Vol.:(0123456789) 1 3 Journal of Polymers and the Environment https://doi.org/10.1007/s10924-023-02805-1 ORIGINAL PAPER Improvement of Moisture Barrier and Tensile Properties of Pectin Films by Incorporating Terminalia catappa Linn. Leaf Wax and Xylitol Shumyla Mehraj 1  · Yamini Sudha Sistla 1  · Mayank Garg 2  · Bisweswar Santra 3  · Harpreet Singh Grewal 2  · Aloke Kanjilal 3 Accepted: 16 February 2023 © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2023 Abstract Terminalia catappa Linn. (Indian almond) leaf epicuticular wax was extracted for the frst time and the presence of aliphatic alkane and ester chains was confrmed using Fourier Transform Infrared (FTIR) Spectroscopy. The wax crystals had tubular microstructure and displayed excellent thermal stability. Four pectin flms were developed from ~ 5% w/v flm forming solu- tion by adding wax (5 & 10% w/w) and xylitol (15 & 30% w/w). The resulting flms showed a twofold reduction in water vapor permeability and a fve to eight orders of magnitude reduction in oxygen permeability than control pectin flms. The flms showed an enhanced melting point of 160 °C against 95 °C for control pectin. Water contact angle (WCA) of 67° at 40 s after sessile drop indicated signifcant improvement in hydrophobic properties (WCA of control pectin was 20° at 40 s). The flms showed a fvefold increase in elongation at break and toughness compared to control pectin flms. Therefore, the present study introduces and demonstrates that the T. catappa leaf wax can act as an efcient hydrophobic agent with some plasticizer properties. The addition of appropriate quantities of T. catappa leaf wax and xylitol (as plasticizer) could produce pectin flms with enhanced barrier and tensile properties. Keywords Biopolymer · Packaging flm · Food safety · Pectin · Terminalia catappa wax · Xylitol Introduction Biopolymer based packaging flms are vital in making the global food-packaging industry more sustainable. The con- ventional petroleum derived synthetic plastic packaging material based on polyethylene, polypropylene, polysty- rene, polyethylene terephthalate, etc., proved to be harmful to the environment, human, animal, and aquatic life in many ways [1, 2]. The role of food packaging flm is to protect and extend the shelf life of food by controlling contact with moisture, oxygen, microorganisms, and ultra violet light. In addition, the packaging flm should also prevent the loss of favors and odor while providing a strong protective layer for the food [3, 4]. Biopolymers derived from natural resources are a sustainable choice as the main flm-forming matrix for packaging flms. The biopolymers used to develop packag- ing flms include polysaccharides, lipids, and proteins due to their gelling tendency in water [5–7]. Each type of biopoly- mer has one or more limitations, such as poor moisture and/ or gas barrier properties, weak ability to protect the food from microorganisms, and poor mechanical properties. Therefore, additives such as hydrophobic agents, plasticiz- ers, emulsifers, binders, and antimicrobial and antioxidant agents should be integrated with the biopolymer [3–6]. Vari- ous research groups synthesized packaging flms based on proteins (whey protein, soy protein, casein, and collagen) and polysaccharides (starch, cellulose, pectin, gluten, and chitosan). Lipids (waxes and oils) are generally hydrophobic and are typically used as coatings and hydrophobic addi- tives for packaging flms [8–16]. Polysaccharide and protein based composite flms could improve the gas barrier proper- ties but reduce the moisture barrier properties [17, 18]. * Yamini Sudha Sistla yamini.sistla@snu.edu.in; iam.yamini@gmail.com 1 Department of Chemical Engineering, Shiv Nadar University, Gautam Buddha Nagar, Greater Noida 201314, India 2 Surface Science and Tribology Lab, Department of Mechanical Engineering, Shiv Nadar University, Gautam Buddha Nagar, Greater Noida 201314, India 3 Department of Physics, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, Greater Noida 201314, India Content courtesy of Springer Nature, terms of use apply. Rights reserved.