Chemical cross-linking of different plant protein-based meat analogues was examined based on protein solubility of 8 different buffer solutions. The specific chemical bond and their interactions were further analyzed. Isolated soy protein (ISP), mung bean protein (MBP), peanut protein (PNP), pea protein (PP) and wheat gluten (WG) were texturized using a co-rotating twin-screw extruder at 50% moisture content. The results showed that protein solubility of meat analogues significantly decreased after extrusion, compared to their raw materials (P<0.05). The protein solubility of meat analogues increased with increasing reagent in buffer solutions. Hydrophobic interactions, hydrogen bonds, disulfide bonds and their interactions were found in the structure of meat analogues. The highest amount of covalent bond was observed in PP-meat analogues followed by ISP, WG, PNP, and the lowest MBP-meat analogues. The study demonstrated that PP are valuable raw materials for the development of meat analogue, which could promote high cross-linking bonds.

The comparison of physicochemical properties and cell structure of texturized vegetable protein (TVP) and different types of meats (beef, pork, and chicken samples) were studied. TVP from the blend of 40% isolated soy protein (ISP) and 60% wheat gluten (WG) was texturized with a twin-screw extruder at 100 g/min feed rate, 45% moisture content, 250 rpm screw speed and 140℃ die temperature. The nitrogen solubility index, integrity index, chewiness, longitudinal cutting strength and microstructure of TVP were similar to the chicken sample, when compared to the other meats. However, water absorption capacity (WAC) of TVP (217.38%) was significantly (P<0.05) higher than those of meat samples (109.53 to 165.35%). The microstructure of TVP showed the fibrous structure. Non-uniform air cells were observed in the microstructure of TVP, which could indicate high WAC. The study demonstrated that the physicochemical and cell structure of TVP from the blend 40% ISP and 60% WG with 45% moisture extrusion process was similar as chicken sample.