Application of Sorbitol in Aquatic Products Processing

Sorbitol is derived from plants and is the reduction product of hexose, hexitol. It is a non-volatile polysaccharide alcohol with stable chemical properties. It is sold in liquid or solid state on the market; Sorbitol has a sweet taste, which is 60% of the sweetness of sucrose, and its calorific value is similar to that of sucrose. However, eating too much sucrose can cause dental caries in children, and it has great health hazards for patients with diabetes and obesity. Sorbitol is not controlled by insulin in the process of human metabolism, and its metabolites are CO2 and H2O, which will not affect blood sugar levels. Therefore, it is often used as a sweetener, loosening agent, moisturizer, etc., and is used in candies, bread, noodles, rice products and other foods.

Studies have shown that the more hydroxyl groups in sugar molecules, the better the effect of inhibiting protein freezing denaturation. Sorbitol has strong water absorption and can combine with the moisture in the product and the surrounding environment through hydrogen bonds to reduce the water activity of the product and prevent the product from drying, aging, dehydration, crystallization of sugar or salt during storage, which can guarantee the best flavor and quality of the product.

Application of sorbitol in aquatic product processing.

With the continuous growth of the aquatic product market, the quality of aquatic products will deteriorate during transportation, processing, storage, etc. The quality of products during storage has become the focus of research by more and more scholars. Therefore, sorbitol is widely used in aquatic products as a water activity reducing agent, biological preservative and antifreeze agent.

1. As the water activity reducing agent.

Water activity has a great influence on microorganisms during storage. The survival of microorganisms requires a certain amount of water activity, but too low water activity will limit the growth, metabolism and reproduction of microorganisms, and even die. Therefore, the size of the water activity will affect the shelf life of the product. Sorbitol is a hydroxyl compound, which mainly achieves water retention through the strong combination of hydrogen bonds and water, thereby effectively reducing water activity. Some studies have also found that sorbitol can increase the moisture content of products, not only can promote the retention of external moisture in the product, but also can promote the retention of internal moisture in the product. Compared with xylitol and maltitol, sorbitol can significantly inhibit the growth of microorganisms, has less water loss, and has the best sensory quality, such as the best storage quality effect on squid shreds.

2. As the biological preservative.

Aquatic products have high moisture content (70% to 80%) and high protein content (15% to 22%). Under the action of microorganisms and enzymes, aquatic products will eventually spoil and lose their edible value after caught or slaughtered. Therefore, it is necessary to use some fresh-keeping techniques to delay or inhibit the spoilage of aquatic products. At present, the fresh-keeping technology of aquatic products mainly uses physical means such as low temperature, air conditioning, irradiation, high-voltage electric field, and adding preservatives to delay the spoilage of aquatic products. Among them, preservatives are valued due to their advantages of wide sources, strong anti-oxidation and good antibacterial effect, and are mainly divided into chemical preservatives and biological preservatives. Chemical preservatives are gradually reduced in use or compounded with other preservatives due to certain potential safety hazards; however, biological preservatives are gradually being widely used due to their natural and safe advantages. Sorbitol belongs to plant-based biological preservatives. It is a natural preservative extracted from plants. It has high safety and strong specificity. It is often compounded with various biological or chemical preservatives. Sorbitol has a certain chelating effect. It can chelate the metal ions in the system, which can not only promote the retention of internal water, but also prevent the metal ions from combining with the active center of the enzyme, thereby reducing the activity of protease. Therefore, the application of sorbitol in aquatic products can effectively promote the anti-corrosion, fresh-keeping and water-retaining effects of aquatic products.

3. As the antifreeze agent.

In order to maximize the storage period of aquatic products, low-temperature freezing storage technology is widely used. However, during the frozen storage of aquatic products, the ice crystals will continue to grow with the prolongation of storage time, resulting in mechanical damage to the cells of aquatic products. Protein molecules coagulate and its spatial structure is destroyed and denatured, so the quality and taste of aquatic products are affected. The quality deterioration of different aquatic products is related to the factors such as freshness of raw materials, types of aquatic products, freezing rate, freezing temperature, freezing time and additives used. Antifreeze is one of the more effective ways to reduce freezing denaturation. It can inhibit the formation of ice crystals in free water in cells when aquatic products are frozen, reduce mechanical damage to muscle tissue, better protect the integrity of cells, and inhibit the freezing denaturation of proteins. As an antifreeze agent, sorbitol can be added to fish meat to retain water, and significantly reduce water activity, so that surimi can reduce water loss in a frozen environment, prevent protein denaturation, maintain good elasticity, and improve the frost resistance. Therefore, the application of sorbitol in aquatic products has become a research focus of scholars.