Optimization of Soaking Duration and Temperature for Two Nigerian Rice Cultivars

Abstract

Optimization of soaking duration and temperature for two Nigerian rice cultivars were evaluated. Temperatures of 50oC, 70oC and 90oC were used for both long and short grain rice paddy. Each treatment had three replicates of 12, 18 and 24 h of soaking durations. The physical analysis of the long/short rice paddies were 1000 kernel volume 24.3/22.3 cm3, 1000 kernel weight 24.2/24.3 g, density 1.3/1.1 gcm3, length, 9.9/8.2 mm, width, 2.95/3.3 mm, water absorption rate of 34/11% and moisture content of 14/11% respectively. Sensory evaluation of the long/short grain
rice yield based on colour and general acceptability showed that significant differences existed among the samples with colour 8.05/7.85, general acceptability 8.10/7.80 respectively. The long/short grain percentage breakages were 2.7/1.2% and total yield 70/67%, respectively. At 70oC long grain rice yield increased as soaking duration increased, and at 90oC, short grain rice yield increased as soaking duration increased. The best quality was achieved by soaking the long grain at 70oC for 24 h and short grain at 90oC for 24 h.

Keywords: Temperature, soaking duration, processing, rice cultivars