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

Authors: Sun, Xiuxiu; Cameron, Randall - Randy; Bai, Jinhe

Submitted to: Food Hydrocolloids
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/3/2019
Publication Date: 1/1/2020
Citation: Sun, X.N., Cameron, R.G., Bai, J. 2020. Effect of spray-drying temperature on physicochemical, antioxidant and antimicrobial properties of pectin/sodium alginate microencapsulated carvacrol. Food Hydrocolloids. 100:105420. https://doi.org/10.1016/j.foodhyd.2019.105420.
DOI: https://doi.org/10.1016/j.foodhyd.2019.105420

Interpretive Summary: Carvacrol is a strong antimicrobial activity, and could be used to reduce food-borne and plant disease contamination thus enhance food safety and reduce decay caused food waste. However, the strong odor makes it impossible to be directly applied to food. Previously we developed a technology to make microencapsulated carvacrol in a pectin/sodium alginate matrix using spray drying. In this research, we compared how inlet air temperature influences the quality of the microencapsulated carvacrol and consequently affects the antioxidant and antimicrobial properties. 100-130°C was found the best inlet air temperature which produced high quality microcapsules.

Technical Abstract: The effectiveness of essential oils against a variety of microorganisms has been well documented in the literature. Although most essential oils are classified as Generally Recognized As Safe (GRAS), their use in foods as preservatives is often limited due to the strong odor. Microencapsulation techniques have been extensively utilized in the pharmaceutical and food industries to entrap essential oils related to flavoring. Spray-drying is the most commonly used microencapsulation technique in the food industry due to its low cost and readily available equipment. The spray-drying operating parameters, particularly inlet temperature, affect the physiochemical and functional properties of the microcapsules. In this research, four inlet air temperatures (100, 130, 160, and 190 °C) were applied for the encapsulation of carvacrol in a pectin/sodium alginate matrix. The 100 °C treatment resulted in the highest moisture content and bulk density wettability, but lowest wettability and hygroscopicity. The antioxidant activity evaluated by 2, 2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay decreased, while the antimicrobial activity against Escherichia coli K12 assessed by minimum inhibitory concentration (MIC) increased with the increasing inlet temperature due to the reduced encapsulation efficiency. Our results indicate that an inlet temperature between 100-130 °C is the ideal for processing pectin/sodium alginate encapsulated carvacrol.