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Abstract
The process conditions of dielectric barrier discharge cold plasma using nonlinear regression analysis for enhanced shelf life of tender coconut water (TCW) were optimized. Face centre composite design was used to optimise process condition of cold plasma treatment and desirability of treated TCW was determined on the basis of microbial load, DPPH scavenging activity, free fatty acid content and transmittance. Microbial load, DPPH scavenging activity and transmittance decreased with plasma treatment time and voltage whereas fatty acid content increased. However, TCW developed ‘chemical’ odour at the optimized cold plasma treatment condition of 18.00 kV voltage and 1.75 min treatment time. Pasteurized orange juice (1–4%) was added to the cold plasma treated coconut water to counter the off flavour and the developed blended beverage was subjected to sensory optimization using fuzzy logic. From the application of fuzzy logic, it was determined that cold plasma treated TCW with 1% orange juice has acceptable sensory properties. The study revealed that cold plasma was helpful in reducing microbial load of TCW and its blending with 1% orange juice gave beverage that was acceptable for sensory attributes besides being able to mask the ‘chemical’ odour. Cold plasma can therefore be used in place of thermal treatment for processing of TCW.