Cassava is a major food crop for approximately 700 million people, especially in African countries. A large quantity of waste is produced during processing of cassava, mainly consisting of tuber peels. Although previous research has shown that these peels can be an ingredient for substrate to cultivate mushrooms, yields were usually inferior compared to traditional substrates such as sawdust. In a project funded by the European Union (www.fp7-gratitude.eu/) trials were done for the production of oyster mushrooms using fermented peels and stems from cassava crops produced in Ghana. Four mushroom strains representing two species (Pleurotus ostreatus and Pleurotus pulmonarius) were grown on fermented substrates made from cassava waste (peels and stems) without further heating/sterilization. Peels and cassava stems were tested in different ratios and supplemented with different amounts of rice or wheat bran. All substrates colonized quickly (15–16 days) and time to pinning varied between 18 and 24 days. The P. pulmonarius strains produced three flushes within 47 days (starting from inoculation) and the P. ostreatus strains needed 57–63 days completing flush 3. Biological efficiencies after three flushes varied between 38 per cent and 100 per cent. Addition of bran (rice or wheat) increases yields significantly. The trials have shown that cassava waste can be used well for the production of oyster mushrooms and that production from substrates containing up to 75 per cent cassava peels compares well to yields obtained on the traditional sawdust-based substrates.
A survey was conducted to study production, vending, and consumption of kenkey, a sour dumpling in Ghana. Information was obtained on the socio-cultural profile of the actors, processing technologies, practices which adversely affected product quality, shelf life, and quality attributes important to consumers. Kenkey production and retailing was the domain of women, and carried out mainly as a family business in home-based operations. Three types of kenkey were encountered: Ga-, Fanti-, and nsiho-kenkey. Production was dominated by the Ga and Fanti socio-cultural groups but consumption cut across all socio-cultural groups. The majority of producers processed 10–100 kg of maize per week but frequency of production varied from 1 to 10 times in a week. Unit operations in kenkey production were labour intensive and manually carried out apart from milling. The texture of kenkey was more critical to most consumers than taste and depended on a procedure called aflatalization yielding a product with a semi-sticky, elastic consistency.