Extended shelf-life of many foods is a modern requirement that has been achieved by means of fossil-based plastic films despite their environmental issues. Recently, starch-based, fully biodegradable thermoplastics are gaining momentum as packaging material; however, if they are in contact with food, aspects such storage, water interaction and spoilage due to microorganisms must be considered. Essential oils are of great interest due to their antimicrobial action, so incorporating these compounds into natural polymers can promote a longer shelf life through active packaging. In this study, antibacterial activity, optical, mechanical and barrier properties of thermoplastic starch (TPS) films based on cassava starch (Manihot esculenta Crantz) and rosemary essential oil (REO) were studied. Furthermore, the effect of cellulose nanocrystals (CNC) on TPS properties were surveyed. Film mechanical properties and those related to the interaction with water, showed that the highest resistance and barrier properties corresponded to the TPS/CNC 15% film, while adding oil to the films increased morphological heterogeneity, contributed to reduce tensile strength, and increased water solubility and water vapor permeability. Likewise, TPS films containing rosemary oil showed enhanced antibacterial activity mostly against E. coli and S. aureus bacteria and A. niger fungus. Therefore, adding essential oils as natural additives favors using these biocomposites as functional packaging, and as potential replacements for single-use plastics.

许多食品的保质期延长是现代要求，尽管存在环境问题，但已通过化石塑料薄膜实现。最近，基于淀粉的、完全可生物降解的热塑性塑料作为包装材料正在获得动力。但是，如果它们与食品接触，则必须考虑储存、水相互作用和微生物引起的腐败等方面。精油因其抗菌作用而备受关注，因此将这些化合物加入天然聚合物中可以通过活性包装延长保质期。在这项研究中，基于木薯淀粉 ( Manihot esculenta Crantz ) 的热塑性淀粉 (TPS) 薄膜的抗菌活性、光学、机械和阻隔性能) 和迷迭香精油 (REO) 进行了研究。此外，研究了纤维素纳米晶体 (CNC) 对 TPS 性能的影响。薄膜机械性能和与水相互作用相关的性能表明，最高电阻和阻隔性能对应于 TPS/CNC 15% 薄膜，而向薄膜中添加油会增加形态不均匀性，有助于降低拉伸强度，并增加水溶性和水蒸气渗透性。同样，含有迷迭香油的 TPS 薄膜显示出增强的抗菌活性，主要是针对大肠杆菌和金黄色葡萄球菌以及黑曲霉菌。因此，添加精油作为天然添加剂有利于将这些生物复合材料用作功能性包装，并作为一次性塑料的潜在替代品。