Peel, also known as rind or skin, is the outer protective layer of a
fruit
In botany, a fruit is the seed-bearing structure in flowering plants that is formed from the ovary after flowering.
Fruits are the means by which flowering plants (also known as angiosperms) disseminate their seeds. Edible fruits in particu ...
or
vegetable
Vegetables are parts of plants that are consumed by humans or other animals as food. The original meaning is still commonly used and is applied to plants collectively to refer to all edible plant matter, including the flowers, fruits, stems, ...
which can be peeled off. The rind is usually the
botanical
Botany, also called , plant biology or phytology, is the science of plant life and a branch of biology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. The term "botany" comes from the Ancient Greek wo ...
exocarp
Fruit anatomy is the plant anatomy of the internal structure of fruit. Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Aggr ...
, but the term exocarp also includes the hard cases of
nuts, which are not named peels since they are not peeled off by hand or peeler, but rather
shells because of their hardness.
A fruit with a thick peel, such as a
citrus
''Citrus'' is a genus of flowering plant, flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as Orange (fruit), oranges, Lemon, lemons, grapefruits, pomelos, and lim ...
fruit, is called a
hesperidium
A hesperidium (plural hesperidia) is a modified berry with a tough, leathery rind.
Etymology
Carl Linnaeus gave the name Hesperideæ to an order containing the genus ''Citrus'', in allusion to the golden apples of the Hesperides.
Development
...
. In hesperidia, the inner layer (also called ''
albedo
Albedo (; ) is the measure of the diffuse reflection of sunlight, solar radiation out of the total solar radiation and measured on a scale from 0, corresponding to a black body that absorbs all incident radiation, to 1, corresponding to a body ...
'' or, among non-botanists, ''pith'')
is peeled off together with the
outer layer (called
flavedo
Fruit anatomy is the plant anatomy of the internal structure of fruit. Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Aggr ...
), and together they are called the peel.
The flavedo and albedo, respectively, are the
exocarp
Fruit anatomy is the plant anatomy of the internal structure of fruit. Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Aggr ...
and the
mesocarp
Fruit anatomy is the plant anatomy of the internal structure of fruit. Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Agg ...
. The juicy layer inside the peel (containing the seeds) is the
endocarp
Fruit anatomy is the plant anatomy of the internal structure of fruit. Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Agg ...
.
Uses
Depending on the thickness and taste, fruit peel is sometimes eaten as part of the fruit, such as with
apple
An apple is an edible fruit produced by an apple tree (''Malus domestica''). Apple fruit tree, trees are agriculture, cultivated worldwide and are the most widely grown species in the genus ''Malus''. The tree originated in Central Asia, wh ...
s. In some cases the peel is unpleasant or inedible, in which case it is removed and discarded, such as with
banana
A banana is an elongated, edible fruit – botanically a berry – produced by several kinds of large herbaceous flowering plants in the genus ''Musa''. In some countries, bananas used for cooking may be called "plantains", distinguis ...
s or
grapefruit
The grapefruit (''Citrus'' × ''paradisi'') is a subtropical citrus tree known for its relatively large, sour to semi-sweet, somewhat bitter fruit. The interior flesh is segmented and varies in color from pale yellow to dark pink.
Grapefruit is ...
s.
The peel of some fruits — for example,
pomegranates
The pomegranate (''Punica granatum'') is a fruit-bearing deciduous shrub in the family Lythraceae, subfamily Punicoideae, that grows between tall.
The pomegranate was originally described throughout the Mediterranean region. It was introduc ...
— is high in
tannin
Tannins (or tannoids) are a class of astringent, polyphenolic biomolecules that bind to and precipitate proteins and various other organic compounds including amino acids and alkaloids.
The term ''tannin'' (from Anglo-Norman ''tanner'', ...
s and other
polyphenol
Polyphenols () are a large family of naturally occurring organic compounds characterized by multiples of phenol units. They are abundant in plants and structurally diverse. Polyphenols include flavonoids, tannic acid, and ellagitannin, some of ...
s, and is employed in the production of
dye
A dye is a colored substance that chemically bonds to the substrate to which it is being applied. This distinguishes dyes from pigments which do not chemically bind to the material they color. Dye is generally applied in an aqueous solution an ...
s.
The peel of
citrus fruit
''Citrus'' is a genus of flowering trees and shrubs in the rue family, Rutaceae. Plants in the genus produce citrus fruits, including important crops such as oranges, lemons, grapefruits, pomelos, and limes. The genus ''Citrus'' is native to So ...
s is bitter and generally not eaten raw, but may be used in cooking. In gastronomy, the outermost, colored part of the peel is called the
zest
Zest may refer to:
Common usage
* Zest (ingredient), the outer peel of a citrus fruit
** Zester, a tool for preparing zest
** Twist (cocktail garnish), a piece of zest
* Zest (positive psychology), a component of character
Brands
* Zest (brand ...
