Orange, peeled

Oranges, also called sweet oranges, can be used in a diverse range of dishes, both raw and cooked. Oranges not only contain delicious pulp, organic orange peel can also be used for flavoring and decoration as well as to make tea and fragrances.

Culinary use:

Oranges are a well-known source of vitamin C. Orange juice also contains healthy nutrients like flavonoids and carotinoids.¹

Whether peeled as a raw snack, mixed into salads, or cooked in jams and chutneys, oranges are diverse and delicious. They can also give cakes, desserts, and even savory dishes a sophisticated and tropical tang.

In alcoholic beverages, oranges are not only used decoratively but also constitute an essential ingredient of some cocktails such as sangria and tequila sunrise.

Do oranges have seeds? The navel orange is low in acid, has no seeds, and is easy to peel. However, it is not suitable for juicing as this causes the bitter compound limonene to dissolve, giving the orange juice a bitter taste. If you are planning on juicing oranges, use Valencia oranges instead. If you have oranges that are difficult to peel, you can leave them at room temperature for a few days. This makes it easier to peel.

Orange essential oil can be extracted from orange peel and used as a versatile aroma enhancer. Candied orange is a great baking ingredient that can also be made from the peel. Thin strips of orange peel, orange slices, and orange blossoms are popular decorations for dishes and drinks. Dried orange peel and orange blossoms are furthermore often found in tea blends.

Orange is an ingredient in the gluten-free, raw vegan Erb Muesli. The muesli not only contains a variety of fruits full of antioxidants such as bananas and berries, it also contains pseudograins, seeds, and golden millet. You can also try the version Erb Muesli with Rolled Oats!

Vegan recipe for orange chutney:

Mix 3–4 filleted oranges together with one chopped apple (peeled), a handful of cranberries, and 100 g brown sugar in a large saucepan. Add some orange juice, white wine vinegar, and orange liqueur and bring to a boil. Continue to simmer until the mixture reduces and the fruit disintegrates. Add your favorite spices such as ginger, nutmeg, lemon juice, and garlic. Garnish with a cinnamon stick or edible flowers (e.g., mallow, nasturtium, dandelion).

Vegan recipe for chicory and orange salad with walnuts:

Chop two heads of chicory and one filleted orange. Juice an additional orange and mix with 150 g soy yogurt. Sweeten if necessary. Mix in 2 tablespoons of walnut oil and garnish with a handful of chopped walnuts. For a spicy touch, add some freshly ground pepper before serving.

Recipe for fresh orange ginger tea:

For the basic recipe, cut the peel of a clean organic orange into pieces and place these in a saucepan. Add a walnut-size piece of ginger. Pour boiling water over the orange and ginger and let it brew for about 10 minutes. If the tea is too bitter, reduce the amount of orange peel. To give your tea an extra kick, you can add spices such as cardamom pods and star anise. You can also add some green tea, black tea, or rooibos tea to make a tea blend.

Purchasing — where to shop:

Given the multitude of orange varieties and the fact that they are grown in many parts of the world, oranges are available for purchase year-round. The most common varieties, such as navel oranges, are available from all large supermarket chains such as Walmart, Whole Foods Markets, Kroger, and Safeway (United States); Extra Foods, Metro, and Freshmart (Canada); Asda, Sainsbury’s, Tesco, Aldi, and Lidl (Great Britain); and Woolworths, Coles, Aldi, and Harris Farm (Australia). Oranges can also be bought year-round in organic supermarkets, health food stores, and fresh food markets. Or you can subscribe to fruit and vegetable delivery box services such as Farmbox Direct and Hungry Harvest (US) or Abel & Cole and Riverford (UK).

In the US, most Valencia oranges (juicing oranges) are grown in Florida, while navel oranges are mainly grown in California, Arizona, and Texas. Navel oranges are most commonly available in the US from November to April, with peak season being from January to March. This season is similar throughout the Northern Hemisphere; however, it is the opposite in Australia and New Zealand, where navel oranges are usually available from May to October. Valencia oranges tend to be consumed in summer and fall, with a peak season of May to July in the US and November to February in Australia. In winter, you may also want to try blood oranges and half blood oranges, which have a much stronger flavor than navel and Valencia oranges.

It is not advisable to eat the peel of citrus fruits, as these fruits are often treated with pesticides to increase their durability during transportation and prevent them from rotting. The use of pesticides that are not only harmful to health but also to the environment should be viewed critically. Certified organic oranges are subject to stricter regulations; however, consumer protection groups recommend washing organic oranges as well before eating.

