Browsing by Author "Obiero George"

Now showing 1 - 3 of 3
  • Thumbnail Image
    Publication
    Strategies for Improving Hydrolytic Efficiency of Crude Multienzyme Extracts in Mushroom Processing
    (Elsevier Inc, 2022-11) Ojwang D. Otieno; Mulaa F. Jakim; Obiero George; Midiwo Jacob
    The current study investigated and optimized key process parameters affecting mushroom hydrolysis with crude enzymatic extract. The crude enzyme was prepared by solid-state fermentation of pineapple peels using Aspergillus niger. The reaction parameters viz. time, temperature, pH and enzyme concentration were optimized using the central composite design of the response surface methodology. The model predicted glucose yield of 1.49 mg/mL at optimal pH of 6.5, temperature of 50 °C, enzyme loading of 5 % (v/v), and reaction time of 12 h. Mushroom hydrolysis at the same optimal model conditions, increased glucose yield by 10%. More so supplementing SSF media with 0.2% (w/v) Tween-80 and 0.08% (w/v) yeast extract at moisture level of 70–75% significantly (p value < 0.05) improved hydrolytic efficiency of the crude enzyme extract by 2.2-fold. This study provides baseline data that will be useful in developing a low-cost enzyme-based process for hydrolyzing mushrooms to recover high-value products.
  • Thumbnail Image
    Publication
    Utilization of Fruit Waste Substrates in Mushroom Production and Manipulation of Chemical Composition
    (Elsevier B.V, 2022-01) Ojwang D. Otieno; Mulaa Francis J.; Obiero George; Midiwo Jacob
    The current study evaluated the effect of mushroom cultivation using fruit waste substrates on yield performance and antioxidant activities. The total phenolic content and the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of the mushroom extracts were determined using colorimetric method. Mushroom P. eryngii had the highest yield of 87.2 ± 2.4 g/100 g dry substrate when grown on pineapple peels, while P.ostreatus yielded the least fruiting bodies 53.1 ± 1.8 g/100 g dry substrate when grown on orange peels. Similarly, P. eryngii grown on pineapple peels and P. ostreatus grown on orange peels had the highest and lowest biological efficiencies of 94.2 ± 3.5% and 69 ± 4.3%, respectively. The total phenolic content of P.ostreatus grown on avocado peels was 26.4 ± 3.8 mg GAE/g dry extract, while P.eryngii grown on avocado peels had the lowest at 9.3 ± 0.2 mg GAE/g dry extract. Mushrooms cultivated on fruit wastes generally exhibited higher DPPH activities than those grown on wheat straw (control) substrate. This study provided baseline information on the potential role of fruit waste substrates in mushroom growth and chemical composition.
  • Thumbnail Image
    Publication
    Utilization of Fruit Waste Substrates in Mushroom Production and Manipulation of Chemical Composition
    (Elsevier B.V, 2022-01) Ojwang D. Otieno; Mulaa Francis J.; Obiero George; Midiwo Jacob
    The current study evaluated the effect of mushroom cultivation using fruit waste substrates on yield performance and antioxidant activities. The total phenolic content and the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activities of the mushroom extracts were determined using colorimetric method. Mushroom P. eryngii had the highest yield of 87.2 ± 2.4 g/100 g dry substrate when grown on pineapple peels, while P.ostreatus yielded the least fruiting bodies 53.1 ± 1.8 g/100 g dry substrate when grown on orange peels. Similarly, P. eryngii grown on pineapple peels and P. ostreatus grown on orange peels had the highest and lowest biological efficiencies of 94.2 ± 3.5% and 69 ± 4.3%, respectively. The total phenolic content of P.ostreatus grown on avocado peels was 26.4 ± 3.8 mg GAE/g dry extract, while P.eryngii grown on avocado peels had the lowest at 9.3 ± 0.2 mg GAE/g dry extract. Mushrooms cultivated on fruit wastes generally exhibited higher DPPH activities than those grown on wheat straw (control) substrate. This study provided baseline information on the potential role of fruit waste substrates in mushroom growth and chemical composition.