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Biodegradable packing materials with antimicrobial properties have been a concern for years because of its positive environmental implications. The present work aimed to develop the formulation of hydroxyethyl cellulose (HEC)/wheat-starch based film in which the active compound, thymol (0.5, 1, 1.5, 2, and 2.5% w/w) were incorporated into the polymeric material. Solution casting method was used for the film preparation while thymol was incorporated prior to casting. The physical and chemical properties of the developed film were determined. SEM was found to have a smooth and homogeneous with a small amount of thymol which grows coarser with 1.5% or higher thymol content. FTIR was used to find the chemical property of the film and suggested that the carbonyl functional group was unchanged in the film, however, -OH groups increased substantially with increased amount of thymol. Thermal properties were profiled through thermogravimetric analysis and differential scanning calorimeter where the AM film containing 1.5% (w/v) of thymol shows the highest thermal stability and decomposes less in comparison to other samples. The inhibitory capability of the film was tested against a list of microbial contamination and was found to successfully inhibit the growth of selected gram positive and gram negative bacteria in a wide range of studied concentration. The mechanical properties of the films were improved by 60.3% with an optimum tensile strength at thymol concentration of 1.5% w/w. It can be concluded that the film properties are retained chemically whereas mechanical properties, strength, flexibility and function of the film are being enhanced remarkably by the incorporation of thymol.

In addition to offering a host of health benefits, antimicrobial (AM) wheat-based packaging is a promising form of active food packaging with great economic and environmental potential. The main objective of this study is to develop a formulation of AM wheat-based film in which the active compound, lysozyme, is incorporated into the polymeric material. A solution casting method was used in the film preparation, and lysozyme was incorporated prior to casting. The resultant film is slightly less opaque, more translucent and whitish in appearance, implying that the AM film could retain similar property with the initial opacity value of the wheat-based film. The water uptake of wheat-film is reduced with the incorporation of lysozyme. The reduction in moisture content of AM film indicates a relationship between lysozyme and water molecules in the diffusion mechanism throughout the film matrices. This film helps to reduce the growth of E. coli and B. subtilis to 1.74 and 3.48 log CFU/mL, respectively, for an incubation of 48 h. FTIR analysis implies the consistency of the chemical composition and structure of the AM film compared to the control film, which indicates that the addition of lysozyme into the wheat-based film did not affect or alter the carbonyl function groups of the wheat-based film. The study will help the researcher to discover and understand wheat-based films for incorporating antimicrobial properties and to explore new matrices for further development.

Active and smart packaging is a promising form of food packaging that offers a great economical potential due to consumer demand for a packaging that accommodate a hectic way of life. An antimicrobial film with pH colour indicator (pHF) can be made by incorporating suitable antimicrobial (AM) agent and colour indicator into food package matrices whilst applying a bio switch concept to inhibit the pathogenic microorganisms and respond automatically to changes (external stimuli) in the environment. The present work aimed to study the developed formulation of hydroxyethylcellulose (HEC)/wheat-starch based pHF film in which the active compound, thymol (0.5, 1, 1.5, 2, and 2.5% w/w) and 50:50% w/w bromothymol blue and methyl red (as the colour indicator) against microbial growth. A solution casting method was used in the film preparation while thymol and colourant were incorporated prior to casting. The effect of thymol showed a range of microbial inhibition zones of 16.3 - 26.4% and 22.1 - 39.9% towards E. coli and B. subtilis, respectively. Whilst, a lower inhibition zone of 0.4 - 5.1% was demonstrated for fungus A. niger.