Fruit juice concentration

While theoretical compressor power requirements are reduced slightly by going to lower evaporating temperatures, the volume of vapor to be compressed and hence compressor size and cost increase so rapidly that low-temperature operation is more expensive than high-temperature operation. The requirement of low temperature for fruit-juice concentration has led to the development of an evaporator... 

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. 

J.-P. Goiffon, P.P. Mouly and E.M. Gaydou, Anthocyanic pigments in red fruit juices, concentrated juices and syrups using liquid chromatography. Anal. Chim. Acta 382 (1999) 39-50. 

Hydrolysis of mannan-type polysaccharides by P-mannanase is dependent on substitution on and within the main-chain as well as the source of the P-mannanase employed. Characterisation of reaction products can be used to define the sub-site binding requirements of the enzymes as well as the fine-structures of the polysaccharides. Action of c/xt/o-arabinanase and em/o-galactanase on arabinans and arabinogalactans is described. Specific assays for ndo-arabinanase and arabinan (in fruit-juice concentrates) are reported. 

Measurement of Arabinan. Excess quantities of arabinan in fruit juice can lead (after prolonged storage) to hazy fruit-juice concentrates. This problem can be resolved by ensuring that the pectinase preparation employed contains adequate levels of endo-arabinanase to hydrolyse the amounts of debranched arabinan likely to be present. A limiting factor is that currently, there are no methods available for the measurement of arabinan in fruit juice or juice concentrates. 

Figure 2. Enzymic measurement of a-L-arabinan in fruit-juice concentrates, (a) Effect of time of incubation of sample with arabinofuranosidase and ndo-arabinanase. Diluted pear juice concentrate (1 10 0.1 ml) or sugar beet arabinan solution (0.1 ml) was incubated with an aliquot (0.1 ml) of arabinofuranosidase (5 units) plus ndo-arabinanase (0.2 units) at 35 C and pH 4.0. Aliquots were analysed for arabinose. (b) Arabinose determination using the NAD-Galactose Dehydrogenase method. Arabinose solution (0.2 ml, 50 digrams) was incubated with Tris-HCl buffer (2.5 ml, pH 8.6), NAD (0.1 ml, 10 m ml) and galactose dehydrogenase (20/i, 140 milliunits) at 35°C. Absorbance (340 nm) was measured after various time intervals.

Fruit juice concentrates, ready to drink fruit juices (still and carbonated)... 

The world of aroma compounds is becoming more and more complex. In the early days people used aromatic products like fruit juices or fruit juice concentrates which were relatively weak and still close to the related foodstulf. Later, with more knowledge of separation techniques, infusions, extracts, oleoresins and absolutes ranging from weak to strong impact were used to impart aroma. Essential oils such as spice oils already had a very strong impact. Modern analytical technologies allowed the evaluation of the chemical compositions of extracts and essential oils, so that isolates either as powerful mixtures or even as single compounds could be obtained. 

Chuda, Y., H. Ono, M. Ohnishi-Kameyama, K. Matsumoto, T. Nagata, and Y. Kikuchi. 1999. Mumefural, citric acid derivative improving blood fluidity from fruit-juice concentrate of Japanese apricot (Prunus mume Sieb. et Zucc.). J. Agric. Food Chem. 47 828-831. 

Oxalic, citric, isocitric, gluconic, lactic, malic, fumade, quinic, acetic, succinic, formic, glycolic Beer, wine, and fruit juices (concentrates) AMINEX PHX 87H (300 X 7.8 mm) 65°C 0.005 M H2S04, pH 3.02 UV, 210 nm 73... 

Being a food bearing the reserved description fruit juice , concentrated fruit juice , fruit juice from concentrate or dehydrated or powdered fruit juice , it has not been prepared by adding to it ... 

Figure 3.7 Flow diagram of the fruit juice concentration process.

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. 

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],... 

Microfiltration, ultrafiltration, and nanofiltration are becoming standard in feed pretreatment for water desalination, wastewater treatment and fruit-juice concentration. 

Fruit juices, concentrated fruit juices (for direct consumption), and fruit nectars 0.05... 

Brix Passion fruit juice-concentrated Fruit juice-temperature effect 18.8... 

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. 

Sulc, D. Fruit juice concentration and aroma separation, Confructa., 28(3), 258, 1984. 

Rao, M.A. and Vitali, A.A. Fruit juice concentration and preservation. In Rahman MS. ed. Handbook of Food Preservation. Marcel Dekker, New York, 1999. 

This process is used industrially to desalinate sea water for the production of potable water. However, it can also be used for fruit juice concentration. The achievable concentration depends very much on the viscosity of the concentrate. If the viscosity is too high the process is not economical. Since this process is rather expensive due to the high cost equipment it can only be employed for speciality products. In the future new membrane types with larger flow capacities could improve the economy of the RO process. 

Salmonella, Vibrio parahaemolyti-cus, Clostridium botulinum, Serra-tia, Lactobacillus, Pediococcus, some molds, yeasts (Rhodotorula, Pichia) Some cheeses (cheddar, swiss, muenster, provolone), cured meat (ham), some fruit juice concentrates foods containing 55% (w/ w) sucrose or 12% sodium chloride. 

High juice content is defined by a content of more than 20% by weight in the final drink. In this category, the turbidity derives from a stable colloidal dispersion of fruit cells. Stability and quality of the final drink are mainly based on the quality of fruit juice concentrates formulated into the product. Additional stabilisers, mainly hydrocolloids, might be added. 

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