Improving produce quality for wholesale markets © University of Greenwich

The Post-Harvest and Value Addition Group works on durable and perishable crops after harvest to reduce losses, enhance financial or nutritional crop-value, and assure food safety. Research ranges from the fundamentals of storage and preservation of quality throughout the marketing chain, to food-science aspects of agro-processing and responses of consumers to new food products.

Achievements

Achievements include: development of a reliable technique for predicting risk to farmers of attack by Prostephanus truncatus, a devastating stored-grain pest in Africa, and successful application of the technique in Ghana, thus allowing farmers to safeguard their valuable harvest; development of an innovative method for small-holders in sub-Saharan Africa to protect their limited grain stocks against insect damage by using diatomaceous earth (DE), and proven feasibility of exploiting local DE deposits to replace synthetic organophosphate-based insecticides; and development and validation of improved cassava processing systems. Improved handling, storage and marketing methods for sweet potato, an increasingly important urban food as well as a vital food in times of drought, were adopted and promoted to end users as part of the CGIAR HarvestPlus Challenge Program. Novel methods were developed to test acceptability of food products to low-income consumers, based on price, nutritional value and sensory preference. Improved understanding of variation of storability amongst sweet potato cultivars has enhanced the breeding programmes of the International Potato Centre. In a novel approach to food toxin (mycotoxin) detection, a fluorometric assay of toxicity using genetically-engineered yeast cells was created, prompting industrial interest, and yeast genome DNA chips have been exploited to develop new models of toxin action using transcriptomic methods.

Future Plans

The team’s future research strategy includes: use of refined behavioural analysis techniques in studies of insect pests of grain, to identify new options for pest management without synthetic pesticides; studies of food safety in the informal food sector of developing countries, to improve quality and safety in a sector vital for employment of poor people; investigating food and energy security to improve sustainability of rural livelihoods in semi-arid developing countries reliant on renewable natural resources; and developing optimum approaches for uptake of post-harvest value-addition in cassava (supported by Gates Foundation) and bio-fortified food crops (with HarvestPlus Challenge Program).

Staff

Dr Rick Hodges
Dr Ray Coker
Dr Ivor Evans
Dr John Orchard
Dr Debbie Rees
Tanya Stathers
Keith Tomlins
Prof Andrew Westby

Recent Publications

Best, R., Westby, A. and Ospina, B. (2006) Linking small-scale cassava and sweetpotato farmers to growth markets, experiences, lessons and challenges. Acta Horticulturae 703: 39-46.

C. Tortoe, J. Orchard, A. Beezerc and M. O'Neil (2007). Potential of calorimetry to study osmotic dehydration of food materials. Journal of Food Engineering 78: 933-940.

Carter, R. M., Yan, Y and Tomlins, K. (2006) Digital imaging based classification and authentication of granular food products, Measurement Science and Technology 17: 235-240.

Charles Tortoe and John Orchard. (2006). Microstructural Changes of Osmotically Dehydrated Tissues of Apple, Banana, and Potato. Scanning 28: 172-178.

Johnson P-NT, Gallat, S., Oduro-Yeboah, C., Osei-Yaw, A. and Westby, A. (2006) Sensory properties of instant fufu flour from four high-yielding Ghanaian varieties of cassava. Tropical Science 46: 134-138.

Nguyen D.T., Hodges R.J. and Belmain S.R. (2008) Do walking Rhyzopertha dominica (F.) locate cereal hosts by chance? Journal of Stored Products Research 44: 90-99

Nguyen D.T. (2008) Effects of starvation on the locomotory response of Rhyzopertha dominica (F.). Journal of Stored Products Research 44: 100-102.

Tomlins, K., Ndunguru, G., Stambul, K., Joshua, N., Ngendello, T., Rwiza, E., Amour, R., Ramadhani, B., Kapande, A. and Westby, A. (2006) Sensory evaluation and consumer acceptability of pale fleshed and orange fleshed sweetpotato by school children and mothers with young children, Journal of the Science of Food and Agriculture (accepted)

Tomlins, K., Manful, J., Gayin, J., Kudjawu, B and Tamakloe, I. (2006) Study of sensory evaluation, consumer acceptability, affordability and market price of rice, Journal of the Science of Food and Agriculture (accepted)

Tomlins, K., Sanni, L., Oyewole, O., Dipeolu, A., Ayinde, I., Adebayo, K. and Westby, A. (2006). Consumer acceptability and sensory evaluation of a fermented cassava product (Nigerian fufu), Journal of the Science of Food and Agriculture (accepted)

Obadina, A.O., Oyewole, O.B., Sanni, L.O., Tomlins, K.I. and Westby, A. (2007) Identification of Hazards and Critical Control Points (CCP) for Cassava fufu processing in South-West Nigeria Food Control, Available online 3 February 2007

Sanni, L.O., Adebowale, A.A., Filani, T.A., Oyewole, O.B., and Westby, A. (2006) Quality of flash and rotary dried fufu flour. Journal of Food, Agriculture and Environment 4: 74-78.

Stathers, T.E., Riwa, W., Mvumi, B.M., Mosha, R., Kitandu, L., Mngara, K., Kaoneka, B., Morris, M. (accepted Feb 2006) Do diatomaceous earths have potential as grain protectants for small-holder farmers in sub-Saharan Africa: the case of Tanzania? Crop Protection

Stewart-Jones A., Hodges R.J. Farman D.I. and Hall D.R. (2006) Solvent extraction of cues in the dust and frass of Prostephanus truncatus and analysis of behavioural mechanisms leading to arrestment of the predator Teretrius nigrescens. Physiological Entomology 31: 63-72.