Husk

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Husk of Corylus colurna (Turkish Hazel), containing 7 nuts Involucre d'un noisetier de Bysance.jpg
Husk of Corylus colurna (Turkish Hazel), containing 7 nuts

Husk (or hull) in botany is the outer shell or coating of a seed. In the United States, the term husk often refers to the leafy outer covering of an ear of maize (corn) as it grows on the plant. Literally, a husk or hull includes the protective outer covering of a seed, fruit, or vegetable.

Contents

It can also refer to the exuvia of insects or other small animals left behind after moulting.

The term husk dates to c.14, it is probably based on Middle Dutch word huusken meaning 'little house', which is derived from hūs meaning house. [1]

In cooking, hull can also refer to other waste parts of fruits and vegetables, notably the cap or sepal of a strawberry. [2]

Grains such as wheat and barley have husks. The grains are the entire seed of a plant. The seed of a grain (which the grain industry calls a “kernel”) is made up of three key edible parts – the bran, the germ, and the endosperm – which are all protected by an inedible husk that protects the kernel from damage by sunlight, pests, water and disease. [3]

Tree husks

In Hazel trees, the nut is surrounded by a short leafy husk (which is technically a involucre). This leaf-like husk encloses most of the nut. It starts off green and will fade to brown at the end of the season. Usually, the ripe nut falls out of (or can be separated from) the husk some 7–8 months after pollination has occurred. [4]

In some places, both shells and the husks of walnuts ( Juglans regia L.) which are produced as waste crops during the fruit harvesting and processing, [5] are sometimes burned as fuel for heating purposes. [6] In 2019, it has been demonstrated that the walnut green husk could be valued as a source of different natural bio-active compounds with excellent antioxidant and antimicrobial properties. [7] [8] As well as cosmetic uses. [9] An organic compound Naphthalenone, (derivative of Naphthalene) is found in green walnut husks of Juglans mandshurica Maxim. for various uses. [10] Juglans nigra , black walnut, husks have antioxidant potentials. [11] Confusingly, Walnut husks are also called hulls as well. [12] [13] Rhagoletis juglandis , also known as the 'walnut husk fly' is a common pests of walnuts. The larvae are small and live under the surface of the husk of the walnut. They cause damage to the fruit and husks which then become difficult to remove. The husk fly also infests ripe apricot and peach fruits, usually if infested walnuts are located within flying distance. [14]

Some fruit shell and hull derived bio-adsorbents have also been used for wastewater treatment purposes. For example, the almond hull and shell have been used to remove metals such as Pb, Cd, and Co in various quantities. [15] Iranian almond ( Prunus amygdalus L.) hulls have antioxidant and anti-radical properties. [16]

The coconut husk and shells can be used for fuel and are a source of charcoal. [17] In Thailand, the coconut husk is used as a potting medium to produce healthy forest tree saplings. A dried half coconut shell with husk can be used to buff floors. It is known as a bunot in the Philippines and simply a "coconut brush" in Jamaica. Coir, also called coconut fibre, is a natural fibre extracted from the outer husk of coconut. [18]

Husking and dehulling

Corn being husked in the yard of a Dungan farmer in Kyrgyzstan E8025-Milyanfan-corn-huskers.jpg
Corn being husked in the yard of a Dungan farmer in Kyrgyzstan

Husking of corn is the process of removing its outer layers, leaving only the cob or seed rack of the corn. Dehulling is the process of removing the hulls (or chaff) from beans and other seeds. This is sometimes done using a machine known as a huller. To prepare the seeds to have oils extracted from them, they are cleaned to remove any foreign objects. Next, the seeds have their hulls, or outer coverings, or husk, removed. There are three different types of dehulling systems that can be used to process soybeans: Hot dehulling, warm dehulling and cold dehulling. Hot dehulling is the system offered in areas where beans are processed directly from the field. Warm dehulling is often used by processors who import their soybeans. Cold dehulling is used in plants that have existing drying and conditioning equipment, but need to add dehulling equipment to produce high protein meal. The different dehulling temperature options are for different types of production, beans and preparation equipment.

In third-world countries, husking and dehulling is still often done by hand using a large mortar and pestle. These are usually made of wood, and operated by one or more people.

The husk is biodegradable and may be composted. [19]

See also

Related Research Articles

<span class="mw-page-title-main">Almond</span> Species of nut

The almond is a species of small tree from the genus Prunus, cultivated worldwide for its seed, a culinary nut. Along with the peach, it is classified in the subgenus Amygdalus, distinguished from the other subgenera by corrugations on the shell (endocarp) surrounding the seed.

<span class="mw-page-title-main">Drupe</span> Fleshy fruit with hard inner layer (endocarp or stone) surrounding the seed

In botany, a drupe is an indehiscent type of fruit in which an outer fleshy part surrounds a single shell of hardened endocarp with a seed (kernel) inside. These fruits usually develop from a single carpel, and mostly from flowers with superior ovaries.

<span class="mw-page-title-main">Sunflower seed</span> Seed of the sunflower (Helianthus annuus)

Sunflower seed are the seeds of the sunflower. There are three types of commonly used sunflower seeds: linoleic, high oleic, and sunflower oil seeds. Each variety has its own unique levels of monounsaturated, saturated, and polyunsaturated fats. The information in this article refers mainly to the linoleic variety.

