Studies on parboiled rice: Part 1—Comparison of the characteristics of raw and parboiled rice

Various properties of raw and parboiled rice were compared in an effort to elucidate the factors responsible for the changes induced by parboiling.The parboiled rice was less prone to disintegration on cooking, the kernels remaining well separated and less sticky than the non-parboiled sample. The solids leached into the cooking water and the extent of solubilisation of the kernels on cooking were both considerably lowered by parboiling. Amylograms of flour prepared from the rice revealed that this was due to the resistance of the starch in the parboiled rice to swelling and solubilisation in hot water.From the results of X-ray diffraction spectra it was concluded that the behaviour of parboiled rice is influenced by the presence of an insoluble helical amylose complex and not, as is generally assumed, by retrogradation.