Biodegradable Packaging Films from Alfalfa Cellulosic Residue: A Facile Route to Address Plastic Concerns and Extend the Shelf-life of Strawberries — 45p — Sandeep Paudel, Srinivas Janaswamy

Department of Dairy and Food Science, South Dakota State University, Brookings, SD 57007

Plastic is popular for packaging as it is durable, lightweight, and versatile. However, it takes several centuries to degrade. During this process, it disintegrates into microplastics and nanoplastics, contaminating water, air, and food and affecting human and animal health and the ecosystem. In this regard, biopolymers are being explored as packaging alternatives. More importantly, cellulose, an abundant plant structural component that is a non-toxic, biodegradable, and non-food constituent, is being explored. However, it is primarily sourced from trees through deforestation, which contributes to climate change, global warming, and biodiversity loss, to name a few. In this regard, cellulosic residue from agricultural biomass forms a sustainable resource and contributes to conserving the environment. Herein, alfalfa field residue was used to extract its cellulosic residue (ACR), and biodegradable food packaging films were developed. Alfalfa was treated with 5% KOH and 3% NaClO₃ to extract the ACR. The ACR, crosslinker Ca²⁺ ions_, and plasticizer sorbitol were optimized as the independent variables using Box Behnken Design against the responses tensile strength (TS), elongation at break (EB), and water vapor permeability (WVP). The optimized film was analyzed for color, UV-Vis-IR transmittance, water uptake, soil biodegradability, and the shelf-life extension of strawberries. The film is strong with a higher TS of 18.3 MPa and is comparable to commercial high-density polyethylene films of 19 MPa. The TS and WVP improved with added ACR and Ca²⁺ ions, but the EB with ACR and sorbitol. The film was translucent and blocked the UVB radiation. It followed Peleg water absorption kinetics and degraded within 35 days at 24% soil moisture. The films extended the shelf-life of strawberries by two extra days at room temperature compared to polystyrene films. The outcome provides a win-win situation for the environment and the agricultural industry by addressing plastic pollution, promoting sustainability and circular bioeconomy, adding value to discarded agricultural streams, and creating a novel income path for the alfalfa producers.

South Dakota State University
Dr. Srinivas Janaswamy