okra

What is okra

Okra (Hibiscus esculentus L. Moench) or lady finger or “gumbo” is a well-known tropical vegetable in the Malvaceae family, although the latter term is more often applied to soups or other dishes which contain okra 1). Okra apparently originated in what the geobotanists call the Abyssinian center of origin of cultivated plants, an area that includes present-day Ethiopia, the mountainous or plateau portion of Eritrea, and the eastern, higher part of the Anglo-Egyptian Sudan. Okra is now widely planted from Africa to Asia and from South Europe to America.

Okra is rarely used “straight” except when fried with meal, just a little of it usually being cooked with other vegetables or put into soups and stews. Okra alone is generally considered too “gooey,” or mucilaginous, to suit American tastes. In recent years, however, it has become an important commercial crop in certain localities in the South, where thousands of tons of the pods are grown for the large soup companies.

Okra is easily dried for later use. A little dried okra in prepared dishes produces much the same results as does the fresh product.

In some lands the seeds rather than the whole young pods are of most interest. When ripe the seeds yield an edible oil that is the equal of many other cooking oils. In Mediterranean countries and the East, where edible oils are scarcer than in our country, okra oil is no rarity.

The ripe seeds of okra are sometimes roasted and ground as a substitute for coffee. Okra seeds may be roasted and ground to form a caffeine-free substitute for coffee.

Okra leaves may be cooked in a similar way to the greens of beets or dandelions. The leaves are also eaten raw in salads. In Turkey, the leaves are used in preparing a medicament to soothe or reduce inflammation. A close relative of okra, roselle, is used as a source of fiber for cloth.

Figure 1. Okra

okra

Okra nutrition facts

Raw okra is 90% water, 2% protein, 7% carbohydrates and negligible in fat. In a 100 gram amount, raw okra is rich (10% or more of the Daily Value, DV) in dietary fiber, vitamin C and vitamin K, with moderate contents of iron, calcium, thiamin, folate manganese and magnesium.

Table 1. Okra (raw) nutrition facts

NutrientUnitValue per 100 g
Approximates
Waterg89.58
Energykcal33
EnergykJ138
Proteing1.93
Total lipid (fat)g0.19
Ashg0.86
Carbohydrate, by differenceg7.45
Fiber, total dietaryg3.2
Sugars, totalg1.48
Sucroseg0.6
Glucose (dextrose)g0.32
Fructoseg0.57
Lactoseg0
Maltoseg0
Galactoseg0
Starchg0.34
Minerals
Calcium, Camg82
Iron, Femg0.62
Magnesium, Mgmg57
Phosphorus, Pmg61
Potassium, Kmg299
Sodium, Namg7
Zinc, Znmg0.58
Copper, Cumg0.109
Manganese, Mnmg0.788
Selenium, Seµg0.7
Vitamins
Vitamin C, total ascorbic acidmg23
Thiaminmg0.2
Riboflavinmg0.06
Niacinmg1
Pantothenic acidmg0.245
Vitamin B-6mg0.215
Folate, totalµg60
Folic acidµg0
Folate, foodµg60
Folate, DFEµg60
Choline, totalmg12.3
Vitamin B-12µg0
Vitamin B-12, addedµg0
Vitamin A, RAEµg36
Retinolµg0
Carotene, betaµg416
Carotene, alphaµg27
Cryptoxanthin, betaµg0
Vitamin A, IUIU716
Lycopeneµg0
Lutein + zeaxanthinµg280
Vitamin E (alpha-tocopherol)mg0.27
Vitamin E, addedmg0
Tocopherol, betamg0
Tocopherol, gammamg0.16
Tocopherol, deltamg0
Vitamin D (D2 + D3)µg0
Vitamin DIU0
Vitamin K (phylloquinone)µg31.3
Lipids
Fatty acids, total saturatedg0.026
04:00:00g0
06:00:00g0
08:00:00g0
10:00:00g0
12:00:00g0
14:00:00g0
16:00:00g0.022
18:00:00g0.003
Fatty acids, total monounsaturatedg0.017
16:1 undifferentiatedg0
18:1 undifferentiatedg0.016
20:01:00g0
22:1 undifferentiatedg0
Fatty acids, total polyunsaturatedg0.027
18:2 undifferentiatedg0.026
18:3 undifferentiatedg0.001
18:04:00g0
20:4 undifferentiatedg0
20:5 n-3 (EPA)g0
22:5 n-3 (DPA)g0
22:6 n-3 (DHA)g0
Fatty acids, total transg0
Cholesterolmg0
Phytosterolsmg24
Amino Acids
Tryptophang0.017
Threonineg0.065
Isoleucineg0.069
Leucineg0.105
Lysineg0.081
Methionineg0.021
Cystineg0.019
Phenylalanineg0.065
Tyrosineg0.087
Valineg0.091
Arginineg0.084
Histidineg0.031
Alanineg0.073
Aspartic acidg0.145
Glutamic acidg0.271
Glycineg0.044
Prolineg0.045
Serineg0.044
Other
Alcohol, ethylg0
Caffeinemg0
Theobrominemg0
Flavonols
Isorhamnetinmg0
Kaempferolmg0
Quercetinmg21
Isoflavones
Daidzeinmg0
Genisteinmg0
Total isoflavonesmg0.01
[Source 2)]

