Preparation of halloysite nanotubes coated with Eudragit for a controlled release of thyme essential oil

Abstract

Active food packaging that releases active agents can extend the shelf-life and improve the quality and safety of food products. Essential oils have been used as natural food preservatives due to their antioxidant, antimicrobial, and anti-insect properties. However, one of the limitations of using essential oils as active agents is their high volatility. In this study, thyme essential oil, an active antioxidant agent, was encapsulated into halloysite nanotubes (HNTs) using a vacuum process to sustain the release rate and to solidify the thyme oil (TO) from a liquid state. Moreover, the TO-loaded HNT capsules (TO/HNT capsules) were coated with Eudragit EPO polymer to avoid burst release and to prolong the release time. The morphology of the prepared samples was characterized using SEM, TEM, and nitrogen adsorption-desorption analysis by BET method. Zeta potential and FTIR analysis were used to verify the encapsulation of the TO and the Eudragit EPO polymer coating of TO/HNT capsules. After Eudragit EPO polymer coating of TO/HNT capsules, the surface charge of the samples was converted from 217.5 6 0.2 mV to 119.4 6 1.5 mV. The amount of encapsulated TO was determined using a GC-FID. Encapsulation efficiency and payload of TO/HNT capsules prepared using 26.7% (w/v) TO solution were 14.94% and 14.58%, respectively. The encapsulated TO was released in a sustained manner for 96 h. In addition, antioxidant activity of the samples was evaluated using a DPPH assay and a reducing power assay. In both two assays, the antioxidant activity of the TO/HNT capsules was increased along with the increasing concentration of TO/HNT capsules.

Halloysite nanotubes loaded with peppermint essential oil as filler for functional biopolymer film

“…HNT are suitable as catalytic supports (Machado, de Freitas Castro, Wypych, & Nakagaki, 2008;Massaro et al, 2014;, adsorbent nanomaterials for wastewater decontamination (Szczepanik & Słomkiewicz, 2016;Zhang et al, 2016), and nanofiller for sustainable packaging (Liu, Wu, Jiao, Xiong, & Zhou, 2013;Tescione, Buonocore, Stanzione, Oliviero, & Lavorgna, 2014). Research reports (Gorrasi, 2015;Lee & Park, 2015) that pristine HNT exhibited an excellent essential oils solubilization ability as well as controlled release of properties. In addition, HNT loaded with essential oils were successfully used as nanofiller for polymers (Gorrasi, 2015;Lee & Park, 2015) making the obtained composite biofilms appropriate for packaging applications.…”

“…Research reports (Gorrasi, 2015;Lee & Park, 2015) that pristine HNT exhibited an excellent essential oils solubilization ability as well as controlled release of properties. In addition, HNT loaded with essential oils were successfully used as nanofiller for polymers (Gorrasi, 2015;Lee & Park, 2015) making the obtained composite biofilms appropriate for packaging applications. HNT improve physical barrier properties of polymeric materials such as poor barrier properties to water vapor (Sorrentino et al, 2007).…”

Thyme Oil Encapsulated in Halloysite Nanotubes for Antimicrobial Packaging System

“…Vacuum treatment was used to encapsulated thyme oil into the lumen of the HNTs according to a previous report (Abdullayev and others ; Lee and Park ). Briefly, about 5.0 mL of thyme oil was fully mixed with 15.0 mL of ethanol by voltexing.…”

“…HNTs have geometry similar to that of carbon nanotubes; however, they are low‐priced, environmentally friendly, nontoxic, and biocompatible. In addition, kaolin clay, including kaolinite and HNTs, is classified as generally recognized as safe for food packaging materials by the U.S. Food and Drug Administration (Lee and Park ), hence HNTs have been studied as an additive in the production of nanocomposites to enhance mechanical and barrier properties of the film (Liu and others ; Gorrasi and others ) and to give functional properties such as antioxidant, antimicrobial, and insect repellent (De Silva and others ; Biddeci and others ; Kim and others ). Owing to their unique tubular structure, HNTs have been also studied as a nanosized container for loading functional ingredients like drugs, pesticides, antifouling agents, and cosmetics (Levis and Deasy ; Abdullayev and others ; Suh and others ; Bielska and others ).…”

Clay and Polymer-Based Composites Applied to Drug Release: A Scientific and Technological Prospection

“…These polymers were employed predominantly as matrices (22,26,32,35,49,66,74,89), but in some cases formed the composite coating (64,70,71).…”