Work Package 4:

 Ensuring the safety and quality of processed cassava products in market--orientated production

 REVIEW OF PREVIOUS WORK ON CASSAVA CYANOGENIC GLYCOSIDES

 Executive summary

 Cassava is one of the most important root and tuber crops, providing nourishment for more than half a billion people the world over. It derives its importance from the fact that it is a valuable source of less costly calories, widespread and an integral contributor to food security in developing countries. The crop can grow and produce significant harvests even in environmental conditions which are inclement for most crops. World production quantity of the produce increased by more than 30 % over the period between year 2000 and 2010, with more than half of the total amount produced in Africa. Cassava is primarily grown for use as food and has over the years played an inimitable role in providing valuable calories for people of diverse socio-cultural standings. That notwithstanding, the crop has received attention as a raw material for a wide range of industrial applications including the production of bioethanol, adhesives, pharmaceuticals, plastics as well as pelletized animal feed.

 One of the drawbacks of the root crop for use as food is its potential toxicity, a phenomenon which stems from the cyanogenic glycoside content of the crop. These compounds, which naturally serve wards off insect and herbivore attack, undergo enzymatic degradation to produce HCN which is lethal at 35 - 150 µmol/kg, administered in a single dose. Sub-fatal doses over a long period have been reported to affect the nervous system and thyroid glands. HCN has also accounted for cases of reduced blood pressure, diabetes mellitus and growth retardation in children. Cyanogenic compounds have also been identified as contributing to bitterness in certain cassava varieties. Reduction of cyanogen content reduces the risk of intoxication associated with cassava consumption.

 Detoxifying cassava of cyanide presents an avenue for expanding both domestic and industrial applications. Even though contemporary interventions such as genetic engineering and breeding have been applied to generate cyanide-free varieties, traditionally, detoxification is achieved by    processing. Methods such as fermentation, cooking, drying and roasting have resulted in significant reduction of cyanide content of cassava. These techniques involve a combination of unit operations that trigger the breakdown of cyanogens by endogenous enzymes into HCN, which is subsequently evaporated (by heating) or dissolved in water (depending on the processing method under consideration). Processing has resulted in markedly lessened potency of cyanogenic glycosides in cassava, even though the reduction in toxicity depends on the starting material, and the method used and the extent of processing.

OBJECTIVE(S): To provide knowledge and technologies to allow the development of value chains linking small-holder farmers to growth markets for HQCF in the context of climate change & variability.

METHODOLOGY:  Transfer of composite flour baking technology through training workshops with the use of posters, brochures; Bank facility facilitation and search for new markets. 

ACTIVITY/PROGRESS MADE SINCE PREVIOUS REPORT:

1. Project Review meeting  held 

2. Field survey and data collection was undertaken in the Volta and Brong Ahafo Regions

3. Establishment of the Functional properties of HQCF  has been done

4. Examination of New uses of HQCF at the laboratory scale in Ghana is yet to be completed, Specific innovations and knowledge from associates in India are to be evaluated, specifically the potential of using HQCF to make bio-plastics and snack and composite foods. Samples from India has arrived .Products are yet to be tested for their acceptability in a variety of end use markets.

5. Production processes of HQCF has been standardized as follows: sorting, peeling, washing, grating, pressing, sifting, chipping and drying 

6. Evaluation of the market potential for innovations has been carried out.

7. Non-food products such as animal feed , microbial yeast and adhesives 

8. Testing of innovative new products tested with end use industry partners have already been identified through the C: AVA project.

WAY FORWARD:

1. Awaiting technology of production from India for the sample products received

2. Acceptability and end use of products yet to be tested.

3. Publication of impact of climatic change on cassava value chain (post-harvest losses)

OBJECTIVES: 

1) To cultivate four different species of edible mushrooms, Pleurotusostreatus, P. tuber-regium, Ganoderma sp. and Termitomyces sp.

2) To develop a new mushroom-based food

3) To assess consumer acceptability of the new mushroom-based products.

EXPECTED BENEFICIARIES: 

1) Pharmaceutical and Food Industries

2) Mushroom farmers

3) Unemployed youth

BACKGROUND INFORMATION AND JUSTIFICATION

Many forests in Ghana are home to several species of edible mushrooms.

