Lemongrass essential oil–loaded kidney bean starch/nano-starch biopolymer films for active food packaging applications

The aim of this study was to develop edible films using kidney bean native and nano starch, incorporating lemongrass essential oil (LEO). In this study, starch was extracted from kidney beans and reduced to the nano-scale, further incorporated with LEO to develop active food packaging films. Nano starch from kidney bean exhibited markedly higher ash content (0.97%), water absorption capacity (53.76%), and oil absorption capacity (39.23%) compared to native starch (0.11%, 2.34%, and 25.34%, respectively). Films prepared with nano-starch showed significantly higher water solubility (62.4%) and biodegradability (15.05%) than native starch films (21.1% and 6.76%, respectively), while LEO addition reduced moisture content (from 11.88% to 8.31%) and biodegradability (3.91%). Structural improvements by nano starch enhanced barrier properties, whereas LEO imparted antioxidant and antimicrobial activities. LEO acted as a natural preservative, helping to inhibit microbial growth. The developed films were further applied for packaging of grapes, where they effectively reduced microbial spoilage and maintained fruit firmness and appearance during storage. Overall, kidney bean starch–based films demonstrated strong potential as eco-friendly, active packaging materials, contributing valuable insights into legume starch utilization in sustainable food packaging.