dc.description.abstract | Sugarcane juice would be an ideal substrate as it contains 94 – 98.5 % sugars
(Sucrose, glucose, and fructose); 1.5 – 6% non – sucrose components (amino
acids, proteins, starch). In addition, Vietnam is considered as one of the major
sugar producers and consumers in the world. There has been little understanding
in feasibility of wine or alcoholic beverage production from sugarcane juice.
Therefore, the main object of this research was to evaluate, sugarcane juice
utilization and ethanol production of different yeast strains which were previously
isolated from sugar enriched fermented fruits. In addition, natural fermentation
utilizing the microbial communities in the sugarcane juice was also conducted for
comparison.
After 7 days of fermentation, samples were collected for the measurements of
microbial growth (OD600), ethanol production (by GC), total reducing sugar
(using DNS assay), and total soluble solids (Brix).
The glucose utilization was used to construct by Excel software at 540nm
wavelengths. The first fermentation of reducing sugar after putting different
yeast strains into sugarcane juice was 1.519g/L. After 7 days of fermentation,
banana yeast peaked at 0.652 g/L, the other strains decreased to around
0.06g/L. In terms of total soluble solids, the first fermentation of the medium
was 18 ºBrix. After 7 days of fermentation, banana yeast strains were moderate
fallen to 16 ºBrix, which was over triple as much as the amount of ambarella
yeast, at around 5 ºBrix. During fermentation, all the yeast strains were able to
produce alcohol concentration. The amount of ambarella yeast accounted for the
highest alcohol production, at 87 g/L.
As a result, strain from ambarella as member of Saccharomyces genus were
chosen for the culture combining sugarcane juice with green tea or sugarcane
juice without adding green tea. After calculation, every culture was not affected
deeply on the growth of ambarella yeast in particular the ethanol made up
around 58g/L, sugar concentrations stood at nearly 0.055g/L. | en_US |