Abstract:Objective To investigate the application of thermal analysis in the identification of chili powder adulteration.Methods Chili powder samples and adulterated samples (corn, wheat bran, rice husk, and rice) from different sources, different simulated adulterated samples, simulated samples with different adulteration ratios, and commercial samples are analyzed by a thermal analyzer. Samples are crushed, passed through a 60-mesh sieve, and then analyzed in the thermal analyzer at the heating rate of 10 ℃/min from the room temperature to 800 ℃, with a flow rate of 100 mL/min of nitrogen as the atmosphere and an empty aluminum crucible as the reference material. The thermal characteristics of each sample are analyzed.Results The main weight loss temperatures of the pure chili powder samples are within the range of 180~579 ℃, and the weight loss rate is 60.50%. The main weight loss temperatures of the adulterated samples with corn flour, wheat bran powder, rice husk powder, and rice flour are within the ranges of 256~386, 252~392, 203~414 ℃, and 249~349 ℃, respectively. The adulterants show a more concentrated thermal decomposition interval, and the difference between the starting and ending temperatures of the main weight loss stage can be used as a basis for identifying the authenticity of chili powder. In addition, according to thermogravimetric curve and thermal conductivity differential curve, different proportions of simulated adulterated samples and pure chili powder samples can be well distinguished.Conclusion Thermal analysis can be employed to identify the adulteration of chili powder samples. The method is simple and does not require complicated sample pretreatment.