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Browsing Theses and Dissertations by Author "Mashau, M. E."
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Item Open Access The effect of Moringa Oleifera leaves and termite (Isoptera) powders on nutritional and sensory properties of an instant-maize porridge(2017-09-18) Netshiheni, Khavhatondwi Rinah; Jideani, A. I. O.; Beswa, D.; Mashau, M. E.White maize-based porridge is a staple food for about 80% consumers in South Africa and sub-Saharan African countries contributing significantly to the diet of rural populations in developing countries. White maize is deficient in some amino acids and over-dependency on its porridge may lead to high prevalence of malnutrition-related health conditions. Moringa oleifera (MO) and termite (Isoptera spp.) are known to contain a substantially high amount of protein. The aim of this study was to determine the effect of powders from MO leaves and termite on the nutritional and sensory properties of instant-maize porridge. Inclusion of MO and termite powders in instant-maize porridge, at different treatments, was considered using a completely randomised design. Factor levels were: AOB-control (maize flour); BEA (maize, powders of cooked dried MO and termite); CIA (maize, powders of blanched dried MO and termite) and DJE (maize, powders of uncooked dried MO and termite). Data were analysed using SPSS version 23. The protein content of fortified instant-maize porridge (FMP) significantly (p < 0.05) increased from 10.02 to 21.20% compared to unfortified porridges. The mineral content of FMP was higher in terms of Zn, Fe, Ca and Mg. Moisture content of FMP increased from 5.00 to 6.00%. Sensory analysis showed that among fortified porridges, CIA was rated high for colour and texture, BEA higher in taste and DJE higher for aroma. AOB had higher acceptance than fortified porridges for taste. Powder from MO leaves and termite could be used in complementary foods and food supplements to increase protein and mineral contents.Item Embargo Effect of partial mutton meat substitution with Bambara groundnut (Vigna subterranea (L.) Verdc.) flour on physicochemical properties, lipid oxidation and sensory acceptability of low-fat patties(2024-09-06) Ramatsetse, K. E.; Ramashia, S. E.; Mashau, M. E.Health concerns regarding fat consumption, as well as shifts in customer preference, have prompted substantial studies into low-fat products. This study examined the nutritional, colour, functional, and antioxidants properties of Bambara groundnut (BGN) flour varieties (cream, brown, and red-coated) grains as well as their influence on the physicochemical properties, lipid oxidation, and sensory acceptability of reduced-fat mutton patties. The patties were formulated with 2.5%, 5%, 7.5%, and 10% of BGN flours for each variety, and 100% mutton patties were used as a control. The BGN flours showed significant (p ˂ 0.05) differences in their nutritional composition (except for ash content), colour, functional (excluding the emulsion stability), antioxidant properties. The inclusion of BGN flours significantly increased the fibre (0.00 to 0.79%) and ash (1.16 to 1.99%) contents of the formulated mutton patties. However, moisture, protein contents, and carbohydrates decreased. The cooking yield of the formulated patties significantly increased with values ranging from 76.39 to 86.80% but the diameter decreased. The inclusion of BGN flours significantly increased the lightness, hue angle, colour difference and whiteness of patties. Nevertheless, the redness, yellowness, chroma, and yellowness index of the patties decreased. The hardness and resilience of formulated patties significantly increased with values varying from 16.41 to 17.66 N, and from 0.35 to 0.48 J/J, respectively, whereas the springiness, cohesiveness, and chewiness decreased. The lipid oxidation of formulated mutton patties significantly increased from day 7 to 21 but was still less than that of the control sample within storage days. The sensory properties of formulated patties were not significantly different from the control sample and were above the acceptable score of five. Different types of BGN flour varieties can each be utilised as additives in mutton patties without detrimental effects on the quality parameters of the patties.Item Open Access Extraction and characterization of pectin from prickly