Freezing technology extends the shelf life of products, reduces losses during long-distance transport, and makes it possible to industrialize food production. With the rapid growth of the prepared meat dish market in China, meat products need long-term cryogenic transportation and preservation. However, freezing technology faces some problems such as susceptibility to damage, quality decline, poor texture properties, water loss and taste deterioration during the freezing of meat products. Many kinds of food antifreeze agents are available now, which have a wide range of sources and low cost, and can solve the problem of freezing degeneration in various kinds of food. Therefore, food antifreeze agents play an extremely important role in improving the quality of frozen meat products. The development and application of food antifreeze agents are directly related to the development of the frozen meat industry. At present, the commonly used food antifreeze agents mainly include antifreeze protein, phosphate, and modified starch. Through different mechanisms of action, they can protect meat components, reduce ice crystal damage, increase water retention, and thus improve the quality of frozen food. In this paper, the types, mechanism of action and application of antifreeze agents in food are reviewed, aiming to provide more theoretical references for the wide application of antifreeze agents in meat products.

The emulsifying and gelling properties of myofibrillar proteins are extremely important for the texture, flavor, and sensory properties of foods. Non-meat proteins are gradually becoming a better choice for exogenous supplementation in meat products due to their higher nutritional value as well as lower price. This review focuses on the effect of the addition of various non-meat proteins on the emulsification of myofibrillar proteins and the stability of myofibrillar protein gel systems and analyzes the effect of non-meat proteins on the quality of meat products. This review will hopefully provide theoretical guidance for the application of non-meat proteins in improving the quality of meat products and in foods.

This study aimed to clarify the effect of adding different amounts of spray-dried blood cells (SBC), soybean protein isolate (SPI), egg white protein (EWP), or porcine plasma protein (PPP) on the quality and myofibrillar protein (MP) structure of minced pork. A sample with no added non-meat protein was used as a control. The cooking loss, color, pH value, microstructure and texture of meat samples were measured. The results showed that compared with the control group, the sample added with EWP showed a loose and porous structure and reduced water-holding capacity (WHC). The addition of PPP significantly improved the WHC, texture, and microstructure and increased the pH value of meat gels. The results of texture analysis showed that the addition of non-meat protein could significantly improve the chewiness of meat. The addition of SBC increased the redness value. Analysis of the secondary structure of MP demonstrated that the addition of PPP or SBC caused a red shift of the amide Ⅰ maximum absorption peak, indicating an increase in the α-helix content, and correspondingly the random coil content decreased, ultimately causing the gel structure to become denser and cause the gel strength and WHC to increase. The ultraviolet (UV) absorption intensity of MP treated with each of the non-meat proteins was decreased. The maximum absorption peak in the UV spectrum was slightly red shifted, indicating the occurrence of protein aggregation. In conclusion, adding SBC can effectively improve the quality of meat.

In this study, three different probiotics (Lactobacillus plantarum LP1, Lactobacillus fermentum LF1, and Bacillus subtilis BS1) were used to ferment chicken liver. Among these, Lactobacillus plantarum LP1 was found to have the strongest growth and acid production capacity and thus was selected as the starter for further fermentation. Single-factor experiments were carried out with five variables, initial fermentation pH, glucose addition, inoculum size, fermentation time and solid-to-liquid ratio. On this basis, the fermentation process was optimized by response surface methodology using three variables at three levels each. The results showed that the influence of three variables on the absorbance at 280 nm (A_{280 nm}) of fermented chicken liver was in decreasing order as follows: initial pH of fermentation medium > solid-to-liquid ratio > inoculum size. The optimal fermentation conditions were determined as initial pH of fermentation medium, solid-to-liquid ratio for 5.57, 1:3.55 (m/V) and 1.5%, respectively. The A_{280 nm} of fermented chicken liver obtained under the optimized conditions was 1.537. The total contents of free amino acids and essential amino acids in chicken liver increased significantly after optimization (P < 0.05), indicating that fermentation can promote the decomposition of chicken liver protein and thereby improve the nutritional value of chicken liver.

Gelatin is a polymer derived from the hydrolysis of collagen. As a natural polymer material with good biocompatibility and biodegradability, gelatin has been widely used in product packaging and thickening and as a delivery carrier due to its good foaming, emulsifying and film-forming properties. In this paper, the physicochemical properties of gelatin such as gel strength, viscosity, color, yield and isoelectric point and the factors influencing them are reviewed, as well as the modification of different types of gelatin, the types and ways of cross-linking of gelatin and the preparation of various functional gelatin-based hydrogels. Gelatin composite hydrogel adhesives with different functional properties can be synthesized by introducing different functional groups into different artificially designed materials, which can enrich the application of gelatin in daily life and provide some new ideas for the extraction and comprehensive utilization of gelatin.

The effect of mixed food gums combined with ultrasonic treatment on physicochemical properties, rheological properties and in vitro digestibility of chicken blood tofu gels was studied. Guar gum mixed with Arabic gum (3:7, m/m) and guar gum mixed with konjac gum (5:5, m/m) were evaluated. The quality of chicken blood tofu was evaluated in terms of its yield, particle size, zeta potential, protein secondary structure, rheology and in vitro digestibility. The results showed that the yield of chicken blood tofu was increased by 15.91% after the addition of guar gum mixed with konjac gum combined with ultrasonic treatment. Additionally, the absolute value of zeta potential was significantly increased (P < 0.05). Fourier transform infrared (FTIR) spectroscopic analysis and microstructure observation indicated that mixed food gums combined with ultrasonic treatment enhanced protein-protein interactions in chicken blood tofu, resulting in the formation of a more stable gel network. The storage modulus G’ and loss modulus G” were increased significantly, but there was no significant difference in phase angle. Additionally, in vitro digestibility of chicken blood tofu was increased to 82.93%. The two treatments had similar effects on the yield, particle size, zeta potential, protein secondary structure, rheology and in vitro digestibility of chicken blood tofu. But guar gum mixed with Arabic gum was generally more effective than guar gum mixed with konjac gum. These results suggested that mixed food gums combined with ultrasonic treatment not only improved the quality of chicken blood tofu gels, but also increased the in vitro digestibility, which can provide a theoretical basis for broiler breeding, slaughtering and processing enterprises to increase the added value of their products.