physicochemical

MANOJ et. al.
The two yeast cultures MTCC-172 and AMY-
2 were used for fermenting the over ripened sapota
fruit pulp for alcohol production. Based on the
literature available, for finding out the optimal
fermentation conditions like pH and temperature,
different pH’s (4.0, 4.5 and 5.0), temperature
conditions (ambient and 26 0 C) and different time
intervals (24, 48, 72 h) were used, in the present
experiment, and alcohol content measured during 72
h of fermentation. Before fermentation, an experiment
was carried out to know the minimum concentration
of pectinase which will increase the flowability of
sapota pulp. Flowability was found to be maximum
with 0.5% pectinase concentration. Pectinase
treatments decreased the viscosity of the juice and
increased the fermentation rate during the ethanol
fermentation (Joshi and Bhutani, 1991).
Alcohol content
Saccharomyces cerevisiae MTCC-172
exhibited higher alcohol production with over ripened
sapota fruit pulp. Alcohol content observed was
maximum (67.00 g L -1 ) at 24 h of fermentation and it
decreased with increase in fermentation time i.e. up
to 72 h (Table 2). The findings, in the present studies,
also indicate that 24 h time is sufficient for maximal
formation of alcohol with both cultures MTCC-172 &
AMY-2.
Table 2. Alcohol content in over ripened sapota pulp during three days of fermentation
Treatments Alcohol content (g L -1 )
Day 1 Day 2 Day3
S. cerevisiae MTCC-172 + pH 4.0+ Ambient Temperature (30-38.6 0 C) 39.80 42.41 41.10
S. cerevisiae MTCC-172 + pH 4.0+ Control Temperature (26 0 C) 40.21 39.60 39.89
S. cerevisiae MTCC-172 + pH 4.5+ Ambient Temperature (30-38.6 0 C) 55.82 55.85 55.80
S. cerevisiae MTCC-172 + pH 4.5+ Control Temperature (26 0 C) 58.80 56.60 57.42
S. cerevisiae MTCC-172 + pH 5.0 + Ambient Temperature (30-38.6 0 C) 62.80 61.50 59.78
S. cerevisiae MTCC-172 + pH 5.0 + Control Temperature (26 0 C) 67.00 65.47 64.92
S. cerevisiae AMY-2 + pH 4.0+ Ambient Temperature (30-38.6 0 C) 30.17 26.50 29.80
S. cerevisiae AMY-2 + pH 4.0+ Control Temperature (26 0 C) 32.40 34.34 33.37
S. cerevisiae AMY-2 + pH 4.5+ Ambient Temperature (30-38.6 0 C) 46.50 45.83 42.17
S. cerevisiae AMY-2 + pH 4.5+ Control Temperature (26 0 C) 45.22 48.20 45.71
S. cerevisiae AMY-2 + pH 5.0 + Ambient Temperature (30-38.6 0 C) 55.61 53.71 52.80
S. cerevisiae AMY-2 + pH 5.0 + Control Temperature (26 0 C) 58.19 57.85 58.00
SEm± 0.43 0.39 0.37
CD at 5% 1.29 1.17 1.11
*values presented are mean of three replications
The data clearly reveal that both cultures
produced higher alcohol content. The alcohol
content with sapota pulp was higher (67.00 g L -1 ) in
treatment with S. cerevisiae MTCC-172 + pH 5.0 +
Control Temperature (26 0 C). The alcohol content
produced ranged from 39.80 to 67.00 g L -1 in different
treatments against the culture AMY-2 which produced
alcohol in the range of 30.17 to 58.19 g L -1 in different
treatments. Liimatainen et. al., (2000) reported
average alcohol yields of 7.69g 100g -1 when
fermentation was carried out with waste potatoes.
The data indicate that alcohol content
increased significantly with increase in pH of over
ripened sapota pulp i.e. from 4.0 to 5.0 with both
cultures. Maximum alcohol production was at pH
5.0 (Fig 1). Thuesambat et. al., (2007), reported that
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