Compare the Physical Quality of Dried Cocoa beans from drying methods in terms of Appearance, Structural Features, Shelf life and other Defects

The research was conducted to investigate the effect of drying methods on the drying properties on the quality of cocoa beans in Agricultural Engineering Department, Njala University, and Njala Campus, Sierra Leone. The pods were divided into 8 parts, 53 pods per sample and depodded. Four samples were washed and four unwashed from the 53 pods and fermented with box methods. Also, from these samples, four were solar dried and four sun dried. All samples were labeled with randomization, Samples A, D, F and H were solar dried while Samples B, C, E and G sun dried. Furthermore, laboratory investigations: pH test, sucrose test, bulk density, cutting test, physical properties and sensory evaluation: colour, taste, texture, aroma and grade were. Sensory evaluation revealed that washed bens scored 70% chocolate colour for both drying methods, 80% aroma, texture 90% for all washed. When graded, solar dried beans scored 70% grade 1 and sun dried scored 80% grade 1. Also, the weight of unwashed solar dried beans recorded 9.61 kg and 10.09 kg sun dried, the pH of all washed beans are high with maximum value 7.3 and the sucrose content of unwashed was reported high as 0.405% in box fermented beans. Keywords— Beans, cocoa, defects, quality, shelf-life.


Background to the Study
Cocoa (Theobromacacao) with family Malvaceae alternate Sterculiaceae is an ancient crop of the lowland tropical forest, which originated from the Southern and Central America [7] and originated from tropical rain forests of South America. Three domesticated groups are distinguished: Criollo, Forastero and a hybrid group, Trinitario [3]. Generally, fine flavour cocoa beans are produced from Criollo or Trinitario varieties, while bulk cocoa beans come from Forastero trees, but there are exceptions, Nacional trees in Ecuador considered to be Forastero by some, but with traits distinguishing them from all other groups [4] produce fine flavour cocoa, while Cameroon cocoa beans, which are produced by Trinitario trees and whose cocoa powder has a distinct and sought-after red colour, are classified as bulk cocoa beans [6].
In West Africa, cocoa is one of the most important cash crops. Studies show that the cocoa bean contains flavonoids with antioxidant properties that can reduce blood clot and the risk of stroke and cardiovascular attacks [5]. The crop is very low in cholesterol and a good source of protein, potassium, zinc, and dietary fibres.
The first cocoa plant brought in to Sierra Leone came from Ghana. These were established in Kpuwabu, Gaura Chiefdom in the Kenema District, Sierra Leone. This served as the first research centre in the Kenema Forestry and Tree Crops Research Centre (KFTCRC) for cocoa scientists and rural farmers in the Eastern Province. Through the use of extension techniques coupled with the full participation of traditional rulers, farmers developed high interest in the cultivation of cacao. Cocoa is currently the most important export crop in Sierra Leone, commanding a very high price at international markets in Europe, Asia and America.
The cultivated forms of cacao farms in Sierra Leone are Amazon (Ghana Cocoa), Trinitario and Amelonado (Mende Cocoa).
Cocoa is produced in the Eastern and Southern Provinces, with most of the crop coming from Kailahun and Kenema Districts. Cocoa production in Sierra Leone involves operations like harvesting, depodding (pod breaking), fermentation, drying, bagging transportation and storage.
After processing, the farmers take their processed consignment of dried cocoa beans directly to the produce buying agents at the various buying centres within the Provinces (Southern and Eastern Provinces). Sometimes farmers sell their produce to petty traders who in turn sell to the buying agents.
At the buying agent's stores, produce inspectors or examiners inspect and grade all the produce intended for sale in sealed bags before the issuance of trade certificates.
These certificates indicate the fitness of the produce for the export market. Inspected and graded beans are packed in trucks for transporting to transit stores at or around the Port of Freetown.
Further checks are conducted at the port before a final certificate of fitness for export is issued. Certified beans are then shipped to their export destination overseas.
Cocoa export declined considerably during the war and was gradually increased over the last five years and presently the exports are estimated to have risen to about 18,000mt in 2008 which is quite below the export performance of the Ivory Coast and Ghana which export an average 1.5 million mt and 440,000mt respectively. It production has long been the principal economic activity in Sierra Leone especially Kono and Kailahun. In the past Sierra Leone used to be the leading producer of cocoa in West Africa, alongside suppliers like Ghana. In those days the country was highly reputed in the world market for its high quality. This reputation was lost during the war years when legal exports were very low. In the pre-war era production level for cocoa was around 16,000 to 20,000mt from over 40,000ha. But another favourable area for cocoa production is in the belts that span the Moa River drainage basin, from north east of Kailahun to Barri and Makpele Chiefdoms in the Pujehun District.
Kenema District also said to be a producing cocoa but very little as compare to the other districts mentioned above.
During the war years most of the cacao farms were abandoned and became over grown with bush. This situation led to a major decline in the production levels and quality of cocoa produced in the country [1]. However, organic cocoa processing facilities have recently come into the scene and appear to be playing major roles in Sierra Leone's cocoa subsector.

