It is just phenomenal how we are surrounded with countless valuable plants that are not only essential for maintaining a friendly ecosystem but as well as for supporting our bodies. While some of these plants serve as food for man, others are used for medicinal or some other significant purposes.
But the concern is that we often fail to acknowledge most of these valuable plants in other to gain all the necessary benefits they can offer. One of such important plants is Parkia biglobosa, which is a perennial deciduous tree that belongs to the family of Fabaceae. It is cultivated mainly for its pods that contain small seeds and sweet pulp and belongs to the plant family of Mimosaceae of the order Leguminisae. The tree is a fire-resistant heliophyte that grows best under full sunlight.
The tree is distinguished by its thick dark brown-grayish bark and it bears hanging pods that measure approximately 30 to 45 cm long and each pod contains up to 30 seeds. The pods are commonly known as locust beans that tend to be pinkish in colour on their early stages but changes to dark brown on full maturity.
Parkia biglobosa is most common in countries such as Nigeria, Sudan, Sierra Leone, Cote D’ivoire, Senegal, Chad, Gambia, Cameroon, Zaire, Guinea Bissau, Ghana, Mali, Niger, Burkina Faso, Togo, Uganda and Benin. Parkia biglobosa is known as African locust bean, dorowa or dawadawa in Hausa, ogiri or daddawa in Igbo, nune in Tiv, nere or néré in Bambara, iru, irugba, igba or iyere in Yoruba. It is also known as sikomu, nété, arbre à farine, monkey cutlass tree, nitta-tree or fern leaf.
African locust bean (iru) is of great importance in the underdeveloped and developing countries as many people rely on it as a source of food, firewood, timber, fodders, dye, traditional medicines and remedy for several ailments. Both the fruits, seeds, leaves, nuts, pods and essential oils of the African locust beans are highly valuable to the economy of these countries.
The seeds, which are enclosed in the yellow pulp are the most important and the most widely used part of this plant. Interestingly, these seeds are usually converted into a flavourful and aromatic spice which is locally known as iru, ogiri or dawadawa.
Processing Parkia biglobosa into the final aromatic product (iru, daddawa, dawadawa) is very crucial as it helps to boost its nutritional value, reduces the antinutrients (i.e natural or synthetic compounds that hinder the absorption of nutrients), boosts its digestibility and enriches its unique flavour in other to boost the smell and taste of food.
Nutritional Values of the African Locust Beans
The African locust beans seeds contain 35% protein, 16% carbohydrate and 29% lipid while the bark contains between 12 to 14% tannin. The pod contains 60% carbohydrate whereby 10 to 20% of this carbohydrate is sucrose, with a 29 milligram of vitamin C per 100 gram of the pod.
The husk is made up of 27 to 44% tannin. The ripe sweet yellow pulp of the locust beans contains 60% simple sugar (except maltose), higher sucrose and cellulose but less ascorbic acid.
Parkia biglobosa is also an excellent source of essential vitamins and minerals such as calcium, fat, potassium, ascorbic acid and phosphorus. The seeds also have some antinutritional contents such as tannin, phytate and oxalate.
Benefits of Iru (African Locust Beans)
1. Culinary Purposes
African locust bean is mainly used as an aromatic condiment for seasoning assorted traditional soups such as palm fruit soup (banga soup), bitter leaf soup (ofe onugbu), melon (egusi soup), corchorus soup, African salad (abacha) and ayamase stew etc.
Other similar oil seeds that are similar to the African locust bean and serve similar culinary purpose are; mesquite bean, melon seed, soybean and castor oil seeds.
2. Boosts the Immune System
Researchers reveal that the African locust beans are useful for boosting the immune system especially in immunocompromised individuals.
3. Wound Healing Properties
The bark of the African locust beans can be crushed, ground, soaked and boiled for preparing herbal tea for treating and healing wounds.
4. Treatment of Hypertension
The fruits are normally used in folk medicine for treating hypertension.
