Functional properties and bioactive compounds of pigmented brown rice flour

Abstract

This study aimed to investigate physicochemical and functional properties as well as bioactive compounds from Thai pigmented brown rice flours from four varieties of indigenous kinds of rice in Thailand, namely Hom mali (HR), Red hom mali (RHR), Riceberry (RBR) and Homnil (HNR). The results showed that all Thai pigmented brown rice flours contained high contents of carbohydrate, protein, vitamins and minerals. The highest amylose content was present in RHR. All Thai pigmented brown rice flours have low RAG (rapid available glucose) and GI (glycemic index), especially RHR. The pasting properties were slightly altered when heated. The gelatinization temperature was high, but the enthalpy was non-significant. These flours have good water and oil absorption, swelling, solubility, emulsion, and foaming properties. In addition, these flours have a high syneresis during storage at low temperatures. The study of bioactive compounds demonstrated that all Thai pigmented brown rice flours contained significant total amount of total phenolic compounds, flavonoids, and antioxidant activities, especially in RHR. The morphology study revealed that all samples are in polyhedral shape and varied in sizes.