Glycaemic index of potatoes: myth and reality from a European perspective

Evaluation of By-Products of Potato Peel as Food Additive

Abstract:

The potato plant is an important food source produced all over the world and it provides a significant portion of daily energy intake in nourishment. In addition, a significant rate of vitamins, fibre, mineral matters, protein, and fat can be obtained by consuming potato. In this study, the production, consumption, and usage areas of potato, a crucial source of our diet, and the possibilities of using it as food additives with the nutritional properties of its peel have been investigated. Generally, potato is consumed after its peel is removed in the homes and industrial areas and many of these peels are disposed off as wastes. Studies show that potato peel has a high content of dietary fibre, protein, carbohydrate, mineral matters, vitamin, phenolic, and antioxidant. The use of potato peel as food additives have also been discussed in this study.

Glycemic index of different varieties of yam as influenced by boiling, frying and roasting

Yam is one of the commonly consumed carbohydrate staples. The objective of this work was to investigate the effect of boiling, roasting, and frying on the glycemic index (GI) of white yam (Dioscorea rotundata), yellow yam (Dioscorea cayenesis), and water yam (Dioscorea alata). Yam tubers were obtained (peeled, sliced, washed) deep fried in vegetable oil for 35-40 min and boiled in water for about 35-45 min. Sliced unpeeled tubers were also roasted at about 120°C for 40-45 min. The cooked yam samples were fed to 10 healthy subjects aged between 20-50 years. A glucometer was used to measure the blood glucose concentrations of the test individuals before consuming the yam diets and after the 15th, 30th, 45th, 60th, 90th, and 120th min of consumption. The average incremental area under the curves (IAUC) obtained from the recorded blood glucose concentrations were used to calculate the GI of various yam diets. The GI of the yam diets were found to be in the following increasing order: White-yam-boiled (44.26%) < Water-yam-boiled (50.12%) < White-yam-roasted (50.62%) < Water-yam-roasted (54.04%) < White-yam-fried (59.13%) < Yellow-yam-fried (65.08%) < Water-yam-fried (69.16%) < Yellow-yam-roasted (70.62%) < Yellow-yam-boiled (75.18%). White yam diets relatively had lower GI compared to yellow yam and water yam. Boiling was found to give generally lower GI in the white and water yams and could therefore be applied in the preparation of lower GI diets for diabetics.