Comparison of Volatiles in Cooked Rice with Various Amylose Contents

Abstract

Gas chromatography-mass spectrometry (GC-MS) was employed to analyze the volatiles in thirty-five samples of cooked rice (Oryza sativa L.) including the low-amylose rice cv. ‘Oborozuki’, normal-amylose rice, and glutinous rice. A distinct flavor is exhibited in cooked glutinous rice (containing no amylose) because of the high amount of unsaturated aldehydes; therefore, low-amylose rice might also have a glutinous-like flavor due to the decrease in amylose. Thus, volatile profiles were analyzed to determine the relationships with amylose content. The profiles of 42 volatiles in three types of cooked rice were compared. There were significant differences between glutinous and non-glutinous rice samples. Several volatiles detected at significant levels in the glutinous samples were characterized as glutinous-rich volatiles. These volatiles were predicted to be negatively correlated with amylose content. However, of the 22 glutinous-rich volatiles, only indole had significant negative relationship with amylose content. These results suggest that glutinous-rich volatiles are not affected by decreases in amylose content.