Wheat bran, cassava bagasse and sugar cane bagasse were shown to
be adequate substrates for the growth and aroma production by
the mould Ceratocystis fimbriata. Among the nutritive media
tested, sugar cane bagasse complemented with a synthetic medium
containing glucose (200 g l−1) gave a fruity
aroma while the leucine or valine-containing medium gave a strong banana
aroma.
Aroma production was dependent on growth and the maximum aroma intensity
was detected at about the time of the maximum
respirometric activity. Twenty-four compounds have been separated by
GC headspace analysis and 20 were identified, among them:
1 aldehyde, 7 alcohols, 4 ketones and 8 esters. It was clearly
demonstrated that the chromatographic profile of the headspace of the
culture was dependent on the substrate used and on the eventual precursor
added. When leucine or valine was added to the
substrate, the production of total volatiles in the headspace reached
values up to tenfold higher than that for ripe bananas. The
Gompertz model, a logistic-like equation, was used to fit the integrated
CO2 and volatiles production data.