This research aimed to study the effect of fat content (15-30%) and preheat temperature (70-90 degrees C) on the apparent viscosity of coconut milk after homogenization. By using a power-law model, all samples exhibited pseudoplastic behavior with the flow behavior index (n) between 0.713 and 0.930. Overall, the results showed that preheat treatment had a significant effect on the apparent viscosity of coconut milk. At similar fat concentration, an increase in viscosity was observed at higher preheat temperatures. This phenomenon was more pronounced in the samples with increasing fat content. The microscopic study showed that smaller aggregates of fat globules were detected for the sample passing higher heating temperature. The presence of small aggregates hence increased the resistance to flow leading to an increase in the viscosity of the homogenized heat-treated coconut milk. (c) 2005 Elsevier Ltd. All rights reserved.