33A-20 |
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J. G. BÁEZ-GONZÁLEZ1, C. Pérez-Alonso1, J. P. Pérez-Orozco2, C. I. Beristain3, E. J. Vernon-Carter4, and M. G. Vizcarra-Mendoza5. (1) IPH, Universidad Autonoma Metropolitana-Iztapalapa, San Rafael Atlixco # 186, Mexico City, 09340, Mexico, (2) IPH and DIQBQ, Universidad Autonoma Metropolitana e Instituto Tecnológico Zacatepec, Zacatepec, Mexico, (3) Instituto de Ciencias Básicas, Univ. Veracruzana, Apartado Postal #575, Xalapa, Veracruz, 91000, Mexico, (4) IPH, Universidad Autónoma Metropolitana Iztapalapa, San Rafael Atlixco No. 186, Col. Vicentina, Mexico City, 09340, Mexico, (5) IPH, Universidad Autonoma Metropolitana, San Rafael Atlixco # 186, Mexico City, 09340, Mexico Oxidation of carotenoids may occur by auto-oxidation by free-radical chain reaction with oxygen or by photo-oxidation, produced by oxygen in the presence of light. Degradation of the carotenoids can be prevented providing them with a protective layer of biopolymers that deter the diffusion of oxidizing environmental factors. Microencapsulation by the spray-drying is a wide-spread technique which has been performed traditionally by empirically selecting the wall materials, and by drying the emulsion without consideration of the thermal properties of the biopolymers and of the material being encapsulated. The objective of this work was to determine the effect of two biopolymer blends deemed as providing an efficient encapsulation capacity and good protection against the oxidative degradation to carotenoids from red chili by a non-isothermal differential scanning calorimetry (DSC) technique. Two aqueous blends were made with different ratios of gum arabic (GA), mesquite gum (MG) and maldodextrin DE10 (MD): blend 1 (17%GA-66% MG-17%MD) and blend 2 (50%GA-50%MG). Oil-in-water emulsions were made with a ratio of wall material to core material of 4 to 1. The emulsions were dried in a mini Buchii spray-dryer. The measurements were performed using a dynamic temperature scan with heating rates of 5, 7.5 and 10 °C/min from 25 °C to 400 °C, and air flow 25 ml min-1. The maximum temperature value of the oxidation exotherm at the three heating rates studied was obtained and the parameters of Arrhenius equation were computed. Activation energy for microcapsule made with blend 1 was 117.7 kJ.mol-1, whereas that for microcapsules made with blend 2 was 62.2 kJ.mol-1. These results indicate that the composition of the biopolymer blend affects the structure of the wall matrix, and that blend 1 gave way to a more interwoven matrix
Session 33A, Carbohydrate: General
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