Volatile flavour compounds analysis of solid state fermented Thai rice wine (Ou)

Abstract

Solid-state fermented Thai rice wines (Ou) were analysed to determine their chemical components. Determined parameters were pH (4.5-5.5), protein (0.45-0.99 g/100g), ash (0.10-0.30 g/100g), total solid (1.72-14.34 g/100g), glucose (4.07-7.91 mg/ml) contents and volatile compounds. The ethanol concentration was in the range of 12.15 to 104.60 mg/ml. Profiles of volatile compounds were analysed by dynamic headspace coupled with gas chromatography mass spectrometry and gas chromatography olfactometry. The potent odours were alcoholic and solvent-like, sweet, fruity, buttery, and pungent aromas. The concentration in Ou of n-propanol, iso-butyl alcohol, iso-amyl alcohol, furfuryl alcohol, benzene ethanol, acetol, 2,3-butanediol, glycerol, ethyl lactate, acetoin, furfural, 5-methyl furfural, 5-hydroxymethyl-2-furfural, and acetic acid were also determined by a direct injection technique. From principal component analysis, Ou samples could be categorized into two groups based on the concentration of ethanol and their profiles of volatile compounds.