pear (Opuntia spp.) peel(2020-08-24) Lekhuleni, Isobel Lerato Gosh; Jideani, A. I. O.; Kgatla, T. E.; Mashau, M. E.The study aimed to determine the physicochemical properties, extract and characterise pectin from three varieties (green, purple and orange) of prickly pear (Opuntia spp) fruit peel. Research samples were collected from Bothlokwa Mphakane village in Limpopo province of South Africa. The experimental design for this study was randomized complete block design and each treatment was conducted in triplicate. Pectin was extracted using sulphuric acid at four different pH levels (1, 2, 3 & 4) and microwave power levels (low, medium & high). The characterisation of extracted pectin was done by calculating the ash, moisture, equivalent weight, anhydrouronic acid, methoxyl content, and degree of esterification. Functional groups present in extracted and commercial pectin were investigated for similarities using Fourier Transform Infrared Spectroscopy. The yield of pectin for purple ranged from 2.9% to 13.8%, orange from 1.4% to 9.8% and from 2.3% to 10.0% for green prickly pear peel. A decrease in pH resulted in an increased pectin yield and an increase in microwave power level increased the pectin yield. Maximum yields of 13.8% on purple, 10.0% on green and 9.8% on orange were obtained at pH 1.0 and medium power level. The best condition for extraction using sulphuric acid was at a medium power level and pH 1.0. The pectins obtained were compared against each other in terms of yield, physicochemical characteristics and chemical structure. The ash content of the extracted pectin was significantly higher at 25.16 ± 0.69, 34.26 ± 1.92 and 36.30 ± 1.07, however the pectin showed lower moisture content and equivalent weight. The methoxyl contents were 2.28 ± 0.26, 2.38 ± 0.21 and 3.86 ±0.31, anhydrouronic acid contents were 25.58 ± 2.03, 25.93 ± 2.35 and 38.84 ± 2.29, and degree of esterification were 49.87 ± 0.17, 50.63 ± 4.76 and 56.39 ± 1.60 across the orange, purple and green varieties, respectively. The prickly pear peel pectin spectra exhibited similarities in its absorption pattern to that of commercial citrus pectin. Therefore, the extraction of pectin from prickly pear peels is feasible in viewpoint of yield and quality, and that the pectin has potential for substitution of citrus pectin in the food processing industry.Item Open Access Nutritional quality, microstructural properties and consumer acceptability of biscuits obtained from fermented finger millet (eleusine coracana) flours(2022-11-10) Mudau, Masala; Ramashia, S. E.; Mashau, M. E.Finger millet (FM) (Eleusine coracana) is one of the most important minor cereal grains. Its fibre and ash contents are higher than that of major cereals such as wheat and rice. The grains are gluten-free therefore, they should be incorporated in the diet of celiac patients. The objective of this study was to determine the nutritional quality, microstructural properties, and consumer acceptability of biscuits prepared using spontaneously fermented FM flours. The FM grains were fermented at Different period (24, 48 & 72 h) of fermentation. The mineral content of FM flours used in biscuits making, as well as their functional, thermo-pasting, and microstructural properties were investigated. Biscuits were subjected to nutritional quality analyses (proximate composition & minerals), antioxidant, microstructural and sensory properties analyses. The results obtained showed that spontaneous fermentation (SF) decreased the packed bulk density (PBD), swelling capacity (SC), and increased water absorption capacity (WAC), and oil absorption capacity (OAC) of FM flours. The loose bulk density (LBD) values showed that SF had no effect, as no significant differences (p < 0.05) were noted. The LBD, PBD, WAC, OAC and SC of FM flours were within the range of 0.47 to 0.56 g/g, 0.71 to 0.79 g/g, 1.96 to 2.14 g/g, 1.24 to 1.44 g/g, and 13.33 to 14.33 mL, respectively. The cooked paste viscosity of FM flours decreased with increasing period of SF, ranging from 253.67 to 421.67 cP. The process of SF also induced changes in the thermal properties of FM flours as an increment of gelatinization temperatures and gelatinisation enthalpy with increasing time of SF was observed. The onset, peak, and conclusion temperature of FM flours ranged from 69.42 to 82.47 °C, 70.98 to 84.48 °C, and 78.24 to 86.39 °C, respectively. The gelatinisation temperature range and gelatinisation enthalpy of FM flours were within the range of 3.01 to 9.59 °C and 2.99 to 5.07 J/g, respectively. The reduction in the peak viscosity (PV), trough viscosity (TV), and final viscosity (FV) and increment in the breakdown viscosity (BDV), setback viscosity (SV), peak time (Pt), peak temperature (PT) of fermented FM flours were observed. The PV, TV, BDV, FV, SV, PT, and Pt ranged from 1709.67 to 2876.67 cP, 1349.67 to 2739.7 cP, 102.00 to 360.00 cP, 1616.33 to 2959.00 cP, 105.33 to 349.33 cP, 5.11 to 6.80 min, and 74.82 to 75.73°C, respectively. The enhancement in the mineral compositions of FM flours as SF time increased was noted. The microstructural changes in the starch granules as SF time increased were also observed. As for the biscuits, the decrease in moisture, ash, crude fiber, and crude fat contents as well as total phenolic and flavonoids contents as SF time increased was observed. Protein content, carbohydrates content, antioxidant activity, and mineral compositions of FM biscuits increased as SF time increased. The colour attributes such as lightness (L*), showed a significant increase as fermentation time increased in light brown FM biscuits, however dark brown FM biscuits showed no significant differences (p < 0.05). The hue angle and total colour differences (ΔE) iii of FM biscuits increased with increasing time of SF. The reduction in the physical properties of FM biscuits including diameter, weight, spread ratio and an increment in thickness and texture as SF time increased were also observed. The diameter, thickness, weight, spread ratio and hardness of FM biscuits were within the range of 4.54 to 4.76 cm, 0.66 to 0.76 cm, 11.99 to 12.77 g, 6.05 to 7.25 and 689.61 to 2372.23 g, respectively. Spontaneous fermentation also induced changes on the microstructure of FM biscuits. Among the fermented FM biscuits, panellists preferred 24 h gluten-free fermented FM biscuits since they had better sensory properties. Overall, SF enhanced the functional properties, thermo-pasting properties, mineral compositions, and nutritional value of FM flours, as well as the potential health benefits of eating gluten-free FM biscuits.Item Embargo Physicochemical, antioxidant and microstructural properties of malted finger millet (Eleusine coracana) flour(s) and their use in gluten-free biscuits.(2024-09-06) Murungweni, Kundai Thelma; Ramashia, S. E.; Mashau, M. E.Finger millet is a gluten-free crop with outstanding malting qualities, and a low glycaemic index. The study aimed to determine the physicochemical, antioxidant, and microstructural properties of malted finger millet flours (light and dark brown) and their use in gluten-free biscuits. The two varieties of finger millet grains were germinated for 0, 24, 48, and 72 hours (h) and kilned for 8 h at 30°C. The lightness (L*) values of malted finger millet flours significantly increased (p ≤ 0.05), with light brown having the highest L* value of 76.62. The moisture, ash, fibre, protein, mineral, total phenolic and total flavonoid contents and DPPH activity of both malted finger millet flours and biscuits significantly increased (p ≤ 0.05). Both malted finger millet flours' solubility index, water and oil absorption capacity increased significantly, while the packed and loose bulk density decreased. A significant decrease in the viscosity of the cooked paste in both finger millet flours was observed. Malting resulted in an increase in the onset, peak, and conclusion temperatures. FTIR showed that malting slightly changed the peaks of both finger millet flours. Scanning electron microscopy showed that malting altered the microstructural characteristics of finger millet flours. The yellowness and whiteness index of FM biscuits significantly increased, ranging from 41.47 to 42.12 and 42.21 to 45.47 (light brown) and from 67.78 to 70.97 and 71.92 to 75.41 for dark brown, respectively. The weight, diameter, thickness, and spread ratio significantly decreased with an increase in malting in both FM biscuits. The hardness of the biscuits significantly increased from 762.53 to 1720.28 g (light brown) and 747.50 to 1918.71 g (dark brown). The LB biscuits had more desirable sensory attributes as compared to the DB biscuits. It was concluded that malted FM flour can be used to prepare nutritious and healthier gluten-free bakery products.