Effect of storage on the chemical composition of husked, undermilled and milled rice.

Raw husked rice, raw undermilled rice containing 1.8 μg. of thίamine/g., parboiled rice
and raw milled rice were stored in gunny bags for a period of one year. The samples were
kept free from infestation. The changes in the grain during storage have been studied.
The amylase activity in freshly harvested rice decreased rapidly ; there was an improvement
in the cooking quality, and in all the samples, except parboiled undermilled rice,
a loss of thiamine of about 20—30% was observed. A decrease in nitrogen soluble in 3%
sodium chloride solution was observed, and this may be due to denaturation of protein
during storage. There was an increase in the acidity and the peroxide value of the fat
present in the different samples of rice, the increase being at a maximum for husked rice.
The storage lives for the various samples, as estimated by plotting the peroxide values of
the fat against the storage period for all the samples in conjunction, with organoleptic tests
at the end of one year, are approximately as follows : raw husked rice, 7 months ; raw
undermilled rice, 12 months ; parboiled undermilled rice, 11 months ; and raw milled rice,
13 months.