Nigeria – the sixth largest producer of cashew nuts globally – exports greater than 80% of its uncooked cashews primarily to Vietman and India the place they’re processed into varied client merchandise reminiscent of butter, meals and beauty substances.
However Africa’s most populous nation can extract extra financial worth out of cashews through the use of their wastes to provide citric acid.
Cashew is a tropical tree cultivated for its fruit (cashew nut) and pseudofruit (cashew apple). The nut is the key motive for planting cashew – it is rather nutritious. The fleshy “apple” half yields a juice which is excessive in nutritional vitamins and minerals.
However the juice is excessive in anti-nutrients too. These are compounds that forestall the physique from absorbing vitamins. Additionally they make the juice much less palatable. Due to this, cashew apples are largely discarded.
The apple pulp, shell and liquid from the shell are all wasted or underutilised. But, these are worthwhile supplies and they are often improved by biotechnology.
We’ve been conducting work into the potential of manufacturing citric acid from cashew juice. It was the primary effort globally to provide citric acid from cashew juice. Citric acid is broadly used to protect blood, medication and processed meals and drinks. Its international worth is anticipated to achieve US$4 billion in 2027.
We used cashew from Ogbomoso, south west Nigeria, an space that produces a few of the greatest cashew nuts in Nigeria.
Cashews in Nigeria
Nigeria at the moment harvests 200,000 to 240,000 metric tons of uncooked cashew nuts every year, with about 85% of this exported. Nigeria’s no completely different to different African nations that export the majority of their manufacturing as uncooked cashew nuts.
Africa, with manufacturing of two,334,405 tons, is the world’s largest producer and exporter of uncooked cashew nuts, accounting for greater than 50% of manufacturing. Between 2000 and 2018, world commerce in uncooked cashew nuts greater than doubled to 2.1 million tons, and African producers – led by Côte d’Ivoire – accounted for nearly two-thirds of the expansion. In 2020, commerce in cashew nuts was value US$6.87 billion.
Cashew farming contributes about N24 billion (about US$58 million) to the Nigerian financial system yearly. It employs greater than 600,000 individuals.
The sector may do extra. Our work reveals that citric acid might be produced from cashew apple juice, which is plentiful in Nigeria. Home manufacturing would save Nigeria US$31 million a 12 months in overseas alternate, primarily based on citric acid imports for 2020.
Nigeria can produce citric acid from cashew apple juice through the use of biotechnology – the science of utilizing organic processes to provide worthwhile supplies and providers. As an example, man makes use of some micro organism to transform milk to yoghurt. Yeast is utilized in producing bread by way of biotechnology. Biotechnological merchandise have been valued at US$752.88 billion in 2020 with projected progress of 15.83% for 2021-2028.
Cashew wastes, too, might be turned to wealth by creating new merchandise. As an example, cashew nut shell liquid produces chemical compounds that can be utilized within the making of paints, varnishes, agrochemicals and medicines. Shell and pulp are used by means of biotechnology to provide animal feeds and bioethanol. Biotechnology may also flip the juice into drinks and ethanol.
Citric acid from cashew
In our efforts so as to add worth to cashew, we targeted on the underutilised cashew apple juice and aimed to check the potential for producing citric acid from the juice.
The demand for citric acid is rising due to its usefulness in meals, pharmaceutical and beauty industries. New sources of vitamins are wanted to develop microorganisms that produce citric acid.
Vitamins within the cashew juice and pulp assist the expansion of microorganisms.
We used cashew apple juice to develop black mould to provide citric acid for the primary time globally. Black mould is a fungus that’s broadly distributed within the atmosphere. It produces black spores when it grows. It’s scientifically often known as Aspergillus niger.
The mould grows on easy and low-cost supplies. It has been used to provide citric acid since 1919. It’s used to provide completely different merchandise, together with enzymes, proteins and animal feeds. It’s celebrated as a microorganism that has made large contributions to biotechnology for 100 years.
The most effective regionally sourced black mould consumed the juice to provide citric acid in massive portions. It produced 92.8g of citric acid per litre of juice after 10 days of progress. The yield is taken into account very excessive in contrast to those who have been earlier reported.
We used the citric acid to coagulate soy milk to make cheese. Citric acid is used as coagulant in producing cheese. We requested a panel to check the standard of the cheese. They discovered the soy cheese to have higher traits than these produced regionally utilizing fermented liquor of corn. These embrace higher color, texture, flavour and firmness.
We then used scientific strategies to extend the citric acid manufacturing. We manipulated progress circumstances of the mould and utilized nanomaterials in its vitamin on this regard. It was the primary report globally to extend citric acid manufacturing by making use of nanotechnology.
At varied instances, we used 4 strategies to enhance functionality of the mould. These embrace acquiring high-yielding mould by publicity to radiation. Then, we added sugar to the juice to check its impact on yield of citric acid. We evaluated the addition of zinc oxide nanoparticles on citric acid manufacturing. Lastly, we decided the most effective progress circumstances to assist citric acid manufacturing by our mould.
These efforts elevated citric acid manufacturing by the mould in cashew juice by about 2.38 to 11.98 instances of the unique manufacturing. As an example, addition of zinc oxide nanoparticles gave yield of 34.62% citric acid per day. The most effective progress circumstances turned in 92.61% citric acid per day. These outcomes confirmed that we are able to enhance productiveness of the mould to reinforce industrial manufacturing of citric acid.
Massive scale manufacturing of citric acid utilizing cashew apple juice may obtain a number of advantages. It may:
add worth to cashew farming and improve revenue from planting the crop
cut back the environmental nuisance of disposal of cashew apple
improve Nigeria’s potential to provide citric acid regionally
enhance the financial system and save overseas alternate reserves.