Diversity of grain quality characteristics of traditional rice (Oryza sativa L.) varieties in Sri Lanka

Physical properties of rice (Oryza sativa L.) grain namely, kernel length, width, milling recovery, head grain yield, and physicochemical properties including amylase content, gelatinization temperature, gel consistency and volume expansion ratio were analyzed for 21 selected traditional rice varieties. The brown rice and hull percentages varied from 77-80% and 20-23%, respectively while the head rice yield varied between 55- 73% for raw rice milling except for the variety Kuruluthuda. The volume expansion over cooking was more than 2.6 times compared to uncooked rice in all the varieties except for Kuruluthuda and Masuran. The gelatinization temperature (GT) was determined based on alkali spreading score and the majority of the rice varieties evaluated showed intermediate GT (70-74 oC). The rice varieties Madathawalu, Pokkali, Maa Wee, Gonabaru, Inginimitiya and Dular showed low GT values (55-69 oC). No variety was found with a high GT (above 74 oC). Intermediate amylose content (AC) was observed in the majority of varieties except Suduru Samba that recorded a low AC while Herath Banda and Kalu Heenati recorded high ACs. Pachchaperumal and Maa Wee reported a low AC close to intermediate AC. The gel consistency (GC) was highly varied among the selected varieties. Usually soft GC is preferred over hard GC by the consumers. Rice varieties Herath Banda, Wanni Dahanala, Rathal, Hondarawalu, Kuruluthuda, Deveraddiri, Sulai and Masuran were identified as the soft GC varieties. Tropical Agricultural Research Vol. 25 (4): 570 – 578 (2014)