Effects of storage conditions and periods on glycoalkaloid content and nutritional value of Solanum tuberosum

A study was carried out to investigate the effects of storage conditions and periods on glycoalkaloid content and nutritional value of Solanum tuberosum. Freshly harvested tubers of Solanum tuberosum were purchased from terminal market in Jos and the glycoalkaloids contentand proximate evaluation of the stored tubers were carried out based on the length of storage. The tubers were randomly grouped into 9. Groups 1-4 represent tubers stored for a period of 1-4 week(s) respectively under sunlight at room temperature while group 5 represents the control, inwhich the glycoalkaloids content was determined immediately after purchase. Tubers in groups 6- 9 were stored in the dark for 1-4 weeksrespectively. The results showed that the concentration of glycoalkaloid (900mg/100g ±0.01) in gr oup 5 tubers is significantly low (p<0.05) when compared with groups 1-4 tubers. Also the glycoalk aloids concentrations (1050mg/100g±0.01, 1100 mg/100g±0.01, 1200mg/100g±0.01 and1350mg/100g±0.01) of groups 1-4 respectively were significantly elevated (p<0.05) when compared with the control and tubers stored in the dark. However, there was no significant difference (p>0.05) in the concentrations of glycoalkaloids of groups 6-9 and the control. Nutritional evaluation revealed considerable amount of measured nutrient without significantdifference (p>0.05) in all the tubers stored in darkness, but there were significant reductions (p<0.05) in the proteins of groups 1-4 tubers when compared with the control and tubers stored under the dark condition. The increase in the glycoalkaloids content of Solanum tuberosum storedunder sunlight could be attributed to exposure to light causing greening, mechanical stress and damage to the tubers, one of which is depletion of protein concentration. Such tubers can predispose consumers to acute symptoms, such as gastrointestinal disorders. Storage in the dark ishereby suggested