ORIGINAL PAPER Journal of Polymers and the Environment https://doi.org/10.1007/s10924-022-02581-4 resources like fruits and vegetables [1–4]. Some examples of biopolymers include proteins, lipids, fats, carbohydrates, polysaccharides, etc. Researchers have developed thin flms from various biopolymers such as proteins, collagen, starch and cellulose [5–9]. These natural polymers are capable of forming gels when dissolved in water and form homoge- neous flm matrices upon drying. The edible or biodegrad- able coatings and flms are intended to protect the food by providing a controlled atmosphere of moisture, oxygen, and carbon dioxide in order to delay the drying, cell reactions, ripening, and fouling [10, 11]. The additives, such as anti- microbials and antioxidants, reduce the growth of harmful microbes [7, 12, 13]. Further, the flms are also expected to exhibit good tensile properties, fexibility, transparency, ability to form thin flms, and stability under diferent stor- age conditions. Among various biopolymer materials, polysaccharides are known for their excellent gas barrier properties and poor moisture barrier properties [13]. The focus of present study is pectin biopolymer which belongs Introduction As the world is moving towards fnding green solutions in many felds, biopolymers have emerged as sustainable alternatives for conventional petroleum derived plastics. Biopolymers, the main flm forming matrix for edible/ biodegradable flms, are usually extracted from natural  Yamini Sudha Sistla yamini.sistla@snu.edu.in; iam.yamini@gmail.com 1 Department of Chemical Engineering, Shiv Nadar University, Gautam Buddha Nagar, 201314 Greater Noida, India 2 Surface Science and Tribology Lab, Department of Mechanical Engineering, Shiv Nadar University, Gautam Buddha Nagar, 201314 Greater Noida, India 3 Department of Physics, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, 201314 Greater Noida, India Abstract Castor oil (CO) and cocoa butter (CB) were studied as potential hydrophobic and plasticizer additives for pectin bio- polymer flms. The optimum concentration of CO and CB additives and drying temperature were determined by using a 2 3 (two-level, three-factor) statistical factorial design of experiments. The CO and CB integrated pectin flms displayed remarkably lower moisture and oxygen transmission rates relative to the control pectin flms. Furthermore, the hydropho- bicity, ductility (elongation at break) and fexibility (low elastic modulus) of the CO and CB added flms are signifcantly higher than that of the control pectin flms. The modifed flms retained 90% of their weight at a temperature of 200 °C, indicating their excellent thermal stability. A very low glass transition temperature of 2 ± 2 °C and a melting point of ~ 150 °C of the flms designates their stability under processing and storage conditions. Scanning electron microscopy analysis confrmed the formation of homogeneous flms without any micro-cracks or agglomerations. Detailed statisti- cal analysis shows that the optimal conditions for producing improved pectin flms: the concentration of CO (15% w/w of pectin) and CB (10% w/w of pectin) and flm drying temperature (T = 35–52 °C). A coating of flm forming solution comprising optimum amounts of pectin, CO and CB was able to delay the ripening of a banana by 4 days and of capsicum by 15 days at atmospheric conditions. Keywords Edible flms · Pectin · Castor Oil · Water Vapour Transmission Rate · Tensile Properties · Water Contact Angle. Accepted: 1 September 2022 © The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature 2022 Castor Oil and Cocoa Butter to Improve the Moisture Barrier and Tensile Properties of Pectin Films Shumyla Mehraj 1  · Gouri Pandey 1  · Mayank Garg 2  · Bisweswar Santra 3  · Harpreet Singh Grewal 2  · Aloke Kanjilal 3  · Yamini Sudha Sistla 1 1 3 Content courtesy of Springer Nature, terms of use apply. Rights reserved.