Development and application of polysaccharide-lipid edible coating to extend shelf-life of dry bakery products

摘要

This study investigated the effect of the deposition process used for film-forming dispersion (spreading and spraying), relative humidity gradient across the film (from 22-65% to 22-85%) and film thickness (15-90 μm) on water vapor permeability (WVP), tensile strength (TS), percentage elongation at breaking (E) and structure of an emulsified edible film composed of corn starch, meth-ylcellulose (MC) and soybean oil. The effectiveness of edible coating in controlling moisture transfer in moisture-sensitive products was evaluated by coating crackers, a low a_w-type cereal food. Spread film gave better water vapor barrier and mechanical properties than sprayed film. High atomization pressure and thickness increased film WVP. Atomization pressure of 2 bar and film thickness of 30 μm were identified as optimum for the application of edible coating to bakery products. Coated and uncoated (reference) crackers were stored at 65%, 75% and 85% relative humidity. Moisture uptake and resistance to water vapor transmission (r) were then calculated. Coated crackers had longer shelf-life and higher r than reference at all storage conditions.