Effect of pH and heating conditions on the properties of Alaska pollock (Theragra chalcogramma) surimi gel fortified with fish oil

Abstract

To improve the quality and functionality of emulsified surimi gels, the effect of pH and heating conditions on the properties of surimi gel fortified with fish oil was investigated. Results showed that pH conditions influenced the solubility and emulsifying properties of surimi proteins and that the gel properties were associated with the protein properties. Under direct heating, the highest gel strength was achieved at pH 8.0, in which condition the solubility was significantly higher than others. Higher emulsifying stability resulted in enhanced gel strength relative to that of the control group. However, the changes in the gel strength were not consistent under two‐step heating. In addition, the expressible moisture and oil content were found to vary depending on the pH values under both heating conditions. The corresponding changes in expressible moisture and oil content could be attributed to the high protein solubility and emulsifying properties of surimi proteins. Analysis of the dynamic rheological properties of the resulting surimi paste revealed that the gelation properties varied depending on the pH conditions during the heating process. In addition, the temperatures of myosin cross‐linking changed according to the structure of surimi proteins, which in turn varied depending on the pH conditions. Practical applications To improve the functionality of surimi‐based product, the fish oil was added to prepare surimi gel. pH and heating conditions play important roles in the gelation of fish proteins. Therefore, this study investigated the effect of combined pH and heating condition on the property of surimi gel fortified with fish oil. The emulsified surimi gel with fine texture was obtained at pH of 8–8.5; moreover, heating conditions (direct heating and two‐step heating) also influenced texture of emulsified surimi gel. These results provide the evidence to produce the emulsified surimi‐based product with the high gel strength, water‐ and oil‐holding capacity.

Improvement of Gel Quality of Squid (Dosidicus gigas) Meat by Using Sodium Gluconate, Sodium Citrate, and Sodium Tartrate

“…The solubility of squid protein was determined according to the method described by Gao [ 14 ], with slight modifications. Approximately 1 g of squid muscle was homogenized with 20 mL of 0.6 M salt solution by a homogenizer (T18 digital, IKA Group, Staufen, Germany) at 10,000 rpm for 30 s. The mixture was then centrifuged at 13,000× g (Multifuge X1R, Thermo Fisher Scientific Co., Ltd., Shanghai, China) at 4 °C for 20 min.…”

The effect of sodium tartrate and sodium citrate on quality changes of squid (Dosidicus gigas) surimi gel

“…Protein solubility was determined according to the method described by Gao et al (2018) with some modifications. Squid meat (1 g) was homogenized with 10 ml of different salt solutions.…”

“…Li, 2020). Then, G' and G 00 began to decline due to endogenous protease activity, which led to the degradation of the gel network structure (Gao et al, 2018). Finally, G' and G 00 continued to increase with increasing temperature above 60 C. The addition of SC and ST induced different trends in G' and G 00 .…”

Gel‐type emulsified muscle products: Mechanisms, affecting factors, and applications

“…Notably, the addition of polyunsaturated fatty acids (PUFAs) not only improves the healthy functionality but also the properties of MP gels (Z. Han et al., 2021). For example, some reports have concluded that the introduction of fish oil improved the gelation performance, WHC, and whiteness of surimi‐based products (Gao et al., 2018; Jiao et al., 2019; Yu and So et al., 2022). Moreover, the contributions of PUFAs to gel properties may depend on the oil types and levels.…”

“…Difference in the response of actomyosin to pH may be ascribed to their distinct amino acid compositions. Gao et al (2018) found that pH influenced the solubility and emulsifying attributes of surimi proteins and the subsequent gel properties. A greater gel strength was obtained at pH 8-8.5, where the surimi gel also showed the highest emulsifying stability.…”