Protein-Packed Nigerian Fermented Seeds

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Fermented leguminous seeds are integral to Nigerian cuisine, especially among the Yoruba and Igbo tribes. They are mainly used as condiments in many Nigerian foods. These condiments are not only rich in protein but also have enhanced flavors and improved digestibility due to fermentation. Popular Nigerian fermented leguminous seeds include ogiri, iru/dawadawa, okpei, and ugba/ukpaka.

Unlike fermented cassava and grains, these condiments are alkaline-fermented, which means that their pH is greater than 7. The protein in the seeds is broken down into amino acids and peptides with a release of ammonia which raises the pH of the final products to about 8 and gives them strong smell of ammonia1. The high pH helps preserve the products from disease causing microbes. Alkaline fermentation has the potential to preserve foods, decrease toxicity, enhance nutritional value, and add flavor to final products1.

Ogiri

Ogiri is a fermented condiment made from castor oil seeds (Ricinus communis) or melon seeds (Citrullus vulgaris), commonly used by the Igbo people of Nigeria. It’s a major seasoning used in Igbo soups such as onubu, oha, and nsala. It’s also added to the red-palm oil sauce used for eating roasted yam and plantain and in preparing a special Igbo dish called “abacha”. Ogiri Igbo, as it’s popularly known, is recognized by its pungent smell.

Ingredients

  • Castor oil seeds or melon seeds.
  • Salt (optional)

Preparatory Procedure

  1. Dehulling: The seeds are dehulled and properly washed with clean water to remove dirt.
  2. Boiling: The clean seeds are wrapped with banana leaves and boiled for 6 – 8 hours.
  3. Fermentation: Still wrapped in banana leaves, the boiled seeds are left to ferment for 4 – 6 days.
  4. Grinding: The fermented seeds are removed from banana leaves, mixed with ash from oil palm bunch, and ground into a paste with some granules of the fermented castor oil seeds.
  5. Packing: The final product (ogiri) is packaged in fresh leaves or recently in plastic or glass bottles.

Nutritional and Health Benefits

  • Protein: Ogiri is rich in protein and essential amino acids.
  • Antioxidants: It contains antioxidants that help protect the body from oxidative stress.
  • Flavor Enhancement: Fermentation adds a unique umami flavor to dishes.
  • Probiotics: As a fermented food, ogiri is rich in probiotics.

Iru/Dawadawa

Iru/dawadawa are fermented seeds of African locust bean (Parkia biglobosa). Iru and dawadawa are from the same source but may be prepared slightly different. While iru is commonly used by the Yorubas in the South-West of Nigeria, dawadawa is common to the North-Central and South-East parts of the country. These fermented products are important condiments in many cuisines prepared by people of these regions.

Ingredients

  • African locust beans
  • Salt (optional)

Preparatory Procedure

  1. Bean Preparation: The locust beans are boiled for about 12 – 24 hours until soft and then dehulled by hand.
  2. Fermentation: The dehulled beans are wrapped in banana leaves and left to ferment for 2-3 days.
  3. Addition of ash: Wood ash is added to the fermented seeds. Ash will increase the pH of the product to the alkaline region.
  4. Drying: The fermented beans are sun-dried for 1 – 2 days to form black or dark-brown iru/dawadawa. The sun drying also helps to preserve the product.

Nutritional and Health Benefits

The nutritional and health benefits of iru may be associated to the fermentation process which converts some chemical constituents of the Parkia biglobosa seed into more active and bioavailable forms. The antioxidants, nutrients, and other chemical components of the seed are enhanced through fermentation. Some the nutritional and health benefits of iru include:

  • Protein: Locust bean is a rich source of plant-based protein (31 to 40%).
  • Fats: Locust beans is also rich in fats (39 to 40%).
  • Vitamins: It contains vitamins A, B1, B2, B3, C, D, and E2, which are important for immune function and skin health.
  • Digestive Health: The fermentation process enhances the digestibility of the seeds.
  • Probiotics: Iru/dawadawa is a probiotic-rich food, which is good for your gut microbiome.
  • Cardiovascular Health: Iru may possess antihypertensive and cardioprotective effect due to its richness in cardioprotective minerals such as potassium and magnesium3.
  • Antidiabetic and hypolipidemia effects: Iru condiment may improve lipid profile by increasing high-density lipoprotein (HDL) cholesterol and decreasing low-density lipoprotein (LDL) cholesterol. It also showed decrease in blood glucose levels when tested in animals4.
  • Anticancer properties: In a test tube analysis of iru extract, it showed a positive cytotoxic effect against MCF-7 breast cancer cells and leukemia cell lines5.

Ugba/Ukpaka (African Oil Bean Seed)

Ugba is yet another fermented leguminous seed widely consumed in the Eastern part of Nigeria, which is obtained from the African Oil Bean plant, Pentaclethra macrophylla. Ugba seeds are protected in hard, dark brown, flat, and oval shaped seed coats. Fermented African oil bean seeds can be taken as a snack, prepared and eating alone, or mixed with other foods like “abacha”. Ugba is rich in many nutrients and vitamins and it’s also very tasty and delicious. It doesn’t have the strong smell of other fermented leguminous seeds.

