Common Nutrients and Nutraceutical Quality of Apples

Fruits and vegetables that are consumed in large quantities may make a significant contribution to nutrient intake even though their nutrient content is not high. Apples fit into this category. Fresh apples are considered a food of moderate energy value among common fruits, while processed apple products are either comparable to fresh apples in energy value or higher because of concentration (dehydrated) or addition of sugars during processing. In common with other fruits, apples contain insignificant amounts of protein (less than 0.2%) and lipid (less than 0.4%). Apples are not bursting with vitamins and minerals like some other fruits, though they do provide a bit of vitamin C and potassium. However, apples are a good source of soluble fiber, especially pectin, which helps control insulin levels by slowing the release of sugar into the bloodstream (low glycemic index). Pectin is also known to help reduce cholesterol levels by lowering insulin secretion. Today’s natural approaches to wellness are becoming more popular and interest in the role of nutrition in overall health is increasing. Therefore, in addition to common nutrients indicated above, there is continued interest in other phytochemicals that appear to link to the prevention and amelioration of a variety of human diseases. Among the different phytochemicals, special interest has risen in plant polyphenols, specifically the flavonoids, whose key role appears to be in acting as antioxidants, similar to vitamin C and E. Hippocrates, the ancient Greek physician who is known as the father of modern medicine, was the man who inspired this famous phrase over two thousand years ago, “an apple a day keeps the doctor away.” These special traditional attributions of apples may be originated from the nutraceutical function of bioactive polyphenolic compounds. Recently there has been a strong interest among scientists on anti-oxidative, anti-cancer, anti-neurodegenerative, and anti-obesity activities of apple phenolic compounds. This paper will discuss nutritional composition of today’s common commercial apples and some of new bioactive phenolic compounds that have shown nutraceutical functions in vitro studies.