Browsing by Author "Haukongo, Kristine"

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    Comparative study on the quality of Namibian commercial oyster mushrooms cultivated on encroacher bushes as substrates
    (University of Namibia, 2023) Haukongo, Kristine
    Humans need a wide range of nutrients to have a well-balanced diet, nutritious edible mushrooms can be part of a healthy lifestyle. The objectives of the study were to evaluate the yield and yield components, to determine antioxidant activity, total phenolic content (TPC), total flavonoid content (TFC) and nutrient composition of different mushroom species cultivated on four different bush encroacher substrates. To provide mushroom cultivation training to farmers in Okondjatu district. Mushrooms were cultivated in 2kg bags of dry substrate, harvested, dried and powdered. Mushrooms powder was extracted in 99.9% methanol. Antioxidant activity of the mushroom extracts were analysed by reducing power and 2, 2 Diphenylpicrylhydrazyl (DPPH) assay. The TPC and TFC were quantified. Crude protein was calculated (N x 6.25) from determining the amount of nitrogen (N) in mushroom powder using the Dumas combustion method. Potassium and Phosphorus were determined by using the flame emission spectroscopy, while Phosphorus was determined by colorimetry. Neutral detergent fibre (NDF) and Acid detergent fibre (ADF) were analyzed using the Ankom 220 fibre analyzer unit. Mushroom cultivation training was conducted at three randomly selected villages. There was a significance difference in weight of fresh mushrooms, days to first harvest and number of fruiting bodies which was due to mushroom species used at p=0.002, p<0.001 and p=0.019 respectively. Pleurotus florida (PF) yielded more mushrooms with 350 g, followed by PS with 322 g, followed by Pleurotus ostreatus (PO) with 314 g, and the least was on HK 35 with 243 g. The inhibitory concentration at 50% (IC50) values ranged from 0.380±0.098 mg/ml to 0.780±0.007 mg/ml on different mushroom species grown. The inhibition of the DPPH radical by PO extracts cultivated on Terminelia sericea ii (0.380±0.007 mg/ml) showed the highest activity. All Mushroom species grown on different bushes showed an appreciable ability to reduce ferricyanide complex to ferrous form at different concentrations (0.063–1.00 mg/mL). The TPC varied from 3.93 mg GAE/g to 8.016 mg GAE/g. TFC ranged from 0.515 mg QE/g to 12.1 mg QE/g, which showed a significant difference on the bush species (p-value < 0.01). Crude protein content ranged from 28.0% to 39.0%. A significant difference in % NDF on mushroom species was found, where a variation was detected in HK35 while PF, PO, and PS showed a similar performance in % NDF. The study showed that ash content ranged from 5.77% to 17.9%. Percentage moisture ranged from 86.0% to 87.5%. A significant difference in mineral composition, with PO showing a high content of potassium (2.292%), PF showing a high content of sodium (0.059%), and PS showing a high content of phosphorus (0.746%) as compared to other mushroom species. A total of 45 community members participated in the training. In conclusion, all four encroaching bushes can be used as the substrate for mushroom cultivation. All mushroom species showed antioxidant activity and appreciable nutrient and mineral composition, thus can be used as a remedy to illnesses and a supplement to human diets. Therefore, it is essential to promote awareness and train farmers on mushroom cultivation
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    Effects of different substrates as medium for mushrooms cultivation
    (Academia Publishing, 2021) Haukongo, Kristine
    Different Mushrooms species prefer different substrates as growth medium. For example, medicinal mushrooms such as Shiitake, pearl and yellow oysters grow better on straws and gourmet. Reishi and Maitake grow better on sawdust and logs, whereas Agaricus mushrooms are grown on manure with the likes of button mushrooms, portobella mushrooms. As a result, mushrooms have gained interest around the world, not only because mushroom are easily cultivated using locally available agricultural waste, but also because mushrooms contribute to employment and reduce food scarcity, while meeting nutritional and health demands. In Namibia, mushroom cultivation is not well exploited due to various factors such as unfavourable climatic conditions and suitable mushroom strains. Different encroacher bushes and other related crop residues can be studied to establish the variation of mushroom nutrition and therapeutic properties as a result of mushrooms growing on different substrates. Therefore, the utilization of encroacher bushes locally could also contribute towards rangeland restoration and creating economic opportunities. This review aims at investigating the importance of mushrooms production at local levels using alternative materials as substrates in comparison to other countries as case studies.