Abstract

This study aimed to determine the nutritional, physicochemical and bioactive characteristics of brown rice from the Noui Khuea (NK) cultivar, a non-pigmented short grain from Southern Thailand, in comparison with commercial non-pigmented long-grain Hom Mali (HM) and pigmented long-grain Sung Yod (SY) cultivars. The A-type XRD pattern was found in all samples of flour. All starch granules had a spherical shape with variable diameters (3.1-3.9 μm). The discrepancies in pasting properties across rice flours were explained by variances in compositions, particularly the amylose level. NK was classified as a high amylose rice, whereas SY and HM were classed as intermediate and low amylose types, respectively. Protein, minerals (phosphorus, potassium, magnesium, manganese, zinc and iron) and α-tocopherol were all higher in NK. SY showed the highest total phenolic content (29.38 mg GAE/g), largely in bound form. Several phenolic compounds (e.g. phenolic acids, esters and glucosides) were discovered. NK extract had the highest ACE-inhibitory activity (72.12%), but SY extract showed the strongest DPPH^•/ABTS^•+ inhibitions, FRAP and α-amylase/α-glucosidase inhibitions. Thus, the rice variety had a significant impact on its quality and bioactivity, and NK could be a viable alternative for both domestic and industrial use as a functional food ingredient.