Inspecting an orange’s skin can often suggest its quality: if the skin is shiny, this indicates that it has been treated with pesticides. If it is pale, the orange is possibly not ripe enough. If the orange smells musty, this may indicate that it is moldy.

Storing:

Ideally, oranges should be stored in a cool, dry room at about 10–15 °C. In these conditions, they can be stored for over a week. When refrigerated, oranges will remain fresh for much longer, but will lose their flavor. In warm temperatures, oranges tend to mold and spoil quickly. Avoid storing oranges in a fruit basket with other fruits as these may let off the ripening gas ethylene and cause the oranges to spoil. Spots further encourage fruit to spoil. You should try to store oranges separately and regularly check your fruit bowl for moldy or spotted oranges.

You should generally try to buy ripe oranges as, unlike other fruits, oranges do not ripen once they have been harvested.

Nutrients — nutritional information — calories:

Oranges contain approximately 9 % sugar,³ which is a combination of sucrose, fructose, and glucose.⁴ The dominant fruit acid contained in oranges is citric acid and its main flavonoid/flavan-on glycoside is the neutral-tasting hesperidin. Anthocyanins are furthermore responsible for the red-colored flesh of blood oranges. Orange peel is rich in pectin and essential oils. Oranges have a comparatively low mineral content.²

Oranges are well known to be a good source of vitamin C. However, in reality their vitamin C content (53 mg per 100 g orange flesh) is lower than that of several other fruits and vegetables including bell peppers (183.5 mg), blackcurrants (181 mg), wild garlic (bear’s garlic) (178.5 mg), and kiwis (93 mg).³ Unripe oranges have a higher vitamin C content than ripe oranges, and in orange peel the content of vitamin C can be up to 7 times higher than in the flesh.⁷

Not only can oranges be stored for a long time without spoiling, they also retain their flavor and nutrients. This makes oranges a reliable source of vitamin C. It would nonetheless be exaggerated to consider oranges a superfood, given that other fruits and vegetables contain considerably more vitamin C.

Detailed nutritional information can be found in the tables below, including the recommended daily intake (RDI) for various nutrients found in oranges.

Health aspects — effects:

How healthy are oranges? Oranges contain flavonoids such as hesperidin and anthocyanin that protect vitamin C from oxidization.² Hesperidin can also strengthen vein walls and has vascular protective properties. This phytonutrient is an approved supplement for treating swelling, hemorrhoids, and other symptoms of venous insufficiency.⁵

Vitamin C has an array of metabolic functions. As a powerful antioxidant (radical scavenger), vitamin C strengthens the immune system and improves the absorption of iron contained in other plant foods.⁶

Vitamin protects folic acid, vitamin E, and LDL cholesterol from oxidization. Antioxidants can prevent the early-stage development of arteriosclerosis. Oxidized LDL is now known to be a key risk factor for developing atherosclerosis.⁶ A breakdown of vitamin C and its health benefits can be found in our article on vitamin C (ascorbic acid).

Orange seeds, peel, and flesh contain limonoids, which have in some cases been shown to have health benefits. Limonoids in oranges were found to contain antidiabetic, antioxidant, antibacterial, and antiviral properties. Studies have moreover examined whether limonoids can be used to treat certain types of cancer; however, further clinical studies are needed to confirm this.^7,8 Limonoids also reduce the amount of cholesterol released by the liver, and have been shown to lower LDL cholesterol levels in animal experiments. While it is assumed that some limonoids have antiatherogenic properties, there are yet to be clinical studies demonstrating this.⁹

Dangers — intolerances — side effects:

Most allergic reactions to oranges are instances of oral allergy syndrome (OAS), with symptoms that include swollen lips, a furry feeling on the tongue, and blistering skin and mucous membrane. These symptoms may appear up to one or two days after consumption. Fructose intolerance can trigger similar reactions, so this should be ruled out before having an allergy test done. It should be kept in mind that intolerances are often also caused by preservatives and pesticides used in conventional farming.⁴

Citric acid attacks tooth enamel, both as a natural component and an additive (E 330). You should therefore avoid brushing your teeth too rigorously after eating or drinking acidic foods as this may lead to tooth wear on the upper layers of your teeth. Instead, we recommend that you rinse your mouth with water. This dilutes the acids from the citrus and accelerates the replacement of the minerals that the citrus has dissolved.⁴

Occurrence — origin:

Like other foods such as almonds, orange seeds contain a negligible amount of amydalin (cyanogen glycosides). Consuming such a small amount of amydalin is usually harmless. But it is important to consider that consuming seeds incidentally while eating oranges is not the same as eating lots of seeds alone. You should avoid regularly eating orange seeds in quantities of 100 g or more. If you wish to eat orange seeds, heating the seeds in an open saucepan or crushing and drying the seeds helps to remove the amygdalin.^11,12

