Postharvest losses for cassava can be significant and come in three forms: physical, economic through discounting or processing into low-value products, and from bio-wastes. Postharvest physical losses are reported to be exceptionally high (ca. 30%) and occur throughout the value chain.
Losses in economic value are also high, for example, prices can be discounted by up to 85% within a couple of days of harvest. Waste comes in various forms e.g. peeling losses can be 15–20%. Waste is often a lost economic opportunity, which if realised can turn a marginal business proposition into a viable one.
NRI has been undertaking a collaborative programme of research and development with 16 international research and private enterprise partners with support from the European Union Framework 7 Programme (UK, the Netherlands and Portugal), Africa (Ghana and Nigeria) and Asia (Thailand and Vietnam). This programme seeks to produce technologies and systems to create benefits for smallholder households whilst offering increased income-earning opportunities through SME development and links to large-scale industry. The project, Gains from Losses of Root and Tuber Crops focuses on: value-added processing to reduce physical and economic losses; and improved utilisation of waste such as peels, liquid waste, and spent brewery waste to make products for human consumption, including snack foods, mushrooms and animal feed.
The project took the innovative approach of comparing waste handling in cassava value chains in Africa and Asia and facilitating south to south learning. Economic losses in cassava value chains were found to be higher than initially thought. Annual losses varied from USD 20 million in Vietnam to USD 500 million in Ghana, information that may direct future government policy.
Innovative uses of HQCF were developed to access the gluten free market in various countries, together with business plans to encourage implementation. HQCF has also been successfully tested at the consumer level in Vietnam, where it was found to be a viable option for inclusion in bread making.
The project has discovered that using a mixture of cassava peels and stems on which to grow mushrooms provides a similar yield to traditional sawdust. Cassava waste has two advantages; it is more environmentally friendly by being less energy demanding, faster growing and also more profitable. A business plan has been developed for a Ghanaian company to produce mushrooms in this way.
In Thailand, factories produce starch from cassava, a process that creates waste fibrous pulp. The project team developed alternative methods for recovering further starch from the waste using enzymes. Three million tonnes of pulp produce 300,000 tonnes of recovered starch, which has many uses and adds great value to these cassava wastes. A business plan has been developed for a Thai starch company to develop this opportunity and pilot trials are currently being undertaken to increase production during 2015.
The project has delivered six approaches in four countries that will provide £200 million per year of additional income to the cassava sectors. The approach demonstrates the institute’s leadership in international projects, bringing together scientists from different countries to provide solutions that improve the environment, reduce waste and improve the livelihoods and incomes of people in Africa and Asia, and drawing on the science and technology expertise in each country.