Masticatory performance has often been measured by determining an individual's capacity to comminute a test food. Another method to determine masticatory performance, which is now widely used, evaluates the ability to mix and knead a food bolus. Two-coloured chewing gum and paraffin wax have been used as test foods for the quantification of the mixing ability. The aim of our study was to compare the results obtained with the comminution of an artificial test food and the results obtained from mixing of a two-coloured chewing gum. The degree of mixing of the colours of the chewing gum was quantified with an optical method. Twenty young subjects with a natural dentition (average age 24 years) and twenty elderly subjects, mostly with complete dentures (average age 72 years), participated in the study. Significant differences in masticatory performance between the two groups were detected with both methods. However, the comminution test was better in discriminating the masticatory performance of the two groups. The mixing ability test with the two-coloured chewing gum proofed to be a good method to determine masticatory function in subjects with a compromised masticatory performance (elderly subjects). However, the method appeared to be less suitable for subjects with a good masticatory performance (young subjects).