Statement of the Problem
Over the past years drying has been a serious problem in the processing of cocoa beans more especially in the raining season. Based on this most of the cocoa beans processed in most areas fall in some of the following defects such as mould, germinate or slate as a result of lack of proper drying technology.
Majority of farmers in Sierra Leone are believed to be facing difficulties with lack of proper drying floors and adequate storage facilities. Most of their crop (cocoa beans) is frequently reported to be dried on unpaved floors and stored in building that are highly infested with insect pests (weevils) which made the cocoa beans unfit for sale. Such reduction in the quality and quantity of cocoa beans eventually results in serious financial losses to the farmers. A previous investigation [1] shown that most farmers reported selling grades 2 and 3 cocoa beans to produce buyers; and this situation may have resulted in significant reduction in farmers' potential incomes at that time.
That was supposed to abandoned state of the farms, poor field and post-harvest practices, low level of farmer's participation following the end of the civil unrest and low levels of private sector participation in the national cocoa subsector could be responsible for such low quality outcomes at the time.
Recent reports indicated a vibrant private sector involvement in the cocoa industry resulting in significant improvement in the incentive system, farmer participation, better field and post-harvest practices, and a more active cocoa industry. There are speculations that these improvements have led to major increase in the status of the quality system for low input (organic) cocoa production in the country. There is however, no scientific evidence to substantiate these speculations.

Aim of the Research
The ultimate aim of this research is to compare the physical quality of dried cocoa beans from drying methods in terms of appearance, structural features, shelf life and other defectsin Sierra Leone.

Justification of the Research
Although several efforts have been made in different parts of the world to improve on cocoa drying processing, serious attention has to be paid on the fermentation and drying processes. Sierra Leone still relies on the natural sun drying, very few solar dryers are available in the country.
The sun drying method is usually slow especially in the rainy season and ineffective, involves human drudgery.
This research intends to recognize some of the problems faced in cocoa drying processing and handling, therefore justifies the necessity to evaluate the performance of washed and unwashed beans, box and basket fermentation methods, solar and sun drying methods.

Hypothesis of the Research
The following hypothesis will be investigated:

Box Fermentation Method
H0: There is no significant variation in the box fermentation method between washed and unwashed dried beans.

H1:
Boxfermentation method varies significantly between washed and unwashed dried beans.

Basket Fermentation Method
H0: There is no significant variation in the basket fermentation method between washed and unwashed dried beans.

H1:
Basket fermentation method varies significantly between washed and unwashed dried beans.

Sun Drying Method
H0: There is no significant variation in the sun drying method with washed and unwashed dried beans.
H1: Sun drying method varies significantly between washed and unwashed dried beans.

Solar Drying Method
H0: There is no significant variation in the solar drying method with washed and unwashed dried beans.
H1: Solar drying method varies significantly between washed and unwashed dried beans.

