GB2318969A - Coconut beverage - Google Patents

Abstract

A high quality, cold pasteurised, natural coconut water is prepared by microfiltration. The result is a unique coconut water beverage which maintains all of the delicate organoleptic properties of fresh coconut water as well as all of the beneficial nutritional qualities. The microfiltration may be preceded by centrifugation. The beverage may be carbonated and may contain sucrose and ascorbic acid.

Description

NATURAL BEVERAGE BACKGROUND OF THE INVENTION This invention relates to natural beverages and more particularly the invention provides a high quality, cold pasteurised coconut water prepared by a combination of centrifugation and microfiltration.

SUMMARY OF THE PRIOR ART Coconut water refers to the liquid endosperm of a tender coconut at an age of approximately 9 months from time of pollination, the period before the solid endosperm or white meat forms. It is a pure and nutritious beverage in the natural state ';. The coconut husk is an excellent package for the water which contains sugars, minerals, amino acids and vitamins 3,4,5,6,7 The organoleptic properties of coconut water have long been renowned as evidenced by the remarks of Charles Darwin after drinking under the shade of coconut trees on Keeling Island in 1836, "Those alone who have tried it, know how delicious it is to be seated in such shade and drink the cool pleasant fluid of the coconut" Other famous travellers such as Marco Polo, Ibn Batuta and Ralph Fitch had eulogised the high value of this natural drink in their travelogues s Its refreshing and invigorating properties are known to both natives and travellers of the tropics, where it is commonly said, "If you consume the delicate water of a tender nut, tiredness and thirst will subside immediately". The isotonic and bacteriologically sterile properties of fresh coconut water, straight out of the nut, promoted its use as a direct plasma replacement by military forces in the Asian theatre of combat during Word War II. Unfortunately, a few days after harvesting, the organoleptic and nutritional characteristics of the coconut water deteriorates rapidly and the liquid begins to ferment.

The average composition of young coconuts (aged 6-8 months is shown on Table 1.

Table 1 - Average Composition of Tender Coconuts (per Nut)

Variety Age Total Water Jelly Husk pH Total Total (months) Weight Acidity Solids g g g g Tall 6/8 2,933 349.3 92 2,501 5.2 0.06 4.6 Y. 7/8 2,443 327.5 62.1 2,056 4.8 0.10 5.0 Dwarf R. 7/8 2,753 319.2 92.3 2,350 4.8 0.06 6.4 Dwarf G. 6/8 2,360 435.3 33.2 2,176 4.8 0.09 5.6 Dwaf The production of beverages from coconuts, particularly as a by-product from other processing operations such as coconut cream processing or coconut desiccation, has long interested food manufacturers. Formulations for both carbonated and noncarbonated coconut beverages have been developed. The processing of coconut water from tender nuts has been very difficult to accomplish because the temperatures required for conventional pasteurisation has been too high to maintain the delicate organoleptic properties and nutritional qualities.

Newer ultra high temperature (UHT) processing offers some advantages over traditional heating techniques in the processing of coconut water. Gonzales et al reported a process for the production of a coconut water beverage based on high-temperatureshort-time (HTST) treatment9. This procedure is said to produce a coconut water product free from off-flavours and odours. Coconut water was filtered immediately after removal from the nut and then pumped to a centrifugal separator to remove any coarse extraneous particulate material. The centrifuged product was then cooled for storage. Before UFIT treatment, pH was adjusted with food grade acid, and total soluble solids was raised with sugar. Del Rosario and Rubico added also sodium citrate 10 as stabilises After HTST serilization, the product was packed under aseptic conditions. Meat of young coconut can be mixed with the water to give a stronger coconut taste to the beverage. Processes based on this procedure are currently being used commercially, and cans or UHT aseptic packs are readily available. However, all the commercially available coconut milk or water beverages have a distinct off-flavour described as a "cooked taste" and a very faint or non-existent fresh coconut water taste.

The market for these products is very limited and not an attractive option to those who wish to have a product identical to coconut water from a freshly picked young coconut.

