Nigeria, the sixth largest cashew nut producer in the world, exports over 80% of raw cashews to Vietnam and India. These cashews are then processed into butter, cosmetics, and food ingredients.
Cashews waste can be used to make citric acid, which is more valuable for Africa’s largest nation.
The cashew tree is cultivated to produce its fruit (cashew nuts) and pseudofruits (cashew apples). The cashew is primarily planted for the nut, which is a very nutritious food. The “apple-like” fleshy part produces a high vitamin and mineral juice.
The juice also contains a lot of anti-nutrients. These compounds prevent the body’s absorption of nutrients. They also make the juice less palatable. Cashew apples are thrown away because of this.
The pulp, the shell, and the liquid of the apple shell are waste. These materials are still valuable and can be enhanced by biotechnology.
We have been researching to determine the potential for producing citric acid using cashew juice. This was the world’s first attempt to make citric acid out of cashew juice. Citric acid can be used to preserve food and drink, blood, and drugs. In 2027, its global value is estimated to reach US$4 Billion.
We used cashews from Ogbomoso in south-west Nigeria. This area produces some of Nigeria’s best cashews.
Cashews in Nigeria
Nigeria harvests between 200,000 and 240,000 metric tonnes of cashew nuts each year. About 85% of these are exported. Nigeria is no different from other African countries that ship a large portion of their raw cashew nut production.
Africa is the largest exporter and producer of raw cashews in the world, accounting for over 50% of total production. The world’s raw cashew nut trade has more than doubled between 2000 and 2018. African producers, led by Cote d’Ivoire, accounted for two-thirds. Transaction of cashew nuts is expected to reach US$6.87 Billion by 2020.
Cashew farming is responsible for contributing about N24 billion ($58 million) annually to the Nigerian Economy. It employs more than 600,000.
The sector could do better. Citric acid can be made from the abundant cashew apple juice in Nigeria. Citric acid imports in 2020 would cost Nigeria US$31,000,000 per year.
Nigerians can make citric acid using Biotechnology, a science that uses biological processes to create valuable products and services. Man uses bacteria to turn milk into yogurt. Biotechnology is used to produce bread using yeast. In 2020, biotechnological products were worth US$752.88 Billion, with a projected growth rate of 15.83% from 2021-2028.
By creating new products, cashew waste can also be converted into wealth. Cashew nut liquid can be used to make chemicals for paints, varnishes, or agrochemicals. Shells and pulp can be converted into animal feeds or bioethanol through biotechnology. Biotechnology is also able to turn the juices into drinks or ethanol.
Cashew acid is a source of citric acid.
We focused our efforts on adding value to the cashew by testing the production of citric acid using the underutilized juice from cashew apples.
Citric acid’s demand is increasing because it has many uses. New sources of nutrients are needed in order to grow bacteria that produce citric acid.
Cashew pulp and juice contain nutrients that support the growth of microorganisms.
For the first time in history, we used apple cashew juice for growing black mold and producing citric acid. Black mold is an environmental fungus. When it grows, black spores are produced. It is also known scientifically as niger.
It grows on cheap and simple materials. It has been used as a microorganism that has contributed to biotechnology for over 100 years.