Guardian

Researchers are discovering more nutritional values of African star apple, though amid worries that the species are declining in cultivation. WOLE OYEBADE reports.

SOME centuries ago, African locals picked the “wonder fruit” on the way to the farm, ate it as snack and the seedlings become plaything for children. Now, current generation find it in the marketplace or shelves of grocery store, eat one and want more.

Researchers are currently unraveling why the unique fruit has survived several generations of the West African region, yet preserved in huge nutritional value. This is the story of African star apple or local cherry. And according to findings, it underscores significant health benefit than current findings would exhaust.

Botanically called Chrysophyllum albidum, African star apple belongs to the Sapotaceae family.

The fruits are sub-spherical in shape, about 3cm in diameter, usually 5-celled and contain an edible, sweet fruit-pulp. The skin or peel, is orange to golden yellow when ripe and the pulp within the peel may be orange, pinkish, or light yellow, and within the pulp are at least five seeds, which are not usually eaten.

The fleshy pulp is eaten especially as snack and it has been found to have high contents of ascorbic acid and is also reported as an excellent source of vitamins, irons, flavours to diets.

In Southwestern Nigeria, the fruit is called agbalumo and popularly referred to as Udara in the Southeast of Nigeria. Agbalumo’s skin is rich in latex, and its seeds are light brown and hard.

In Benin, where researchers recently focused on the used pattern of the fruit, the African star apple occurs on ferallitic soils. C. Albidum is a lowland rain forest tree species, which can reach 25 to 37 m in height at maturity with a girth varying from 1.5 to 2 m. It nature occurrence has been reported in diverse ecozones in Nigeria, Uganda, Niger Republic, Cameroon and Cote d’ Ivorie.

The locals, for several centuries, have traditionally used the bark of the tree to treat yellow fever and malaria, while the leaf treated wounds, stomachache, and diarrhea. This fruits are good remedies for sore throat, toothache, constipation, and much more. The seeds were also used to treat vaginal and skin infections in some parts of Nigeria.

A research on “Evaluation of proximate compositions and mineral elements in the star apple peel, pulp and seed” by Ukana D. Akpabio, Aniekan E. Akpakpan, and Godwin N. Enin of the Department of Chemistry, University of Uyo, Akwa Ibom State, suggests that African star apple fruit is an edible fruit of uncommon nutritional benefit.

In the study recently published in the Journal of Basic and Applied Scientific Research, its peel, pulp and seed were analyzed to determine the proximate composition and mineral elements.

The findings showed that the pulp contain greater amount of crude fibre, fat, ash and caloric value, while greater amount of moisture was found in the peels.

Carbohydrate content and crude protein was higher in the seed. Mineral elements composition revealed that pulp has greater amount of sodium and iron while peel contains greater amount of potassium and zinc. Calcium and magnesium were higher in the seed.

Moisture contents of the star apple peel, pulp and seed were 47.95 per cent, 32.65 per cent and 26.55 per cent respectively with an average of 35.76 per cent, these clearly shows that peel contain much moisture.

Moisture content is one of the most important and most widely used parameter in food processing, hence, star apple seed can easily be processed and preserved easily since it contains less moisture.

Crude protein contents of star apple peel; pulp and seed were 6.68 per cent, 4.73 per cent and 8.75 per cent respectively with an average of 6.73 per cent. Food and Nutrition Board of Nigeria (1972) recommended 56kg of protein per day in the diet of adult men weighing 70kg and 40kg for women weighing 56kg of body weight.

Fat contents of the star apple peel, pulp and seed were 8.94 per cent, 10.00 per cent and 3.45 per cent respectively with an average of 7.46 per cent.

This shows that pulp contain highest amount of fat than peel and seed. Fat provide an excellent source of energy, enhance transport of fat soluble vitamins, insulate and protect internal tissues and contribute to vital cell process.

However, it is strongly believed that excess of saturated fatty acids are responsible for a tendency to coronary thrombosis and aortic atheroma in men also high level of poly unsaturated fatty acids is important in lowering blood cholesterol level.

