ARTICLE 72 FEED & ADDITIVE MAGAZINE October 2023 Starches are macronutrients in aquafeeds and acts as binders and provide inexpensive digestible energy to aquatic animals. It consists of amylopectin (soft amorphous) and amylose (hard semi-crystalline) components, influencing its properties. In extrusion, the quality of starch is enhanced by the process of gelatinization where the structure of amylopectin and amylose melts along with leaching to form a gel matrix in the presence of heat and water. Gelatinized starch can reduce mineral absorption, compromise immunity, and lead to glycogen and lipid deposits, impairing growth and liver function. UNVEILING THE HIDDEN POTENTIAL OF STARCH IN AQUAFEEDS Amit Ranjan Assistant Professor, Department of Fish Nutrition and Feed Technology, TNJFU Kalaiselvan Pandi Research Scholar, Department of Fish Nutrition and Feed Technology, TNJFU Starch is the most abundant versatile macromolecule with glycosidic linkages which store energy in the form of granules of size ranges from 1-100 µm. Its property is determined by the extent and degree of polymerization. It is characterized by alternative amylopectin (Low density - soft amorphous) and amylose (High density - hard semi-crystalline). In general, the starch molecule is converted either by enzyme or through chemical modifications. In enzyme conversion, the major carbohydrase enzyme called amylase has a crucial role as a catalyst in converting starch into sugar and alcohol whereas, in chemical conversion, starch will be chemically modified to act as binders, emulsifiers, thickeners, or stabilizers through various processes including oxidation, gelatinization, dextrinization, etc. Starch has wide application and is deliberately included in the aquafeed formulation where it has no specific requirement in fish. The inclusion of starch in the fish diet varies among different species. Starch amounts in fish diets vary by species (carnivores: 20%, omnivores: 25-45%, herbivores: 30-50%) due to different feeding habits, digestive capabilities, and utilization efficiency of starch. The primary function of starch is to provide inexpensive energy to the host by sparing protein and lipids from catabolism and to act as binders to improve pellet quality.
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