Development of A Biodegradable Dual-Layer Edible Bilayer Film (Hydrophilic– Hydrophobic Packaging Film) — "PODIBLE" — For Food Packaging Applications
Keywords:
Edible film, dual-layer sachet, biodegradable packaging, starch-based film, beeswax, moisture barrier, WVTR, instant seasoning, PODIBLE.Abstract
The widespread use of non-biodegradable plastic sachets in instant food products has created acute environmental challenges, with India generating approximately 3.5 million tonnes of plastic waste annually (CPCB, 2022). This study developed and characterised PODIBLE — a biodegradable dual-layer edible bilayer film comprising a hydrophilic inner layer (corn starch + glycerine) and a hydrophobic outer layer (corn starch + beeswax
+ GMS) — as a functional alternative to single-use plastic seasoning sachets. Formulation optimisation through nine inner-layer trials and four outer-layer trials identified Trial 9 and Trial 4, respectively, as the optimal formulations. The inner film exhibited complete dissolution in hot water (95°C) within 60 seconds with no solid residue. The PODIBLE dual-layer sachet reduced moisture gain from 12.5% (inner film alone) to 4.2%, representing a 66.4% improvement in moisture barrier performance. Water vapour transmission rate (WVTR) was 1850 ± 50 g/m²/day for the inner film and 720 ± 35 g/m²/day for the outer film (61.1% reduction). Tensile strength was 18.2
± 1.1 MPa (outer) and 12.5 ± 0.8 MPa (inner). Sensory evaluation (n = 10) yielded an overall acceptability score of
8.1/9 on a 9-point hedonic scale. Microbiological analysis confirmed FSSAI compliance with TPC < 10² CFU/g and complete absence of E. coli and Salmonella. Biodegradability testing demonstrated ~95% weight loss within 14 days under soil burial conditions. A preliminary shelf-life study confirmed product stability for 75 days under ambient storage. Raw material cost was estimated at less than ₹1.00 per sachet. The novelty of PODIBLE has been recognised through an Ordinary Patent Application filed with the Patent Office of India (Application No. 202641030135, dated 13 March 2026). The findings establish a scientifically sound basis for the commercial scale- up of PODIBLE as a next-generation sustainable food packaging technology.
