Modified lotus seed starch and red turnip peel extract based pH responsive edible films

Starch obtained from lotus seed was physically modified through heat-moisture treatment to develop the starch-based biopolymer films. Three different types of films: native lotus seed starch (NLS)- carboxymethyl cellulose (CMC), heat moisture treated modified starch (HMLS)-CMC, and modified starch incorporated with red turnip peel extract (HMLS-RTE)-CMC films were developed. The different filmogenic solutions exhibited non-Newtonian behavior with the shear thinning property and showed weak gel-like and viscoelastic behavior. The three different films' tensile strength ranged from 14.97 ± 0.65–21.13 ± 0.41 MPa and elongation at break ranged from 32.87 ± 1.14–44.31 ± 0.82%. The water vapor permeability in NLS was 3.86 × 10−7 gm−1h−1Pa−1 and in HMLS-RTE film, the WVP was decreased to 2.58 × 10−7 gm−1h−1Pa−1. The findings revealed that the pH-sensitive HMLS-RTE film had higher thermal stability, improved mechanical and moisture barrier properties than the NLS films, making them suitable for the intelligent food packaging system.