Effects of soy protein isolate on gel properties and water holding capacity of low-salt pork myofibrillar protein under high pressure processing

This paper studies the effects of soy protein isolate (SPI; 0, 2% and 4%; Weight/Weight) on texture, rheological property, sulfhydryl groups, and the water distribution state of low-salt (1% NaCl) pork myofibrillar protein systems under high pressure processing (HPP, 200 MPa, 10 min). The L* value, cooking yield, hardness, total and reactive sulfhydryl, surface hydrophobicity, and the G' value at 80 degrees C of pork myofibrillar protein increased significantly (P < 0.05) when SPI was added; however, the springiness, cohesiveness, and chewiness of gels with 4% SPI were lower than of gels with 2% SPI. The rheological findings indicated that the thermal stability of the myofibrillar protein increased when SPI was added. The initial relaxation time of T-2b, T-21, and T-22 decreased when SPI increased; meanwhile, the peak ratio of P-21 increased significantly (P < 0.05), implying that water had lower mobility. Overall, the 2% SPI could enhance gel characteristics and water-holding capacity of pork myofibrillar protein under 200 MPa.