Colour measurement
The surface colour of the dried durian chips was measured by a colorimeter (HunterLab, model ColorFlex, VA,USA) with a D65 light source and 10◦view angle. The colour measurement of the durian chips was expressed in terms of L* (lightness/darkness), a* (redness/greenness) and b*(yellowness/blueness). The colorimeter was calibrated with a standard black and white plate before measurement. Aver-age colour values of ten dried durian chips were recorded in each experiment.