Tender coconut water is a natural source of electrolytes, minerals, vitamins, complex carbohydrates, amino acids and other nutrients. The natural carbohydrate content is between 4 and 5% of the liquid solution. This makes coconut water particularly suitable for the burgeoning sports drink market. It has to be noted that in 1994 the sports drink market in the USA alone, reached nearly $1 billion and this represents only approximately 3% of the total soft drink sales. A natural beverage product having all the delicate aroma, taste, drinking characteristics and nutritional value of pure, fresh, tender coconut water, and having all the functional characteristics required of a sports drink, should be able to acquire a segment of the energy drink market'1 According to the Sports Science Institute (USA), sports drinks containing under 5% carbohydrates are less likely to provide benefits, while those exceeding 10% carbohydrate content, like most soft drinks, are associated with abdominal cramps, nausea and diarrhoea. The optional addition of sucrose (research has shown that this sugar is absorbed faster than the other carbohydrates) can optimise flavour while ensuring that the carbohydrate content is in the desirable range. Vitamin C, which is important in reducing the generation of oxygenated free radicals caused by intensive exertion as well as for the healthy maintenance of bones, tendons and cartilages can also be added to this beverage.

SUMMARY OF THE INVENTION Micro-filtration process The present invention provides microfiltered coconut water.

Preferred Embodiments In order to commercially produce a genuine tender coconut water without altering the flavour of the fresh product, an integrated cold-sterilisation process was employed.

Preservation was achieved by passing the water through a microporous filter under pressure so that all bacteria and spores were excluded, rendering the permeate commercially sterile. High-speed pre-centrifugation was integrally employed as a primary step to remove all particulate materials and any colloidal material which might significantly reduce the throughput and working life of the filter employed. The coconut water thus processed was then packaged aseptically, providing the consumers with the convenience of a fresh-tasting product that is shelf-stable for a period of more than six months. As no thermal treatment was used at any point in the sterilisation of the coconut water, the problem of off-flavour development was completely avoided, thereby ensuring the delicate flavour of the original staring material.

Materials and Methods Water from coconuts of about 9 months of age was pre-filtered to separate out solids particles and then cooled at 60C to avoid fermentation and enzymatic deterioration during the cold sterilisation phase. Centrifugal separation at or above 15,000 x 'g', is required to remove about in excess of 65% of the colloidal polysaccharides which comprise mainly of arabinogalactans, galactomannans and small amounts of pectin.

The was found to extend the life and increase the throughput of the various filters employed in the cold-sterilisation process. Refrigerated, pre-filtered water can also be blended with sucrose and L-ascorbic acid prior to or after centrifugation, but before cold-sterilisation. Natural polyphenol oxidase enzymes (which can cause browning during storage) can be inactivated using commercial resins specifically designed for this application if the market requires a clear product without any colour change. The coldsterilisation processing was achieved using microporous filters designed to exclude all bacteria. The cold-sterilized coconut water was aseptically filled in sterile containers.

A flow-diagram of the process is shown on Scheme 1. Four different coconut varieties (Green Tall, Yellow Dwarf, Red Dwarf and Green Dwarf), with and without the addition of sucrose and/or ascorbic acid were processed in this manner.

Products were stored at room temperature (280C-340C), as well as at refrigerated temperature (9"C-10"C). Samples were examined immediately after processing and after each week of storage. At each testing period measurements were made of pH (acidity) and total soluble solids. Total microbiological plate counts were carried out to determine microbial load. Organoleptic tests were carried out using the 9-point Hedonic Rating Scale and Triangle testing. Fresh coconut water was filtered and centrifuged to prevent easy identification during taste panels (which were carried out with individuals who had regularly consumed fresh coconut water throughout their lives). Samples of both fresh and cold-sterilized, packaged water were refrigerated before testing.

SCHEME 1. COCONUT WATER MICROFILTRATION FLOW DIAGRAM

Coconut receiving (with shell, singly or in bunches) Water extraction, inspection and collection U Pre-filtering U Cooling U Optional addition of sugar and food acid U Centrifugation (215,000 x 'g') U Optional addition of sugar and food acid U Optional removal of polyphenols oxidase enzymes U Micro-filtration to remove bacteria (Cold-sterilisation) U Aseptic filling in containers U Storage Results and Discussion Packaged coconut water was transparent and bright after the cold-sterilisation process.

All samples prepared from Dwarf Coconut varieties, packed in both dark and clear bottles, stored at room temperature developed an attractive pink coloration after about 50 hrs. The taste was not affected. This phenomenon was not observed with the Tall variety. All samples stored at 9"C-100C did not show this effect but, after two days exposure to ambient temperatures, all the Dwarf varieties again turned pink. As before, the Tall variety showed no colour change.

