Flowability of Rice Thermally Processed in Pouches: A Pilot Study

Rice has long been one of the most important foods in the world. There have been many attempts to create thermally processed rice products since the advent of modern canning. There has been a constant challenge to create free-flowing, separate grains in these products. Factors affecting the flowability of rice products include rice type, moisture content, rice pretreatments, the addition of oil, and retort conditions. Traditional rice products are packaged in steel cans and thermally processed, while flexible pouches are being increasingly used. Contrasting a wealth of information for canned rice, research on pouch products is limited both in scope and volume. A method used to quantify the grain separation and flowability of canned rice was applied to rice in pouches. The first objective if this work was to determine the hydration behavior of rice prior to thermal processing. The second objective was to evaluate the flowability of rice thermally processed in pouches as affected by rice type, moisture content, rice condition, retort temperature, and the addition of oil.

The affects of hydration time and temperature were dependent on rice type, with parboiled white rice taking up water the fastest. A method to determine flowability was useful for thermally processed rice in pouches. The most flowable rice was completely hydrated to a moisture content of 50%_{wet basis} then filled into pouches and thermally processed at 117 ^oC.