Cover Image
close this book Food Chain No. 13 - November 1994
View the document Greetings
View the document The ancient art of biotechnology
View the document Equipment
View the document Booklines
View the document Fermented foods in Sudan
View the document Mursik - fermented miIk in Kenya
View the document The production of Hate de coco
View the document Resource page
View the document Bakers' yeast
View the document Recipe page
View the document Acknowledgments

The production of Hate de coco

The most marketable coconut food products that can be satisfactorily produced at small scale are nata de coco, coconut jam and coconut cookies. The first two products are derived from the coconut milk which is extracted from ground coconut meat. After the milk is extracted a white residue called sapal remains which contains nutrients and is a good source of roughage. Sapal can be baked or cooked into several snack foods including macaroons coconut brittle and cocoballs.

Nata de coco is a gelatinous material used for the production of sweets for desserts. It is produced by the action of a micro-organism Acetobacter aceti subsp. xylinum. Marketing studies indicate that the demand for nata de coco is increasing, particularly in Japan and the United States. Enquiries have been received about the possibility of supplying between 50 and 100 tons of nata de coco per month, but local production units are not capable of producing such large quantities.

In order to produce 50 tons of nata de coco per month 20 processing units with production capacity of 100kg each would l needed. The daily raw material requirement for each unit, with a capacity of 100kg nata de coco per day, would be 20 mature nuts. The residue obtained from these nuts would amount to approximately 3.6kg of wet sap daily. Most of this would be dried or light toasted so that it could be packed and easily transported for later manufacture of macaroons, coconut brittle or cocoballs. To me local demand, some of the dried sapal could be baked into macaroons in the processing plant itself.

PRODUCTION OF NATO DE COCO Nut preparation

The nuts are split and the coconut water collected This water can be used for making vinegar or for drinking water for farm animals. The meat is then removed from the shell with a manual or electric grater. Splitting and manually grating 20 nuts takes about two hours but the use of an electric grater can reduce this to about 30 minute A medium size nut yields about 200ml, water, 300 grams of grated meat and 150 grams of coconut shell

Milk extraction

To extract the milk approximate 1kg of grated coconut meat wrapped in cheesecloth and squeezed manually. When coconut milk is extracted from grated coconut meat In this manner the yield is 30-35 per cent of the grated meat used. The residue or sapal obtained is 65-70 per cent of the grated meat

Formulation

The batch is formulated by adding the following to the milk extracted from each kilogram of grated meat 2kg of refined sugar

- 400ml of glacial acetic acid

- 5 litres of 'mother liquor' (which contains the micro-organism that initiate the fermentation)

- 28 litres of water.

 

Fermentation

The mixture obtained from the formulation stage is poured into sterilized plastic fermenting trays to a depth of 1.5 to 2 inches. The trays commonly used measure 2.5 x 6 x 6 inches. Three trays are needed to produce 1kg of raw nata de coco. The containers are then covered with two sheets of clean paper and stacked. The mixture is left undisturbed in the trays for 10-12 days to ferment. When the right temperature is maintained (28-32°C), the solid nata de coco will be 0.75 to 1 inch thick. At lower temperatures the nata formation will be thinner and if the temperature is too low the fermentation process will fail. The product is harvested and the cream on the lower surface scraped off with a clean knife.

The final product

The cleaned harvested nata is cut into cubes of approximately 1cm, and soaked in several changes of water for at least one day to remove the sour vinegar taste. It is then boiled in water for five minutes and tasted to check that no sour flavour remains. Sugar is added (1 part sugar to 1 part nata) and the mixture is then left to stand overnight The next day a small amount of water is added and the mixture brought to the boil. Flavourings and colouring may be added The final product should have a clear crystalline appearance.

Finally the product is packed into presterilized jars, syrup added, capped and sterilized by immersing in boiling water for half an hour.

PROBLEMS IN NATA DE COCO PRODUCTION

Many attempts to produce nata de coca in large quantities have failed due to various problems faced during the production process. Poor quality nata results from the presence of undesirable micro-organisms in the fermenting mixture. Strict sanitary procedures must be followed therefore, since no heating of the nata substrate takes place. The utensils and containers must be sterilized with boiling water before use. Similarly, the processing area must be kept clean and proper hygienic practices must be observed by the workers.

Inadequate nata thickness is caused by an inferior starter culture. There are different strains of the nata organism and some strains produce thinner and softer nata than others. Moreover, some strains of nata produce a very leathery textured product which is unacceptable when processed into the sweetened products.

In cases where there is no yield at all, the cause is spoiled, contaminated or weakened mother liquor. Undesirable organisms can dominate the growth of nata in the mother liquor which, when used in the preparation of nata, results in decreased growth, very soft nata or just a thin film of nata growth.

The nata organism becomes weaker in successive cultures due to metabolic substances produced during fermentation. This occurs when the spent liquor remaining after the nata collection is used as the mother liquor. It is therefore necessary that a fresh batch of replacement mother liquor made I from starter culture be used every 6 months. Furthermore, the nata organism is not stable and has been found to mutate into less active strains. There is no reason however, given strict control, why commercial production is not feasible.