Studies on parboiled rice—Part 3: Characteristics of parboiled rice on recooking

The apparent solubility and cookwater loss of samples of parboiled rice, subjected to various steam treatments, were measured after recooking the rice in boiling water. Both parameters were reduced according to the severity of treatment received, the reduction of apparent solubility being the most marked.The results showed a highly significant, negative linear correlation (r = 0.972) between apparent solubility and the relative amount of complexed amylose in the starch. This confirmed the suggestion made in Part 1 of this paper that complexed amylose was responsible for the resistance of the starch towards solubilisation.Estimation of the amylose and amylopectin released into the cooking water and solubilised inside the kernel revealed that both fractions were insolubilised to a similar extent. It was proposed that amylose was insolubilised by complexing with free fatty acids and the amylopectin insolubilised by interaction with the complexed amylose.