, which can be scraped off and used for its tangy flavor. A large piece of citrus peel, called a "
twist
Twist may refer to:
In arts and entertainment Film, television, and stage
* ''Twist'' (2003 film), a 2003 independent film loosely based on Charles Dickens's novel ''Oliver Twist''
* ''Twist'' (2021 film), a 2021 modern rendition of ''Olive ...
", is often used to garnish
cocktail
A cocktail is an alcoholic mixed drink. Most commonly, cocktails are either a combination of spirits, or one or more spirits mixed with other ingredients such as tonic water, fruit juice, flavored syrup, or cream. Cocktails vary widely across ...
s. The fleshy white part of the peel, bitter when raw in most species, is used as
succade
Succade is the candied peel of any of the citrus species, especially from the citron or ''Citrus medica'' which is distinct with its extra-thick peel; in addition, the taste of the inner rind of the citron is less bitter than those of the other ...
or is prepared with
sugar
Sugar is the generic name for sweet-tasting, soluble carbohydrates, many of which are used in food. Simple sugars, also called monosaccharides, include glucose, fructose, and galactose. Compound sugars, also called disaccharides or double ...
to make
marmalade
Marmalade is a fruit preserve made from the juice and peel of citrus fruits boiled with sugar and water. The well-known version is made from bitter orange. It is also made from lemons, limes, grapefruits, mandarins, sweet oranges, bergamo ...
or
fruit soup
Fruit soup is a soup prepared using fruit as a primary ingredient, and may be served warm or cold depending on the recipe. Some fruit soups use several varieties of fruit, and alcoholic beverages such as rum, sherry and kirsch (a fruit brandy) ma ...
. The peel can also be
candied
Candied fruit, also known as glacé fruit, is whole fruit, smaller pieces of fruit, or pieces of peel, placed in heated sugar syrup, which absorbs the moisture from within the fruit and eventually preserves it. Depending on the size and type o ...
, or dried to produce a seasoning (e.g.
chenpi
Chenpi, chen pi, or chimpi is sun-dried mandarin orange peel used as a traditional seasoning in Chinese cooking and traditional medicine. It is aged by storing them dry. The taste is first slightly sweet, but the aftertaste is pungent and bitter. ...
).
Nutrition
In a 100 gram reference amount, raw orange peel supplies 97
calorie
The calorie is a unit of energy. For historical reasons, two main definitions of "calorie" are in wide use. The large calorie, food calorie, or kilogram calorie was originally defined as the amount of heat needed to raise the temperature of on ...
s, with
dietary fiber
Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by the ...
and
vitamin C
Vitamin C (also known as ascorbic acid and ascorbate) is a water-soluble vitamin found in citrus and other fruits and vegetables, also sold as a dietary supplement and as a topical 'serum' ingredient to treat melasma (dark pigment spots) an ...
in rich content having 42% and 227% of the
Daily Value
The Reference Daily Intake (RDI) used in nutrition labeling on food and dietary supplement products in the U.S. and Canada is the daily intake level of a nutrient that is considered to be sufficient to meet the requirements of 97–98% of health ...
(DV), respectively.
Calcium
Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
content is 16% of the DV, with no other
micronutrient
Micronutrients are nutrient, essential dietary elements required by organisms in varying quantities throughout life to orchestrate a range of physiological functions to maintain health. Micronutrient requirements differ between organisms; for exam ...
s in significant amounts.
[ A {{convert, 1, oz, g serving of raw orange peel provides 63% DV for vitamin C and 12% DV for dietary fiber.][
]
See also
* Banana peel
A banana peel, called banana skin in British English, is the outer covering of the banana fruit. Banana peels are used as food for animals, an ingredient in cooking, in water purification, for manufacturing of several biochemical products as w ...
* Biorefinery
A biorefinery is a refinery that converts biomass to energy and other beneficial byproducts (such as chemicals). The International Energy Agency Bioenergy Task 42 defined biorefining as "the sustainable processing of biomass into a spectrum of bio ...
: conversion of citrus peel to succinic acid
Succinic acid () is a dicarboxylic acid with the chemical formula (CH2)2(CO2H)2. The name derives from Latin ''succinum'', meaning amber. In living organisms, succinic acid takes the form of an anion, succinate, which has multiple biological ro ...
* Fruit anatomy
Fruit anatomy is the plant anatomy of the internal structure of fruit. Fruits are the mature ovary or ovaries of one or more flowers. They are found in three main anatomical categories: aggregate fruits, multiple fruits, and simple fruits. Aggre ...
, describing the botanical terms of fruit and skin layers
* Peeler
A peeler (vegetable scraper) is a kitchen tool, a distinct type of kitchen knife, consisting of a metal blade with a slot with a sharp edge attached to a handle, used to remove the outer layer (the "skin" or "peel") of some vegetables such as ...
* Zest (ingredient)
Zest is a food ingredient that is prepared by scraping or cutting from the rind of unwaxed citrus fruits such as lemon, orange, citron, and lime. Zest is used to add flavor to foods.
In terms of fruit anatomy, the zest is obtained from the ...
References
Fruit