Effects of Fermentation on the Proximate Composition of Irish ( Solanum tuberosum) and Sweet Potato ( Ipomoea batatas) Peels

Abstract

Fermentation has been exploited to improve agricultural waste products. Fermentation of Sweet potato (Ipomoea batatas) and Irish potato (Solanum tuberosum) peels was carried out by soaking in clean water for 96 hours at room temperature during which samples were collected daily for microbial, physicochemical and proximate analysis. Microbial load of both peels ranged from 9.0 × 105 to 8.6 × 106 cfu/ml; 1.5 × 106 to 7.4 × 106 sfu/ml and 1.2 × 106 to 2.0 × 106 sfu/ml for bacteria, fungi and yeast respectively. The pH value of both peels decreased significantly (P ≤ 0.05) with corresponding increase in the total titratable acidity (TTA) (P ≤ 0.05) and temperature (P ≥ 0.05) with time during fermentation. The percentage composition of moisture, ash, fat and protein content of both peels increased insignificantly (P ≥ 0.05) with values ranging from 8.91ab ± 0.62 to 12.19b ± 0.51, 3.69a ± 0.41 to 5.77a ± 0.58, 1.86a ± 0.54 to 4.57c ± 0.51 and 4.55a ± 0.45 to 7.74b ± 0.51 respectively, while the crude fiber and carbohydrate composition decreased insignificantly (P ≥ 0.05) with values ranging from 2.16a ± 0.43 to 3.97bc ± 0.64 and 41.83a ± 2.64 to 70.05bc ± 2.55 respectively, until the last day of fermentation as compared with the unfermented peels at 0 hour. However, there was no significant difference (P ≥ 0.05) in the proximate composition of both peels. The results obtained from this study revealed that fermentation can bring about desirable changes in the nutrient composition of potato peels.