The traditional method for extracting coconut water is extremely simple: 1) climb a coconut palm; 2) hack an immature coconut from the bunch; 3) trim off the husk and chop a hole in the top; and 4) drink the contents (steps 3 and 4 are best done on terra firma).
Among people in tropical countries with ready access to coconut palms - or to fresh coconuts sold by urban street vendors - coconut water is renowned as a refreshing, highly nourishing drink with a delicate aroma and flavour. But, despite coconut water's potential as a competitor in the bottled beverage market (see box below), attempts to capture those qualities in a commercial product have been largely unsuccessful. Once exposed to air, coconut water begins to ferment, and rapidly loses most of its organoleptic and nutritional characteristics. To eliminate the risk of bacterial growth, commercial bottlers are forced to sterilize the product using high-temperature/short-time pasteurization (the same technology used in long-life milk), which destroys some of coconut water's nutrients and almost all of the flavour.
Training guide. The mid-range technology, developed in Jamaica in collaboration with the University of the West Indies, the Coconut Industries Board and the Scientific Research Council, is described in a new FAO training guide, Good practices for the production of bottled coconut water, to be published in English, French and Spanish early in 2007. Says Rosa Rolle, an FAO food biochemist who coordinated development of the process: "While microfiltration can guarantee a commercially sterile product, it requires skills and investments that are often beyond the capacity of small and medium-scale processors. What we aimed for was a technology that is easier to implement and costs less, but ensures good quality and reasonable shelf-life in a convenient format that satisfies consumer demand for a 'natural product'."
Essentially, the cold preservation process involves filtration to remove particulates that might mar the coconut water's appearance, bottling under hygienic conditions and rigorous temperature control. But the guide points out that the coconut water processing chain - like that of any other food product - is only as strong as its weakest link. Good practices need to be applied at every step, from harvesting, loading and transporting to cutting, bottling and sale.
The starting point is selection of coconuts suitable for processing. Key considerations are the variety - e.g. Jamaica's Maypan hybrid tree yields larger volumes of water than other varieties - and the fruit's stage of maturity: maximum yields of water, of around one litre, are consistently obtained from nine-month old coconuts. Quality also depends on how carefully the coconuts are harvested. Bunches should be lowered to the ground with a rope, not cut and dropped, to avoid the risk of cracking the internal shell (studies at the University of the West Indies show that water collected from coconuts that had been dropped from a height of 8 m suffered high levels of spoilage).
Even under ideal conditions, water should be extracted within 24 hours of harvest. During inspection, poor quality coconuts - those with cracks, cloudy water or a rancid odour - should be rejected, while those of good quality need to be kept on clean surfaces to avoid contact with soil and chemical agents, and stored away from the sun. Selected coconuts should then be washed in potable water to remove dirt, debris or other forms of surface contamination, and sanitized in a 1% bleach solution for at least 15 minutes. Finally, the coconuts should be transferred to a clean surface, off the ground, and air-dried.
Rapid cooling. Now comes the easy part: extracting the precious liquid. That is done by first trimming the husk with a sanitized stainless steel cutlass, then opening the shell. The water inside is decanted into a sanitized container equipped with a strainer lined with a sanitized silk screen or cotton cloth. The filtered water should be promptly transferred to a cooling tank and cooled to 4°C, or placed in a freezer for three to four hours. Where large volumes of coconut water are to be bottled, the use of a refrigerated cooling tank for rapid cooling is highly recommended. Waste material - mainly husks - must be removed from the processing environment and promptly disposed of.
The water must be quickly bottled and sealed - in bottles that have been rinsed in potable water and sanitized for 15 minutes - then stored in a chiller at 4°C. The bottling facility needs to be clean and "free of animals, insects, dust or garbage", and physically separate from area where the coconuts are cut open.
"Bacteria and yeasts are the main micro-organisms that threaten freshly bottled coconut water," the FAO guide says. It is critical, therefore, that the temperature of the bottled water be kept at between 0 and 4°C during transportation in order to preserve quality and to prolong shelf-life. Finally, the manual advises, processors need to make sure that their product is handled with care after delivery: "Monitor retail outlets to ensure that the bottled coconut water is stored at the correct temperature and away from direct light".