Where do oranges come from? Oranges originate from the area between northeast India and southwest China. There, they have been known as a naturally occurring hybrid of grapefruits and mandarins for over 4,000 years. In the fifteenth century, Portuguese merchants introduced oranges to the Mediterranean region, and from here they came to be grown throughout the world. Today, oranges are one of the most important tree fruits in the world. The fruits principally thrive in the subtropics and in parts of the tropics. Most commercial plantations are situated between the 20th and 40th parallel lines north and south of the equator.²

Cultivation as a potted plant:

Grafted orange trees can be cultivated well in pots in temperate parts of Great Britain and the US. As a subtropical plant, orange trees need lots of direct sunlight, little water, and a frost-free winter. As orange trees grow quickly, young plants should be repotted in spring before they begin active "growing". During the summer growing period, orange trees should be given citrus fertilizer on top of watering. Orange trees can bloom several times a year and bear fruit in slightly colder locations, but the fruits are usually smaller and less sweet than oranges from the grocery store. Orange trees should be pruned moderately before winter.¹³

Cultivation and harvest:

Orange trees are small to medium-size trees with a round, evenly branched treetop. They are evergreen trees that may have thorns and can grow to heights of 3 to 10 m.^2,14 Oranges are self-pollinating and produce fruit without cross-pollination.¹⁴ The development time between flowering and harvest varies but is on average six to nine months.¹⁵ Oranges can be stored for between several weeks to a few months without a significant loss of quality, in both harvested form or still hanging from the tree. This is thanks to the fact that physiological and chemical processes occur particularly slowly in oranges.

What color are ripe oranges? The juice content, sugar-acid ratio, and the change in skin color from green to yellow are used to determine the ripeness of the non-climacteric fruit (fruit that does not ripen after being picked). In the case of tropical oranges, the skin color is not a meaningful indicator of the fruit’s ripeness. This is because the lack of temperature difference between day and night means that the fruits remain green or greenish yellow even when fully ripe. Night temperatures colder than 12.5 °C are a stress factor for oranges that accelerates the ripening process and color change because it causes the plant to produce more of the ripening gas ethylene.²

In order to give ripe green oranges a “typical” orange color, they are degreened. Degreening involves exposing oranges to small amounts of ethylene to stimulate a change in color of the skin.² Degreening is legal in the EU, the US, and Australia, and is encouraged and in some cases even mandated. In the EU, for example, oranges may only be sold if a maximum of 1/5 of their surface is green.

The cleaning process that oranges are subject to before sale destroys their natural wax layer. To protect them from drying out and spoiling prematurely, oranges are given an artificial wax layer. Sellers must indicate that fresh oranges have undergone this process with the label “waxed.” Waxed citrus fruits have a brighter color and stronger shine than untreated citrus.²

In the EU, oranges that have been treated with pesticides after harvest must also be labeled as such. If the additives are used before harvesting, labeling is not required for sale.²

According to the Fruit and Agriculture Organization of the United Nations (FAO), the global production of oranges totaled 73.3 million tons in 2017. Oranges ranked third after bananas and apples as the most produced fruit in the world. The largest producers of oranges are Brazil, followed by the US, India, Mexico, China, Iran, Italy, Indonesia, Egypt, Pakistan, South Africa, and Turkey.^2,14

Animal protection — species protection — animal welfare:

Like many other citrus fruits, oranges are self-pollinating and don’t require cross-pollination to produce fruit.¹⁴ Pollination by wind and bees is also possible.

General information:

The orange (citrus x sinensis L.) belongs to the genus citrus and the rue (Rutaceae) family. Almost all cultivated citrus species can be traced back to three basic species: grapefruit (Citrus maxima), lemon (Citrus medica), and mandarin (Citrus reticulata).² The orange is therefore the natural hybrid of mandarin and grapefruit.¹⁴

Aside from bitter oranges (Citrus × aurantium L.), there are more than 400 varieties of sweet oranges (citrus x sinensis L.), which can be divided into four groups: navel oranges, Valencia oranges, pigmented oranges (blood or half-blood oranges), and acidless oranges (“sweet oranges”).^{2, 14}

Keywords used:

Wikipedia mentions that orange peel contains the terpene d-limonene, which is extracted and used for the production of perfume and biogenic solvents.¹⁴

Literature — sources:

Author: Michael Weber | 27 Jul 2016