Parameters for appraising the storage quality of paddy rice

Abstract: Respiration rates of paddy rice (var: Tebonnet) were examined at moisture contents
ranging from 12.5 to 15.5 % (wet basis) and at temperatures of 26 °, 30 °, and 35 °C. To enable
prediction of safe storage periods, graphs were drawn to express the influence of grain moisture content and temperature on the storage times required to produce a dry weight loss of 0.5 % of the paddy. Even at 13.7 % moisture content microflora development was very low. Only at 14.5 % there is a moderate but significant rise in microflora counts. However, the effect of the tested three temperatures was not reflected in those results. There was a significant increase in microflora development at the end of three months’ storage at 15.5 % moisture content equivalent to 83 % equilibrium relative humidity at 26 °C. Considering that the minimum relative humidity needed for microflora development is 65 %, it is apparent that at 26 °, 30 ° and 35 °C the safe storage moisture content is 12.8 %. It was corroborated that to stimulate microflora activity an equilibrium relative humidity higher than 75 % is necessary. Equilibrium relative humidity curves drawn for the three storage temperatures indicated that the critical moisture content was about 14.5 % equiva1ent to 75 % relative humidity in air.