Potential of Antioxidant and Total Phenolic Content of Se Bu Kan Tang Rice, Hom Kra Dang Nga Rice and Sang Yod Rice

Three southern local rice varieties—Sibukanthang rice, Hom Kradangnga rice, and Sangyod rice—were studied. The crude extracts from the seeds of Hom Kradangnga, Sangyod, and Sibukanthang rice showed the highest extraction yields of 2.68 ± 0.031%, 2.09 ± 0.006%, and 0.45 ± 0.006%, respectively. The total phenolic content was highest in Hom Kradangnga (783.21 ± 27.74 mg gallic acid/100 g sample), followed by Sangyod (283.69 ± 16.29 mg/100 g), and Sibukanthang (46.60 ± 4.22 mg/100 g). The antioxidant activity of the crude ethanol extracts was highest in Hom Kradangnga rice at 69.78 ± 2.44%, followed by Sangyod rice (66.49 ± 1.62%) and Sibukanthang rice (57.00 ± 0.69%), with statistically significant differences at the 0.05 level (p ≤ 0.05). Based on these results, the three local rice varieties showed different levels of total phenolic content and antioxidant activity. Hom Kradangnga rice had the highest total phenolic content and antioxidant activity, followed by Sangyod and Sibukanthang rice, respectively. This suggests a correlation between antioxidant activity and total phenolic content. This research highlights the nutritional potential of southern Thai local rice varieties for future applications.