Starch and flour are important ingredients that determine the quality and carbohydrate nutritional value of human foods, pet foods, and animal feeds. In the agri-food field, there has been a continuous interest in advancing our understanding of the functional characteristics and digestibility of starch and flour under high-temperature cooking conditions (> 100°C). This presentation will cover our recent research of utilizing differential scanning calorimeter, Rapid Visco Analyzer 4800, and texture analyzer to characterize the thermal, pasting and gelling properties and/or in vitro digestibility of different starches, resistant starches, and flours over cooking temperatures of 95-140°C. For commercial isolated starches of different botanical origins, amylose contents and thermal properties are important factors influencing their pasting and gelation behaviors at different heating temperatures. Commercial resistant starches of type 2-4 were cooked at 95-140°C to measure their in vitro digestibility, and the mechanisms of how the digestibility was affected by their thermal, pasting and gelling properties were clearly elucidated. With the gained understanding, functionalities of commercial flours from various botanical sources were also analyzed after cooking over 95-140°C. Different from high-purity starches and resistant starches, it was revealed that chemical compositions and particle sizes of the flours also played a vital role in determining their thermal, pasting and gelation behaviors. The presented new knowledge will be beneficial for the agri-food industry to jointly deploy the aforementioned instruments to evaluate and predict the performance of starch and flour ingredients under high-temperature processing conditions, such as in canning, extrusion and jet-cooking, which thus can be used to maintain and improve the quality and nutritional value of the final products.
1. Understand the functionalities and digestibility of starches at high heating temperatures as measured jointly by DSC, RVA 4800, and texture analyzer
2. Acquire new knowledge on the behaviors of flours at high cooking temperatures as revealed jointly by the three instruments
3. Gain a greater understanding of how different processing and modification methods influence the functional attributes and digestibility of starches and flours