## 1 Introduction
The amorphous structure of pectin allows the incorporation of additives and facilitates their retention within the film structure. This property makes pectin suitable for carrying active compounds like essential oils, which could be applied to the production of active film packaging [17]. Pectin-based active packaging has great potential for food preservation applications. Some studies reported practical examples of pectin-based packaging used for food preservation. Edible pectin film containing carvacrol and cinnamaldehyde successfully inactivated _Listeria monocytogenes_ on ham [18]. Reduced bacterial growth and increased oxidative stability were obtained for butter packaged with pectin-based film containing _Carum copticum_ essential oils [19]. In another study, pectin film containing clove essential oil were successfully preserved beam (_Magalobrama ambycphala_) fillet in the refrigerator for 15 days [20]. Essential oils (EOs) consist of various compounds such as terpen, aldehydes, fatty acids, phenols, ketones, esters and alcohols, have significant food preservation potential [21; 22]. EOs with the ability to disrupt and penetrate the bacterial cell wall have shown interesting antimicrobial activities [23]. One important component is _trans_-cinnamaldehyde (TC), which is a major constituent of cinnamon oil. It is widely used as a flavoring agent and has agrichemical, antimicrobial, and anti-cancer properties. _trans_-cinnamaldehyde is classified as safe for use in foods by the Food and Drug Administration (FDA) [24; 25]. It has antimicrobial activity against a wide range of foodborne pathogens, including both Gram-positive and Gram-negative bacteria [26; 27]. Direct incorporation of EOs into water soluble biopolymer matrices such as pectin caused poor miscibility and phase separation. In addition, the free EOs in the film matrix can undergo rapid migration and lose their activity for a short time. To overcome these difficulties, the incorporation of encapsulated EOs instead of free EOs in film-forming solutions could be applied [28]. Consequently, oil-in-water nanoemulsion (NE) has been studied in various biopolymer-based active films [29; 30; 31; 32].The use of the nanoemulsion of bioactive compounds can contribute to the improvement of pectin film properties. A reduction in water sorption and water vapor permeability, as well as an increase in the mechanical and biological properties of pectin film incorporated with the nanoemulsion of _Origanum majorana L_. oil were reported by [28]. Pectin films containing the nanoemulsion of copaiba oil also showed a decrease in water vapor permeability and an increase in extensibility along with less stiffness, in addition to higher antimicrobial activity [33]. Therefore, this study aims to develop pectin-based films incorporating different concentrations of _trans_-cinnamaldehyde as an antimicrobial agent. The investigation will evaluate the effect of _trans_-cinnamaldehyde concentration on the physical, thermal, mechanical, and biological properties of pectin films for food packaging applications. By exploring the potential of _trans_-cinnamaldehyde-incorporated pectin films, this study contributes to the creation of eco-friendly and sustainable packaging, aiming to prolong food shelf life while mitigating plastic pollution.