ABSTRACT
A comparative study of the nutritional, mycological and aflatoxin content of sun dried and oven dried unripe plantain flour was performed using standard analytical procedures. The total heterotrophic fungi count recorded for the fresh (day 0) plantain flour was 2.40 x 105cfu/g. For the sun dried plantain flour this ranged from 4.30 x 105 cfu/g (day 1) to 17.20 x 105 cfu/g (day 2), for the oven dried flour it ranged from 2.00 x 105 cfu/g (day4) to 5.40 x 105cfu/g (day 3). Proximate analysis showed that the fresh unripe plantains flour contained 52.67%, 2.40%, 2.30%, 0.80%, 2.54% and 39.23% of moisture, ash, fat/oil, crude fibre, crude protein and carbohydrates respectively. The sun dried sample recorded 26.67%, 3.170%, 0.120%, 5.40%, 2.01%, and 64.63% of moisture, ash, fat/oil, crude fibre, crude protein and carbohydrates respectively. The oven dried recorded 19.10%, 4.33%, 2.26%, 5.00%, 2.00%, and 67.31% of moisture, ash, fat/oils, crude fibre, crude protein and carbohydrates respectively. Phosphorous, sodium, potassium, calcium, iron and magnesium were determined to be 0.28ppm, 1.34ppm, 104.25ppm, 0.36ppm, 5.67ppm and 0.96ppm respectively for the fresh flour, while the sun dried recorded 0.35ppm, 1.42ppm, 106.20ppm, 0.10ppm, 5.00ppm and 0.80ppm respectively. The oven dried recorded 0.20pm, 1.40ppm, 106.50ppm, 0.20ppm, 4.07ppm and 0.68ppm for Phosphorous, sodium, potassium, calcium, iron and magnesium respectively. A total of 64 fungi genera were isolated (40 with sundried and 24 with oven dried). Their frequency of occurrence and percentage distribution are as follows; Aspergillusspp20(31.30%), Penicillium spp 7 (10.90%), Rhizopus spp. 6 (9.40%), Mucor spp 11(17.20%), Trichoderma spp10 (15.60%) and Alternaria spp10 (15.60%). Aflatoxin analysis revealed that the sun dried plantain flour recorded a very low total aflatoxin level and the aflatoxin B1 and B2 levels were below the limit of detection. However, the oven dried flour recorded total aflatoxin content of 40ppb, the aflatoxin B1 and B2 levels were 20ppb and 15ppb respectively. In conclusion, while flour produced by both oven dried and sun dried methods yielded products with similar nutritional composition, oven dried flour had lower moisture content within a short time, thus increasing the shelf life of the product. However its unexpectedly high concentrations of aflatoxin render it unsafe.
