Abstract:
Cactus (Opuntia ficus-indica),which was introduced to Ethiopia in 1848, is a drought resistant
and lif-saving crop. In Ethiopia, particularly in Tigray, Cactus has been used as a major
source of household income and nutrient-rich food. Eventhough Cactus cladodes are
processed into flour via optimization of drying condition to use in various food industries
globally, this practice is not yet adopted in Ethiopia. Therefore, the main objective of this
thesis work was to optimize the drying process of cactus cladode for the purpose of powder
production based on the drying temperature (55, 65 and 75 oC), pretreatment (unblanched,
blanched with and without removing skin) and slice thickness (0.5, 1 and 1.5 cm) factors. The
experiemt was designed with factors in full factorial arrangement of 3x3x3 in a completely
randomized design (CRD) with three replications. The functional properties, phytochemicals
and anti-nutritional factorsof cladodes powder were analaysed by response-surface method of
Box-Behnken design using Design Expert software (version 6.0.8). The Curve Expert 32
(version 1.4) was applied to select the best fitting model and get the various equations used
for the ploting of the graph of moister ratio and drying rate based on the value of R2
and
standard devaition, while the Design Expert software (version 6.0.8) was used to fit various
responses. The obtained data of proximate composition and mineral contents were statistically
interpreted using one-way ANOVA. The findings of this study indicated that the moister content of fresh and dried powder of leaf of Cladodes was obtained 87.81% and 7%,
respectively. The values of water abospriton capacity, water solubility index, and chlorophylla for the unblanched, blanched with and without removing skin of the cladodes’ leaves were
found to be 5.63 g/g-26.73g/g, 24.17%-45% and 0.032 mg/g-0.041 mg/g, respectively. In this
finding, the un-blanching treatement, drying temperature of 55 °C, and a slice thickness of 1.5
cm were found to be the optimal conditions for the drying process of cladodes’ leaves. In
conclusion, the majority of the proximate compositions and mineral contents were not
significantly affected by drying temperature and slice thickness. The anti-nutrient contents
were not affected at all by the indicated factors. It is recommended that further research on
the determination of shelf-life of dried powder of various species and its application for the
formulation of various food products be conducted
