Cocoa is a crop that needs to be fermented and dried before export. How these procedures take place can affect the development of the flavour in the final product. There are many different varieties of cocoa; the choice of plant type can also have an effect on flavours and the physical and chemical attributes that are important to the industry. The type of shell and the fat content are two of the most important features. If these are not within the range desired by the industry, then the cocoa will sell for a lower price or will not find a market.
Preliminary research and development of the technology by the PNG Cocoa and Coconut Research Institute (CCRI) in collaboration with QDPI occurred under previous AusAID-supported research. Cocoa is an important export crop for Papua New Guinea. Technologies that can help ensure that the local cocoa is premium grade are of high priority. Previous work involving the CCRI has shown that fermentation need not necessarily take place in a large processing plant. Smaller scale fermentation, using what is known as a minibox, can allow the growers themselves to prepare smaller volumes of harvested cocoa beans for drying. Fermented, dried cocoa beans sell for more than twice the value of wet beans.
The new technology for drying involves a sun-dryer, which is made of an A-frame of timber and clear laminated plastic sheeting. Black-painted rocks heat up in the sun, and the warm air passes by convection through the drying rack. This technique could replace the current diesel and wood-powered drying kilns. This is particularly important in those cocoa-growing areas where fuelwood is becoming scarce.
Minibox fermentation and solar kiln drying have already been tested at 30 sites in East New Britain in previous research. It was found that, if carried out correctly, the fermentation procedure did not affect the final product. The solar drying resulted in a product with lower levels of acidity and an enhanced chocolate flavour compared to artificially dried samples.
The aim of this project was to evaluate the effectiveness of two novel ways of cocoa fermentation and drying for use by smallholder farmers in Papua New Guinea and to test existing cocoa genotypes to find the ones with the best attributes for the industry.
The project extended the trialling of minibox fermentation and solar kiln drying to other PNG provinces. Further work scaled up the solar drier design and developed alternative designs that were compatible as add-ons to existing diesel-fired driers. The project team evaluated procedures for reduced fermentation times and a washing procedure to see if these resulted in a decreased shell content of the beans and improved flavour. Next they screened the existing CCRI cocoa plant germplasm and studied the effects of environment, climate and season on the resulting fat content, bean and shell size of the various genotypes. Finally they conducted training sessions for CCRI and the Cocoa and Coconut Extension Agency (CCEA) staff in the construction, use and maintenance of solar dryers and miniboxes.
The major task was to evaluate the effects of minibox (250 kg) fermentations and solar drying technology on cocoa quality in PNG. Such solar drying technology could lower reliance on diesel and wood-fired kiln drying.
More information was needed about what fermentation processes to employ throughout the country, especially in wetter areas. The project scientists used computer simulation modelling to redesign the solar dryers to optimise their performance for such sites. They investigated the drying properties of cocoa so that they could employ the solar drying technology in the place of kiln and diesel dryers. They also studied the effects of manipulating fermentations - focusing on length of fermentation, washing the beans prior to drying and the fermentation of smaller quantities of beans than were processed in the existing miniboxes.
On sites shown to be too wet for satisfactory use of solar dryers the project team investigated the feasibility of combination solar/kiln dryers and also provided support to convert existing wood-fired dryers to solar/fuel-fired dryers. In East New Britain (ENB) Province the earlier AusAID project had installed about 50 solar dryers back in 1996, but they had fallen into disrepair. The team decided that rather than just repair them they would modify the design to make them more efficient and less likely to need recurring maintenance. The final design had a concrete base and a flat roof. It showed good performance and had advantages in ease of maintenance and operation. This resulted in a unit that will replace the earlier units in six locations around ENB province.
At CCRI they tested the quality attributes of cocoa lines selected from the breeding program, including lines proposed for provisional release. The team looked for superior attributes such as bean size, shell content and fat content, and demonstrated that the lines for release all produced cocoa of acceptable 'PNG flavour' standard.
The project made possible the involvement of CCRI in an International Cocoa Confectioners' Organization (ICCO) four-country project (PNG, Venezuela, Ecuador and Trinidad & Tobago) on cocoa fine/flavour quality evaluation. The task was to provide comparative documentation of PNG standard fine cocoa for use as a 'bench-mark' against the product from other countries. The initial work was to determine the best fermentation times and roasting protocols for the samples of selected genetic material from the different countries. This was largely completed.
Regardless of the technology that best suits each province, researchers recognised that a key issue was ongoing use and maintenance of the units. Therefore they placed great emphasis on the development of skills and experience amongst extension personnel to encourage the recipients of dryers to better use and maintain them.
CCRI, the PNG Cocoa and Coconut Extension Agency (CCEA) and Cocoa Board staff took part in training and capacity-building activities that involved participatory people-based action learning and paper-based extension materials. This also entailed developing and 'field testing' training materials and user guides for both men and women smallholders.
Part of the project involved drafting suggested revisions to the PNG Cocoa Inspectors and Assessors Manual, the PNG Export Regulations and the PNG Cocoa Act of 1982. One suggested change to Cocoa Board regulations was the phasing out of kiln dryers in provinces and districts in which rainfall levels allow the use of solar dryers. This is to address the issue of smoke contamination, which is the single largest complaint regarding PNG cocoa. This may cause economic hardship to many growers and some type of credit or discounting system may need to be negotiated with the Cocoa Board.
A suggested change to the Cocoa Act was to move from the set levy of 40 kina per tonne-originally imposed to finance the Cocoa Board, CCRI and (today) CCEA. Now K40 is worth much less, and the analysts believed it would be better to enter into the Act a formula that relates to the export price of cocoa. The drafts have been presented to the relevant bodies in PNG for them to implement the recommendations.
The project supported CCRI's efforts to develop a PNG brand name chocolate in Australia or PNG. Mars Confectionary Australia, a major user of PNG cocoa, has assisted with the development of chocolate samples.
Links:
[1] http://www.aciar.gov.au/country/Papua New Guinea
[2] http://www.aciar.gov.au/programarea/Horticulture