| 摘要 |
Disclosed are edible film coating compositions of low moisture permeability and their methods of preparation. The compositions comprise cross-linked, refined shellac and preferably an edible member having a reactive hydroxyl or acid moiety selected from the group consisting of edible sources of polyphenolics, edible sources of benzaldehyde and derivatives, acetylated monoglycerides, polyglycerol esters, edible straight chain mono-carboxylic acid, edible di-carboxylic acids and mixtures thereof. Useful weight ratios of shellac to reactant range from 1:0.001 to 0.1. In the preferred method of preparation, the shellac is cross-linked with the reactants in a dry, molten mixture by heating at 130 DEG to 175 DEG C. for 2 to 15 minutes. The resulting coating compound while molten is dissolved in a food grade solvent, applied to a substrate and dried. The coating compositions are particularly useful as a moisture barrier in composite food articles having phases in contact which differ substantially in water activity. Effective films range from 0.1 to 5 mils in thickness.
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