Study on the mechanism of soy protein isolate to improve quality of reduced-salt Hypophthalmichthys molitrix surimi gel: Focus on gel quality, protein structure, and in vitro digestibility

Xuehua Zhang; Hao Pan; Xin Jiang; Wenzheng Shi

doi:10.1016/j.fochx.2023.100878

Study on the mechanism of soy protein isolate to improve quality of reduced-salt Hypophthalmichthys molitrix surimi gel: Focus on gel quality, protein structure, and in vitro digestibility

Food Chem X. 2023 Sep 12:20:100878. doi: 10.1016/j.fochx.2023.100878. eCollection 2023 Dec 30.

Authors

Xuehua Zhang¹, Hao Pan¹, Xin Jiang¹, Wenzheng Shi^{1

2}

Affiliations

¹ College of Food Science and Technology, Shanghai Ocean University, Shanghai 201306, China.
² National R&D Branch Center for Freshwater Aquatic Products Processing Technology (Shanghai), Shanghai 201306, China.

Abstract

Excessive intake of sodium chloride may bring a series of diseases; as a result, reduced-salt surimi gels have gained growing popularity for sodium reduction. This paper studied soy protein isolate (SPI, 2.0%, 4.0%, and 6.0%, w/w) as a gel enhancer for reduced-salt silver carp surimi. Compared with the control (2.0% NaCl), the addition of SPI significantly increased (P < 0.05) the total SH content, hydrophobic interaction force, disulfide bond, hardness, gel strength, and water-holding capacity of the gels. During the thermal denaturation process, SPI and myofibrillar protein jointly participated in the formation of the gel network, resulting in a G' value increase at 90 °C, forming a denser/more stable gel network structure. In vitro pepsin digestion results showed the digestibility of the reduced-salt gel with SPI was higher than that of the control. Therefore, appropriate SPI addition can improve the gel performance of reduced-salt surimi gel without affecting digestion and absorption.

Keywords: In vitro digestibility; Reduced-salt surimi; Rheological property; Secondary structure; Soy protein isolate; Texture.