Milling, pasting, and texture changes in rice as affected by aging

摘要

This study was conducted to verify the effect of aging on rice grain quality, and to determine the minimum period wherein rice properties become stable. Four varieties (PSBRc 10, PSBRc 14, IR64, and IR74) of freshly harvested rice differing in amylose content and gelatinisation temperature, and stored at room temperature for 90 days, were assessed every 15 days for their milling quality, pasting characteristics, and texture properties. As the storage period increased, a decreasing trend in total milled rice recovery was observed for all the rice varieties. Percentage brown rice of PSBRc 10 and head rice recovery of IR64, however, were not affected by storage. Aging of the four varieties also resulted in changes in their characteristics. Peak and cooked paste viscosity and breakdown values increased with prolonged storage. Changes in cooked rice hardness occurred within 15 days of storage, but the texture of aged IR64 remained unaffected up to the end of the 90-day storage period. A minimum of 60 days of storage was required for stabilisation of the grain characteristics.