| Abstract | The preparation method of alginate based films was introduced. The effect of composition of film on film properties was investigated and the effectiveness of film coating in preventing browning reaction that occurs on the surface of peeled fruits and vegetables was evaluated. Types of alginate based films made included: Alginate film with and without plasticizer (glycerol), composite film of alginate and tapioca starch, composite film of alginate and lipid (shortening). Based on film properties, namely tensile strength, elongation, water vapor, oxygen permeability, sensory quality and opacity, the optimum formula for each type of film was found. The various combinations studied were alginate film (2.5% alginate); alginate and 5% glycerol, alginate and 1 % tapioca starch, alginate and 2% shortening, alginate, 5% glycerol and 1 % tapioca starch. The calcium chloride concentration used in all formulas was 3.5%. Among the different types, film with the formula of alginate (2.5%), glycerol (5%) and starch (1 %) was found to be the best when compared with the others. Its properties were as follows: tensile strength (5.25kgforce/mm2 ), elongation (1.9%), oxygen permeability (201.lx10-18mol. m/m2 .s.Pa), water vapor permeability (4.87 g.m/m2 .d.kpa) and opacity (0.12 A.nm). In addition, it got an acceptable sensory quality score of 8.3 when scored by ten panelists based on Bedonie scale. Applications of composite alginate based film with alginate (2.5%), tapioca starch (1 %) and glycerol (5%) were carried out on fresh sliced potato, dried sliced mango and whole lime because of its property as good oxygen barrier. There was significant difference in color difference and moisture content for film coated potato as compared to control and sample treated with ascorbic acid (2%) and bisulfide (0.2%), after 24 hour of storage, at both temperature conditions, ambient temperature (28°C) and cool temperature (15°C). Color difference, brightness and sensory score of coated dried mango was nearest to raw material when compared with control and sample treated by bisulfide solution (0.2%) after drying as well as during storage at ambient temperature. In addition, after 8 weeks of storage coated sample had no sign of mold development as observed visually while mold development could be found on the surface of control after 2 weeks stored under the same condition. Color difference in coated lime was significantly lower than that of control after 9 days of storage at ambient temperature (28°C) and low temperature (12 - 15°C). However, the weight loss of both types of sample did not differ much. |