTERIZATION

Abstract

The growing global population and environmental concerns around conventional meat production are driving demand for sustainable, nutritionally balanced protein alternatives. Plant proteins, while environmentally favorable, often have incomplete amino acid profiles, necessitating targeted fortification and structural modification. This study developed high-moisture extruded meat analogues via ultrasonication-assisted microbial transglutaminase (MTG) crosslinking of soy protein isolate (SPI) and whey protein isolate (WPI) at 100:0, 95:5, 90:10, and 85:15 ratios. The extrudates were characterized for physicochemical, textural, structural, microbial, nutritional, and volatile (electronic nose) properties. Increasing WPI content reduced moisture, expansion, porosity, and water-holding capacity, while increasing density, hardness, and chewiness, indicating denser protein networks. Lightness and pH shifted slightly with whey addition, and microbial counts decreased, suggesting improved shelf stability. FTIR confirmed structural modifications, and amino acid profiling revealed enhanced essential amino acids, including leucine, lysine, isoleucine, valine, and threonine. E-nose analysis demonstrated that controlled whey fortification progressively increased sulfur- and amine-responsive volatile signals, with the SPI–WPI (85:15) formulation exhibiting aroma profiles statistically similar to chicken meat. These findings indicate that strategic protein blending can enhance both the nutritional quality and the meat-like sensory profile of soy-based high-moisture extrudates. Ultrasonication-assisted MTG crosslinking combined with high-moisture extrusion offers a promising approach for producing nutritionally balanced, structurally robust, shelf-stable, and sensorially authentic meat analogues.