The purpose of this study was to investigate three assessments of food-mixing ability (a*) values under different chewing instructions using color-changeable chewing gum and examined the associations of a* values with food-comminuting and perceived chewing ability in order to evaluate masticatory function in maxillectomy patients. According to set criteria, 40 maxillectomy patients were enrolled in this study. Objective food-mixing ability (a*) was assessed using color-changeable gum with three different chewing instructions: a*60, chewing 60 strokes; a* 100, chewing 100 strokes; and a* 1min, chewing for 1 min. the time-taken and number of strokes were recorded. Objective food-comminuting ability as an index of masticatory performance (MP) was assessed using gummy jelly. Perceived chewing ability rated as masticatory score (MS) was assessed using a food intake questionnaire. Spearman’s rank correlation coefficients were analyzed between a* values, MP, and MS. Of the three different food-mixing ability assessments, a*1min showed the highest multiple correlations with MP and MS compared with a*60 and a*100. The food-mixing ability test with the – min chewing instruction was better corelated to the food-comminuting and the perceived chewing ability in maxillectomy patients, suggesting the potential utility of such assessment.