5. Anti-oxidizing Properties
Parkia biglobosa has a very strong free radical scavenging and reducing abilities and as such can be used as an antioxidant for detoxifying the body. The fruit has remarkable amount of polyphenols that accounts greatly for its anti-oxidizing properties. The anti-oxidizing properties of the fruit extracts of iru is very similar to that of ascorbic acid.
6. Dental Care
The bark can be infused, soaked and boiled for use as a mouthwash and for treating toothache.
7. Dermatological Care
The root, bark, pod and leaves of the African locust beans can be infused, soaked and used for bathing by individuals suffering from skin infections such as leprosy and sores. It can also be applied on the skin to soothe burns.
8. Treatment of Respiratory Infections
It can be macerated (infused or soaked in liquid) for treating respiratory infections such as pneumonia, bronchitis, cold, cough and fever.
9. Construction Purposes
Thick extracts of the locust bean pods are normally used for construction purposes as it offer elasticity to ceramics, walls and floors. The binding nature of the husks is due to its constituents of tannins and their polymeric nature. These attributes help to make the surface of ceramics, walls and floors waterproof.
10. Soap Production
The oil of the African locust bean contains high saponification value and as such very useful for soap production. Both the oil and the pod ash are normally used for making soap.
11. Textile Manufacture
African locust beans can be used alone or mixed with either starch or synthetics for producing textiles. It can equally be used as a print thickener for dyeing textiles and indigo clothes.
12. Insecticidal Purposes
The pods can be used for making insecticidal powders for treating crops and for preventing insecticidal and pesticidal attacks.
13. Treatment of Gastrointestinal Disorders
African locust bean is a rich source of tannins and as such both the seeds, roots, stems, barks, fruits, flowers and leaves can be used for treating gastrointestinal diseases such as diarrhoea and ulcer.
14. Ocular Care
The roots of the locust bean is used in folk medicine for preparing lotion for sore eyes. Studies reveal that it helps to promote good eyesight.
15. Reduction of Blood Pressure
The leaves contain procyanidin, which have been proven effective for reducing blood pressure. They significantly reduce the diastolic blood pressure more than the systolic blood pressure.
16. Livestock Fodder
The locust beans pods are consumable and are normally fed to livestock as fodder.
17. Anti-malarial Properties
Researchers reveal that Parkia biglobosa is very effective for treating malaria. Both the leaves, pods, stems and barks can be macerated and used as a herbal remedy for tackling malaria.
18. Antibacterial Properties
African locust bean plant contains antibacterial properties that are similar to those of streptomycin and as such can be used for preventing and treating bacterial infections.
19. Treatment of Coccidiosis
The roots of Parkia biglobosa are normally decocted and used for treating coccidiosis in veterinary medicine. This is a disease condition of birds and mammals that mainly affects the intestines as a result of coccidia.
20. Fishing Bait
The green pods are normally ground and added to rivers in other to kill fishes.
21. Other Uses of the African Locust Beans
African locust bean tree helps in erosion control, offer shade from sunlight, serves as windbreak, used as firewood and timber for construction purposes.
The roots and pods are used locally as sponges for washing and can also be used as local strings for musical instruments.
How to Process the African Locust Beans
To enhance the organoleptic properties and nutritional qualities of the locust beans, the seeds are normally processed. Organoleptic properties are the aspects of food, water or other substances that people experience through their senses such as smell, taste, touch and sight. It is worthy to note that its organoleptic properties are enhanced through fermentation process.
Fermentation is the chemical conversion of organic substrate into simpler compounds through the action of enzymes produced by microorganisms such as bacteria, yeasts or moulds. This process helps to augment the taste, micronutrients, minerals and protein constituents of the locust bean seeds.
Processing the African locust bean pods into the final product involves the following steps;
1. The pods are first collected after which they undergo depodding to extract the seeds from the yellowish pulp.
2. The seeds are then collected and selected before cooking for 1 to 2 days to remove the seed coats. While cooking, wood ash can be added to the iru seeds to fasten the boiling process of the cotyledons.
3. The boiled iru seeds are then dehulled, washed and rinsed in clean water.
4. Afterwards, the seeds are cooked further for another 2-3 hours to soften the cotyledons and kuru is normally added at this stage.
5. The seeds are drained with a local sieve and then spread in a fermenting perforated calabash known as nkata or ajere.
6. The seeds are allowed to ferment for 2 to 5 days at room temperature in other to give the desired result.
7. Once the locust beans are fermented, two types of the final product (iru, dawadawa) can be obtained.
The fermented iru can be mashed and molded into shapes or can be let loose as seeds. It can turn out to be harder (iru woro) or softer (iru pete), but any of these types of iru can be used for seasoning assorted food dishes such as soup and stews.
N:B – To accelerate the fermentation process of the seeds, Gmelina arborea (gamhar) or banana leaves are normally used.
This post is for enlightenment purposes only and should not be used as a replacement for professional diagnosis and treatments. Remember to always consult your health care provider before making any health-related decisions or for counselling, guidance and treatment about a specific medical condition.
Ajayi, O. A. (2014), Bacteriology and Qualitative Study of African Locust Bean (Parkia biglobosa), Open Journal of Social Sciences, 2014, 2, pp. 73-76.
Akintayo, E. T. (2004), Characteristics and Composition of Parkia biglobosa and Jatropha curcas oils and cakes Bioresource Technology. 92: pp. 307-309.
Akande, F. B., Adejumo, O. A., Adamade, C. A., & Bodunde, J. (2010), Processing of locust bean
fruits: Challenges and prospects, African Journal of Agricultural Research, 5(17), pp. 2268–2270.
Campbell-platt G. (1980), African locust bean (Parkia species) and its West African fermented food product, dawadawa. Ecol. Food Nutr., 9: pp.123-130.
Elemo, G. N, Elemo, B. O, Oladunmoye, O. O. and Erukainure, O. L. (2011), Comprehensive Investigation into the Nutritional Composition of Dehulled and Defatted African Locust Bean Seed (Parkia biglobosa). African Journal of Plant Science, 5, pp. 291-293.
Gernmah, D. I., Atolagbe, M. O. and Echegwo, C. C. (2007), Nutritional Composition of the African Locust Bean fruit pulp, African Journal Online, Ngerian food Journals, 25(1), pp. 190-195.
Ijarotimi, O. S., Keshinro, O. O. (2012), Comparison between the amino acid, fatty acid, mineral and nutritional quality of raw, germinated and fermented African locust bean (Parkia biglobosa) flour. Acta Sci. Pol., Technol. Ailment, 11(2), pp. 151-160.
Odunfa, S.A. (1986) Dawadawa in Legume Based Fermented Foods. Journal of Plant Foods, 6, 155-163.
Ogbadu, L. J. and Okagbue, R. N. (1988), Fermentation of African Locust Bean (Parkia biglobosa) Seeds: Involvement of Different Species of Bacillus. Food Microbiology, 5, pp. 195-197.
Okunlola, A. I. Adebayo, R. A. and Orimogunje, O. D. (2011), Methods of braking seed dormancy on germination and early seedling growth of African locust bean (Parkia biglobosa) (JACQ) Benth, Journal of Horticulture and Forestry Vol. 3(1), pp. 1-5.
Oladunmoye, M. K. (2007), Effect of fermentation on nutrient enrichment of locust beans (Parkia biglobosa). Res. Journal Microbial. 2, pp. 185-187.
Ntui, V. O., Uyoh, E. A., Urua, I. S., Ogbu, U., & Okpako, E. C. (2012), Regeneration of Parkia biglobosa Benth, An important tree species of Africa, Journal of Microbiology and Biotechnology Research, 2(1), pp. 169-175.
Sacande, M. and Clethero, C, (2007). Parkia biglobosa (Jacq.) G. Don. Millennium Seed Bank Project Kew, Seed Leaflet No 124.
Yusuf, O. I. S., & Rahji, M. A. Y. (2012), The processing and preference for locust bean products (Parkia biglobosa) in Lagos, Nigeria, Journal of Biology, Agriculture and Healthcare, 2(11), pp. 105–110.