Tender coconut water processing: hurdle approach, quality, and accelerated shelf-life measurements

Abstract

In the current study, we examined the applicability of hurdle technology as a simple cost effective viable approach to process tender coconut water (TCW). The hurdles included one or more combinations of the following (i) acidification: ascorbic acid (180 ppm), citric acid (200 ppm), and malic acid (400 ppm); (ii) antimicrobial additives: potassium metabisulphite (≃ 75 ppm SO₂) and potassium sorbate (700 ppm); (iii) mild heat treatment (50 °C for 20 min), and; (iv) two-stage microfiltration process (0.8 µm and 0.45 µm filters). Results suggested that two or more hurdles in combination effectively restricted browning enzymes and microbial growth while maintaining quality during storage. Storage time and temperature significantly affected quality parameters viz. pH, titratable acidity, and percent transmission/clarity. Accelerated shelf-life studies revealed that ascorbic acid followed both zero-order and first-order degradation kinetics models amongst different hurdle combinations. Arrhenius estimations of ascorbic acid levels and rate constant at 27 °C and 5 °C were comparable to experimental results. Also, shelf-life predictions considering 50% ascorbic acid degradation suggested a shelf-life extension of 3–12 months under refrigeration, depending on the combination of hurdles used. The results demonstrate the sufficient utility of combining hurdles to process TCW.