100B-34 |
Water vapor permeability of mesquite gum-candelilla wax emulsion coatings incorporating plasticizers |
E. BOSQUEZ-MOLINA1, A. Badillo-Casasola1, I. Guerrero-Legarreta1, and E. J. Vernon-Carter2. (1) I.B., Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco # 186, Col. La Vicentina, Mexico City, D.F., 09340, Mexico, (2) IPH, Universidad Autonoma Metropolitana-Iztapalapa The principal function of an edible film or coating is to limit moisture transfer. Mesquite gum-candelilla emulsion formulations have potential as edible coatings. However they have to overcome limitations as poor moisture barrier and brittleness performance. It has been reported that plasticizer type and amount added to films or coatings have significant effects in reducing brittleness and increasing flexibility, but can also modify film permeability. The objective of this study was to determine the effect of several common plasticizers on the water vapor properties of mesquite gum-candelilla wax coatings. Mesquite gum-candelilla wax emulsions coatings were prepared using standard procedures with mixtures of Tweens-Spans (20-20,60-60,80-80, 20-80,80-60,60-80,40-80) blended together at 1% respect to hydrophobic phase with HLB=12; also sorbitol, lecithin, propylene glycol, polyethylene glycol (PEG 200,400,600) were tested using a concentration of 1.5%. Stability of each emulsion to coalescence was determined. Water vapor transmission rate (WVTR) and water vapor permeability (WVP) values of coatings were calculated using ASTM standard method and WVP correction method, respectively. The best formulations were used to coat persian limes, which were stored at 20 ± 1°C, 70-80% RH for up to 30 days. The weight loss of fruits were monitored during storage. Among the plasticizers studied, the mixtureTween 60–Span 80 and PEG 200 were the most effective in reducing the water vapor transmission of mesquite gum-candelilla based edible coatings compared with those obtained for a coating without added plasticizers. Both WVP values were improved respect to mesquite gum with a blend of candelilla wax-mineral oil (at 2:1 ratio), previously reported. The coatings obtained also exhibited a better adhesiveness, no fractures and uniform appearance on the coated fruits. These results are important in that they establish mexican natural resources from arid zones as potential materials for development of packaging materials for foodstuffs.
Session 100B, Food Packaging
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