Okra uses

Okra is considered as an important constituent for balanced food due to its dietary fibers and amino-acid composition which is rich in lysine and tryptophan 3). Its fruits are harvested when immature and are commonly consumed as salads, soups, and stews 4). The roots and stems are used for cleaning the cane-juice during brown-sugar preparation 5). The seeds have also gained much interest as a new oil (30–40%) and protein (15–20%) source 6). Okra has been found to possess various ethno-pharmacological and medicinal properties against cancer, high-cholesterol, and Diabetes mellitus 7).

Benefits of eating okra

Because of its high amount of mucilage, okra is also used in traditional medicine as a dietary meal to treat gastric irritation. The structural elements of mucilage have recently been characterized as pectin-like rhamnogalacturonans 8) with unusual structural features 9). Additionally, these okra rhamnogalacturonan polysaccharides reportedly possess antiadhesive properties that interrupt the adhesion of Helicobacter pylori to human stomach tissue 10).

The fiber in Okra help to stabilize blood sugar by regulating the rate at which sugar is absorbed from the intestinal tract 11). Previous studies reported that Okra polysaccharide possesses hepatoprotective 12), antidiabetic 13), antiulcer 14), anticancer 15), anti-inflammatory, laxative, antihyperlipidemic, antifungal, and analgesic activities 16). Recently, some quercetin derivatives, well-known antioxidants, were identified and isolated from Okra 17). Nutritionally, the richest part of Okra plant is the dried seeds. The oil of Okra seeds is edible and the residual meal after oil extraction is rich in protein. However, further investigations are required to characterize the active constituent(s) responsible for the observed activities and to elucidate the detailed mechanism of action at the cellular and molecular levels.

Okra toxicity and side effects

Acute oral toxicity of Okra seed extracts was determined as per Organization for Economic Cooperation and Development (OECD) guidelines 423 18). A single oral dose (5, 50, 300, and 2000 mg/kg) of extracts was administered to four mice groups (n = 6) and was observed individually at least once during the first 30 min, periodically during the first 24 h, with special attention given during the first 4 hours and daily thereafter, for a total of 14 days for abnormal signs, diarrhea, and food and water intake. The animal body weight and locomotor activity score using actophotometer were measured at 0th (initial) and 14th (final) days. On the 14th day, the mice were anesthetized through intraperitoneal injection of a cocktail containing ketamine (80 mg/kg) and xylazine (10 mg/kg). Blood samples were collected by cardiac puncture and hematological parameters were analysed using ABX Micros-60 hematology analyser. All the vital organs were collected and weighed. The heart, liver, and kidney of the mice treated with AE and ME (2000 mg/kg, p.o) were processed for haematoxylin and eosin (H&E) histopathological staining. In the acute oral toxicity study, mice did not show any signs of toxicity or death up to a dose of 2000 mg/kg,  hence the LD50 cut-off value might exceed 2000 mg/kg; hence, 1/10th of the dose 200 mg/kg was taken as an effective dose for in vivo pharmacological studies 19). Further acute and subchronic (28 days) oral dose toxicity studies are warranted to investigate the potential toxicity after single and 28-day repeated oral dosing of Okra seed extracts in experimental animals.

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