Juice concentration processes

A newer juice concentration process, requiring minimal heat treatment, has been appHed commercially in Japan to citms juice concentration. The pulp is separated from the juice by ultrafiltration and pasteurized. The clarified juice containing the volatile flavorings is concentrated at 10°C by reverse osmosis (qv) and the concentrate and pulp are recombined to produce a 42—51 °Brix citms juice concentrate. The flavor of this concentrate has been judged superior to that of commercially available concentrate, and close to that of fresh juice (11). 

Figure 3.7 Flow diagram of the fruit juice concentration process.

Gollucke APB, Catharino RR, de Souza JC, Eberlin MN and de Queiroz Tavares D. 2008. Evolution of major phenolic components and radical scavenging activity of grape juices through concentration process and storage. Food Chem 112(4) 868—873. 

Maltini, E., Torreggiani, D., Fomi, E., and Lattuada, R. 1990. Osmotic properties of fruit juice concentrates. In Engineering and Food Physical Properties and Process Control (W.L.E. Spiess and H. Schubert, eds), Vol. 1, pp. 567-573. Elsevier Science, London. 

Herbal preparations are defined as preparations obtained by subjecting herbal substances to treatments such as extraction, distillation, expression, fractionation, purification, concentration or fermentation. These include comminuted or powdered herbal substances, tinctures, extracts, essential oils, expressed juices and processed exudates. 

The development of the freeze concentration process for fruit juices has been hampered by the fact that solute concentrate is entrained by the ice crystals. This incomplete separation of the entrained concentrate from the ice results in a considerable increase of the cost of the process. In this investigation sucrose solutions were concentrated by the formation of an ice layer on the externally cooled walls of the crystallizer. The formation of the layer was initiated by secondary nuclei induced by rotating ice seeds, at subcoolings smaller than the critical subcooling needed for spontaneous nucleation. A minimum in the amount of sucrose entrapped in the ice layer was observed at a subcooling smaller than the critical subcooling for spontaneous nucleation. The effect of soluble pectins on the minimum was also studied. 

The application of the fteeze concentration process has been successful in various cases such as the preconcentration of wine (. The application of the process for the concentration of fruit juices, which are mainly consumed for their flavor and taste, seems to be ideal because of the improved volatile retention. Nevertheless, the process is not as widely accepted because of its increased economic r uirements. These are related to the difficulty of effectively separating the resulting solid phase from the liquid phase (mother liquor). The formation of a large number of very fine... 

When the final juice product is a concentrate, the clear filtered or cleaned cloudy juices are automatically subjected to heat treatment during the course of their concentration. (Figure 3.7 provides on overview of the concentration process.) Heat treatment of juices is an area where the design of process requires careful consideration in order to avoid any detrimental effects on flavour and appearance of the product. Early evaporators had demonstrated that high-vacuum-low-temperature processing produced concentrate of good flavour quality, but it was soon discovered that there was a drawback in that the heat treatment was insufficient to deactivate pectin methylesterase, which gave rise... 

Quality can be regarded as a measure of the suitability of a fruit juice, fruit juice concentrate or fruit juice extract for an intended application. In general, whatever the application, it will be the consistency in performance of the product, from batch to batch and season to season, that is the prime concern. In order to meet quality targets, therefore, it becomes critical that processing is carried out in the correct manner using fruit of an optimum level of maturity, and that the product is stored under suitable conditions to limit effects of degradation during a required shelf-life. 

Introduction. Air becomes incorporated into juice during processing or upon reconstitution of concentrates. The incorporated air must be removed if the Brix of the juice is to be determined by hydrometer. It is essential to deaerate juice when determining the color with a colorimeter. The color is slightly less affected by air when visual comparisons are made. 

The RO potentialities as a concentration technique to remove water from fruit juices for the production of high-quality fruit-juice concentrate are well known [24], The most relevant advantages of the RO process over traditional evaporation are in the reduced thermal damage of the product, increase of aroma retention, and lower energy consumption, since the process is carried out at low temperature. 

Figure 12.7 Scheme of an integrated membrane process for fruit-juice concentration [26],... 

Endogenous pectin esterases play an important role in citrus processing they have therefore been studied intensively. They cause cloud loss in citrus juices, which is due to the calcium precipitation of enzymatically de-esterified pectin. This is desirable in the production of lemon and lime juices but undesirable in the production of orange juice. In orange juice concentrates strong calcium pectate gels may form which cannot be reconstituted... 

Improve yield of press juices, prevent cloudiness, improve concentration processes Extraction of oil Clarification... 

Citrus essences are distilled aqueous solutions of the more volatile components from the corresponding citms juices, as defined by Shaw (10). Commercially, they are added to concentrated citms juices to impart fresh fmit flavor that may be lost during the concentration process. Essence may be collected from fresh juice either by partial distillation prior to juice evaporation or by condensation of volatiles from the early stages of evaporation (11). Two phases, namely, aqueous essence and essence oil, are obtained during recovery. 

FIGURE 2.15 (See color insert following page 588.) Membrane contactor for fruit juice concentration using membrane distillation process. 

Alves VD and Coelheso IM, Low temperature membrane processes for fruit juice concentration. Euromembrane 2004, Hamburg, Germany, September 28-October 1, 2004. 

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