SummaryThe viscoelastic properties provide guidelines to help give meaning to the observations on food products, to relate them to the way in which their structures behave, and to predict or modify their properties. This study analyses the incidence of varying the initial fat content of goat milk on the rheological properties of prepared sour cream. Storage (G 0 ) and loss modulus (G″), as well as complex viscosity (g*) and loss factor values (tan d), were determined at different initial fat contents in goat milk (3.75%, 4.00% and 4.25%). The experimental data were adapted to Maxwell model. All the prepared samples of sour cream meet national and international microbiological standards, and the initial fat content of goat milk influenced the viscoelastic behaviour of sour cream. Structures with prevalent elastic (G 0 ) behaviour were found, and the product that was prepared from goat milk with 4.00% fat content showed the highest elastic modules. This sour cream exhibited higher firmness and better adherence when compared to the samples that were obtained from 3.75% and 4.25% fat-content milk. This sample also exhibited the lowest tangent of the phase angle. Sour cream that was prepared from milk with higher fat content (4.00% and 4.25%) exhibited a semi-solid behaviour along the entire temperature range that was studied. On the contrary, rheological properties of sour cream from 3.75% fat-content milk tend to increase at temperatures above 333.15 K. The viscoelastic behaviour of sour cream was successfully explained under Maxwell model, while data from dynamic viscosity (g 0 ) were adapted to Arrhenius model. Microstructure analysis to the sample considered as the best (from milk with 4.00% of initial fat content) showed that the protein network presented a rough, open surface with aggregates and wide spaces.

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Abstract-The objective of this research was to determinate the moisture and oil thermal diffusivity coefficients in the breadfruit vacuum frying in control, blanched and coated samples. Mass transfer coefficients were determined from the graphs of dimensional temperature and moisture content ratios vs. time, and the specific oil absorption rate was calculated using a first-order kinetic model.It was observed that the diffusion coefficient increased with increasing temperatures for all treatments.For coated samples, the specific oil absorption rate increased with temperature. In this study, it was reported that the treatment that reported the greatest diffusion E a was pectin-coated.

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<p>El objetivo de globalizar el consumo de los alimentos<br />autóctonos es contribuir al aumento de la exportación y<br />a la propagación de las diferentes culturas alimentarias.<br />En el mercado mundial, no obstante, la competencia es<br />fuerte y se requiere que los productos sean diferentes<br />con el fin de no perecer. Actualmente, la sociedad<br />demanda productos naturales con menos aditivos<br />químicos, de modo que los productores de alimentos<br />se han visto en la necesidad de evitar al máximo el uso<br />de antimicrobianos químicos y de adoptar alternativas<br />naturales para el mantenimiento o extensión de la vida<br />útil de sus productos. El propósito de esta investigación<br />Palabras clave: avenas, Cinnamomum verum, Córdoba (Colombia), preservación de alimentos, procesamiento de<br />alimentos, Syzygium aromaticum<br />fue evaluar el tiempo de vida útil de la avena sinuana,<br />una bebida autóctona del departamento de Córdoba<br />(Colombia), adicionada con clavo (Syzygium aromaticum)<br />y canela (Cinnamomum verum) en tres concentraciones<br />diferentes (0,073, 0,146 y 0,219 % v/v), envasada<br />en frascos de plástico (PET) y de vidrio de 500 mL,<br />almacenados a 4 °C durante 15 días. A los datos se<br />les aplicó un análisis de varianza y prueba de<br />comparación de Tukey (p≤0,05), utilizando el paquete<br />estadístico SAS. La avena con la concentración más<br />alta de especias (0,219 % v/v) logró un mayor tiempo<br />de almacenamiento.</p>