Enhancing ultrasound-assisted extraction for evaluating antioxidant activity and total phenolic contents in Thai Hom Mali rice: A K-means clustering approach

Abstract

The extraction of antioxidants from Thai Hom Mali rice and its brown rice variant was optimized using ultrasound-assisted extraction. The optimal extraction conditions involved treating a 1 g rice sample with 20 mL of a 60% v/v ethanol–water solution at 30 °C for 10 min. A total of 292 rice samples were analyzed to evaluate their antioxidant activity and total phenolic contents. These rice samples were found to be a rich source of phytochemicals with antioxidant activity. To further evaluate rice quality, K-means clustering was applied, enabling the efficient classification of the two rice varieties into three quality levels (low, medium, high) based on their phytochemical profiles. The clustering results revealed distinct regional quality distributions, providing valuable insights for enhancing agricultural practices and marketing strategies. These findings underscore the functional properties and health-promoting potential of phytochemicals in Thai Hom Mali rice.