Volatile compounds, including γ-lactones, in brown and white rice fermented by Lactobacillus paracasei, were compared using gas chromatography-mass spectrometry (GC–MS) with stir-bar sorptive extraction (SBSE). The contents of most esters, alcohols, lactones and some aldehydes were higher in brown rice samples containing higher amount of free fatty acids after fermentation. In particular, the contents of γ-lactones increased more in fermented brown rice containing high amounts of fatty acids than in fermented white rice, suggesting that γ-decalactone and γ-nonalactone were formed from oleic acid and linoleic acid during rice fermentation. In addition, the contents of γ-decalactone in fermented brown rice samples with added 4-hydroxydecanoic acid and ricinoleic acid were determined. The content of γ-decalactone in fermented brown rice samples with added 4-hydroxydecanoic acid was considerably higher than that in the control after fermentation, indicating that 4-hydroxydecanoic acid could be an effective intermediate for the formation of γ-decalactone in rice during fermentation.
Bibliographical noteFunding Information:
This work was supported by Korea Institute of Planning and Evaluation for Technology in Food, Agriculture, Forestry and Fisheries ( IPET ) through the High Value-added Food Technology Development Program (No. 317035-03), funded by the Ministry of Agriculture, Food and Rural Affairs ( MAFRA ) and by the Technological Innovation R&D Program (S2340863) funded by the Small and Medium Business Administration ( SMBA , Korea).
© 2018 Elsevier Ltd
- Brown rice
- Fatty acids
- White rice