NUTRIENT, SECONDARY METABOLITE AND PHYSICOCHEMICAL CONSTITUENTS OF SELECTED PLANT PEELS

Abstract

Food scarcity has been a major scourge to majority of third-world countries as many plant food materials are being lost to spoilage or are diverted into livestock breeding. This study was aimed at evaluating the nutrient, physicochemical and antioxidant properties of flours of the peels of selected tuber crops (potato, plantain and yam). Standard procedures were used in determining the nutrient, antioxidant and phytochemical constituents of the peel flours. The proximate composition revealed that moisture and ash content of the samples showed no significant difference (p>0.05). However potato peel flour had a significantly (p<0.05) higher concentration of fat (1.13±0.06 %) and carbohydrate (59.72±0.02 %), while plantain peel flour had higher (p<0.05) protein (2.14±0.01%) and crude fiber (77.87±0.06 %) content. The peels showed appreciable amount of mineral composition (mg/100 g), although potatoes peel flour had significant (p<0.05) amount of phosphorus, sodium, potassium and magnesium. The Na+/K+ was significantly low in plantain peel flour (0.0057±0.25). The water absorption capacity was significantly higher (p<0.05) in yam peel flour (49.33±0.58 %), while gelatinization temperature was higher (p<0.05) in plantain (80.50±0.50 oC). The result for antioxidant properties showed that yam and plantain peel flour had the highest (p<0.05) total phenol (57.86±0.56 mg/100g) and flavonoid (7.18±0.28 mg/100 g) contents respectively. The nutrient, mineral, antioxidants as well as low anti-nutrient content of tuber peels present them worthy for animal-feed production and plant solid waste management.