For crude fibre, according to the research, the values of 1.83 per cent, 3.0 per cent and 2.42 per cent was obtained for the star apple peel, pulp and seed respectively with an average of 2.41 per cent. Crude fibre content is higher in the pulp and lower in the peel.

The physiological role of fibre is to maintain an intestinal tract. Also client with low fibre have been associated with diseases of the colon like piles, appendicitis and cancer. However, low fibre contents are also known to reduce the rate of glucose and fat absorption. Hence the low fibre contents in the star apple peel, pulp and seed are advantageous in absorption of glucose and fat.

As if that is not enough, the carbohydrate contents of the star apple were found to be 79.392 per cent, 79.025 per cent and 83.38 per cent for peel, pulp and seed respectively with the average of 80.60 per cent.

The major metabolic role of the carbohydrate in the diets is for energy production. There are different types of carbohydrate, but in food only total carbohydrate is considered and it is what is left when protein, fat, moisture and ash of the foodstuff have been removed.

Earlier findings on the fruit had suggested that it contains more vitamin C than guava or orange. They are also an excellent source of calcium, potassium, phosphorous, magnesium, tannins, flavonoids, terpenoids, and phytochemicals.

While they are regularly consumed as a snack, recent studies indicate that it has properties that can be used to lower blood sugar and cholesterol prevent and treat heart diseases.

It has anti-oxidant properties and the bark is considered a tonic and stimulant. A number of closely related species, also called star apples, are grown in Africa, including C. albidum and C. africanum.

The fruit is said to contain a hundred times more vitamin C than oranges, and ten times that of guava and is common during the months of December to April.

The fruit pulp is rich in vitamin C and iron and an excellent source of raw material for industries. Tannins, flavonoids, terpenoids, proteins, carbohydrates and resins are the phytochemicals that have been reported in it.

African star apple is mostly grown in the rural areas in the country but research has shown a decline of its cultivation in many African countries and this can be linked to the tendency for animals to eat them before they reach the matured stage for human consumption.

Nowadays, in Benin, C. albidum is considered as vulnerable and its habitat seems to be restricted to traditional agro forestry systems or remnant semi-evergreen rain forest stands often protected for religious reasons.

C. Albidum is highly used and appreciated in southern Benin, where it is called azongogwe or azonbobwe in local language “Fon, Goun” and azonvivo, azonvovwe or azonbebi in local language “Aïzo”.

In a study titled: “Ethno-botanical study of the African star apple (Chrysophyllum albidum G. Don) in the Southern Benin (West Africa)” and published in the Journal of Ethnobiology and Ethnomedicine 2012, noted that despite its importance, in Benin C. albidum was poorly investigated and this species was mentioned in the group of wild fruit tree species, which need more detailed scientific information regarding their use pattern, ecology and reproduction biology in order to define a better conservation strategy.

Four use categories namely food, medicine, firewood and timber were recorded for C. albidum and food purpose represented the most dominant category.

About 95.8 per cent of the informants exploited the species for its fruits whereas 25.1 per cent and 16.4 per cent respectively exploited it for medicinal and firewood purposes.

Besides the common uses (food, medicine, wood), C. albidum leaves were occasionally used for fodder. Rotten or damaged fruits were also used to feed pigs. The species was also used in traditional rituals and was reported to have medico-magical properties.

Some informants also stated that the species was used for life renewing by old people and patients who were close to death. It was also used to chase bad spirits.

The significant increasing medicinal use value of C. albidum with increasing informant age confirms the assertion of increasing ethno-medicine knowledge of plant species with age.

“Because of this age related knowledge, there could be a long-term loss of medicinal knowledge. The disappearance of the current ‘old generation’ might involve the loss of folk medicine on C. albidum since young informants mostly rely on modern medicine.

“Instead of being complementary, modern medicine appears sometimes as an impediment to the development of folk medicine. So far, intensive and continued research on ethnomedicinal value of plants is needed not only for C. albidum but for many other species in order to document and to preserve the traditional knowledge of local population other the time.”