Yinji Chen

The red swamp crayfish (Procambarus clarkii) was introduced from Japan to China in the 1920s. Crayfish are now widely distributed in almost all types of freshwater wetlands, including rice fields, ditches, swamps, lakes, and ponds in most provinces of China, owing to their multi-directional movement, rapid growth, adaptability to the environment, and relatively high fecundity. The delectable taste and high nutritional value of crayfish have made them popular among consumers, leading to the significant development of red swamp crayfish farming in the last two decades. Currently, it represents the largest proportion of commercially farmed freshwater crustaceans in China and has become an integral component of China’s aquatic economy. Crayfish are highly valued for their edibility and for their by-products, which have various important uses. This review discusses nutrient composition, active ingredients, safety evaluation, processing and preservation, and comprehensive utilization of crayfish by-products to explore and organize the existing knowledge about crayfish and to promote the growth of the crayfish industry. This comprehensive review aims to provide a basis for the optimal utilization and sustainable development of crayfish resources worldwide.

The purpose of this study is to explain the mechanism of porcine myofibrillar protein gel properties modulated by κ-carrageenan. The textural properties results showed that the stress at fracture of the composite gel with 0.4% κ-carrageenan had the highest value (91.33 g), which suggested that the 0.4% κ-carrageenan addition was the limitation. The strain at fracture was significantly reduced with κ-carrageenan addition. The composite gel with 0.4% κ-carrageenan had the lowest proportion of T22 (7.85%) and the shortest T21 relaxation time (252.81 ms). The paraffin section showed that the phase separation behavior of the composite gel transformed from single-phase behavior to dispersed phase behavior to bi-continuous phase behavior, and the ratio of CG/MP phase area significantly increased from 0.06 to 1.73. The SEM showed that the three-dimensional network of myofibrillar protein transformed from a loose structure to a compact structure to an unaggregated structure with κ-carrageenan addition. The myofibrillar protein network of the treatment with 0.4% κ-carrageenan had the highest DF value (1.7858) and lowest lacunary value (0.452). The principal component analysis was performed on the data of microstructure and textural properties, and the results showed that the dispersed phase behavior and moisture stabilization promoted the aggregation of myofibrillar protein and the composite gel had better water holding capacity and textural properties, while bi-continuous phase behavior hindered the aggregation of myofibrillar protein and the composite gel had worse water holding capacity and textural properties.

BACKGROUND: Emulsification is important for food quality and processing functionality. Most emulsification occurs under high‐fat conditions that eventually cause health concerns. Protein emulsifiers also have drawbacks such as lower dispersity. This study considered the effects of different high‐speed shear homogenization (HSH) speeds on the emulsifying and structural properties of myofibrillar proteins (MPs) under low‐fat conditions.RESULTS: High‐speed shear homogenization significantly increased the emulsifying activity and emulsifying stability of MPs at lower speeds (8000 to 14 500 rpm). The primary structure of MP was not altered significantly by HSH, whereas its secondary, tertiary, and quaternary structures were changed. Particle size decreased first and then increased significantly, and reached a minimum when the HSH speed was 14 500 rpm. The absolute zeta potential values increased significantly and the dendritic fibrous structure of sample was destroyed when the speed exceeded 14 500 rpm. High‐speed shear homogenization (14 500 rpm) decreased the particle size and unfolded the protein, which improved the emulsifying properties of MPs. Excessive HSH speeds (20 500 rpm or higher) caused an aggregation of MP molecules, which was not conducive to improving their emulsifying properties.CONCLUSION: Optimal HSH speed was achieved at 14 500 rpm to modify MPs' emulsifying and structural properties under low‐fatconditions. © 2019 Society of Chemical Industry