J Food Process Preserv. 2019;00:e14265. wileyonlinelibrary.com/journal/jfpp | 1 of 10 https://doi.org/10.1111/jfpp.14265 © 2019 Wiley Periodicals, Inc. 1 | INTRODUCTION Edible films can be defined loosely as an edible thin and continuous layer that can be formed as food coatings and placed between food components with the ability to act as a mass transfer barrier, food in‐ gredient/additive carrier, and improving the mechanical integrity or handling characteristics (Krochta, 1992). Research and development of environmentally friendly edible packaging is of high interest due to food processors’ needs for novel storage techniques and new mar‐ ket outlets (Gennadios & Sumner, 1999). In addition, the low time to store food due to microbial contamination and the use of artificial carcinogenic preservatives have encouraged various studies in food packaging, especially edible film technology involving natural preser‐ vatives sourced from animals, plants, and microorganisms. Foods con‐ taminated with microbes will experience changes in texture and taste. Therefore, they are not suitable for consumption (Gram et al., 2002). Received: 28 May 2019 | Revised: 17 September 2019 | Accepted: 9 October 2019 DOI: 10.1111/jfpp.14265 ORIGINAL ARTICLE Physiochemical and antibacterial analysis of gelatin–chitosan edible film with the addition of nitrite and garlic essential oil by response surface methodology Faridah Handayasari 1 | Nugraha Edhi Suyatma 1,2 | Siti Nurjanah 1,2 1 Department of Food Technology, IPB University, Bogor, Indonesia 2 Southeast Asian Food and Agricultural Science and Technology (SEAFAST) Center, IPB University, Bogor, Indonesia Correspondence Nugraha Edhi Suyatma, Department of Food Technology, IPB University, Kampus IPB Darmaga, Bogor 16680, Jawa Barat, Indonesia. Email: nugrahaedhi@yahoo.com Abstract The mechanical properties of edible films upon variation of gelatin (G) and chitosan (C) concentration (G%/C%) were compared using constrained mixture and response surface methodology (RSM) and their antibacterial activities against P. aeruginosa, B. cereus, and L. monocytogenes by the addition of sodium nitrite and garlic essential oil (GEO) were analyzed. Both methods show that increasing chitosan concentration will gradually enhance edible film tensile strength but decrease their elongation at break. Optimization to find the gelatin–chitosan edible film with the maximum elasticity was performed by minimizing the Young’s modulus which yields a value of 0.41 MPa cor ‐ responding to a G60/C40 gelatin–chitosan concentration using constrained mixture and 0.31 MPa corresponding to a G76/C24 gelatin–chitosan concentration using the RSM method. Antibacterial analysis of the edible film showed that the addition of sodium nitrite and GEO in gelatin–chitosan edible film enhances their antibacterial activity significantly and increasing the GEO concentration also improve the antibac‐ terial activity of the film. Practical applications The outcome of our work has practical applications in the field of biodegradable ed‐ ible film, for example, for environmentally friendly meat coatings due to its optimum elasticity property. In addition, our gelatin–chitosan film with garlic essential oil also exhibits significant antibacterial properties which can compete with commercial film that uses nitrite addition and therefore prolong the shelf life of the food without the risk of carcinogenic effects. From the potential point of view, our work should stimulate more research toward the development and optimization of biodegradable edible films with noncarcinogenic antibacterial properties.