Resumen de Thyme Oil Encapsulated in Halloysite Nanotubes for Antimicrobial Packaging System
Min Hyeock Lee, Hyun-Sun Seo, Hyun Jin Park
An antimicrobial capsule releasing thyme oil was developed using modified halloysite nanotubes (HNTs). In order to increase the pore volume, HNTs were treated with 5.0 mol/L NaOH solution, which resulted in the encapsulation of more thyme oil molecules inside the HNTs. The morphology of the raw HNTs and NaOH-treated HNTs (N-HNTs) was characterized using transmission electron microscopy and nitrogen adsorption-desorption analysis. The loading capacity increased from 180.7 ± 12.7 to 256.4 ± 16.7 mg thyme oil/g HNT after the NaOH treatment. The aerial release characteristics of thyme oil from both the HNT capsules were investigated in a closed-package atmosphere system at 4, 25, and 40 °C. The antimicrobial activity of the capsule against Escherichia coliO157:H7 was determined using the vapor phase assay. Moreover, the antimicrobial effects of the capsule against E. coliO157:H7, total mesophilic aerobic bacteria (MAB), and molds and yeasts (MY) on the surfaces of cherry tomatoes were investigated at 4 and 25 °C for 5 d. When the cherry tomatoes were exposed to the thyme oil-loaded N-HNT capsule, the number of E. coliO157:H7, MAB, and MY significantly reduced during storage. A sustained release of thyme oil from halloysite nanotubes (HNTs) continued up to 21 d in a closed-package atmosphere system at 4 and 25 °C. Inactivation of Escherichia coliO157:H7, mesophilic aerobic bacteria, and molds and yeasts using this thyme oil-loaded HNT capsules was investigated. This antimicrobial capsule could play an important role in the preservation of fresh produce.
