Effect of spray-drying temperature on physicochemical, antioxidant and antimicrobial properties of pectin/sodium alginate microencapsulated carvacrol

Microencapsulation has been extensively utilized in the pharmaceutical and food industries to entrap essential oils related to flavoring. Spray-drying is one of the most commonly used microencapsulation techniques in the food industry because of its low expense and readily available equipment. The spray-drying operating parameters, particularly inlet temperature, affect the physicochemical and functional properties of the microcapsules. In this research, four inlet air temperatures (100, 130, 160, and 190 degrees C) were applied for the encapsulation of carvacrol in a matrix composed of pectin/sodium alginate. The 100 degrees C treatment resulted in the highest moisture content, bulk density, and retention efficiency, but lowest dissolution time, hygroscopicity, and encapsulation efficiency. The antioxidant activity evaluated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay decreased, while the antimicrobial activity with respect to Escherichia coli K12 assessed by minimum inhibitory concentration (MIC) increased with the increasing inlet temperature due to the reduced retention efficiency. The microcapsules produced at lower temperature were smaller, smoother, and more spherical. Our results indicate that an inlet temperature between 100 and 130 degrees C is the ideal for processing pectin/sodium alginate encapsulated carvacrol.