Abstract:
There is a growing global demand for coconut water as a beverage due to its health benefits
rather than artificial drinks. Most of the concentration techniques operate on a temperature
around or above room-temperature. This will lead to the deterioration of the original quality of
the liquid. Freeze concentration (FC) is the most suitable method for coconut water over
evaporation and membrane concentration methods since FC operates below 00C. Suspension
Freeze Concentration (SFC) and Progressive Freeze Concentration (PFC) are the available FC
methods. SFC is a complex and expensive method compared to PFC which requires a high
investment cost. PFC is a novel freeze concentration method using a simple apparatus which
removes water molecules from the liquid by attaching to the progressively growing single ice
front. At proper operating conditions with a low crystal growth rate, the concentration efficiency
is high. The objective of the present study was to develop a PFC method for the high-quality
concentration of coconut water. A simple cylindrical apparatus was used for PFC which consists
of a sample vessel, agitator system, and a cooling bath (Ethylene glycol/Water). Optimum
operating conditions of the apparatus were found using standard sucrose solutions. The final
concentration of the liquid product was directly affected by the agitator speed and sample vessel
dipping speed. PFC agitator speed of 290 rpm and dipping speed of 1.3cmh-1 were reported as
the optimum operating conditions to achieve the highest concentration for the used PFC
apparatus in the present study. Using optimized agitation speed and dipping speed, coconut
water was concentrated up to Brix 8.50 from the initial concentration of Brix 3.50. The total yield
(based on brix) of the Progressive freeze concentrated coconut water was 0.669 ± 0.10 (67%).