36E-43 |
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M. S. TAPIA1, F. J. Rodríguez2, M. A. Rojas-Graü3, and O. Martín-Belloso3. (1) Institute of Food Science and Technology, Univ. Central de Venezuela, PO Box 47097, Caracas, 1041-A, Venezuela, (2) Institute of Food Science and Technology, Venezuela, (3) Dept. of Food Technology, Univ. of Lleida, UTPV-CeRTA Av. Alcalde Rovira Roure, 191Spain, Lleida, N/A 25198, Spain Edible coatings can reduce the deleterious effects imposed on fresh-cut fruits by minimal processing extending its refrigerated shelf life by reducing moisture loss, gas exchange and serving as carriers of food additives. The objective of this work was to formulate alginate and gellan based edible coatings for fresh-cut apples and papayas in combination with antioxidants compounds, that would be moderate barriers to water and gases transfer. Effect of the treatment with hydrophilic antioxidants on the resistance to water diffusion of the carbohydrate coatings on the fruit pieces was investigated along with the addition of sunflower oil. Film forming solutions from alginate (2% w/v) and gellan (0.5% w/v) were used. Antioxidants: citric acid (CA) and ascorbic acid (AA); cysteine (CYS) and gluthatione (GLU), were added to the dipping calcium chloride solution required for crosslinking of the carbohydrates polymers. Glycerol (G) was added as plasticizer in various concentrations. Coating formulations were investigated in two steps. A response surface analysis was first run in order to decide the final amounts of glycerol and antioxidants to incorporate into the formulations. Water vapor resistance -response variable- values ranged from 11.90 to 16.30 cm/s in both fruits. Selected alginate based-coating formulations for apple and papaya were 1.5%G, 1%CYS and 2%G, 1%AA, 1%CA respectively, and for gellan-based coatings were 0,60%G, 1%CYS, and 1%G, 1%AA, 1%CA, respectively. The addition of sunflower oil was investigated next. Solutions were emulsified with three different concentrations of sunflower oil (0.025, 0.05, and 0.125% w/v). Results of water vapor resistance showed that addition of sunflower helped improved barrier properties in coatings intended for fresh-cut fruits based on alginate and gellan polymers.
Session 36E, Fruit & Vegetable Products: General
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |