Please use this identifier to cite or link to this item: https://hdl.handle.net/10321/3802
Title: Nutritional value and bioactive properties of Opuntia ficus-indica cladodes
Authors: Mabotja, Mologadi Bernard 
Issue Date: 2020
Abstract: 
Medicinal properties and pharmacological activities of plants have been attributed to their
bioactive compounds. However, research has shown that bioactive compound
concentrations, biological activities and nutritional profile are influenced by cultivar type.
The aim of the study was to characterize the cladodes of 42 spineless cultivars of Opuntia
ficus-indica at the Agricultural Research Council in terms of their chemical, nutritional and
medicinal properties. The antidiabetic potential of selected extracts was investigated in
vitro against alpha-glucosidase enzyme. Aqueous methanol extracts were assayed for
total phenolic and flavonoid content, and antioxidant activities using 1,1-Diphenyl-2-
picrylhydrazyl (DPPH) and β-carotene linoleic acid system assays. Antibacterial activities
of different extracts were assessed against two Gram (-) and two Gram (+) bacteria and
their minimum inhibitory concentration (MIC) values recorded. Vitamin C, β-carotene and
individual phenolic acid contents were analysed using a Shimadzu HPLC (LC-2030C 3D)
equipped with a C18 Luna® column. Quantification was achieved by calibration curve
plotted using different standards. Mineral elements were quantified using inductively
coupled plasma - optical emission spectrometry.
There were variations in the yield depending on the cultivars, however, 50% methanol
extracts generally had higher yield as compared to petroleum ether extracts. Significant
variation in phytochemical composition, pharmacological activities and nutritional value
was observed in the different cultivars studied. The total phenolic content of Berg x
Mexican was about 5 times higher than that of Robusta and Montery. Similarly, the
flavonoid content of Turpin and Berg x Mexican was about six folds higher than that of
Corfu, Montery and Amersfoort. Different cultivars showed different percentage
antioxidant activities. Many of the cultivars exhibited antioxidant activity comparable to that of butylated hydroxytoluene (BHT), a synthetic antioxidant usually used as a food
additive to prevent the damage caused by free radicals during oxidation processes.
Alpha glucosidase inhibitory assay revealed a dose dependent activity with IC50 values
ranging from 0.06 - 1.85 mg/ml and 27 of the cultivars showing IC50 values lower than
that of acarbose. Noteworthy antibacterial activity was observed against Bacillus subtilis
and Escherichia coli with MIC values below 1 mg/ml. The poorest activity was observed
against Klebsiella pneumoniae. Petroleum ether extracts generally had the best
antibacterial activity when compared to 50% methanol extracts.
Compounds profiling indicated that catechin and gallic acid were found to be present in
significant quantities in all the cultivars investigated, whilst the least occurring compound
was quercetin. Vitamin C content ranged from a lowest of 8.95 mg/100 g to a highest of
124.10 mg/100 g. β-carotene content ranged from a lowest of 3.9 mg/100 g and highest
of 31.4 mg/100 g. Potassium and calcium were the most abundant elements present in
the Opuntia ficus-indica with a highest of 4980.00 mg/100 g for potassium, whilst iron
was found to be the least present with a range of 0.20 to 54.67 mg/100 g.
In conclusion, the observed findings indicate that the spineless cladodes of Opuntia ficusindica cultivars are important sources of nutrients and bioactive properties and can be
considered as functional foods. Although no cultivar could be singled out as the best as
each pharmacological, phytochemical and nutritional trait was different in each cultivar,
the observed findings indicate the need for careful cultivar selection when using spineless
cactus pear cultivars for product development to ensure product integrity.
Description: 
Submitted in fulfilment for the Degree of Master of Applied Sciences in Biotechnology in the Department of Biotechnology and Food Technology, Durban University of Technology, Durban, South Africa, 2020.
URI: https://hdl.handle.net/10321/3802
DOI: https://doi.org/10.51415/10321/3802
Appears in Collections:Theses and dissertations (Applied Sciences)

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