In many parts of the world, including Ghana, wild mushrooms are regularly collected when in season and used directly as a main source of food or added to dishes such as soups, stews, and teas to enhance flavor and texture. Recently, edible mushrooms have attracted much interest as functional foods because of their anti-mutagenic, anti-tumoral and anti-viral properties (Garcia-Lafuente 2011). There are at least 270 species of mushrooms that are known to possess medicinal properties (Smith et al 2002), and regular consumption has potential to benefit an individual’s diet. Both regions consume mushrooms for both their nutritional value and their medicinal properties, as mushrooms are anecdotally thought to reduce obesity, promote weight gain in underweight children, treat asthma, lower blood pressure in hypertensive patients, treat rheumatism, treat diarrhea, etc. Mushrooms are an excellent source of vitamins, especially the B vitamins (Garcha 1993), and are a natural source of ergosterol, or pro-vitamin D (Kurtzman 2005). While crude fat in mushrooms contains the main classes of lipids, levels are generally low (2-8% of dry weight) (Breene 1990).Increasing urbanization has strengthened consumer demand for more sophisticated food choices that appeal to health, creating an opportunity for innovation in functional food product development, such as convenient mushroom-based foods (Grunert 2011). Successful new product development requires input from the target market throughout the process to obtain consumers’ perspectives, including identification of viable opportunities, development of concepts and physical prototypes, assessment of technology feasibility, and product launch (Grunert 2011). With their high nutritional value coupled with their medicinal properties, farming mushrooms and encouraging their consumption throughout Ghana could improve both the nutritional and health status of its people.

MATERIALS AND METHODS:

Objective 1: To cultivate four different species of edible mushrooms, P. ostreatus, P. tuber-regium, Ganoderma sp. and Termitomyces sp.

Objective 1A: To expand the cultivation of three different species of edible mushrooms, P. ostreatus, P. tuber-regium and Ganoderma sp.

Objective 1B: To cultivate Termitomyces sp. in vitro using tissue culture methods.

Objective 1C: Mushroom analysis will include color, texture, and select nutrient analyses (e.g. vitamin C,vitamin D, B vitamins and amino acid profile).

Objective 1D: Extracts of each mushroom will be screened for anti-inflammatory activity at Ohio State University if supplemental funds are received. 

Objective 2: To develop a new mushroom-based food.

Objective 2A: To formulate and develop prototypes of a new mushroom-based infant food. 

Objective 2B: Samples of the mushroom-based infant food will be analyzed immediately after processingand again after 3, 6 and 12 months at 30°C storage. 

Objective 2C: The shelf-life of the new food will be assessed by storing samples at three differenttemperatures (room (30±2oC), reduced (4oC) and elevated temperatures (37±2oC). 

Objective 3: To assess consumer acceptability of the new mushroom-based products.

Sensory attributes for assessment will include:

(1) Physical appearance

(2) Smell or aroma

(3) Texture and smoothness

(4) Taste and feeling on the tongue and

(5) Overall liking. 

ACTIVITY/PROGRESS MADE SINCE PREVIOUS REPORT:

1. Collection of mushroom germplasm from ATIWA forest. From 19th to 22nd March, team members from CSIR-FRI, embarked on a trip to Atiwa forest for mushroom germplasm collection. Samples collected included the woodear mushrooms (Auricularia species), oyster mushrooms (Pleurotus species), Falvolus brasilensis, Oil palm mushroom (Volvariella volvacea), Termite mushroom (Termitomyces species) and Pcynosporus sanguinesis among several polypores. A report on this collection is being written for submission in the next quarter report. Several of these samples have been air dried and awaiting proximate, nutrient, and phytochemical analysis in July-October, 2014 when team members will visit the laboratories of The Ohio State University, USA.

2. Cultivation of selected mushrooms on sawdust. Four varieties (Pleurotus ostreatus strain EM-1, P. sajor-caju strain PSCW, Auricularia auricula strain AU and Ganoderma lucidum strain GLA) have been grown on a mixture of composted sawdust of Triplochiton scleroxylon and Chlorophora excelsa. Fruit bodies of these mushrooms will be harvested and dried for product development studies scheduled for July-October 2014 at The Ohio State University, USA.

WAY FORWARD:

1. A field trip will be carried out for mushroom germplasm collection in Ayum forest in the Brong Ahafo region.

2. A manuscript titled ‘Mushrooms as functional foods in Ghana’ is under preparation by team members and will be sent to a journal this quarter.

3. Fabrication of an autoclave for increased spawn production 

4. A trip will be made by some team members to The Ohio State University, USA where a project meeting will be held. Also phytochemical analysis of collected mushroom samples from ATIWA and AYUM forests will be carried out. 

5. Product development of mushroom formulated children food using wild and/or cultivated mushrooms will be done.

The Cassava: Adding Value for Africa (C:AVA) Project is currently developing value chains for HQCF in Ghana, Tanzania, Uganda, Nigeria and Malawi. This will improve the livelihoods and incomes of at least 90,000 smallholder households as direct beneficiaries, including women and disadvantaged groups. It promotes the use of HQCF as a versatile raw material for which diverse markets exist.

The Project is led by the Natural Resources Institute of the University of Greenwich, working closely with the University of Agriculture, Abeokuta, Nigeria; the Food Research Institute, Ghana; Tanzania Food and Nutrition, Tanzania; Africa Innovations Institute, Uganda; Chancellor College, University of Malawi; the International Institute of Tropical Agriculture; and a range of other partners.