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Performance of starches in sauces, batters and gels 
New research on the processing of starch-rich materials from maize, wheat, rice and oats for use in sauces, batters and gelled food products will help processors select the materials best suited to their needs. The important changes that occur in starch during cooking - gelatinisation, swelling to form a paste, setting and retrogradation - are being evaluated. Initially, basic raw materials milled from the cereals such as grits and flours were studied to assess the effects of particle size and cereal types. Increasing particle size delayed gelatinisation and swelling, so that some grits remained largely uncooked, whereas fine flours gave the optimum paste viscosity under normal cooking conditions. Studies with a creamy cheese sauce and a more acidic tomato sauce used in ready meals revealed significant changes in cooking patterns due to interactions with other ingredients. Wheat flour performed well in the presence of fats in white sauce, but the more vitreous cereals, rice and maize, gave better results in the more acidic tomato sauce. Initial studies on the retrogradation of starch pastes and gels have shown the importance of optimizing the cooking process to produce the most stable starch-water systems. Addition of emulsifiers tended to retard cooking and a higher cooking temperature (>90°C) (to melt the amylose lipid complexes) was required for optimum development. Further work will study the effects of thermal treatments of flours and starches in sauces and cake systems. Contact: Robin Guy |