# Rosehip Seed Oil-Incorporated Chitosan Films for Potential Fruit Packaging Applications
## 1 Introduction
Different cellulose esters, such as lemongrass, basil, and rosemary pepper, behave like plasticizers in the matrix, affecting Young's modulus, tensile strength, and elongation at break of the films [17]. Among the considered potential sources, rosehip seed oil (RSO) emerges as a promising alternative due to its richness in unsaturated fatty acids, particularly oleic, linoleic, and linoleic acids [18]. Additionally, RSO boasts a high content of vitamins, minerals, carotenoids, tocopherols, phytosterols, flavonoids, tannins, pectin, sugars, organic acids, and amino acids [19]. Thanks to the high content of biologically active substances, RSO demonstrates antibacterial properties against a range of bacteria and fungi, such as _Aspergillus niger_, _Candida albicans_, _Escherichia coli_, and _Staphylococcus aureus_[20]. Different approaches regarding the mechanism of antibacterial and antifungal action have been proposed in the literature--bacterial inhibition due to the deterioration of membrane integrity, loss of cell content (molecules and ions) due to damage of the selective permeable structure of membranes, secondary metabolites (phenolic compounds) in volatile oil composition causing damage to cell membranes, and cell vital activities (energy production and protein synthesis) [21]. Because rosehip oil has a significant amount of vitamins, especially C, E, and A, it is well known for having antioxidant qualities [22; 23]. Considering the mentioned benefits and wide availability, RSO has garnered significant attention across cosmetic [24], pharmaceutical [25; 26], and food industries [24; 25; 27]. Previously [PERSON] et al. have reported that the presence of rosehip seed oil in chitosan films led to the formation of flexible films with improved mechanical, gas, and water vapor barrier properties, antioxidant activity, and antimicrobial properties against _Escherichia coli_,Salmonella enterica_ subsp. _enterica_ ser. Typhimurium, and _Bacillus cereus_[28]. Conducted by [PERSON], FTIR studies indicate interaction by hydrogen bonds between chitosan and rosehip seed oil. Additionally, when shifting to higher wavenumbers, the vibration bounds of chitosan were caused by inhibited inter/intra molecular hydrogen bonding, which existed in the neat chitosan film. One of the main disadvantages of chitosan in its application in the food industry is its dissolution in an acidic environment, mainly in acetic acid. In this case, some precautions are necessary due to the potential migration of the acid into the food matrix. Although volatile organic acids are usually removed during solvent evaporation, residual amounts might remain. Acetic acid is known for its strong odor and taste, which can affect the sensory qualities and decrease the consumer acceptance of the final product [29]. To overcome these limitations, an alternative approach to use water-soluble chitosan could be adopted [30]. To the best of our knowledge, there are no studies on the formulation of edible films on the basis of water-soluble chitosan and rosehip seed oil emulsion. The present article aims to investigate the effect of rosehip seed oil concentration on the morphology, rheological properties, hydrophilic-hydrophobic balance, and antioxidant and antibacterial activities of the multicomponent films based on water-soluble chitosan.