Detectable difference and general acceptability of the products carried out respectively by Triangle Test (TT) and Hedonic Scale (HS) gave the following results: TT - there was no difference between fresh and bottled products (P < 0.05) HS - there was no difference in the overall acceptability of the fresh and bottled coconut water, with and without added sugar and ascorbic acid (level of significance Pro 05), based on the analysis of Variance of the data from the 9 point Hedonic Rating Scale.

In Table 2 are shown the results of physico-chemical, and microbiological properties of the micro-filtered products. Statistical analysis showed no significant difference between the samples initially and during the storage for 1 month. All samples remained transparent and bright without browning or turbidity. It is apparent that the products are sterile with no signs of deterioration during the first month storage period. No fermentation occurred in any of the cold-sterilized products.

Table 2 - Physico-Chemical and Microbiological (Total Plate Count) Analysis

Storage Acidity pH Total Soluble Solids Total Plate Count (weeks) Brix A* B* A≈ B≈ A* B* A≈ B≈ A* B* A≈ B≈ 5 5 5 4.8 4.8 4 4 6 6 N N N N 2 5 5 4.8 4.8 4 4 6 6 N N N N 3 5 5 4.8 4.8 4 4 6 6 N N N N 4 5 5 4.8 4.8 4 4 6 6 N N N N A- Clear bottles B Dark Bottles * Pure Coconut water ≈Water added sucrose and LAscorbic Acid N- Negative Conclusions Microfiltration is an effective method for achieving commercial stability in coconut water. Bottled products do not develop any off-flavours and possess the characteristic flavour of fresh coconut water.

High speed centrifuging is a preferred integral step for removal of the majority colloidal polysaccharides which comprise mainly of arabinogalactans and galactomannans. This was found to extend the life and increase the throughput of the various filters employed in the cold-sterilisation process.

References 1. Jayaleshmy, A., Arumughan, C., Narayanan, C. S., Mathew, A.G., "Changes in the chemical composition of coconut water during maturation." Regional Research Laboratory, Trivandrum, India, (1986).

2. Pee, A.G., Rive, W., Sundarrao, K., Kaluwin, C., Singh, K., "Preliminary studies on changes in coconut water during maturation of the fruit", Science in Papua New Cuinea, 18(2), (1992).

3. Child, R. & Nathanael, W.R.N., "Changes in the sugar composition of coconut water during maturation and germination, " Journal of the Science of Food and Agriculture, 1,326329,(1950).

4. Serrano, L.P., Mina, P.T., Gomez, L.P., Sison, B.S., Tenmatay, A.L., "Studies on the growthfactor present in coconut water" Philippine Journal of Science 96(3), 229-38, (1967).

5. Sierra, Z., Velasco, J.R., "Studies on the growth-factor of coconut water - isolation of the growth promoting activity, "Philippine Journal of Coconut Studies l(2),11-18, (1976).

6. Sison, B.C. Jr., "Disposal of coconut processing waste, "Philippine Journal of Coconut Studies 2(2), 3941, (1977).

7. Ogundiya, M.O., "Glucose content of nut water in four varieties of coconut palm (cocos nucifera)," Nigeria Journal Sci. Food Agric., 56, 399402,(1991) 8. Nanda Kumar, T.B., "Tender Coconut Water: Nature 's Finest Drink," Indian Coconut Journal, August, (1990).

9. Gonzales, O.N., Alejo, J.V., Brilliante, J., Valdecanas, M., "Processforpreparing non-carbonated and carbonated coconut water," Philippine National Institute of Science and Technology, (1983).

10. Del Rosario, R.R, Rubico, S.M., "Formulation of Coco Beverage from Mature Coconut Water", University of the Philippines at Los Banos, Laguna, Philippine Department of Food Science and Technology, (1979).

11. Sport Drink Market Report. "Packaged Facts", New York, U.S.A., (1993)

Claims (8)

1. CLAIMS: 1. Microfiltered coconut water.
2. 2. Centrifuge and then microfiltered coconut water.
3. 3. A packaged drink comprising a bottle, tin, carton, pack or other container of the coconut water of claim 1.
4. 4. The drink of claim 3 which is presented as a sports drink.
5. 5. The drink of claim 3, wherein the volume of coconut water is 100 to 500 ml, such as 250 or 330 ml.
6. 6. The drink of claim 3 which is carbonated.
7. 7. A process for preparing coconut water suited for packaging as a drink which comprises microfiltering coconut water optimally preceding by centrifuging.
8. 8. A process according to claim 7, where sucrose and /or ascorbic acid is incorporated in the coconut water.