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 conditions for optimizing the physicochemical properties of rice. 2 rice varieties (Nerica 14 and Jasmine 85) were parboiled under 4 sets of conditions (soaking and steaming time combinations). A combination of 4 soaking times (6, 20, 24, 36 h) and 3 steaming levels (40, 60, 90 min) was used. Samples were also taken from conventional parboiling groups and used as checks alongside the control samples. The parboiled rice samples were milled and physical properties, such as milling yield, head rice yield (HRY), colour, hardness, broken percentage, translucency and gelatinization temp. were evaluated. Parboiling at 20 to 24 h soaking with 60 min of steaming produced rice with best physical qualities except for colour; milling yield was 80%, HRY was 60% and whiteness was 49%. The commercial samples gave values that were close to medium parboiling values. Also ANOVA results showed that soaking and steaming time have a 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 degrees C followed by steaming for 60 min at 80 degrees C to maximize the physical qualities of parboiled Jasmine 85 and Nerica 14.