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The aim of this work was to study the effect of milk supplementation with lactoferrin of different iron saturation on the manufacturing and characteristics of yogurt. Bovine lactoferrin was added at concentrations of 0.5, 1, and 2 mg/mL in the holo (iron saturated) and apo (without iron) forms. Some physicochemical properties, such as pH, concentration of lactic acid, and texture of supplemented yogurts, were determined throughout the shelf-life period storage (28 d) at 4°C. We also evaluated the stability of lactoferrin in supplemented yogurt throughout the storage time. The supplementation of milk with bovine lactoferrin did not greatly affect the physical properties of the yogurt, though apo-lactoferrin slightly delayed the decrease of pH. This could be attributed to the partial inhibition observed on the growth of Streptococcus thermophilus. The integrity and immunoreactive concentration of lactoferrin, determined by Western blotting and noncompetitive ELISA, respectively, remained constant throughout the shelf life of yogurt.

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RESUMENEfectividad de antioxidantes naturales adicionados a aceite de girasol..Se investigó la actividad antioxidante de ∝-tocoferol, δ-tocoferol, ácido cítrico y palmitato de ascorbilo en aceite de girasol con su conteniendo natural de tocoferol. La efectividad de los mismos fue analizada a través de la medida de la estabilidad oxidativa en Rancimat y el seguimiento de la oxidación con el almacenamiento a diferentes temperaturas. Las muestras extraídas periódicamen-te de la estufa fueron sometidas a los siguientes análisis: índice de peróxidos, valor de p-anisidina, contenido y distribución de compuestos polares y contenido residual de tocoferol natural. La efectividad de cada antioxidante resultó fuertemente dependiente de la temperatura y método de ensayo. Mientras el ácido ascórbi-co resultó ser el antioxidante más efectivo según el índice de estabilidad oxidativa medido en el equipo Rancimat, el δ-tocoferol fue el antioxidante más efectivo en las experiencias de almacenamiento.PALABRAS-CLAVE: Aceite de girasol -Antioxidantes naturales -Autooxidación -Compuestos polares.. SUMMARY Effectiveness of added natural antioxidants in sunflower oil.The antioxidant activity of ∝-and δ-tocopherol, citric acid, ascorbic acid and ascorbyl palmitate was investigated in sunflower oil containing naturally occurring tocopherol. The effectiveness of natural antioxidants in sunflower oil was monitored by the accelerated oxidative stability test Rancimat and oxidation development during storage under different conditions. Samples in storage experiments were periodically removed and analyzed for peroxide value, p-anisidine value, total content and distribution of polar compounds, and residual naturally occurring tocopherol. The effectiveness of each antioxidant was strongly dependent on temperature and the testing method. While ascorbic acid appears to be the most effective antioxidant according to the Rancimat oxidative stability index, δ-tocopherol shows improved performance when considering storage experiments.

The effect of high-pressure treatment (400, 500 and 650 MPa) on the structure and activity of bovine lactoferrin in different iron-saturation forms has been studied by several techniques. The structural changes produced in lactoferrin by high-pressure were analysed by differential scanning calorimetry and fluorescence spectroscopy, and the immunoreactivity by ELISA. The effect of high-pressure was also studied on some biological properties of lactoferrin, such as iron binding capacity, retention of the bound iron, and antibacterial activity against Escherichia coli O157:H7. Results obtained indicate that treatment at 400 MPa does not substantially modify the conformation of lactoferrin, meanwhile treatments at 500 and 650 MPa greatly affect some of its properties. With respect to the antibacterial activity, the apo and native forms of lactoferrin maintain that activity against Esch. coli only after 400 MPa treatment.

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En Panamá el camote es biofortificado con vitamina A para disminuir trastornos a causa de su deficiencia, sin embargo, no se ha evaluado la concentración necesaria del micronutriente en el tubérculo a fin de erradicar enfermedades por insuficiencia o exceso. Es necesario recopilar y presentar información científica que valide la necesidad de indagar experimentalmente las secuelas de ingerir dosis innecesarias de la vitamina a largo plazo. Para esto, se acudió a material bibliográfico y a instituciones involucradas en el proyecto, además se realizaron cuadros comparativos de morbilidad en niños de cero a cuatro años y tablas donde se plasmaron las cantidades de camote que sugiere consumir y los requerimientos nutricionales actuales. Se recomienda realizar estudios de toxicidad crónica y capacitar a las poblaciones con acceso al camote biofortificado.