Cashew nut shell liquid: an agricultural by-product with great potential for commercial exploitation in Kenya

Abstract

Cashew nut shell liquid (CNSL) is the main by‐product from cashew nuts processing and is obtained during roasting of the nuts by the oil‐bath method. It may also be obtained through expression of residual shells or solvent extraction of the pulverized shells. Kenya has the potential to produce 200,000 Tonnes of cashew nuts and 45,000 Tonnes of CNSL if all the nuts were to be processed locally and with recovery of the liquid. Currently, the country realizes only about 5‐10% of its nuts production potential. Processing of the nuts has been left to small scale processors who in many cases, burn residue shells as fuel or as waste. This practice pollutes the environment profoundly through emission of thick dark smoke with particulate matter. No CNSL is recovered in Kenya currently. The aim of this review paper is to highlight a number of products which can be manufactured in Kenya based on research initially done at Kenya Industrial Research and Development Institute and more recently at Jomo Kenyatta University of Agriculture and Technology Recovery of CNSL and its exploitation in Kenya will not only enhance the economic returns to the cashew industry but also contribute significantly to conservation of the environment. It is recommended that further work be done to scale‐up production of CNSL based products and demonstrate feasibility of the same. Production and local processing of the cashew nuts accompanied by recovery of CNSL should be enhanced.