Determination of Physicochemical, Functional and Antioxidant Properties of Pigmented Rice

Abstract

Pigmented rice has a high antioxidant content, and its properties aid in the formulation of nutraceutical food products. This chapter aims to  determine  the physicochemical, functional and antioxidant properties of ten pigmented Indonesian rice varieties - Merah Saleman, Mota, Beureum Taleus, Anak Doro M, Cempo Salamet, Ketan Putri, Ketan Hitam I, Ketan Hitam II, Gogo Niti II, and Care Hitam.  Except for crude fibre, there was a significant difference in the physic properties and proximate analysis of pigmented rice at p<0.05. The sample with the lowest amylose had the highest peak, trough, and final viscosities, but it also had the lowest pasting temperature.  The gelatinization enthalpy ranged between 0.82 and 1.33 J/g, with the sample containing the most amylose having the lowest gelatinization peak.  The functional properties of the water absorption index ranged from 4.22 - 7.63 g/g, and the water solubility index was between 3.62 - 7.40%, the oil absorption index varied from 0.88 - 1.36 g/g, while the swelling power was between 5.31 - 8.42 g/g. Furthermore, the antioxidant properties of the samples measured in terms of the phenolic content ranged from 2.17 - 10.60 mg GAE/g, the flavonoids varied from 0.43 - 2.31 mg QE/g and their activity used the stable 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl radicals. The total flavonoid content of the phenolic component was found to be positively related to antioxidant activity. Finally, the ten pigmented rice samples demonstrated a diverse range of physicochemical, functional, and antioxidant properties, making the samples suitable for the development of a variety of health-related products.