Enzymatic Modification of Starch: A Review

Starch is the most abundant naturally occurring carbohydrate reserve in plants and is found in cereals, roots, tubers, legumes and some immature fruits like bananas or mangos. Starch is usually employed as a food additive, such as a thickening, stabilizer, or texture enhancer to improve some of the products quality characteristics, pharmaceutical and among other. The application of native starch is often restricted owing to its constricted solubility, weak functional attributes and limited tolerance to a wide array of processing conditions. Its low resistance to shear, high retrogradation, and poor freeze-thaw stability, limit the use of starch in industrial applications. These natural shortcomings can be overcome by different methods of modification. In recent decades, enzymatic modifications have been adopted, partly replacing the chemical and physical methods for the preparation of modified starch, as enzymes are safer and healthier than chemical method for both the environment and food consumers. Several enzymes viz., alfa-amylase, beta-amylase, glucose isomerase, pullulanase, xylanase, among others are use in modification of starch. The enzymatic modification of starch molecules directly affected properties of the modified starch especially in freeze-thaw stability of gels and retardation of retrogradation during storage. Combined enzymatic modification resulted in a marked increase in resistant starch and enzyme modified starch can be well utilized as a fat replacer. It is environment-friendly method and can provide desired functional characteristics.