In majority of the Fruits the peel in generally peeled off or scraped when it is edible. The peel is also an essential component of our diet as it contains many nutrients and non-nutrient compounds which protects our body against diseases.
The peel of fruits like Blueberry, grapes, guava, and kumquat contains more anti-oxidants such as anthocyanin pigments, tannins, catechins than the pulp or flesh of the fruit. Blue or purple color fruit peels contains anthocyanidin glycosides while yellow color have xanthin, carotenes and lutein pigments.
Peel is an excellent source of dietary fiber like hemi-cellulose, pectin, tannins, etc. These compounds helps to prevent constipation by reducing gastro-intestinal transit time. They also reduces colon cancer risk that bind to toxins in the food which helps to protect the mucus membrane of gut .The dietary fibers also bind to bile salts and decrease their re-absorption, thus help lower serum LDL cholesterol levels.
Peel is low in calories, sugar, and fats.Certain fruits peel like in orange contains more vitamin C than its juice.The peel is also rich in vitamin A, B-complex vitamins, minerals such as calcium, selenium, manganese, zinc,etc,.
The passion fruit peel contains bronchodilator effect that helps to relieve from bronchospasm in asthma patients.It extract reduces wheeze and cough and improves shortness of breath in adults with asthma.