Rheology, physicochemical properties, and microstructure of fish gelatin emulsion gel modified by γ-polyglutamic acid

Huan Xie; Xiao-Mei Sha; Ping Yuan; Jia-Le Li; Zi-Zi Hu; Zong-Cai Tu

doi:10.3389/fnut.2024.1343394

Rheology, physicochemical properties, and microstructure of fish gelatin emulsion gel modified by γ-polyglutamic acid

Front Nutr. 2024 Mar 20:11:1343394. doi: 10.3389/fnut.2024.1343394. eCollection 2024.

Authors

Huan Xie¹, Xiao-Mei Sha^{1

2}, Ping Yuan¹, Jia-Le Li¹, Zi-Zi Hu¹, Zong-Cai Tu^{1

3}

Affiliations

¹ National R&D Center for Freshwater Fish Processing, College of Chemistry and Chemical Engineering & College of Life Science, Jiangxi Normal University, Nanchang, China.
² Jiangxi Deshang Pharmaceutical Co., Ltd., Yichun, Jiangxi, China.
³ State Key Laboratory of Food Science and Resources, Nanchang University, Nanchang, China.

Abstract

In this work, the effect of the addition of γ-polyglutamic acid (γ-PGA) on the rheology, physicochemical properties, and microstructure of fish gelatin (FG) emulsion gel was investigated. Samples of the emulsion gel were evaluated for rheological behavior and stability prior to gelation. The mechanical properties and water-holding capacity (WHC) of the emulsion were determined after gelation. The microstructure of the emulsion gel was further examined using confocal laser scanning microscopy (CLSM). The results indicated a gradual increase in the apparent viscosity and gelation temperature of the emulsion at a higher concentration of γ-PGA. Additionally, frequency scan results revealed that on the addition of γ-PGA, FG emulsion exhibited a stronger structure. The emulsion containing 0.1% γ-PGA exhibited higher stability than that of the control samples. The WHC and gel strength of the emulsion gel increased on increasing the γ-PGA concentration. CLSM images showed that the addition of γ-PGA modified the structure of the emulsion gel, and the droplets containing 0.1% γ-PGA were evenly distributed. Moreover, γ-PGA could regulate the droplet size of the FG emulsion and its size distribution. These findings suggest that the viscoelasticity and structure of FG emulsion gels could be regulated by adjusting the γ-PGA concentration. The γ-PGA-modified FG emulsion gel also exhibited improved rheology and physicochemical properties. The results showed that γ-PGA-modified FG emulsion gel may find potential applications in food, medicine, cosmetics, and other industries.

Keywords: emulsion gel; fish gelatin; physicochemical properties; rheology; γ-polyglutamic acid.

Grants and funding

The author(s) declare that financial support was received for the research, authorship, and/or publication of this article. This study was supported by the earmarked fund for CARS (CARS-45), the National Natural Science Foundation of China (no. 32160576), and the National Key R&D Program of China (no. 2022YFD2100905).