Fruit peel, or fruit skin is the outer, protective covering in fruits. In general, the skin in some tough-layered fruits such as pomegranate, passion fruit, mangosteen…etc., is known as the <>rind>, while in citrus fruits such as in oranges, it is better termed as peel (zest). Besides its outer cover protect underlying edible portion of fruit from harsh environmental factors as well as micro, and macro organisms, it, indeed, holds some of vital health benefiting constituents such as dietary fiber, and phyto-nutrients that help accomplish overall wellness.
Photo courtesy: fdecomite
|Mango peel with a fruit peeler.
Photo courtesy: ms.Tea
Fruit peel is either firmly adherent to its underlying flesh as in berries, and apples or rather loosely, as in oranges, banana…etc. Its thickness varies widely, even in the same family fruits, ranging from paper thin to very thick shell-like as in mangosteen.
In some raw fruits, the peel has neutral flavor, as in grapes and apples. It can be bitter and inedible because of high tannin (astringent) content in unripe sapodilla and proteolytic enzymes in papaya. As the fruit ripens, the peel becomes easily separable from the pulp (bananas). In addition, its components turn sweeter and become pleasant-tasting as in sapodilla, guava, kiwifruit, and kumquat.
Fruit ripening is purely an enzymatic process, which brings certain characteristic changes to the fruit color, aroma, taste, maturity (hardening) of seeds…etc.
The peel in some fruits like guava is firmly cohesive to its pulp and, indeed, in some fruits it turns tastier than the flesh as the fruit ripens.
Fruit peel is very rich in essential oils which give a characteristic aroma to the fruit. These oil glands are spread all over the peel but denser near its pits. These oil glands are quite uniquely prominent in citrus fruits like lemons, and oranges.
Fruit peel, in general, is discarded in the majority of common fruits even when it found safe for consumption. Here are some salient points to mark why fruit skin is recognized as one of the essential components of our diet since it holds many vital nutrients and non-nutrient compounds that play an important role in the wellness.
fruit peel of some of the common fruits like blueberries, grapes, guava, and kumquat carry higher concentration of anti-oxidants such as anthocyanin pigments, tannins, catechins…etc than in their flesh (pulp). Blue or purple color fruit peels are rich in anthocyanidin glycosides while yellow color fruits have xanthin, carotenes and lutein pigments. Major components of these pigments are concentrated just underneath its outer layer of skin.
Peel is rich source of rough dietary fibers, also known as NSP (non-soluble polysaccharides), such as hemi-cellulose, pectin, tannins, gum…etc. These compounds add bulkiness to the food, and help prevent constipation by reducing gastro-intestinal transit time. They, further, bind to toxin chemicals in the food and protect them contacting with gut mucusa and thereby help cut-down colon cancer risk. Furthermore, dietary fibers bind firmly to bile salts (produced from cholesterol) and eliminate them from the gut, thus, in turn help lower serum LDL cholesterol levels.
Peel is low in calories, sugar, and fats; and is free from cholesterol. Again, it adds to the bulk of the food and helps cut down overall calorie intake.
The fruit peel of some fruits, indeed, contains considerable amounts of mineral and vitamins, especially in guava and citrus category fruits. Certain fruit, like in orange, the peel holds rather higher levels of vitamin C (ascorbic acid) than its juice. 100 g of fresh orange-peel provides 136 mg per 100 g of vitamin C while its flesh carries just about 71 mg/100 g. Please refer the nutrtion database chart.
Likewise, fruit peel is also a good source of vitamin A, B-complex vitamins, minerals such as calcium, selenium, manganese, zinc...etc several fold more than its pulp. Please read the orange peel USDA nutrition data chart in the side table for example, and then compare it with the nutrition facts table in orange fruit.
Recent scientific trial studies suggest that certain compounds in passion fruit peel has bronchodilator effect and can help relieve bronchospasm in asthma patients. A trial study conducted by Watson RR and his colleagues at Tuscon University AZ, suggests that oral administration of the purple passion fruit peel extract reduces wheeze and cough and improves shortness of breath in adults with asthma. (Related link-Pubmed.gov)
While it is advised to eat fruits along with its peel in some allowed fruits, however, certain caution should be kept in mind while eating whole fruits.
1. Multiple insecticide spraying is a common practice on the field fruits. Certain amounts of this may deposit deeply in their skin. So, wash fruits thoroughly before use. Organically farmed fruits are, therefore, recommended for safe use of their peel.
2. Oftentimes, insects lay their eggs/cysts on the fruit surface. Eating raw, unwashed fruits may pose risk to health because of these egg/cysts may end up deposited deep inside the brain, a condition known as neuro-cysticercosis.
3. Excess fiber content in the peel may cause indigestion in some people, especially in children. (Medical disclaimer).
Before you decide to use fruits for peel preparation, it is advised to select fruits that are fresh, organic, without the surface cuts, blemishes, and bruises. Wash the fruit thoroughly in running water to remove surface dirt, soil…etc. Place the fruit in a bowl of salt water for about half an hour. Then wash them again in cold water. This way, you would be sure any surface insect eggs/larvae are removed. Gently pat dry using a soft cloth.
To prepare: use the fruit peeler machine. In case of citrus fruits, one may peel them very easily out of hand after scoring using a knife. Store dried zest/peel powder in a cool, dry place in an air-tight glass container away from moisture.
Here are some recipes of fruit peel you can enjoy while getting most of their health benefits.
|Orange peel candy with chocolate.
Phot courtesy: grongar
Fruit peel, especially of citrus fruits, can be candied.
Citrus fruit zest is added to flavor confectionary.
Lemon peel is used to pickling.
Citrus fruit peel like lemon, tangerines can be dried, powdered, and stored for future usage.
In India, unripe, green mango along with its peel are sundried and ground to powder (Aamchoor). It is basically used as condiment. Aamchoor is generally mixed with a pinch of turmeric and black pepper powder and added to curries, sauces, and chutneys.
In some fruits, the peel is bitter in taste and may contain toxic compounds which when eaten may cause some serious adverse reactions. These fruits can only be eaten after its peel removed. For example, raw, unripe mango peel latex contains urushiol, a compound which may cause mango-latex allergy syndrome in some sensitized persons. (Medical disclaimer).
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Visit here for very informative pages on:-
Research articles on nutrition.
1. USDA National Nutrient Database. (opens new window)
2. Stanford School of Medicine Cancer information Page- Nutrition to Reduce Cancer Risk (Link opens in new window).