Fruity flavour production by Ceratocystis fimbriata grown on coffee husk in solid-state fermentation

Abstract

Ceratocystis fimbriata was grown for flavour production, on steam treated coffee husk supplemented with glucose. Solid media with 20 and 35% glucose, developed a strong pineapple aroma, resulting in the production of 6.58 and 5.24 mmol/l per gram total volatiles (TV), respectively. Compounds such as acetaldehyde, ethanol, isopropanol, ethyl acetate (representing 80.5 and 75.4% of TV, respectively), ethyl isobutyrate, isobutyl acetate, isoamyl acetate and ethyl-3-hexanoate were identified in the headspace of the cultures. At 46% glucose, only a weak odour of banana was detected, and TV production was poor. The addition of leucine increased TV production (8.29 mmol/l per gram), especially for ethyl acetate and isoamyl acetate and a strong banana odour was detected. The biosynthesis of volatile compounds was not improved by the addition of soybean oil and was reduced by that of mineral salts.