73C-30 |
Mass transfer during osmotic dehydration of sardine (Sardinella aurita ) |
G. V. REYES1, O. Corzo, and N. Bracho. (1) Dept. of Food Technology, Universidad de Oriente, Nucleo de Nueva Esparta, ECAM, PO Box 147, Porlamar, Venezuela Sardine is the main fishery resource in Venezuela. Osmotic dehydration (OD) is a water removal process based on placing foods in a hypertonic solution. OD has been studied extensively in fruit and vegetables but not in fish. When pieces of fish are immersed in saturated brines, considerable mass transfer takes place, specifically water loss and salt gain with concomitant weight loss. Our objective was to study mass transfer in osmotically dehydrated sardine sheets (ODSS) and to determine the diffusion coefficient of water (DCW) at different brine concentrations and temperatures. Eight experimental groups (EG) of four sardine sheets (SS) each were set up. One EG was used to determine initial moisture and salt content. 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of 20 min during the first hour, 30 min during the second hour and 1h for the rest of the treatment, the SS were withdrawn and blotted with paper to remove adhering brine. The SS were weighed and final moisture and salt content were determined. SS were osmotically dehydrated at the following brine solutions 15,18,21,24,27% and temperatures 30,32,34,36,38°C. Mass changes were fitted to Peleg equation, R2 statistic varied from 65.17% to 96.74% (p £0.05), its constant K2 decreased (p £0.05)at brine concentrations ³ 18%. DCW was determined at different combinations of brine concentrations and temperatures, R2 varied from 67.62% to 94.32% (p £0.05). The DCW did not vary (p>0.05) with concentration and temperature. Models of prediction of salt gain, water loss and weight reduction were obtained, R2 varied from 0.9187 to 0.9808 (p £0.05)and the Durbin-Watson statistic from 1.430 to 1.577. These results indicate that the fitted models can be used to predict the mass transfer of ODSS at a given set of conditions used in this study.
Session 73C, Food Engineering: Transport Processes and Kinetics
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