effects of fluid flowrate on coconut milk fouling at pasteurization temperature (70ºc - 74.5ºc)

Effects of fluid flowrate on coconut milk fouling at pasteurization temperature (heating from 70ºC to 74.5ºC) were investigated. A test section equipped with four flat plates forming one coconut milk channel and two hot water channels was constructed with the total heat transfer area of 0.051 m2. Three different flowrates of coconut milk (2, 4 and 6 litres per minute (LPM)) were studied. Monitoring of the overall heat transfer coefficient (U) with time (t) and the rate of increase of the fouling resistance (dRf/dt) was done for all experimental runs. The results illustrated that there were two fouling periods: a fouling period and a post-fouling period, where the rate of increase of the fouling resistance of the fouling period was found to be higher than that of the post-fouling period. The effects of fluid flowrate were found to increase the fouling rate when the flowrate decreased. Published fouling models by protein solutions were unable to predict accurately the fouling rate for coconut milk. Non-linear regression models were then provided by using the experimental data to illustrate the effects of fluid flowrate on coconut milk fouling. The role of protein and fat on coconut milk fouling was explained according to microanalysis of the deposit and chemistry data of the coconut milk from previous research.