| Resumen: |
The main purpose of milk powder manufacturing is to transform raw milk, which is a perishable product, into a product with a shelf life of several years without substantial loss of quality. The successive heat treatments, traditionally used, cause damage to the main components, such as denaturation of whey proteins, changes in functional properties and a loss in nutritional value. In addition, the energy cost of milk powder processing is very high. Atomizers require hot air (> 175 °C) representing ~10% of the total energy consumption in the food industry. Electrospraying is proposed as an alternative method of depositing lactic solids without the application of heat. The important parameters for electrospray are basically four: solution viscosity, electric field, nozzle-collector distance and flow rate. In order to evaluate its technological potential, the degree of water extraction and the effect on proteins were analyzed at different concentration levels of initial milk solids and different electrospraying flow rates, keeping the voltage at 29 kV and the nozzle-collector distance at 10 cm. The Ca:P ratio was not altered in 24% milk. The diameter of the droplets was reduced by decreasing the flow rate and/or increasing the concentration of total solids. Finally, electrospraying, at a low flow rate, eliminated water significantly (p < 0. 05) without producing any effect on the structure of proteins (i. e. , caseins and whey proteins). In future, microbiological and enzymatic analyzes should be performed to stablish product shelf life. |
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