Coconut (Cocos nucifera) is one of the oldest fruits in the world and
is confined to seacoast in the humid tropics. It is an important plantation
crop of Bangladesh. The climatic condition of Bangladesh is suitable for the
cultivation of coconut. Good quality of account is grown in the southern part
of the cormtry, especially in the greater Noakhah (10490 mt), Barisal, Jessore
(17860 mt) and Khulna (11835 MT) Districts Green coconut water is the liquid
endosperm that fills the central cavity enclosed by a solid endosperm protected
by the hard cell and husk. Tender coconut water is a delicious and nutritious
drink. In its natural state, it is sterile and is used as an oral rehydration
medium for children suffering from gastro-enteristis. Coconut water is also
reported to contain substances capable of inducing rapid proliferation of plant
tissue culture medium. Vinegar and Nata decoco, a fermented drink popular
in the Philippines, are also prepared using coconut water as base. At its tender
stage, a large nut may contain about 600 mL water with 30 g sugar and 2 g potassium.
The water from green coconut is a refreshing drink during hot days.
Study of green coconut water and ready to serve coconut product has received
much attention to the researchers throughout the world especially in physico
chemical properties, which are being studied all over the world. No sufficient
information are available on processing, preservation and storage of fresh coconut
under Bangladesh condition. In Bangladesh, huge quantity of coconut is grown
in the southern part but the utility of green coconut is limited due to costly
transport. If proper technology is developed to preserve coconut water in bottle
or can, it will lead to easy transport and easy serve. Finally, it will lead
to have higher production encouraging the grower and processors.
With the above views in consideration, the study was rmdertaken to develop
process for preservation of fresh coconut water; to analyze the proximate composition
of the fresh and processed coconut water; sensory evaluation of the processed
coconut water and to study the storage stability of processed coconut water.
MATERIALS AND METHODS
The study was conducted in the Laboratory of the Department of Food Technology
and Rural Industries and Department of Biochemistry, Bangladesh Agricultural
University (BAU) Mymensingh during the period of July 2002 to October 2003.
||Sample specification of processed green account water
|'+' Sign indicates positive activity, '-' Sign indicates on
activity or addition
The green coconut was collected from local markets of Bangladesh Agricultural
University, Mymensingh. With the help of sharp knife, coconut water was collected
from green coconut.
Processing of green coconut water: Coconut water was collected from
freshly harvested coconut and filtered. The filtered water was pasteurized at
85 °C for 1 0 min and then cooled. Eight samples were pre-treated as shown
in Table 1. Potassium metabisulfite (K2S2O2)
and citric acid was used as preservative in different concentrations. Then the
flavor, color, vitamins and β-Carotene were fortified as per requirement of human
body. Then the samples were filled in to can and bottle keeping about 6 mm headspace.
The can was exhausted in boiling water for 20 min and immediately sealed in
a double seaming machine. The bottles were also exhausted in boiling water for
20 min and immediately closed with PP caps and/or crown caps. The cans were
sterilized at 121°C for 30 min in an autoclave and bottles were at 1 00°C
for 15 min. The heat-processed bottles and cans were immediately cooled rmder
nmning water to 40°C. They were than Labeled, stored at ambient temperature
and refrigerated temperature (4 to 10°C) for storage study.
Proximate analysis of green and processed coconut water: The strained
green coconut water and the processed coconut water were analyzed for moisture,
ash, vitarnin-C, β-carotene, Total Soluble Solid (ISS), pH, titrable acidity,
reducing sugar, non-reducing sugar and total sugar content. Acidity was estimated
with standard NaOH using phenolphthalein as indicator. Vacuum oven drying method
was used for moisture determination and AOAC method was used for determination
of -Carotene and ash. A Refractometer was used for determination of total soluble
solid of the water. The ascorbic acid was determined by Rangana
Sensory evaluation: A panel of 10 judges according to lSI specification and BSTI standard methods tasted green coconut water. All judges consisting the panel were conversant with the factors governing the quality of the products. The products were served to each judge who independently examined the characteristics a) colour and texture b) flavour and taste and© absence of defects. The uniformity of judgment among the judges was ascertained by adding up the scores given by them for individual characteristics. The relative importance of each factor was expressed numerically and recorded his/her observation in the score sheet. The average score of each factor with overall average for each product was then calculated. The score was arranged on a numerical scale of 1 00 and acceptability was determined from predetermined acceptability classes as score 91 and above is excellent products, score 86-90 is good products, score 81-85 is fair products and score 80 and below is not acceptable products.
Storage study: The samples of processed coconut water were stored at room temperature and refrigerated temperature (4 to 10°C). The acidity, colour, flavour, turbidity and microbial load were observed at an interval of one up to two months and then at an interval of two months.
RESULTS AND DISCUSSION
Chemical composition of green coconut water: It is shown from Table
2 that fresh coconut water is carotene free and the percentage of acidity
is very low (0.08%). Biancardini and Tastadi reported that the
percentage of moisture, ash, total sugar, pH and ascorbic acid content of fresh
coconut water were 95.3, 0.5, 3.2, 5.1 and 1 mg per 1 00 g of coconut water
respectively. The percentage of moisture, ash and pH obtained from the analysis
was much closed with the Biancardini and Tastadi findings.
Chemical composition of processed green coconut water:
The 8 samples of processed coconut water was analyzed for moisture, ash, vitamin-C,
Total Soluble Solid (ISS), titrable acidity, reducing sugar, non reducing sugar,
total sugar content and β-Carotene.
|| Chemical analysis of green account water
||Chemical composition of processed green coconut water
||Score awarded by the judges for canned green account water
||Score awarded by the judges for bottled een coconut water
|Values in parenthesis indicate total No. of products
There was a variation in acidity in processed green coconut water. The contents of acidity were in the range of 0.149 to 0.399%. This difference is due to addition of citric acid and heat treatment (Table 3).
Sensory evaluation of canned and bottled coconut water: The processed green coconut water stored in canned and bottled were subjected to the sensory evaluation and the mean scores for colour, flavour, texture and overall acceptability of different samples are presented in Table 4 and 5.
From the results, it is evident that the quality of processed green coconut water (Canned) were equally acceptable and did not sho\Vll significance difference with bottled coconut were. There was no significant difference in overall acceptability among the samples C, H and G and those samples were statistically equally acceptable.
Sample A had the least overall acceptable when compared with other. Regarding overall acceptability of processed green coconut water the samples B, E, D and F were the most preferred and significantly better when compared with other samples.
Storage studies of processed coconut water: Eight samples of processed
green coconut water were stored at room temperature (25° to 35°C) and
refrigerated temperature (4 to 10°C). The effect of storage time (0, 4,
8, 10 and 12 months) on physical properties such as colour, flavour and visual
fnngal grovvth (nnder magnifying mirror) and on chemical properties such as
Total Soluble Solid (ISS), acidity were studied (Table 6 and
7). From the storage studies, it was concluded that the colour
of all samples were in good condition up to 12 months of storage in both temperatures.
The flavour of all samples except C and G were in good condition up to 4 months
of storage but after that time fermentation began in sample A. Ftmgal growth
was observed in sample A and G after
||Storage QfOQerties of green coconut water (Refrigeration temQerahJre)
||Storage QrOQerties of green coconut water (Room TemQerature)
four months of storage, which were finally spoiled. Ash, Total Soluble Solid
(ISS) and gas formation remained almost rmchanged during the full period of
The study of sensory evaluation and shelf life of the processed green coconut water indicates that the fresh green coconut water could be bottled and cmed successfully for consumption rormd the year.