Carbohydrase

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Introductions

Sugars are the most abundant class of organic compounds in nature, and their degradation and utilization by organisms is one of the most important reactions. Carbohydrases are a large class of enzymes with the function of degrading, modifying and generating glycosidic bonds. Due to the low solubility of macromolecular sugars, their glycosidic bonds are difficult to reach, and therefore they are relatively efficiently acted upon by enzymes. Therefore, they are relatively inefficient for enzymatic action. The carbohydrate-binding domain can specifically bind polysaccharide substrates and plays a key role in enhancing the enzymatic efficiency of sugar substrates.

Carbohydrases and Poultry Growth Performance

The commercial use of carbohydrases in poultry diets began in the late 1980s and early 1990s, where they could improve the water content of bedding, digestive and apparent metabolic energy problems caused by diets containing high levels of fiber. These enzymes have been used to balance the adverse effects of non-starch polysaccharides (NSP) on poultry intestinal health/productive performance. Several previous studies have shown that enzymes secreted by fungi and bacteria are effective in degrading β-glucan and arabinoxylan in diets with wheat, barley, rye or oats as the main components.

Table 1. Effectiveness of different carbohydrases used in various feed ingredients

Xylanase

Xylanase is commonly used to degrade non-starch polysaccharides such as arabinoxylan and β-glucan in poultry feeds. Studies have shown that the addition of xylanase to wheat-based diets or barley-based diets can reduce the viscosity of surimi in the intestine of poultry by 30% to 50% and 300%, respectively. The reduction in viscosity of intestinal chyme improves protein digestibility, apparent metabolisable energy digestibility, feed intake, weight gain and feed conversion.

New generation of carbohydrases

The term next generation feeding enzymes (carbohydrases) was first used by Cozannet et al. These enzymes have a unique thermal stability, high activity and wide pH range, and can improve the digestibility of a wide range of nutrients. The use of new generation carbohydrases enriched with xylanase and arabinofuranose enzymes can improve the total digestibility of feeds for broilers. Indeed, xylan endonucleases degrade arabinoxylan chains by hydrolyzing the xylan backbone. However, multiple arabinose decreases the efficiency of xylanase, especially in corn and related by-products.

Carbohydrase for modification of starch

The functional properties of modified starches treated with various carbohydrate enzymes have received much attention in the food science and technology community. Enzymes are used to modify starch and change its structural properties for application in food and other industries. Enzymes that hydrolyze straight-chain starches such as cyclodextrin degrading enzymes can be used to produce a variety of straight-chain starches. When deprotonating enzymes react with starch, the branched chains of branched starch will be changed and the resulting modified starch will be stable during freeze-thawing, which is very promising in food industry. The resulting modified starch is stable in the freeze-thaw process and has great potential for application in the food industry.