Sorbic Acid and Potassium Sorbate Permeability of an Edible Methylcellulose-Palmitic Acid Film: Water Activity and pH Effects |
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| Authors: | DELMY C RICO-PEÑA J ANTONIO TORRES |
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| Affiliation: | Author Torres is affiliated with the Food Engineering Group, Dept. of Food Science &Technology, Oregon State Univ., Corvallis, OR 97331. Author Rico-Peña is now with Escuela de In-geniería Quimica, Universidad de El Salvador, San Salvador, El Salvador. |
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| Abstract: | The apparent permeability constants for potassium sorbate and sorbic acid through an edible film composed of methylcellulose and palmitic acid (weight ratio 3:1) were evaluated as a function of water activity (aw) and pH. For films with thickness 55–66 μm, potassium sorbate permeability increased from 2.3 × 10?10 to 2.0 × 10?8 (mg/sec cm2)(cm)/(mg/mL) as aw increased from 0.65 to 0.80. Films were not stable at aw levels above 0.80. Permeability of the film to sorbic acid at aw 0.8 decreased from 3.3 × 10?8 to 9.1 × 10?10 (mg/sec cm2)(cm)/ (mg/mL) as pH increased from 3 to 7. At pH 3 the undissociated acid was 97.5% and at pH 7 it was 0.4%. |
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