Pasting behavior of amylose amylopectin and, their mixtures as determined by RVA curves and first derivatives

The relationship between amylose to amylopectin ratio and functional properties of maize starch blends (system 1) and "model mixtures" (system 11) made of waxy and high amylose maize starch were investigated using the Rapid Visco Analyser (RVA). A 4-5% difference in amylose content caused significant difference in RVA curves and their first derivatives. Based on the first derivative of the RVA curves four different parameters (Peak 2, Peak Time 2, Peak 3, Peak Time 3) were defined. Peak viscosity and parameters were negatively correlated with amylose content confirming that amylopectin is mainly responsible for water uptake. The final viscosity of starch was very high and decreased as amylopectin or amylose was added, indicating that this parameter is the most sensitive to interactions in starch. In system 11 amount and characteristics of amylopectin seemed to primarily determine the pasting properties. Traditional RVA curves and parameters proved to be feasible to detect the differences between gel properties of the two systems after cooling. First derivative viscograms and alternative parameters seemed to be suitable to demonstrate the importance of interactions between the starch components during gelatinization. Our results confirmed that the Rapid Visco Analyser is a sensitive rheological tool for evaluating effects of starch structure and chemical composition on functional properties providing valuable help for food technologists.