A comparative study of effects of storage on basic nutritional composition of two major edible Dioscorea dumentorum varieties

The proximate analysis comprising the carbohydrate, crude protein, crude fibre, ash and moisture contents, and the minerals analysis of two major edible varieties of Dioscorea dumentorum (Esuru), commonly consumed inEkiti State, Nigeria were estimated after a period of storage using standard chemical methods. The crude protein percentage for stored yellow and white varieties are 3.13 and 2.50 respectively. This is contrary to that of fresh varieties whose crude protein percentages for the yellow and white varieties are 8.24 and 5.44 respectively. The results reveal a significant decrease in protein content in stored Discorea dumentorum varieties compared with previous work on fresh varieties. The crude fat content for the stored yellow and white varieties are 6.07 and 6.88% respectively, while the ash content and the crude fibre contents for the stored yellow and white varieties are 2.80, 2.53 and 1.73 and 1.79% respectively. The carbohydrate contents of the two varieties are 26.97 and 21.33% in the same order. The presence of important minerals like iron, magnesium, phosphorus, calcium, and zinc at a very high level showed that bitter yam would find some useful application in the food and pharmaceutical industries.