TRADITIONAL PALM KERNEL OIL PROCESSING IN GHANA PROCESS AND PRODUCT CHARACTERISTICS

ABSTRACT

The process and product characteristics of the

traditional palm kernel technology were studied.

The study was in two phases. Firstly, a survey on the

technology in some selected areas in the Eastern and Greater

Accra regions was done, to collate information on processors,

processing methods, equipment used, raw materials, marketing

of products and some other aspects of the technology. Then

the processing methods encountered were replicated in the

laboratory and investigated to assess the importance of each

of their operations, in relation to production and quality

characteristics of the oil. The laboratory investigation also

sought to determine the optimum parameters of the factors

governing the various operations for better performance and to

develop modified processes based on the original processes

studied,for higher yield and better quality palm kernel oil.

Two palm kernel processing methods were observed in the

areas surveyed.

All the respondents used a method based on roasted

kernels. This method yields the characteristically dark brown,

strong scented and strong flavoured palm kernel oil commonly

found on the local markets. The other method encountered,

scarcely used by one processor, is that based on unroasted

kernels. This yields a pale yellowish, practically odourless

and mild flavoured palm kernel oil.

The roasted kernel process briefly involves roasting of

kernels, milling, boiling of a slurry of the meal and

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collection of oil. The unroasted kernel process rather

involves soaking of the unroasted kernel, milling, boiling of

meal slurry, aging, collection of oi 1 y-emulsion, and boiling

of the emulsion.

The processors involved are mostly women, ranging in age

from 20-80 years and are generally with no formal education.

These women use simple inexpensive, mostly local equipment, in

the multi-stepped processes to obtain the oil. Variations in

yield per batch of processes, variations in raw materials and

overhead cost lead to differences in turn over for each

processor.

The laboratory investigations indicated that the process

characteristics significantly influence the product

characteristics. The roasting of kernels leads to the

darkened colour, strong odour and strong flavour of the oil.

However,- it facilitates efficient milling and hence higher

yield. Soaking, in the unroasted kernel process significantly

reduces the yield but keeps the free fatty acid levels of the

oil low. In general, the investigations indicated that the

individual unit operations influence the yield, the colour,

odour and free fatty acids level of the oil.

Based on the findings of the investigations, the

parameters of some operations were modified in the unroasted

kernel process. The soaking of kernels was limited to the

first 30 minutes, milling was repeated at least 3 times,

boiling and aging of meal slurry were cut down to 10 to 20

minutes and 3 hours respectively. These resulted in cutting

down the processing time of about 36 hours spread over 3 days,

to about 6 hours within a day; and an improved yield and

qua!ity of the oil.