Membrane Concentration Lab Report
Concentration of liquid foods is a fundamental operation in many food processes; it is completely different from dehydration. Usually, foods, which are concentrated, remain in the liquid state; while drying produces solid or semisolid foods with significantly lower water content. The concentration of liquid foods has three different methods; evaporation, membrane concentration, and freeze concentration. Evaporation usages gas liquid phase separation. It has the lowest capital cost and the maximum concentration for freeze concentration is more than 50 Brix. Membrane concentration can be used for separating components of foods on a molecular basis, where the foods are in solution and where a solution is separated from one less concentrated by
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So, there are the advantages, 100 % aroma retention in the freeze concentration, extremely high quality of the freeze concentration, no thermal degradation of the food during its freeze concentration, high hygienic standards due to the low temperature closed system, no intermediate cleaning of the plant required, the volume reduction also allows for considerable saving in packaging, storage, and transportation, frozen concentration juice with a stabilizer has a longer shelf - life (when stored at -20 0C) up to 9 -10 months (Pruthi, J. 1999), frozen concentration juice can be produced with less consumption of energy, and the ice produced can be the reused for the cooling of the incoming juice. While, the disadvantages of freeze concentration are when juice is frozen in continuous slush freezers and subsequently centrifuged, losses of soluble solids up to 5 percent are common and loss of suspended solids during freeze concentration has been more troublesome than loss of soluble solids.
4. Basic methods of freeze concentration There are two basic methods for ice crystal formation in solutions of liquid foods as shown in Fig 2, according to Aider et al. (2009), The first method is suspension crystallization figure 3a; it is containing on an initial phase of nucleation, followed by a second phase that includes the growth of ice nuclei in the solution. The second method is the film crystallization of water that present in the solution in the form of an ice layer on a cold surface (Flesland, 1995).
5. Suspension Freeze
So, there are the advantages, 100 % aroma retention in the freeze concentration, extremely high quality of the freeze concentration, no thermal degradation of the food during its freeze concentration, high hygienic standards due to the low temperature closed system, no intermediate cleaning of the plant required, the volume reduction also allows for considerable saving in packaging, storage, and transportation, frozen concentration juice with a stabilizer has a longer shelf - life (when stored at -20 0C) up to 9 -10 months (Pruthi, J. 1999), frozen concentration juice can be produced with less consumption of energy, and the ice produced can be the reused for the cooling of the incoming juice. While, the disadvantages of freeze concentration are when juice is frozen in continuous slush freezers and subsequently centrifuged, losses of soluble solids up to 5 percent are common and loss of suspended solids during freeze concentration has been more troublesome than loss of soluble solids.
4. Basic methods of freeze concentration There are two basic methods for ice crystal formation in solutions of liquid foods as shown in Fig 2, according to Aider et al. (2009), The first method is suspension crystallization figure 3a; it is containing on an initial phase of nucleation, followed by a second phase that includes the growth of ice nuclei in the solution. The second method is the film crystallization of water that present in the solution in the form of an ice layer on a cold surface (Flesland, 1995).
5. Suspension Freeze