Ingredients

  • African oil bean seeds
  • Salt

Preparatory Procedure

  • Boiling: To ease the dehulling of the seed from the tough seed coat, boil for 6 – 8 hours.
  • Dehulling: Use a sharp knife to remove the seed coat.
  • Slicing: Slice the dehulled seeds into small pieces of about 4.5 x 0.1 cm.
  • Additional boiling and thorough rinsing: To soften the sliced ugba seeds, boil in water for 1 – 2 hours, and rinse three times with clean water.
  • Soak in water: Soak the clean sliced seeds in water for about 10 – 12 hours to remove the inherent bitterness of the seed.
  • Drain and Ferment: Drain off the water completely, mix the sliced ugba with a little salt (NaCl), wrap with fresh leaves, place in a container, and allow to ferment for 3 to 4 days at room temperature.

Nutritional and Health Benefits

  • Protein: Ugba seed contains about 44% protein, made up of 17 out of the 20 essential amino acids6. 
  • Fats: The fat content of ugba is about 38%.
  • Minerals: Fermentation increases the amount of calcium, magnesium, and iron in African oil bean seeds7.
  • Phytonutrients: The fermentation process enhances the presence of beneficial phytonutrients like tannins, alkaloids, flavonoids, sterols, glycosides, and saponins.
  • Digestibility and Bioavailability: Fermentation improves the digestibility and bioavailability of nutrients, making them easier for the body to absorb.
  • Detoxification: The fermentation process helps to remove anti-nutritional factors and potential toxins, making ugba safer and healthier to consume.
  • Probiotic Benefits: Like other fermented foods, ugba may contribute to gut health by introducing beneficial bacteria that support digestion and overall well-being.

Okpei/kpaye (African mesquite or iron tree seed)

Okpei/kpaye is another fermented leguminous seed of Prosopis Africana commonly used as a condiment produced by Nsukka (okpei) and Tiv (kpaye) people of Nigeria. The fermentation process helps make the seed edible, digestible and nutritious since the raw seed is poisonous/inedible. Fermented okpei/kpaye is rich in protein, minerals, and vitamins. A high-quality okpei is recognized by its strong ammonia smell and dark colour.

Ingredients

  • African mesquite seeds

Preparatory Procedure

  • Boiling: To ease the dehulling of the seed from the tough seed coat, boil for 6 – 12 hours.
  • Dehulling: The tender seed coats are removed by rubbing the seeds in-between the palms.
  • Washing: Wash the dehulled seeds thoroughly to remove all dirt.
  • Fermentation: Drain water completely from the seeds, transferred to a flat woven basket lined with banana leaves, cover the seeds with extra banana leaves, and allow the seeds to ferment for about 4 days until they turn dark brown and develop the pungent ammonia odour.
  • Grinding: Grind the fermented seeds into a paste and mold into desired shapes.
  • Dry: Dry the paste completely under the sun and package in an air-tight container for use.

Nutritional and Health Benefits

Protein: Like other fermented legumes, okpei is rich in protein.

Minerals: Fermentation increases the amount of calcium, manganese, phosphorus, potassium, and zinc in okpei.

Probiotics: Okpei is rich in probiotics just like other fermented foods.

Summary

The nutritional value and health benefits of fermented Nigerian seeds are quite enormous. You need to incorporate these condiments into your diet not only as seasoning, but a rich source of protein, magnesium, potassium, vitamins A, Bs, C, and D, as well as numerous natural products with potential therapeutic effects such as low blood pressure, low blood sugar, and low cholesterol levels. The smell of these condiments might be somehow offensive, but their nutritional and health benefits quite outweigh the smell. Whenever you perceive the strong smell of these condiments, remember that it’s the “protective”, ammonia gas produced during the fermentation process that is oozing out and has nothing to do with quality of the nutritious condiments. Make ogiri, iru, okpei, and ugba part of your daily meals and enjoy their rich nutritional and health benefits.

References

1.         Wang, J. & Fung, C. Alkaline-Fermented Foods: A Review with Emphasis on Pidan Fermentation. Critical Reviews in Microbiology vol. 22 (1996).

2.         Biobaku, K. T. et al. Nutriceutical effects of fermented Parkia biglobosa seeds on recovery of malnourished rats. Ceylon Journal of Science 46, 47 (2017).

3.         Ognatan, K. et al. Effect of dietary intake of fermented seeds of Parkia biglobosa (Jacq) Benth (African locust bean) on hypertension in bogou and goumou-kope areas of togo. Tropical Journal of Pharmaceutical Research 10, 603–609 (2011).

4.         Odetola, A. A., Akinloye, O., Egunjobi, C., Adekunle, W. A. & Ayoola, A. O. Possible antidiabetic and antihyperlipidaemic effect of fermented Parkia biglobosa (JACQ) extract in alloxan-induced diabetic rats. Clin Exp Pharmacol Physiol 33, 808–812 (2006).

5.         Aderonke Ayo-Lawal, R., Osoniyi, O., Ilevbare, O. E. & Ekpo, O. CYTOTOXIC EFFECTS OF FERMENTED AFRICAN LOCUST BEAN SEEDS ON A BREAST CANCER CELL. 8, 2020.

6.         Ndudi, W. et al. Traditional fermented foods of Nigeria: microbiological safety and health benefits. Journal of Food Measurement and Characterization vol. 18 4246–4271 Preprint at https://doi.org/10.1007/s11694-024-02490-1 (2024).

7.         Okechukwu, R. I., Ewelike, N. C., Ukaoma, A. A., Emejulu, A. A. & Azuwike, C. O. Changes in the nutrient composition of the African oil bean. J Appl Biosci 51, 3591–3595 (2012).

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