Development of pectin-wax composite edible films with high moisture barrier properties

This thesis aimed development of multipurpose citrus pectin-based edible films showing moisture barrier and antimicrobial properties at the same time. For this purpose, pectin was composited with different waxes and antimicrobial essential oil carvacrol employing emulsification with hot homogenization. Pectin composite films with 15% glycerol and 40% beeswax obtained with CaCl2 cross-linking showed WVP of 1.58 g.mm/m2 .day.kPa (54% lower than WVP of pristine pectin film). In contrast, pectin films with 15% glycerol and 30% carnauba wax showed a dramatically low WVP of 0.16 g.mm/m2.day.kPa without CaCl2 cross-linking (95% lower than WVP of pristine pectin film). These findings clearly showed that use of a wax with high melting point (m.p. of carnauba wax=82-86oC) is more effective than one with low melting point (m.p. of carnauba wax=62-66oC) to achieve composites with high moisture barrier properties. Therefore, antimicrobial films were developed by incorporating carvacrol at 1, 2, or 3% into pectincarnauba wax composite films. The carvacrol incorporated edible composite films showed antimicrobial activity on Escherichia coli and Listeria innocua at a concentration dependent manner, but the increase of essential oil concentration reduced the moisture barrier properties of films. As a result, the antimicrobial pectin-carnauba wax composite films incorporated with 1% of carvacrol showed the highest moisture barrier properties with a WVP of 1.47 g.mm/m2 .day.kPa (57% lower than WVP of pristine pectin film). P). The compositing with waxes reduced the transparency and mechanical strength of pectin based films. However, this thesis showed possibility of reducing moisture loss and microbial load of food by pectin-based packaging.