Dry pasteurization of paprika (Capsicum annuum L.) by short time intensive microwave-infrared radiation: Inactivation of Salmonella Typhimurium and Aspergillus flavus considering quality degradation kinetics

The inactivation of S. Typhimurium and A. flavus along with quality degradation kinetics was studied during combined microwave-infrared (MW-IR) heating of paprika. The spatial changes in the distribution of temperature and variation in water activity (a_w) of the paprika samples resulted in a 7.389 log reduction in S. Typhimurium, and 6.182 log reduction in A. flavus. During heating, the deterioration of red pigments was more pronounced compared to that of the yellow pigments. The alteration of color was observed to be due to the increase in a large number of brown pigments. The inhibition of DPPH radicals accelerated with an increase in the power level of MW-IR radiation; the inhibition rate increased from 0.0859 to 0.1485 s^-1. Also, the pungency of dried paprika was found to increase due to moisture reduction, inactivation of peroxidase, and the short-duration of heating.

Keywords: Ascorbic acid (PubChem CID: 5785); Capsaicin (PubChem CID: 1548943); Dihydrocapsaicin (PubChem CID: 107982); Food safety; Foodborne pathogens; Microbial contamination; Nordihydrocapsaicin (PubChem CID: 168836); Quality; Water activity.