<i>Prunus</i> Genus of trees and shrubs

Prunus is a genus of trees and shrubs, which includes the fruits plums, cherries, peaches, nectarines, apricots, and almonds.

<i>Juglans</i> Genus of trees

Walnut trees are any species of tree in the plant genus Juglans, the type genus of the family Juglandaceae, the seeds of which are referred to as walnuts. All species are deciduous trees, 10–40 metres (33–131 ft) tall, with pinnate leaves 200–900 millimetres (7.9–35.4 in), with 5–25 leaflets; the shoots have chambered pith, a character shared with the wingnuts (Pterocarya), but not the hickories (Carya) in the same family.

<span class="mw-page-title-main">Lentil</span> Species of flowering plant with edible seeds in the family Fabaceae

The lentil is an edible legume. It is an annual plant known for its lens-shaped seeds. It is about 40 cm (16 in) tall, and the seeds grow in pods, usually with two seeds in each. As a food crop, the largest producers are Canada and India, producing 29% and 27%, respectively, of the world's total lentils in 2021.

<span class="mw-page-title-main">Nut (fruit)</span> In botany, type of dry indehiscent fruit

A nut is a fruit consisting of a hard or tough nutshell protecting a kernel which is usually edible. In general usage and in a culinary sense, a wide variety of dry seeds are called nuts, but in a botanical context "nut" implies that the shell does not open to release the seed (indehiscent).

<span class="mw-page-title-main">Juglandaceae</span> Walnut family of trees

The Juglandaceae are a plant family known as the walnut family. They are trees, or sometimes shrubs, in the order Fagales. Members of this family are native to the Americas, Eurasia, and Southeast Asia.

<i>Juglans nigra</i> Species of tree

Juglans nigra, the eastern American black walnut, is a species of deciduous tree in the walnut family, Juglandaceae, native to North America. It grows mostly in riparian zones, from southern Ontario, west to southeast South Dakota, south to Georgia, northern Florida and southwest to central Texas. Wild trees in the upper Ottawa Valley may be an isolated native population or may have derived from planted trees.

<i>Juglans cinerea</i> Species of tree

Juglans cinerea, commonly known as butternut or white walnut, is a species of walnut native to the eastern United States and southeast Canada.

<i>Juglans regia</i> Species of tree (walnut)

Juglans regia, the Persian walnut, English walnut, Carpathian walnut, Madeira walnut, or, especially in Great Britain, common walnut, is an Old World walnut tree species native to the region stretching from the Balkans eastward to the Himalayas and southwest China. It is widely cultivated across Europe and the Caucasus.

<span class="mw-page-title-main">Rice hulls</span> Protective husk of rice grains

Rice hulls or husks are the hard protecting coverings of grains of rice. In addition to protecting rice during the growing season, rice hulls can be put to use as building material, fertilizer, insulation material, or fuel. Rice hulls are part of the chaff of the rice.

<span class="mw-page-title-main">Juglone</span> Chemical produced by walnut trees

Juglone, also called 5-hydroxy-1,4-naphthalenedione (IUPAC) is an organic compound with the molecular formula C10H6O3. In the food industry, juglone is also known as C.I. Natural Brown 7 and C.I. 75500. It is insoluble in benzene but soluble in dioxane, from which it crystallizes as yellow needles. It is an isomer of lawsone, which is the active dye compound in the henna leaf.

<span class="mw-page-title-main">Rice huller</span> Machine for processing whole rice

A rice huller or rice husker is an agricultural machine used to automate the process of removing the chaff of grains of rice. Throughout history, there have been numerous techniques to hull rice. Traditionally, it would be pounded using some form of mortar and pestle. An early simple machine to do this is a rice pounder. Later even more efficient machinery was developed to hull and polish rice. These machines are most widely developed and used throughout Asia where the most popular type is the Engelberg huller designed by German Brazilian engineer Evaristo Conrado Engelberg in Brazil and first patented in 1885.

<i>Juglans mandshurica</i> Species of tree

Juglans mandshurica, also known as monkey nuts, or tigernut, is a species of deciduous tree in the walnut family Juglandacea, native to the Eastern Asiatic Region. It grows to about 25 m.

Juglans sigillata, also called iron walnut, is the second most cultivated species of walnut tree after the Persian walnut Juglans regia. Commonly distributed in the eastern Himalayas and western China. The tree has been cultivated for its edible nuts, and there are at least 80 authorised or approved cultivars produced after successful implementation of grafting technology.

<i>Juglans hindsii</i> Species of tree

Juglans hindsii, commonly called the Northern California black walnut and Hinds's black walnut, is a species of walnut tree native to the western United States. It is commonly called claro walnut by the lumber industry and woodworkers, and is the subject of some confusion over its being the root stock for English walnut orchard stock.

Rhagoletis juglandis, also known as the walnut husk fly, is a species of tephritid or fruit fly in the family Tephritidae. It is closely related to the walnut husk maggot Rhagoletis suavis. This species of fly belongs to the R. suavis group, which has a natural history consistent with allopatric speciation. The flies belonging to this group are morphologically distinguishable.

<span class="mw-page-title-main">Walnut</span> Nut of any tree of the genus Juglans

A walnut is the edible seed of any tree of the genus Juglans, particularly the Persian or English walnut, Juglans regia. They are accessory fruit because the outer covering of the fruit is technically an involucre and thus not morphologically part of the carpel; this means it cannot be a drupe but is instead a drupe-like nut.

References

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