Brown rice (Oryza sativa L., cultivars ‘Koshihikari’) with a moisture
content of 15% wet basis (w.b.) stored at 15, 25, and 35 C for
up to 4 months was used in the present study. Oleic acid (OA,
P99.0%, analytical standard) was purchased from Sigma–Aldrich
(St. Louis, MO, USA) and toluene (P99.5%, Japanese Industrial Standards
special grade) was purchased from Wako Pure Chemical
Industries, Ltd. (Osaka, Japan).