Food Marketing & Technology - India May 2019 | Page 42

Packaging they do not generally form coherent, stand-alone films. Lipid films have good water vapour and oxygen barrier properties. Generally, wax coatings are substantially more resistant to moisture transfer than most other lipid or non-lipid edible coatings. Edible resins such as: shellac; terpene resin; and wood rosin are used to impart gloss to food commodities. Shellac has been used extensively as an edible coating for the confectionary and fresh produce. Other examples of lipids that have been used effectively in coating formulations are: beeswax; mineral oil; vegetable oil; surfactants; acetylated monoglycerides; carnauba wax; and paraffin wax. Proteins: The films and coatings are also made from animal and plant proteins. The examples of the proteins that are being used for coating fruits and vegetables are: soy protein; whey protein; casein; corn-zein; maize; egg albumen; collagen; and wheat. Like polysaccharide-based films, the protein-based edible films also provide excellent mechanical and barrier properties against oxygen, aroma, and oil. But they have very limited resistance to water vapours. Composite Materials: Composite materials are a mixture of edible components that are made to overcome their respective flaws. The above mentioned different forms are not effective in preserving the quality of the fruits and vegetables by themselves. To improve their effectiveness they are being used in combinations. Most of the composite films studied to date consist of a lipid layer supported by a polysaccharide or a protein layer, or lipid material dispersed in a polysaccharide or protein matrix. The lipid components used in the packaging formulation reduce water transmission while the other components serve as selective gas barriers and provide mechanical strength and structural integrity; e.g. a film prepared by combining milk protein and lipid for lightly processed apples and potatoes was reported to provide protection from moisture loss and oxidative browning for up to three days. Edible Film Additives A number of materials are incorporated into edible films to enhance structural, mechanical and handling properties or to provide active functions to the films. The examples are mentioned below: Plasticizers: To improve film flexibility and durability, plasticizers are generally added to edible films. These include mono-, di-, or oligosaccharides like glucose; fructose–glucose syrups; and sucrose; polyols like glycerol, sorbitol, glyceryl derivatives and polyethylene glycols; lipids; and derivatives like phospholipids, fatty acids and surfactants. Emulsifiers: Emulsifiers are essential to achieve sufficient surface wet-ability to ensure proper surface coverage and adhesion to the coated surface as well as for the formation and stabilisation of well-dispersed lipid. Antimicrobials: One of the important emerging functions of edible films and coatings is their use as carriers of antimicrobials and antifungal agents to increase the shelf life of foods; they may also be used as carriers of nutrients to increase the nutritional value of processed food products. The more commonly used antimicrobials are: organic acids; chitosan; nisin; lactoperoxidase system; and some plant extracts and their essential oils. Antioxidants: Antioxidants are added to edible films to delay the start or slow the rate of oxidation reactions. The examples of antioxidants include: butylatedhydroxyanisole (BHA); butylatedhydroxytolu- ene (BHT); propyl gallate; tertiary butylhydroquinone; citric acid; Food Marketing & Technology 42 May 2019 ascorbic acid; ascorbylpalmitate; and tartaric acid. An Overview on Global Edible Films and Coatings Market The global edible films and coatings market is expected to witness steady growth owing to increased use of clean label strategies by food producers. The reason for the bump in the growth for edible films and coatings is their use as an excellent solution to reduce the carbon footprint. As per the market studies conducted by various market research firms’ forecasts suggest that this market is expected to increase by CAGR of 7.1 percent during the period, 2018-2023. The market growth is driven by a number of factors such as: increasing focus on reducing wastage from packaging material; increasing shelf life of products; safety concerns; increasing demand of convenient food offerings in developed regions; Government’s initiatives to reduce the carbon footprint in the food sector; etc. The benefits of edible packaging have increased their acceptability by the food and packaging manufacturers and this factor is boosting revenue growth of the global edible films and coatings market. On the other hand the global edible films and coatings market is also facing challenges such as: absence of local manufacturers of edible films and coatings; higher cost of edible films and coatings over the present packaging solutions, lower recycling cost; and restrictions on the availability are anticipated to act as a major restraint globally for the growth of the edible films and coatings market. ** Assistant Professor (SG), Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore; Email: raajraajeswari@gmail. com * Ph.D. Scholar, Avinashilingam Institute for Home Science and Higher Education for Women, Coimbatore; Email: [email protected]