The Journal of Food Technology in Africa Innovative Institutional Communications ISSN: 1028-6098 Vol. 6, Num. 2, 2001, pp. 56-58

The Journal of Food Technology in Africa, Vol. 6, No. 2, Apr-June, 2001, 56-58

Cottage processing of cashew apple juice in Nigeria: physico-chemical and sensory evaluation of product.

T. O. Akinwale*, O. Olubamiwa, and E. A. Ajav**

Cocoa Research Institute of Nigeria, P.M.B. 5244, Ibadan, Nigeria.

* Author to whom correspondence should be addressed.
** Department of Agriculture Engineering, Faculty of Technology, University of Ibadan, Nigeria.

Code Number: ft01016

Abstract

Some manually operated equipment were employed for cottage processing of cashew apples into juice. These include an extractor, mixer pasteuriser and a bottling machine. The apples were preheated with steam for 10, 20 and 30 minutes before juice extraction. The average capacity and efficiency of the extractor were 31.82g/hr and 87.20% respectively. Treatment time affected the colour, acidity and vitamin C content of the juice. Apples treated for 30 minutes gave a brownish colour (which was not acceptable to consumers) with the least amount of vitamin C (120.60mg/100ml of juice). The 10 minute extracted juice was attractive in terms of colour and acceptability. Soluble solids, pH, and specific gravity values of the juice were not affected by heat treatment. From the sensory evaluation of the products, no significant differences were obtained for taste, mouthfeel and overall acceptability. It was concluded that 10-minute treatment time was ideal for the juice extraction.

Introduction

Cashew tree (Anacardium occidentale) is a cash crop in Nigeria. Most of the nuts produced are exported hence the economy of the producing areas has a considerable dependence on price fluctuation in the international market.

The use of by-products can be an opportunity for diversifying activities on the farm. The farmers' revenue can increase through various opportunities which, exist for using cashew apples. However, these opportunities are presently not utilised adequately. The high level of investment required on fruit juice processing may discourage commercial interests since most farmers are of the peasant status. Farmers can however be encouraged at co-operative level to come together as processors. Being highly perishable, cashew apples will not require to be transported over long distances and need to be processed, if possible, at the farm settlements.

At Cocoa Research Institute of Nigeria, a manually operated fruit juice-processing machine was employed for cashew juice processing at the cottage (or village level). The machine will serve the small holders farmers to process the apples hygienically and bring in more income, thereby improving the social status of the family.

This paper reports the performance of the locally fabricated extractor, and physico-chemical characteristics and sensory evaluation of the juice extracted by the machine.

Materials and Methods

The manually operated equipment was fabricated locally by Edson Engineering Company, an agro-industrial company in Ibadan, Oyo State, Nigeria according to standard specifications for cottage processing of cashew apples. The equipment consists of the extractor, mixer pasteuriser (stainless steel) and bottling machine (Fig. 1). Ripe and matured cashew apples were harvested from Kosoniola farm, Oro, Kwara State. They were sorted, weighed, washed and processed at the farm

The apples were pre-treated with steam using the pasteuriser for 10, 20 and 30 minutes. The apples were allowed to cool down and the juice was extracted using the extractor. The extracted juice was sieved using muslin cloth.

Sodium benzoate (359ppm) was added as preservative and thoroughly mixed into the juice. The juice was filled into 35cl bottles and pasteurised at 80°C for 10minutes. The bottles were allowed to cool down and stored on the bench for 10 days according to the procedures by Harrigan et. al. (1976), for the presence of spoilage spores. Colour was determined visually. Sensory evaluation was done using twenty panelists at the Institute. Soluble solids and specific gravity of the samples were measured with the aid of Abbe refractometer and hydrometer, respectively at 20° C; titratable acidity (as % W/V citric acid) was determined according to AOAC (1980) methods.

Performance of the machine

The juice extraction capacity (kg/hr) of the machine and its extraction efficiency (%) were determined as follows:

Extractor

Mixer pasteuriser

Bottling Machine

Results and Discussion

The average capacity of the machine was 27.64 kg/hr. Though the value was rather small, it was reasonable enough to cope with for cottage industry. That is, the total production for a shift of 8 hours was 83.62% (Table 1).

