Granular cold-water swelling starch; properties, preparation and applications, a review

Due to the advances in process engineering and the emerging market trends, the demand for novel and versatile starches is growing rapidly. Thus, modified starches have been developed to increase the industrial applications of starch and to reduce or eliminate shortcomings of native starches. The main aim of this review paper is to re-introduce granular cold water swelling (GCWS) starch as a physically modified and highly popular material in the food industry particularly in green and clean labelling. This article highlights the recent advances in production of GCWS from different sources and the current research gap for further progress. GCWS starch hydrates and swells instantly without heating and produces the functional properties of fully gelatinised starch. GCWS can reduce or eliminate cooking time and act as thickening agent, stabiliser and emulsifier in instant foods and non-thermal processing. GCWS starch is produced by several methods including spray drying, ball milling, alcoholic treatments at atmospheric or elevated pressure and temperature and alcoholic-alkaline treatments. Compared to native starch, GCWS starch often contains lower fat, amylose and protein content but higher ash content. It contains swollen, deformed and wrinkled granules, exhibits very weak or no maltase cross and birefringence, has significantly higher swelling power and water solubility, often exhibits V-type X-ray diffraction pattern, has lower paste viscosity and retrogradation, and higher clarity, improved freeze thaw stability, no or reduced endothermic DSC profile. Further studies are required to identify novel opportunities for GCWS in terms of manufacturing, applications and nutritional and health benefits.