ارزیابی خواص مکانیکی و فیزیکی فیلم های خوراکی آلژینات کلسیم

In this study two film-forming formulations were prepared. First one was prepared by slowly adding 5gr of sodium alginate & 45gr of dextrose monohydrate in 270ml of distilled water which constantly stirred. Second formulation was as the firs one, but we substituted dextrose monohydrate by maltodextrine and added 20gr glycerol in 210ml distilled water. 50cc film solutions were extended on the 30*40cm polexy glass plates which covered by polyethylene selofan. Films dried after 45h in 23±2˚c & RH50±5%. The dried film layers were immersed for 30" in second solution that was prepared by slowly adding 2.74gr of calcium choloride & 0.9gr of carboxy methylcellulose in 49ml of distilled water which constantly stirred. Film thickness was measured using a digital micrometer at a 0.001mm accuracy. Mechanical properties including tensile strength (TS) and elongation at break (E) were evaluated by a Instron Machin (Zwick, ModelZ 2.5). Results had no statistical significant differences between 2 film formulations. Physical properties including WVP (Water Vapor Permeability) & OTR (Oxygen Transformation Rate) were measured. WVP results had no statistical significant differences between 2 film formulations but OTR in second formulation had a significant decrease. Finally, by all aspects like decrease moisture loss, lipid & myoglobin oxidation, volatile compounds loss and volatile compounds absorb during storage, we recognize second film formulation as a suitable one.