Nutrient Potential of Wild and Cultivated Edible Mushrooms and their Possible Use in Fortifying Snacks for Pre-School and School Children

Abstract

The study determined the nutrient composition of wild and cultivated edible mushrooms, and explored their use of cultivated Pleurotus tuber-regium in food-to-food fortification. Wild edible mushrooms (Pleurotus tuber-regium, Pholiota mutabilis, Pleurotus ostreatus, Corprinus disseminates, and Peziza badioconfusa Korf) were collected from different parts of the University of Nigeria, Nsukka (UNN) residential quarters and identified in the Department of Botany, UNN. Cultivated Pleurotus tuber-regium was collected from the Department of Botany, UNN. The wild and cultivated mushrooms were processed into flour and chemically analyzed using standard methods of analysis. Different proportions (20g, 40g and 60g) of the Pleurotus tuber-regium flour were incorporated into 600g of wheat flour, cocoyam paste and corn starch to produce composites. The composites were used to prepare the following snacks: wheat buns, cocoyam buns and aged jollify. Each of these snacks had their controls made without mushroom. Sensory evaluation of the snacks was conducted using 20 panelists (children aged 8-14 years). The evaluation was done in three days at the rate of one fortified food (snack) per day. A 9-point Hedonic scale of 9 (highest) to 1 (lowest) was used to evaluate the products. The nutrient composition of the snacks was calculated using available food composition Tables as well as the nutrient composition of the cultivated Pleurotus mushroom obtained in the study. The percentage increase in specific nutrients as a result of fortification was calculated. The ability of the most acceptable snacks in meeting some specific nutrient requirements of pre-school and school children was determined using recommended nutrient intakes (RENI) for energy, protein, vitamins and minerals. Data were analysed using one way analysis of variance (ANOVA). Significance was accepted at p<0.05, Duncan’s new multiple range test was used to separate means. The wild and cultivated mushrooms were high in protein (10.1 to 33.0% wet weight), but low in fat and crude fiber (<1% and <2% respectively). Calcium varied from 86.2 mg/100g to 372.3 mg/100g. All the wild and cultivated mushrooms contained good amounts of selenium from 11.3 µg/100g to 48.7 µg/100g, except Pholiota mutabilis which had 1.9g/100g. Copper varied from 32.7 µg/100g to 199.4 µg/100g. Folic acid ranged between 1235.0 µg/100g and 2484.0 µg/100g, vitamin B12 from 1.85 mg/100g to 4.33 mg/100g and vitamin E from 16.28 mg/100g to 33.40 mg/100g. Thiamin varied between 0.04 mg/100g and 0.90 mg/100g, riboflavin from 0.13 mg/100g to 0.36 mg/100g and vitamin C, from 0.20 mg/100g to 9.7 mg/100g. There were no significant (P>0.05) differences in the organoleptic attributes of samples containing mushroom and those not containing mushroom except for texture of cocoyam buns fortified with 40g mushroom (CBM40) which was significantly (P<0.05) different from the control. In wheat buns fortified with 60g mushroom flour (WBM60), protein increased by over 20%, copper by over 700%, selenium by over 50%, folic acid by over 130% and vitamin E by over 230%. There were slight increases in calcium (19.6%), iron (2.8%), vitamin C (32.1%), thiamin (5.0%), riboflavin (16.7%) and niacin (5.3%) with addition of mushroom. For pre-school children (PSC), 100g of the wheat buns fortified with 60g mushroom (WMB60) contributed 268.6% selenium, 180% folic acid, 563.6% vitamin B12 and 43.1% vitamin E of RNI. Wheat buns fortified with 60g mushroom (WBM60), provided 66.5% and 42.9% of the recommended protein intakes of pre-school and school children, respectively. Agidi jollof fortified with 60g mushroom flour (AJM60) had high increases in folic acid (374.7%), vitamin E (281.1%), vitamin B12 (77.8%) and selenium (61.1%) contents over the control. AJM60 furnished the following percentages of the requirements of pre-school children: Selenium (31.4%). folic acid (63.6%), vitamin B12 (90%) and vitamin E (31%). For school children, AJM60 furnished 26.9% selenium and 38.2% folic acid. Cocoyam buns fortified with 60g mushroom (CBM60) had marked increases in selenium (91.5%), copper (104.4%), folic acid (714.9%), niacin (34.5%) and vitamin E (208.0%) over control. CBM60 contributed 24.4% of selenium, 47.3% of vitamin B12, 96.0% of folic acid and 12.0% of vitamin E to the RNI of pre-school children. For school children, CBM60 provided 21.0% of selenium, 29.0% of vitamin B12, 9.0% of vitamin E and 57.3% of folic acid. Wild or cultivated Pleurotus tuber-regium is indeed a highly nutritious food that can contribute to sustainable diets of various population groups. The fortified products could be promoted in place of empty-calorie and other fast foods that are almost replacing the traditional foods.