Abstract:
This is a report of developing edible films from local obtainable biopolymers, gelatin and chitosan, for extending storage life of pomelo pulps cv. Khao-Namphueng. The films were fabricated using gelatin and chitosan using various compositions, ranged from 1 2 %w/v and a plasticisizer, sorbitol, 0.2 0.6 %w/v. Their physical and mechanical properties were studied. The modified films had tensile strength, %elongation, water vapor permeability and glass transition temperature (Tg) in the range of 0.13 10.45 MPa, 11.9 233.6 %, 2.08 4.67 g-m/m2-s-Pa and -14.18 to 58.30 °C respectively. Then, Three formulations of films were selected to use for coating on pomelo plups (cv. Khao-Namphueng) at 21.24 ml solutions/1 kg. Pomelo pulps were stored at 5 °C, and 80% relative humidity for the 21 days. Overall qualities of pomelo pulps coated with edible films were higher than that of the control group (non-coating). The most effective formula for coating pomelo pulps composed of 2% gelatin, 1.5% chitosan, and 0.4% sorbitol (w/v). Results from the experiments showed this formulation was able to keep acceptable quality of pomelo pulps for at least 21 days at 5 °C and 80% relative humidity. This film reduced weight loss by 8.24%, compared to the uncoated pulps. The coated fruit showed no abnormal smells nor tastes. However, respiration rate, ethylene the pulp color, firmness, soluble solid contents, and acid contents of coated pulps were not significantly different from those without coatings. The result could be a promising way for invisible. Edible films produced in this project has promising quality for extending the shelf-life pomelo pulps and can be use as basis for developing edible coating films for other pomelo varieties.