Polylactic acid (PLA) dissolved (15 wt.%) in ethyl acetate (EtAc): dimethyl sulfoxide (DMSO) binary systems (0:1; 1:3, and 2:3 v/v) was used as carrier to obtain carvacrol (CA)-loaded (20 wt.% with respect to PLA) matrices by electrospinning, in comparison with solvent casting. Field emission scanning electron microscopy (FESEM) observations showed that CA-loaded electrospun fibers were thinner than the CA-free ones, and their encapsulating efficiency (EE) increased when EtAc was present in the solvent. The cast films had higher EE (up to 89%) than the electrospun mats (maximum 68%). Thermogravimetric analysis and differential scanning calorimetry revealed that CA-free matrices retain more solvent than the samples with CA; this effect is being more noticeable in fibers rather than in cast films. The thermal analysis revealed stronger retention forces of CA in the fibers than in the cast material and the CA plasticizing effect in the PLA matrices, in accordance with its retained amount. PRACTICAL APPLICATION: The carvacrol-loaded polylactic acid materials obtained in this study are intended to serve as possible active layer in obtaining active (antimicrobial and/or antioxidant) multilayer materials for the packaging of foodstuffs, when applied onto a supporting polymer layer. Active properties of the material, as well as the potential carvacrol sensory impact, in packaged products should be assessed in further studies.

中文翻译：

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通过溶剂浇铸和静电纺丝获得包封香芹酚的聚乳酸基材料

聚乳酸 (PLA) (15 wt.%) 溶于乙酸乙酯 (EtAc)：使用二甲基亚砜 (DMSO) 二元体系（0:1；1:3 和 2:3 v/v）作为载体获得香芹酚与溶剂浇铸相比，通过静电纺丝负载 (CA) 的（相对于 PLA 为 20 重量%）基质。场发射扫描电子显微镜 (FESEM) 观察表明，负载 CA 的电纺纤维比不含 CA 的电纺纤维更细，并且当溶剂中存在 EtAc 时，它们的包封效率 (EE) 增加。流延薄膜的 EE（高达 89%）高于电纺毡（最大 68%）。热重分析和差示扫描量热法表明，不含 CA 的基质比含 CA 的样品保留更多的溶剂；这种效果在纤维中比在流延薄膜中更为明显。热分析表明，CA 在纤维中的保留力比在浇铸材料中更强，并且 CA 在 PLA 基质中的增塑效果与其保留量一致。实际应用：本研究中获得的载有香芹酚的聚乳酸材料，当应用于支撑聚合物层时，旨在作为可能的活性层，获得用于食品包装的活性（抗菌和/或抗氧化剂）多层材料。应在进一步研究中评估包装产品中材料的活性特性以及潜在的香芹酚感官影响。在本研究中获得的负载香芹酚的聚乳酸材料，当应用于支撑聚合物层时，旨在作为可能的活性层，获得用于食品包装的活性（抗菌和/或抗氧化剂）多层材料。应在进一步研究中评估包装产品中材料的活性特性以及潜在的香芹酚感官影响。在本研究中获得的负载香芹酚的聚乳酸材料，当应用于支撑聚合物层时，旨在作为可能的活性层，获得用于食品包装的活性（抗菌和/或抗氧化剂）多层材料。应在进一步研究中评估包装产品中材料的活性特性以及潜在的香芹酚感官影响。