Effect of Varying Parboiling Conditions on Physical Qualities of Jasmine 85 and Nerica 14 Rice Varieties

摘要

As part of research towards enhancing the value chain of parboiled rice in Ghana, a study was conducted to ascertain the ideal parboiling condition that optimizes the physical qualities of rice. The study was carried out at the Spanish Laboratory of University for Development Studies, Tamale, Ghana. Two rice varieties (Nerica 14 and Jasmine 85) were parboiled in the Laboratory at four different conditions (soaking and steaming time combinations) to ascertain the effects of each parboiling condition on the physical qualities of the parboiled rice. A combination of four (4) soaking times (6, 20, 24, 36 h) and three (3) steaming levels (40, 60, 90 min) was used. Samples were also taken from conventional parboiling groups and used as check alongside the control samples. The parboiled rice were milled and physical properties such as milling yield, Head Rice Yield (HRY), colour, hardness, broken percentage, translucency and gelatinization temperature were evaluated. The results showed that parboiling at 20 to 24 h soaking with 60 min of steaming produced rice with best physical qualities except for colour i.e Milling yield was 80%, HRY was 60% and whiteness was 49%. The commercial samples gave values that were close to medium parboiling. Also ANOVA results showed that soaking and steaming time have direct impact on the final quality of parboiled rice. It was recommended for processors to soak paddy rice for 20 h in warm water between 30 to 40°C followed by steaming for 60 min at 80°C to maximize the physical qualities of parboiled Jasmine 85 and Nerica 14.