Citation: Jordão, A.M.; Coutinho, I.T.; Silva, E.K.; Kato, I.T.; Meireles, M.A.A.; Maia-Obi, L.P.; da Silva, B.G.; Champeau, M. Supercritical CO 2 Impregnation of Clove Extract in Polycarbonate: Effects of Operational Conditions on the Loading and Composition. Processes 2022, 10, 2661. https://doi.org/10.3390/pr10122661 Academic Editor: Irena Zizovic Received: 25 October 2022 Accepted: 8 December 2022 Published: 10 December 2022 Publisher’s Note: MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affil- iations. Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). processes Article Supercritical CO 2 Impregnation of Clove Extract in Polycarbonate: Effects of Operational Conditions on the Loading and Composition Amanda Martins Jordão 1,† , Isabela Trindade Coutinho 1,† , Eric Keven Silva 2 , Ilka Tiemy Kato 1 , Maria Angela A. Meireles 2 ,Lígia Passos Maia-Obi 1 , Bruno Guzzo da Silva 3 and Mathilde Champeau 1, * 1 Center of Engineering, Modelling, and Applied Social Sciences, Federal University of ABC, Santo André 09210-580, SP, Brazil 2 School of Food Engineering, University of Campinas (UNICAMP), R. Monteiro Lobato 80, Campinas 13083-862, SP, Brazil 3 Center for Natural and Human Sciences, Federal University of ABC, Santo André 09210-580, SP, Brazil * Correspondence: mathilde.champeau@ufabc.edu.br † These authors contributed equally to this work. Abstract: The development of active packaging for food storage containers is possible through impregnation of natural extracts by supercritical CO 2 -assisted impregnation processes. The chal- lenge of scCO 2 -impregnation of natural extracts is to control the total loading and to ensure that the composition of the loaded extract may preserve the properties of the crude extract. This study aimed at investigating the scCO 2 -impregnation of clove extract (CE) in polycarbonate (PC) to develop antibacterial packaging. A design of experiments was applied to evaluate the influences of tempera- ture (35–60 ◦ C) and pressure (10–30 MPa) on the clove loading (CL%) and on the composition of the loaded extract. The CL% ranged from 6.8 to 18.5%, and the highest CL% was reached at 60 ◦ C and 10 MPa. The composition of the impregnated extract was dependent on the impregnation conditions, and it differed from the crude extract, being richer in eugenol (81.31–86.28% compared to 70.06 in the crude extract). Differential scanning calorimetry showed a high plasticizing effect of CE on PC, and high CL% led to the cracking of the PC surface. Due to the high loading of eugenol, which is responsible for the antibacterial properties of the CE, the impregnated PC is promising for producing antibacterial food containers. Keywords: Eugenia caryophyllus; eugenol; multicompound systems; active packaging 1. Introduction Natural extracts have appeared as potential antimicrobial and antioxidant agents for use in food, cosmetic and pharmaceutical applications. They are especially attractive because they are obtained from natural sources and are environmentally friendly [1–3]. For instance, many natural extracts are already classified by the Food and Drug Administration (FDA) as Generally Recognized as Safe (GRAS), including clove, oregano, peppermint, thyme, basil, tea tree, and cinnamon essential oils [4], allowing their application for human consumption in food. Recently, natural extracts have been loaded into polymeric matrices to develop active food packaging [5–7], drug release systems [8,9], and repellent and antioxidant fabrics [10,11]. By loading natural extracts into polymers, some shortcomings related to their high volatility and hydrophobicity are overcome while their properties are maintained [12,13]. Among the natural extracts, clove extract (CE) is known for its antibacterial, antifungal, and insecticidal properties, similar to those of synthetic preservatives [14–18]. CE is mainly obtained from flower buds, rich in eugenol, and contains eugenyl acetate, β-caryophyllene, and α-humulene. CE, or its majoritarian component eugenol, has been impregnated Processes 2022, 10, 2661. https://doi.org/10.3390/pr10122661 https://www.mdpi.com/journal/processes