A Study on the Effect of Storage Conditions on the Quality of Four Chinese Rice Varieties

Rice quality is partially determined by weather conditions during production but is largely controlled by harvesting methods and postharvest practices particularly during storage and milling. In this present study, the relationship between storage conditions and the quality of milled rice stored in paddy was investigated. One packing material and two storage conditions (temperature and humidity) were evaluated on four Chinese rice varieties (Zhong dao feng you, Er you xiang 66, long grain varieties and Liao xing, Yan feng, short grain varieties). The changes in free fatty acid (FFA) and physiochemical properties (moisture content and grain breakage, hardness and degree of balance, whiteness and taste score) of milled rice were analyzed following seven months storage period. Results show that free fatty acid, moisture content, grain breakage, hardness and degree of balance increased substantially (deteriorated) during storage at higher temperature and relative humidity (40°C, 70% r.h as compared to 15°C, 30% r.h). Taste and whiteness values also indicated deterioration of rice during storage at higher temperature and relative humidity. Highest FFA value of 0.29% was recorded for both long grain varieties after storage at higher temperature and humidity. Highest mean value for grain breakage during milling was 11.01 % and 11.04 % for less resistant long grain varieties. Taste score ranges from 73.11 % - 81.22 % during lower temperature storage as compared to 71.12 % - 78.55 % during high temperature storage. Hardness index of all samples increased significantly with higher temperature storage.