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Browsing Revistas científicas by Subject "Ácido ascórbico"
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Item Cinética de degradación térmica de vitamina C en frutos de guayaba (Psidium guajava L.)(Corporación Universitaria Lasallista, Editorial Lasallista, 2013) Ordóñez Santos, Luis Eduardo; Ospina Portilla, María Alejandra; Rodríguez Rodríguez, Diana XimenaVitamin C is an essential micro nu-trient in human nutrition because it is associated to the synthesis of different molecules that are impor-tant for human health and to its antioxidant effect which reduces the risk of having several types of cancer, according to many epidemiological studies. Its final concentration is considered as an indicator of nutritional quality during the food processing and storage. objective. Evaluate the thermal degra-dation kinetics of vitamin C in guava fruits, within a temperature range between 75-95 °C. Materials and methods. 0,53 cm thick x 6.10 cm diameter guava slices were subjected to thermal treatments (75, 85 and 95 °C during 10, 20, 30 and 40 minutes) in a jacketed kettle at atmospheric pressure. The vitamin C concentration in the samples before and after the thermal treatment were determined by the use of the 2,6 - dichlorophenol-indophenol method. results. After the thermal treatments (75-95 °C), the vitamin C concentration in the guava fruits was reduced in percentages between 56,70-60 %, and its degradation speed and activation energy were k = 0,80-1,45 min-1 (R2 > 0,90), and Ea = 7,57 Kcal/mol, respectively. conclusion. The concentration of vitamin C measured in the guava fruits after the thermal treatments had a reduction as temperature increased and the time of the process and the kinetic parameters of this antioxidant were adjusted to first order kinetics and to the Arrhenius equation.Item Efectos de los tratamientos térmicos en la concentración de vitamina C y color superficial en tres frutas tropicales(Corporación Universitaria Lasallista, Editorial Lasallista, 2016) Cuastumal Canacuan, Hermes Gilberto; Valencia Murillo, Brillitte Lizeth; Ordóñez Santos, Luis EduardoVitamin C is known for its antioxidant properties and the surface color is an important sensory attribute that affects their purchase by the final consumer. Objective. To determine the effect of thermal treatments on the concentration of vitamin C and the surface color in guava (Psidium guajava), mango (Mangifera indica) and tree tomatoes (Solanum Betaceum Cav). Materials and methods.120 g of samples in triplicate and homogeneously cut, underwent baking treatments with water (92 ° C for 10 minutes), saturated steam (92 ° C for 10 minutes), microwave (760 W for two minutes) and oven (250 ° C for 10 minutes). Once the heat treatment was completed, the samples were cooled rapidly and the physicochemical properties of pH, acidity, soluble solids, vitamin C concentration and CIELab colorimetric coordinates were determined. Results. After the thermal treatments were performed, the oven heat method registered the largest vitamin C reduction in the guavas, while the cooking with steam and microwave did not affect the original concentration of this micronutrient. On the other hand, the heat treatments did not affect the superficial color of the mangos. In guavas the value of L*, was significantly reduced and in tree tomatoes all of the color variables were significantly affected. Conclusion. The method microwave cooking was the treatment less affected the final concentration of vitamin