Effect of different levels of inclusion of sugarcane- Pineapple cocktails and packaging materials on Quality of “BISSAP”; A drink made from hibiscus Sabdariff
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Date
2019-07
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KNUST
Abstract
A series of laboratory experiments were conducted to evaluate the effect of
different levels of inclusion of sugarcane-pineapple cocktails and packaging
materials on quality of “bissap”; a drink made from dried calyx of Hibiscus
sabdariffa. The levels of inclusion were generated with the help of Minitab 2017
software and sensory attributes of the resulting cocktails were evaluated for their
flavour, taste, sourness and sweetness. The results of the study showed that, a
cocktail of 30% bissap extract, 20% pineapple and 50% sugarcane juice was the
overall most acceptable cocktail. A 30% bissap extract, 40% pineapple and 30%
sugarcane juice was the most acceptable in terms flavour. The most highly
preferred taste was from the cocktail comprising 33% bissap extract, 33%
pineapple and 34% sugarcane. In terms of sourness the most accepted cocktail
was 30% bissap, 20% pineapple and 50% sugarcane juice. The sweetening effect
derived from the combination of 30% bissap extract, 40% pineapple and 30%
sugarcane juice was the most accepted among the other formulations. The
optimization analysis derived from the Minitab 2017 software used gave the most
favourable product as 30% bissap extract, 38% pineapple and 32% sugarcane
juice which was significantly different (p≤ 0.05) among the treatments over a
four week storage period. The colour of the cocktail reduced in clarity from
33.78 in plastic bottle under ambient condition to 25.08, from 31.16 in glass bottle
under ambient condition to 27.13, from 31.15 in plastic bottle under refrigeration
to 24.98 and from 26.29 in glass bottle under refrigeration to 27.83. The total
soluble acids (TSS) reduced from 10° brix to 9.82° brix in plastic bottle and from
9.68° brix to 9.18° brix in glass bottle. Total titrable acidity (TTA) dropped from
0.45% in plastic bottle under ambient condition to 0.19%, from 0.44% in glass
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bottle under ambient condition to 0.25%, from 0.45% in plastic bottle under
refrigeration to 0.20% and from 0.27% in glass under refrigeration to 0.18%.
The pH levels increased from 2.96 in plastic bottle under ambient condition to
3.76, from 2.90 in glass bottle under ambient condition to 3.74, from 2.88 in
plastic bottle under refrigeration to 3.74 and from 2.96 in glass bottle under
refrigeration to 3.68. The vitamin C content decreased from 4.37 mg/100g to 3.16
mg/100g in plastic bottle and from 3.53 mg/100g to 2.78 mg/100g in glass bottle.
The total ash dropped from 1.37 % in plastic bottle under ambient condition to
0.45 %, from 2.44 % in glass bottle under ambient condition to 1.08 %, from 0.63
% in plastic bottle under refrigeration to 0.34 % and from 0.76 % in glass bottle
under refrigeration to 0.55 %. After four weeks of storage of the drinks, mould
and yeast counts and aerobic plate count (APC) of microbes, were significantly
high (p≤ 0.05) in the plastic bottles under ambient condition (22oC to 28oC) but
there were no moulds and yeasts in the refrigerated bottled drinks. No coliforms
were present in all treatments throughout the storage period.
Description
A thesis submitted to the School of Research and Graduate studies, Kwame Nkrumah University of Science and Technology, in partial fulfillment of the
requirement for the award of Master of Philosophy Postharvest technology