COMPOSITION OF GREEN COFFEE WATER-SOLUBLE FRACTIONS AND IDENTIFICATION OF VOLATILES FORMED DURING ROASTING

Flavour precursors from water-soluble green coffee low molecular weigh t (B) and high molecular weight (C) fractions were investigated and th e volatiles formed during roasting were identified by high resolution gas chromatography/mass spectrometry (HRGC/MS). Roasting promoted exte nsive degradation of trigonelline, sucrose and amino acids in fraction (B) and of arabinogalactan in fraction (C). The analyses of the roast ed isolated fractions showed that furans are not only formed by sucros e degradation but also by arabinogalactan pyrolysis. Also, pyrazines a ppear to be mainly formed by pyrolysis of hydroxy amino acids from fra ction (C). The results also showed that pyridine found in roasted coff ee is not exclusively formed by trigonelline degradation but also by p rotein pyrolysis.