Producing virgin aromatic coconut water by direct plunging and purged with nitrogen gas

This research was attempted to produce sterile virgin coconut water receiving from direct plunging the fruit and purged the coconut water with nitrogen gas. Shelf life of the coconut water stored under different temperatures was used to evaluate its purging effectiveness. The coconut water was drawn from coconut fruit by piercing method. Nitrogen was used to purge the liquid out of the fruit. Compressed air purging was used as a control. Samples were kept under cold storage at -6, 4, and 14 ˚C for 28 days or until bacterial counts exceed 10⁴ CFU/ml limit. The coconut water was taken at every other day for evaluation of microbial counts and other physical characteristics such as pH and color. A Q10 value was also used for determination and evaluation of coconut water shelf life. Results indicated that sterile coconut water from the plunging was possible but contaminations from plunging equipment and transporting to the reservoir tank were observed. They had acidity-alkalinity (pH) value 5.5 and soluble solids of 11.6 with total acidity of 0.06. Color values such as lightness L* a* and b* were 39.37, 0.16 and 0.47, respectively. The nitrogen gas purging through drilling gave coconut water with less contamination than that of the air process. Initial microbial counts of coconut water in reservoir tank were averaged 10-10² CFU/ml. Storage at -6˚C gave good quality products for 29 days, however pink color change due to oxidation of Mn2+ was observed. Bacterial counts of nitrogen and air purging reached 7.4 x 10³ and 8.5 x 10⁴ CFU/ml, respectively. The virgin coconut water with nitrogen and air purging had shelf life of 29, 9, and 5 days at -6, 4, and 14 ˚C, respectively. Air purging gave inferior bacterial shelf life of 12, 7, and 1 days. Nitrogen purging appeared to be more effective in terms of yields and had lower bacterial count compared to the air purging. Direct drill with nitrogen gas purging without contamination from equipment could give virgin coconut water with acceptable sensory quality.