Research progress on properties of pre-gelatinized starch and its application in wheat flour products

Abstract

Starch is the most abundant organic compound in nature, second only to cellulose. However, the conserved structure of native starches limits their properties and applications. Therefore, it is often necessary to modify them to obtain specific properties. As a common green and safe physical modification method, pre-gelatinization can improve the cold water solubility and swelling power of starch. The typical preparation methods of pre-gelatinized starch include spray drying, extrusion, and drum drying. Spray-dried pre-gelatinized starch still had good granule shape, but the increase of cold water solubility and cold paste viscosity was relatively small. Extruded and drum-dried pre-gelatinized starch showed serious structure destruction, significant increases in cold water solubility and cold paste viscosity, but relatively low hot paste viscosity. The properties of pre-gelatinized starch obtained by different methods are different, so do their effects on the quality of flour products. Wheat flour products, as one of the leading staple food for the people all over the world, play a vital role in people's daily life. With the improvement of people's living standards, more and more special flour products with unique features have received attentions of consumers and researchers. However, the sensory characteristics of special flour products are often inferior to traditional flour products, which limits its development. The unique functional characteristics of pre-gelatinized starch make it expected to play an essential role in the quality improvement of featured flour products. In this paper, the granule morphology, crystal structure, hydration and gelatinization properties of pre-gelatinized starch prepared by three common methods and their application in flour products were reviewed, which provides a theoretical basis for the application of pre-gelatinized starch in food industry. The conserved structure of native starches limits their properties and applications. Pre-gelatinized starch prepared by spray drying, extrusion and drum drying, its structure and physicochemical properties changed significantly. Spray-dried pre-gelatinized starch still had good granule shape, but the increase of cold water solubility and cold paste viscosity was relatively small. Extruded and drum-dried pre-gelatinized starch showed serious structure destruction, significant increases in cold water solubility and cold paste viscosity. Due to its good hydration properties in cold water, it has a good application prospect in multi-grain flour products, frozen dough, gluten-free flour products and high-moisture bread.