Studies on parboiled rice—Part 2: Quantitative study of the effects of steaming on various properties of parboiled rice

A study was made of the effect of steaming on the solubilisation of the starch in paddy rice and the relative crystallinity and milling yields of the dried product.The rates of gelatinisation and solubilisation of the starch were extremely dependent on steaming pressure. Solubilisation continued long after gelatinisation was completed and was a more useful index of processing treatment. The relative crystallinity due to amylose complex formation was highly significantly and positively correlated (r = 0·960) with the extent of solubilisation achieved during steaming. Slight steaming markedly increased milling breakage and yields were only improved in relation to unprocessed rice after the starch had been completely gelatinised.