Effect of physical and chemical modifications on arrowroot (Maranta arundinacea) and Kithul (Caryota urens) composite flour for biscuit development and their impact on human blood glucose levels

Abstract

Both Arrowroot (Maranta arundinacea) and Kithul (Caryota urens) are underutilized vital flour sources in Sri Lanka. The development of composite flours and applying different modifications to them are novel trends in the food industry. In the present study, pre-gelatinization, microwave treatment, acidification, and dextrinization treatments were applied to Arrowroot: Kithul composite flour to evaluate the effect of modifications on their nutritional and physicochemical properties. A biscuit formulation was developed, and the consumer preference was evaluated followed by assessing its effect on the blood glucose level of healthy people. Modified flours resulted in lower crude protein and fat content. Pre-gelatinized flour had the highest bulk density (0.8 ± 0.00) while it reached complete gelatinization at a lower temperature (75 °C). Cracks and ruptures were observed in modified starch granules due to the processes they have undergone. Amylose content varied between 9.94 and 24.49% among flour types while the highest viscosity was achieved in microwave treated flour (8222.00 ± 60.9 cP). The lowest swelling power and highest solubility were obtained for dextrinized flour. The application of different modifications increased the gelatinization properties of flour while reducing the gelatinization temperature as an advantage to their use in the food industry. Microwaved flour incorporated biscuit was the most consumer preferred and its effect on human blood glucose levels was not significant.