Beeswax and castor oil to improve the moisture barrier and tensile properties of pectin based edible films for food packaging applications

Biopolymer-based edible films and coatings are vital in making the global food-packaging industry more sustainable. These films/coatings protect and extend the shelf life of food by acting as barriers to moisture, oxygen, microorganisms, and Ultra Violet light. Polysaccharides, due to abundant availability from natural plant-based resources and the tendency to form a gel in water, are excellent low-cost choices for packaging films. Additives such as hydrophobic agents, plasticizers, binders, and antimicrobial agents will improve the properties of films and coatings. The present work aims to develop pectin-based packaging film (from 5% w/v film forming solution) by adding castor oil as a hydrophobic agent, beeswax as a plasticizer, and Clove oil as an antimicrobial agent. Films were developed by using 2³ (two-level three-factor) statistical factorial design of experiments. The amount of castor oil (5% & 15%), beeswax (5% & 10%) and clove oil (2% and 4%) are taken as the three factors. The developed films were analyzed for physical, moisture barrier, morphological, thermal, tensile properties and resistance to microbial growth. The results indicated that clove is a good antimicrobial agent. Further, bees wax greatly changed by enhancing the anti-microbial activity, elongation, and moisture barrier properties. Castor oil integration remarkably lowered the moisture and oxygen transmission rates relative to pure pectin films and some other additives reported in the literature. The optimized biofilms had a thickness of ~0.10 ± 0.004 mm, pH=3, and transparency of ΔΕ= 9.15 to 25. The elongation at break increased at least four times. The films were thermally stable at 400 ℃. The detailed statistical analysis and analysis of various studies indicate that the amount of castor oil (p< 0.05), a combined effect of castor oil and beeswax (p< 0.05) is significant on barrier properties while the effect of beeswax (p< 0.05) is also significant on mechanical properties.