dc.description.abstract |
Coffee husk is the most abundantly available agricultural waste in many coffee-producing
areas of the tropics including Ethiopia. To date, it does not have much commercial or
industrial value other than, becoming the major polluting agent of rivers and lakes. It
contains caffeine and other chemicals which could be extracted and incorporated in to
beverages in the process of brewing. This potential of the coffee husk to be utilized as a raw
material for making a beverage could be among the solutions for the problem of it being a
waste coming out of coffee bean processing operations. Thus, this study was conducted to
investigate the possibilities of developing hot and cold beverages of acceptable sensory
quality from the dry coffee husk. The study, comprised of three roasting temperatures,
roasting times and different levels of dose, laid out in 3x3x3 factorial arrangement for the
sensory evaluation and 3x3 factorial arrangement for proximate analysis in CRD. Data were
collected on physicochemical characteristics and sensorial response variables and analyzed
using SAS version 9.2 Software. The results of the study revealed that almost all of the
response variables were significantly affected by the interaction of roasting temperature,
roasting time and dose. As a result, the caffeine content of roasted coffee husk was higher in
samples subjected to 1400C for 3, minute than in the rest of the samples compared.
Carbohydrate content is higher in row coffee husk than in the roasted ones and lowest in
samples roasted at 1600C for 5 minutes. Coffee husk hot beverage produced from 1600C
roasting temperature, 3 minute roasting time with 24g/l dose was more accepted by
consumers for all sensory attributes except color, which was favored for the same dose of
coffee husk roasted at 1400C for 5 minutes. More than 50% of the treatment combinations
resulted in overall acceptability score of 4 and above showing various degrees of liking of the
hot beverage. Cold beverage produced from 24g of coffee husk roasted at 1400C for 3
minutes and brewed in a liter of water was more accepted by the consumers for most of the
attributes investigated than the others cold beverage produced by different combination of
the treatments. It is possible to produce cold beverages of acceptable sensory quality with a
number of treatment combinations of 140 and 1500C roasting temperatures and 3 and 5
minutes of roasting time at doses of 20 and 24 g/l. Correlation analysis among the response
variables indicated that moisture content was negatively and very highly significantly
(P<0.01) correlated with fiber, ash and protein contents of the roasted husk. However, it had
no significant (P<0.05) correlation with caffeine. Fiber content showed very highly
significant (P<0.01) and negative association with carbohydrate. Caffeine had significant
correlation with protein. The relationship between sensory quality attributes of both hot and
cold beverages of the coffee husk is very highly significant (P<0.01) and positive with each
other. It can be concluded that the chemical composition of coffee husk and consumer likings
of the beverage are significantly affected by roasting temperatures, roasting times and doses.
The findings from this study could promote the consumption of coffee husk in the form of hot
and cold beverages which, with no doubt, can be considered as one of mitigation strategy
against environmental pollution which otherwise would be debilitating to our coffee industry.
However, additional studies need to be done using more number of varieties to come up with
a comprehensive recommendation. |
en_US |