Abstract

Despite frequently being described as a carbohydrate-laden, calorie-rich unimportant part of the human diet, potatoes (Solanum tuberosum L.) are one of the most nutritive vegetable food crops in the world and, in comparison to most other vegetables are richer in essential human nutrients. These include proteins, starch and fibre, major, secondary and trace minerals, vitamins, antioxidants and phytochemicals. Potatoes have an abundance of vitamin C and the mineral potassium (K) which are vital for health. Potassium reduces the risk of Blood Pressure (BP), cardiovascular diseases (CVDs), osteoporosis and strokes. Vitamin C helps reduce strokes and hypertension and prevents scurvy. The predominant form of carbohydrate (CHO) in the potato is starch. A small but significant part of this starch is resistant to digestion by enzymes in the stomach and small intestine, so it reaches the large intestine essentially intact. This resistant starch is considered to have similar physiological effects and health benefits as fibre. A medium size potato (148 g) contains 4 g protein and very small amount of fat or cholesterol. The fibre content of a potato with skin is equivalent to that of many whole grain breads and pastas. Potatoes contain rather large amount of the enzyme catalase, which converts hydrogen peroxide into oxygen and water and thus prevents cell injury. Potatoes contain phytochemicals such as lutein and zeaxanthin; which protect and preserve eyesight and may help reduce the risk of macular degeneration. It is not the high Glycemic Index (GI) in potatoes or in any other food, but the number of calories consumed from all foods that causes weight gain. Overall, potatoes are an underrated source of essential human nutrients.

Potatoes also contain toxic compounds, such as α-solanine and α-chaconine which are known to induce toxicity. These poisons cause gastrointestinal disturbances causing vomiting and diarrhea but severe poisoning may lead to paralysis, cardiac failure and comma. Green areas in potatoes containing chlorophyll are harmless but indicate that toxins may be present. According to the American Cancer Society, food born toxin such as acrylamide is formed when starchy foods such as potatoes and potato products are cooked at temperatures above 121C. However, deep frying at 170C is known to effectively lower the level of toxic compounds, while microwaving is only somewhat effective and freezedrying or dehydration has little effect. The highest levels of acrylamide are found in CHO-rich foods, such as potato chips and French fries, which had been cooked at high temperatures.

Keywords: Carotenoids, macro, minor, micro nutrients, phenolic compounds, soluble fibre.

Graphical Abstract