Synthesis and Characterization of Edible Films from Garlic(Allium sativum) Husk Components

Abstract

Garlic husks are waste biomass and unutilized sources of essential compounds like lignin, pectin, cellulose, hemicellulose, lignocellulose and dietary fibre. Pectin was extracted from garlic husk using ammonium oxalate solution. Lignin is a complex biopolymer consisting of p-coumaryl alcohol, sinapyl alcohol, and coniferyl alcohol. Lignin was extracted from garlic husk using alkali pulping method; the sample was subjected to 10% (w/w) NaOH solution in a pressurized condition at high temperature. The extracted lignin was characterized using Fourier Transform Infrared Spectroscopy (FTIR). Transmittance ratios in FTIR Spectra of extracted lignin were similar to those of the commercial lignin. The edible film was prepared by solution casting method where the film was casted from the solution of pectin and lignin. The physical and chemical properties of the film like moisture content, color, solubility of the film, antimicrobial activity, water vapour transmission rate, pectin and lignin were characterized. The lowest water vapour permeability of the film is 17.48 ± 0.12 g/h m2. Whiteness index and 'L' value of film decreased from film 1 to film 4. An inhibition zone was formed against the Bacillus cereus proving the antimicrobial activity of the lignin extracted from garlic husk.