Potential for developing a beverage with mature coconut water determined on sensory evaluation

Abstract

Coconut water is thermally processed to extend its shelf life, which is otherwise less than few hours under ambient conditions, thus is discarded as a waste material. As heat treatments negatively affect sensory attributes, the potential for developing a beverage from mature coconut water was investigated based on sensory properties.

Citric acid (reduce the pH to 4.6±0) and preservatives (40 mg L⁻¹ sodium metabisulphite and 200 mg L⁻¹ sodium benzoate) were added to filtered mature coconut water, and the sample was heated in a plate heat exchanger; 90 ˚C for 10 s (HS90) and 90˚C for 10 s followed by autoclaving at 100 ˚C for 10 min (HS100). The heated samples were hot-filled into glass bottles, crown capped and stored at 27±2˚C for six-week. The total plate count (TPC), yeast and mould count (YMC), 𝘌𝘴𝘤𝘩𝘦𝘳𝘪𝘤𝘩𝘪𝘢 𝘤𝘰𝘭𝘪 and preference for flavour (paired preference test, 35 panellists) of the initial and 4-week old samples were determined. The TPC and YMC of the samples before and after 4 weeks in storage were less than 1 cfu/mL. E. coli were absent in all the samples. As no significant difference (P>0.05) in preference for flavour between HS90 and HS100 was evident before storage and after 4-week in storage, degree of liking for colour and flavour, and overall acceptability of the samples stored for 4-week were tested (7-point hedonic test, 32 panellists). As no significant difference (P>0.05) was evident in degree of liking between HS90 and HS100, orange flavourant, (0.5, 0.75 and 1 g L⁻¹) was incorporated into HS90, and preference for flavour and aroma was evaluated (ranking test, 30 panellists), and overall acceptability of the samples with and without the flavourant was compared (7-point hedonic test, 32 panellists). The flavourant level did not significantly affect (P>0.05) the preference for flavour. The most preferred aroma was evident in the sample with 1 g L-⁻¹ flavourant. Therefore, the sample containing 1 g L⁻¹ flavourant was compared with a sample without the flavourant using 32 panellists and a 7-point hedonic test and the sample with the flavourant was significantly better (P<0.05) than sample without the flavourant.

Heating coconut water in a heat exchanger at 90 ˚C for 10 s followed by hot-filling into glass bottles and capping them with crown corks can be recommended for processing. Sensory properties of the product can be further improved by incorporating 1 g L-⁻¹ of orange flavour.