Microbial Reduction and Quality Changes in Powdered White and Black Pepper by Treatment with Compressed Oxygen or Carbon Dioxide Gas

Abstract

Powdered white and black peppers were treated with high-pressure oxygen (10 MPa) or carbon dioxide (5 MPa) at 70 – 100°C to decrease the microbial populations. The degree of microbial reduction in the pepper after treatment with high-pressure gases was dependent on the temperature and duration of treatment. Mesophilic aerobic bacterial counts of less than 10³ CFU/g in white and black pepper were achieved with gas pressurization at 100°C for 10 and 40 min, respectively. The reduction in the microbial population of the two types of pepper was attributed to the microbicidal effects of high-pressure gas and heat treatment. The piperine content of the pepper treated with gases decreased by approximately 10%. However, treated pepper also showed lower L* values, indicating a darker color, and qualitative alterations in volatile compounds.