Significance of the Research
The significance of the research is discussed as thus below: To investigate the most effective method of cocoa drying for producers.
Create employment for local fabricators of drying structures.
This research introduced appropriate drying technology to upgrade cocoa product from grade three (3) or two (2) to one or premium and The research was also serve as a base line for future researchers in post-harvest technology of cocoa processing.

Study Area
The

Pod Opening
The pods were divided into eight (8) portions, 53 per portion with labelled A-H and were opened (depodded) on the 19 th January, 2016 in the above mentioned department and prepared for fermentation and drying.

Box Fermentation Method
Cocoa beans with weight 4.5 kg, 5.5 kg, 5.0 kg and 6.0 kg were put into boxes A, B, C and D respectively and fermented at the Agricultural Engineering Department, turned every two days to ensure uniformity during the processing. Beans with labeled C and D were washed twice immediately after pod opening and put into boxes labeled C and D and fermented from the 19 th -25 th January, 2016. While beans with labels A and B were unwashed and put into boxes labeled A and B and fermented on the same date as mentioned above.

Basket Fermentation Method
Cocoa beans with weight 5.5 kg, 5.6 kg, 5.2 kg and 5.5 kg were put into baskets labeled E, F, G and H respectively and fermented on the same date with beans in the boxes, turned every two days to ensure uniformity during fermentation. Beans labeled G and H were unwashed, put into baskets labeled G and H, while beans labeled E and F were washed, put into baskets labeled E and F and fermented. A scheme below shows the Basket Method of Fermentation conducted.

Drying Methods
Two different drying methods were conducted for the experiment, solar and sun drying.

Solar Drying Method
Samples labeled A, D, F and H with weight 4.0 kg, 5.0 kg, 4.5 kg and 4.5 kg respectively were placed in the solar dryer with thin layer drying performed from 10:00 AM to 5:00 PM each day drying was commenced until the moisture content of the dried cocoa beans reached to 7%. The temperature of the dryer was recorded from morning down to evening each day. The drying started on the 25 th -28 th January, 2016 and scheme sample of dried cocoa beans in the solar dryer is shown below.

Sun Drying Method
Fermented cocoa beans with sample labeled B, C, E and G with weight 4.0 kg, 4.0 kg, 4.0 kg and 4.0 kg were respectively exposed under the sun on a tarpaulin from 10:00 AM to 5:00 PM which is considered the standard drying time. The beans were mixed every two hours during drying period to ensure uniformity, collected, stored and dried the next day until the beans attained moisture content of 7%.Samples of dried cocoa beans with sun drying are shown in the table.The sun drying was performed on the same date with solar drying method.

Data Collection
Data was collected during the drying process of cocoa beans from two drying methods conducted.

Experimental Design
The design was a 3 factorial experiment conducted with sun and solar drying methods, using box and basket fermentation methods, treatment washed and unwashed cocoa beans with tap water.

Randomization
A random selection was made after labeling on A4 papers, 2 washed and 2 unwashed for baskets and 2 washed and 2 unwashed for boxes, the procedure was done by dropping 4 labels papers in the first box and 1 was chosen and assigned, 3 labels papers to the second box, 2 labels to the third and 1 to the last box, The same procedure was also done to the 4 baskets.
Also capital letters labeled A-D for boxes and E-H for baskets were assigned. 4 labeled capital letters were dropped in the first box 1 was picked to assign a label, 3 in the second, 2 in the third and 1 in the last box, the same procedure was also done to the baskets where 4 labels were dropped in the first basket and 1 was chosen, 3 in the second, 2 in the third and 1 in the last basket.
These selections were used to labeled baskets and boxes used during fermentation. The same procedure was also carried out for sun and solar drying samples.

Data Analysis
Data obtained were processed using computer software Statistical Package for Social Science (SPSS 16.0), Microsoft excel, presented in tabular form and were analyzed.      Results shown that, unwashed beans scored the highest percentage of good tasted beans by the evaluators with 100% of basket fermented and sun dried. However, solar dried beans shown 90% good, in box fermented, 80% good, in basket fermented. Also washed beans shown 50% and 80% respectively in box and basket fermented and solar dried.