Comparative Appraisal of the Total Phenolic Content, Flavonoids, Free Radical Scavenging Activity and Nutritional Qualities of Pleurotus ostreatus (EM-1) and Pleurotus eous (P-31) Cultivated on Rice (Oryzae sativa) Straw in Ghana

Abstract

Aim: The nutritional and anti- nutritional qualities of Pleurotus ostreatus (EM-1) and Pleurotus eous (P-31) cultivated on rice straw were compared. Methodology: In vitro antioxidant analysis, proximate analysis, refractometry, atomic absorption and Atwaters procedure. Results: Nutritional results recorded for the two Pleurotus spp. ranged 80.51±0.63- 86.81±0.63, 6.11±0.14 - 9.84±0.10, 17.75±0.17- 15.91±0.17, 15.22±0.17- 24.10±0.39, 2.01±0.24- 4.73±0.28, 55.41±2.70- 45.59±2.40, 15.00±0.18- 15.00±0.18 (Brixo) and 300.61- 321.62 Kcal/100g for moisture content, ash, fibre, protein, lipid, carbohydrates, total soluble solids and metabolizable energy respectively. Mineral elements studied recorded results of 14.10±0.7- 6.00±0.15, 31.9±0.5- 12.15±0.35, 1.77±0.18- 0.76±0.01, 0.02±0.001- 0.01±0.001, 0.03±0.001- 0.19±0.004, 0.37±0.1- 0.23±0.01, 0.04±0.001- 0.02±0.01, 6.41±0.35- 7.60±0.45, 11.02±0.3- 0.37±0.03, 0.02±0.001- 0.10±0.001 and 3.61±0.02- 3.60±0.25 for Na, K, Mg, Cu, Zn, Fe, Mn, P, Ca, Pb and N respectively. All the nutritional parameters investigated showed significant difference (P<0.05). Anti-nutritional results recorded ranged 3.57- 5.66 mgGAE/g, 226- 622.6 mgQE/g, 9.0- 13.0 mgGAE/g and 0.25- 1.35 mg ml-1. Total phenolic content, flavonoid content, free radical scavenging ability and IC50 values respectively. Conclusion: There was significant difference (P<0.05) between anti-nutritional parameters. The results obtained generally showed that P. eous was better than P. ostreatus.