The term ‘tuber’ brings to our minds various underground victuals such as cassava, sweet potato, potato and yam. As with all crops, the nutritional composition of roots and tubers is largely based on the place of cultivation. The nutritious value of the same tuber crop varies from place to place on the basis of certain factors such as climate, the soil, the crop variety etc.
The rich presence of carbohydrates make many obese people stay away from tuber roots. But, it should be remembered that tubers are efficient energy producers. They also play a positive role in easing the digestive process due to the abundance of dietary fiber.
Carbohydrates are the main nutrient factor that is supplied by roots and tubers.
The edible source of carbohydrate present in tubers is starch along with certain sugars. The proportion of starch to that of sugars varies from one tuber crop to another. They form the major component of the dry matter of tubers. Plant carbohydrates mainly consist of celluloses, gums and starches.
However, the lion’s share of energy production is contributed by starch since other nutritive sources such as celluloses are not digested. The protein contribution made by tubers is comparatively lower. Most of the tubers are found to contain certain amounts of vitamin C. Apart from that, yellow varieties of sweet potato, yam and cassava also beta-carotene or provitamin A.
Taro is found to be an excellent source of potassium. Cooked taro leaves are also consumed as a vegetable. The Taro leaves contain beta carotene, iron and folic acid. Thus they are good to be added to the diet of people suffering from anemia and other ailments caused by iron deficiency in diet.
Leaves of sweet potato and cassava are also widely consumed as a nutritious green vegetable.
It might be true that roots and tubers are low in their vitamin content, but they from an exceptionally brilliant source of dietary fiber.