30D-25 |
Color and texture changes during osmotic dehydration of sardine ( Sardinella aurita) sheets |
G. V. REYES1, O. Corzo, and N. Bracho. (1) Dept. of Food Technology, Universidad de Oriente, Calle C, Urb. Rincon de la Ceiba, Atamo Sur, La Asuncion, Edo. Nueva Esparta, 6311 Osmotic dehydration (OD) is a water removal process which is based on placing foods in a hypertonic solution. OD has been extensively studied in fruit and vegetables but no in fish. When pieces of fish are placed in saturated brines, two main fluxes occur: the uptake of NaCl and the loss of water. This mass transfer phenomenon affects texture and color of the pieces of fish. In this study sardine was used because it is the main fishery resource in Venezuela. Our objective was to analyze texture and color changes during OD of sardine sheets (SS) Eight experimental groups (EG) of four SS were set up. One EG was used to determine initial firmness and color. Seven EG were simultaneously immersed in different brine concentrations at prefixed temperatures. At intervals of 20 min during the first hour, 30 min during the second hour and 1h for the rest of the treatment, the SS were withdrawn and blotted with paper to remove adhering brine. Firmness of SS was measured by a texture analyzer. SS were homogenized with a mortar, placed in a Petri dish and color parameters (L, a, b) were measured. SS were osmotically dehydrated at the following brine solutions 15,18,21,24,27% and temperatures 30,32,34,36,38°C. Data were analyzed by ANOVA and multiple linear regression. ANOVA showed that color (L, a, b) and firmness values of the SS were significantly affected (p£0.05) by brine concentrations and temperatures and immersion time. The fitted model of firmness explained 88.09 % of its variability (p£0.05), it neither presented lack of fit (p>0.05), nor autocorrelation (Durbin-Watson=1.444). None simple mathematical model of prediction of color changes was found. Results indicate that the fitted model can be used to predict the firmness of osmotically dehydrated sardine sheets at the given set of conditions used in this study.
Session 30D, Food Engineering: Physical and chemical properties
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