Development Of Pectin And Sodium Alginate Composite Films With Improved Barrier And Mechanical Properties For Food Packaging Applications

The rate of plastic deterioration is currently significantly outpacing the rate, at which plastic waste being produced, leading to a biome-wide imbalance. Biopolymers derived from sustainable raw materials are widely explored as potential alternative packaging materials to increasing the shelf life of fresh produce and processed food. Present work aims to develop polysaccharide based composite films. Sodium alginate and castor oil blended pectin films were developed as per 2⁴ (two-level four-factor) factorial design of experiments. Sodium alginate was used as a stabilizer and film forming agent to enhance the mechanical properties of the films. Castor oil was used as an additive to improve moisture barrier and antimicrobial properties. D-Sorbitol was used as a plasticizer to improve the flexibility of the films. The amount of sodium alginate (25% & 50% w/w), castor oil (10% & 15% w/w) and D-sorbitol (15% & 30% w/w) with respect to pectin and sonication time were chosen as the four factors. Based on our prior optimization studies, all other process variables, such as pH (< 4), drying temperature (60 ℃) and humidity (40%) were maintained constant. The moisture barrier, mechanical, surface hydrophobicity, morphological, thermal stability properties and biodegradability characteristics of each film were studied. All films were thin (~ 0.120 ± 0.004) and transparent (ΔΕ = 8 to 20). The moisture barrier properties improved threefold compared to pure pectin films. The elongation at break increased at least three times. The films were thermally stable at 400 ℃. The melting point of the films increased to 150 ℃ compared to 95 ℃ of pure pectin film. Based on the statistical analysis and analysis of variance (ANOVA), the effect of castor oil (p < 0.05) is more on the moisture barrier property and a combined effect of sodium alginate (p < 0.05) and sorbitol is significant on the mechanical properties.