Effects of soybean protein isolate and carrageenan on gel properties of myofibrillar protein from loach

Abstract

Objective: In this study, the effects of exogenous additives on gel properties of myofibrillar protein were explored to improve the property of surimi from fresh-water fish. Methods: The myofibrillar protein of loach was mixed with various contents of soybean protein isolate and carrageenan to prepare composite gel. Its properties were investigated by texture analyzer, color difference analyzer, scanning electron microscope and infrared spectroscopy. Results: With increased content of soybean protein isolate, the gel hardness of myofibrillar protein from loach decreased firstly and then increased; while gel springiness increased firstly and then decreased. Soybean protein isolate could enhance the water holding capacity of gel and decrease its cooking loss. Holes in gel network became larger and the relative contents of secondary structure also changed. However, carrageenan could weaken the hardness and springiness of gel, while improve the whiteness as well as cooking loss. The gel network structure became regular and the unordered structure disappeared. Conclusion: The effects of soybean protein isolate on gel of myofibrillar protein from loach is more obvious than that of carrageenan, and the composite gel formed by soybean protein isolate have better properties.

Keywords

• loach
• myofibrillar protein
• gel
• soybean protein isolate
• carrageenan