Comparative Analysis of Milling, Appearance, and Cooking Qualities of Traditional, Improved Oryza sativa Indica and Oryza sativa Japonica White Rice Varieties Cultivated in Sri Lanka.

Rice is consumed as a staple food by more than half of the world’s population and is also the primary staple food in Sri Lanka. Additionally, white rice is the most popular choice due to its perceived sensory attributes. Therefore, this study compared only white rice varieties, including four traditional rice varieties, two improved rice varieties and the Nipponbare Japonica Variety. This study revealed that the milling quality of traditional, improved varieties and the Japonica white rice variety was significantly different (p<0.05), except for the bran percentage. The head and broken rice percentages for selected white rice varieties ranged between 61% and 75% and 1% and 44%, respectively. Among the selected traditional white rice varieties, a higher head rice percentage (74.28 ± 2.33) and lower head percentage (61.88 ± 3.20) were shown by Suwandel and Rathal, respectively. With alower head rice percentage, the Rathal white rice variety reported a higher broken rice percentage (11.19 ± 4.16), while a lower broken rice percentage (1.98 ± 0.54) was observed in Kahawunu. The Nipponbare white rice variety reported 48.77 ± 0.88% head rice percentage and 20.78 ± 1.10% broken rice percentage. The grain size varied from short to medium to long, while the shape changed from round to oblong to medium, and the Nipponbare rice variety was categorized as middle round. Appearance quality parameters, including surface area, volume, geometric diameter, equivalent diameter, sphericity, aspect ratio, and thousand kernel weight, were significantly different (p<0.05). In contrast, bulk density, true density, and porosity were not significantly different (p>0.05). The rice varieties displayed varying gelatinization temperatures, with all except Nipponbare classified as having a hard gel consistency and being high in amylose. Significant differences (p<0.05) were observed in cooking parameters such as elongation ratio, cooked length-to-breadth ratio, water uptake, volume expansion ratio, and minimum cooking time among the selected white rice varieties.