MICROBIOLOGICAL AND CHEMICAL CHANGES DURING ...

MICROBIOLOGICAL AND CHEMICAL CHANGES DURING BREADFRUIT
FERMENTATION
BY
OLAITAN, Ololade Funke (PG08/0185)
B.Sc. (UNAAB, Abeokuta)
A Dissertation submitted to the Department of Food Science and Technology, College of Food Science
and Human Ecology, University of Agriculture, Abeokuta in partial fulfillment of the requirements for the
degree of Master in Food Microbiology and Biotechnology
SEPTEMBER, 2011
ABSTRACT
Breadfruit (Artocarpus altilis) is a perennial crop that can be processed into food and feed. Its
fermentation process needs to be understood to increase its utilisation. The changes in the microbial
population and chemical composition of fermenting breadfruit are investigated in this study. Freshlyharvested
breadfruits were peeled, washed and divided into two equal portions longitudinally. The first
portion was grated, washed, pressed in jute bags and fermented (SSF) at ambient temperature (28 ± 2 o C)
for 120 h. The other portion was soaked in sterile water and fermented (SBF) at the same temperature and
time. The microbial population of the SSF and SBF were enumerated and identified at 24 h intervals
using morphological, cultural and biochemical tests as well as 16S rRNA sequence analysis. The changes
in the pH, total titratable acidity (TTA), moisture content, total soluble sugar (TSS), total starch (TS),
total reducing sugar (TRS), protein and mineral contents of the SSF and SBF were determined at 24 h
intervals by standard methods while unfermented breadfruit served as control. The lactic acid bacteria and
yeast counts in the SSF and SBF increased from 3.00 x 10 7 to 2.75 x 10 9 , 6.00 x 10 6 to 1.10 x 10 8 and
7.00 x 10 6 to 3.00 x 10 7 , 7.00 x 10 6 to 7.00 x 10 7 cfu/g, respectively and differed significantly (p < 0.05)
from the control (2.64 x 10 4 , 7.00 x 10 4 and 2.00 x 10 4 , 3.00 x 10 4 cfu/g). The dominant lactic acid
bacteria identified from both SSF and SBF were Lactobacillus plantarum strain 6 and Lactobacillus
pentosus while the dominating yeast was Saccharomyces cerevisiae. The pH of the SSF and SBF
decreased from 4.72 to 4.26 and 5.76 to 4.65, respectively and differed significantly (p < 0.05) from the
control (6.57). The TTA of the SSF and SBF increased from 0.34 to 0.80 and 0.23 to 0.62 mg/g,
respectively and also differed significantly (p < 0.05) from the control (0.18 mg/g). The moisture content,
Federal University of Agriculture, Abeokuta (FUNAAB)
www.unaab.edu.ng
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TSS, TS and TRS of the SSF decreased from 61.98 to 49.50 %, 9.10 to 5.30 g/100g, 20.01 to 12.10
g/100g and 7.92 to 4.10 µg/g, respectively and were significantly (p < 0.05) lower than the control (62.12
%, 8.90 g/100g, 21.89 g/100g and 7.49 µg/g). Furthermore the TSS, TS and TRS of the SBF decreased
from 9.20 to 2.10 g/100g, 20.01 to 13.69 g/100g and 7.71 to 5.42 µg/g, respectively while the moisture
content increased from 63.12 to 78.62 % and were significantly (p < 0.05) higher than the control. The
protein content of SSF and SBF also decreased from 6.01 to 3.98 and 5.65 to 1.94 %, respectively and
significantly (p < 0.05) less than the control (5.91 %). The sodium and potassium content of SSF and SBF
decreased from 4.15 to 2.67 mg/g, 11.45 to 6.19 mg/10g and 3.83 to 3.11 mg/g, 2.39 to 1.35 mg/10g,
respectively and were significantly less than the control (4.51mg/g, 11.26mg). This study has established
that fermented breadfruit has desirable chemical attributes while grating prior to fermentation enhances
the protein and potassium content.
Federal University of Agriculture, Abeokuta (FUNAAB)
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