Incorporation of vitamin E into chitosan and its effect on the film forming solution (viscosity and drying rate) and the solubility and thermal properties of the dried film

摘要

Nutrient fortified edible films have been used to improve the health benefit and extend the shelf life of various foods. The effect of vitamin E on the properties of chitosan edible film was evaluated in this study. The edible ingredient solutions were made with 1.0-2.0% chitosan blended with 250 or 500 mg vitamin E by two formats: (1) vitamin E added before lecithin (VE first); and (2) vitamin E mixed with lecithin (VE mixed) then added to the solution. Changes in the drying rate were determined using an OHAUS Moisture Determination Balance, and solubility was determined by dissolving the film in water for 1 min then measuring the weight changes. Results showed that vitamin E additions significantly (p ＜ 0.05) increased the drying rate of the formulation by 3-9 min. The smallest quantity of vitamin E uptake by the films occurred with the 1.0% chitosan materials, which caused vitamin E accumulation on the surface instead of in the matrix of the film. The results showed that the blending process for vitamin E and lecithin influenced the stability of the chitosan-vitamin E network. The 2.0% chitosan had the highest viscosity and the best homogeneity with the blended vitamin E-lecithin mixture. This also decreased the film solubility, especially in samples with higher chitosan and VE first concentrations.