Effect of Process Variables on Rice Flour Functional Properties, and Porous Structure Properties of Rice and Wheat-Based Leavened Food Products
1Department of Food Science and Technology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Gangodawila, Nugegoda 10250, Sri Lanka
2Department of Agricultural Engineering, Faculty of Agriculture, University of Ruhuna, Mapalana, Kamburupitiya 81100, Sri Lanka
Received: 16 March 2021
Accepted: 14 November 2021
factorial design; dry and wet grinding; heat-moisture treatment; particle size; porous crumb structure; rice-wheat composite flour
Research background. Various processing techniques impart significant impacts on physicochemical and functional properties of rice flour and the quality of the final products. This study aims to modify rice flour from different treatment combinations and to select the best treatment combination in developing rice-wheat-based leavened food products.
Experimental approach. Eight treatment combinations were applied on rice flour according to 23 factorial design considering three variables at two levels namely, pre-treatment for rice grain modification [heat-moisture treatment, dual modification treatment (soaking rice grains in a NaHCO3 solution followed by heat treatment)], grinding technique (dry grinding, wet grinding), and flour particle size (75-180 µm, <75 µm). Eight dough samples were prepared by mixing 50 g of rice flour from each treatment with 50 g wheat flour. Thereafter, the dough samples were subjected to fermentation and gelatinization under pressurized condition (externally applied 1.0 kg/cm2 initial air pressure condition) in a pressure adjustable chamber.
Results and conclusions. Results rendered that rice flour sample that underwent heat-moisture treatment followed by wet grinding and particle size at 75-180 µm, impart to improve the leavened gas retention capacity and obtaining highly porous and better textured rice-wheat based leavened food products under 1.0 kg/cm2 externally applied initial air pressure condition.
Novelty and scientific contribution. Rice flour can be modified according to the present method to improve functional flour properties and the textural and structural properties of rice-wheat based leavened food products. Also, conducting fermentation and gelatinization under pressurized condition is a novel food processing technique, which contributes in restricting the escape of leavened gas from rice-wheat composite dough mass.