Pearson correlation analyses of the data obtained from performance of the machine and cashew fruit characteristics was as shown in Table 2. The mass of fruits extracted was positively correlated with a significant difference at 5% probability with the mass of fruits extracted, capacity and efficiency of the machine. The juice extraction efficiency of the machine was on the other hand significantly different at 5 % probability with positive correlation with the capacity of the machine and percent yield of the juice.

However, the average % yield (67.88%) of the juice extracted by the machine was rather lower than the range of values (77-83%) obtained by Akinwale and Aladesua (1999) manual one.

The physico-chemical and microbiological characteristics of the processed juice are as shown in Tables 3 and 4 respectively. The duration of heat treatment of the apples affected the colour of the juice hence the different shades of the colour obtained. Longer heat treatment time gave darker juice colours. The brownish colour obtained from the juice of the apples treated for 30 minutes could be attributed to the caramelization of the sugar as a result of overheating.

However, the pH, soluble solids and specific gravity of the apples were not affected by heat treatment. This observation was similar to those of Akinwale and Aladesua (1999); Aderiye et al., (1991) and Jagtani (1980). Total acidity (as % citric acid) and vitamin C content of the juice were affected by heat treatment with the value decreasing with increased duration of heat for vitamin C. The apples treated for 10, 20, 30 minutes had 152.4 mg, 141.0 mg and 120.5mg/100ml of juice, respectively. High temperature and oxidation had been reported to affect ascorbic acid degradation (Smooth and Naggy 1980). However, the level was
higher than the value obtained when the apples were pretreated at about 5 lbs pressure (Aderiye et al., 1991).

Absence of growth observed for all the samples incubated at 55°C indicated that the pasteurisation (though manually carried out) was effective and the samples were microbiologically safe.

Results obtained from the sensory evaluation of the product (Table 5) indicated a significant difference between the colour of juice, that is, the panelists were able to perceive different shades of colour of the product as a result of heat treatment. Only the sample treated for 10 minutes was acceptable to the panelists. However, no significant differences were obtained for taste, mouthfeel and overall acceptability of the products.

Conclusion

Cashew apple, a highly perishable fruit cannot be transported over a long distance but can now be processed at the cottage level using manually operated set of equipment for apple juice extracted. The average percentage yield was 67.88% while the extraction capacity and extraction efficiency were 31.82kg/hr and 87.20, respectively. These machines will serve the small holders farmers to process the apples hygienically and bring in more income thereby improving the general well being of the family.

The apples will require only 10 minutes of steam treatment to obtain an acceptable product in terms of physical and nutritional quality.

References

• Aderiye, B. I., Akpapunam, M. A Akvborp, P. (1991). Effect of Fermentation variables on the quality of Cashew Wine. Journal of Agric. Sciences and Technology Vol. 1, No.1, June 1991, pp 66-69.
• Akinwale, T. O. and Aladesua, O. O. (1999). Comparative study of physico-chemical properties and effect of different techniques on the quality of cashew juice from Brazilian and local varieties. Nigerian Journal of Tree Crop Research Vol 3, No. 1, 1999 pp 60-66.
• AOAC (1980). Official Methods of Analysis of the Association of Official Analytical Chemists 12^th Edition Washington DC.
• Harrigan, W. F. and McCance, E. Margaret (1976). Laboratory Methods in food and Dairy Microbiology 1976. Academic Press London, New York San Francisco.
• Jagtani, D. (1980) Fruit preservation. Vikas Publishing House, Delhi, India 22p.
• Ruck, J. A. (1969). Chemical methods for analysis of fruits and vegetable products. Canada Dept. Agric Summer Land.
• Smooth, J. M. and Naggy S. (1980). Effect of storage Temperature and duration on total vitamin content and canned single strength Gape fruit juice. Journal of Agriculture, Food and Chemistry 18: 417.

Copyright 2001 The Journal of Food Technology in Africa, Nairobi

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