Cloudy concentrates

Low juice content is defined by a content of 1 to 20% by weight of juice in the final drink. These products are mainly based on citrus juices. As mentioned before, citms juices provide good turbidity and stability even with low juice content. In combination with special raw materials made from citrus, like cloudy concentrates or peel oils, very stable low-juice drinks can be obtained. Turbidity comes from a complex mixture of dispersions of fruit cells and oil-in-water emulsions, stabilised by fruit pulp particles and hydrocolloid stabilisers, such as locust bean gum [9]. 

Gyanoacetamide. Place 150 ml. of concentrated aqueous ammonia solution (sp. gr. 0-88) in a 500 ml. wide-mouthed conical flask and add 200 g. (188 ml.) of ethyl cyanoacetate. Shake the cloudy mixture some heat is evolved and it becomes clear in about 3 minutes. Stand the loosely stoppered flask in an ice-salt mixture for 1 hour, filter rapidly with suction, and ash the solid with two 25 ml. portions of ice-cold ethanol. Dry in the air the yield of pale yellow cyanoacetamide is 110 g. (1). Recrystallise from 190 ml. of 95 per cent, ethanol a colourless product, m.p. 119-120 , is deposited with practically no loss. 

To recover the free base, dissolve the hydrochloride in the minimum volume of boiling alcohol, add concentrated ammonia solution dropwise until a clear solution results and the blue colour has become fight brown. Add water carefully untU a cloudiness appears, warm on a water bath untU the cloudiness just disappears, and allow to cool. Yellow crystals of p-amino-azobenzene separate on coofing. 

The acetone test reagent consists of a 0 1 per cent, solution of 2 4-dinitro-phenylhydrazine and is prepared as follows Dissolve 0-25 g. of 2 4-dinitrophenyl-hydrazine in 60 ml. of water and 42 ml. of concentrated hydrochloric acid by warming on a water bath cool the clear yellow solution and dilute to 250 ml. with water. The acetone test is considered negative when 5 ml. of the reagent and 4-5 drops of the distillate give no cloudiness or precipitate of acetone 2 4-dinitro-phenylhydrazone within 30 seconds. After a negative test is obtained, it is stron y recommended that the mixture in the flask be refluxed for 5-10 minutes with complete condensation and then to collect a few drops of distillate for another test. If no acetone is now detected, the reduction is complete. 

In the extraction of citms juices it is desirable to have as gende an extraction pressure as possible. There should be minimal contact time between juice and pulp to reduce the amount of bitter substances expressed from the peel into the juice. The amount of suspended soHds in citms juice is controlled in a subsequent separation in a finisher. A screw action is used to force the juice through a perforated screen and separate the larger pulp particles from the juice. The oil level in the juice is adjusted by vaporizing under a vacuum (10). The separated pulp is washed and finished several times to produce a solution which is then either added back to the juice to increase juice yield, or concentrated to produce pulp wash soHds, also called water extract of orange soHds, which can be used as a cloudy beverage base. 

Tempera.ture Effect. Near the boiling point of water, the solubiUty—temperature relationship undergoes an abmpt inversion. Over a narrow temperature range, solutions become cloudy and the polymer precipitates the polymer caimot dissolve in water above this precipitation temperature. In Figure 4, this limit or cloud point is shown as a function of polymer concentration for poly(ethylene oxide) of 2 x 10 molecular weight. 

Unlike solar thermal systems or PV concentrator systems, the PV flat plate systems work well in cloudy locations because these latter convert diffuse as well as direct sunlight to electricity. On an aimualized basis, the energy produced by a photovoltaic array varies by only about 25% from an average value for the contiguous 48 states of the United States. As a result, it is practical to use photovoltaic systems in normally cloudy locations such as Seattle or northern Maine. 

Settling does not give a complete separation one product is a con-centratea suspension and the other is a hquid which may contain fine particles of suspended sohds. However, settling is often the best way to process veiy large volumes of a dilute suspension and remove most of the hquid. The concentrated suspension can then be filtered with smaller equipment than would be needed to filter the original dilute suspension, and the cloudy liquid can be clarified if necessaiy. Settlers can also be used for classifying particles by size or density, which is usually not possible with filtration. 

C. i-Melhyllhiol-yphthalamidapropane-2,2,-dicarboxylic Acid. —A solution of 25 g. (0.066 mole) of the above ester in 30 cc. of 95 per cent alcohol is heated on the steam bath in a 200-cc. round-bottomed flask, and 70 cc. of 5 A sodium hydroxide is added. The cloudy liquid is heated until a sample gives a clear solution on dilution with water this occurs after about two hours. The solution is then chilled to 0 and cautiously neutralized to Congo red with 0.2 N hydrochloric acid, whereupon 75 cc. of 5 A hydrochloric acid is slowly added, the temperature being maintained at 0°. The acid separates as colorless crystals. This separation is completed by the slow addition of 60 cc. of concentrated hydrochloric acid (sp. gr. 1.19). The product is filtered by suction and v ashed free of salt with small quantities of ice-cold water. After drying in vacuo, the yield amounts to 21.5-22 g. (95.5-98 per cent of the theoretical amount) of a product melting at 141-143°. 

Pernod is a transparent yellow fluid consisting of water, alcohol and Evil Esters. The Evil Esters dissolve in strong water-alcohol solutions but precipitate out as tiny whitish droplets if the solution is diluted with more water. It is observed that Pernod turns cloudy at 60 wt% water at 0°C, at 70 wt% water at 20°C, and at 85 wt% water at 40°C. Using axes of T and concentration of water in wt%, sketch an approximate phase diagram (Fig. A1.3) for the Pernod-water system, indicating the single-phase and two-phase fields. 

Cooling is effected in the ice-bath while slowly adding concentrated HCI up to a pH of 2, while maintaining the temperature around 5°C. It is filtered and an equal volume of HjO is added. If the solution is cloudy it is washed in ether. It is alkalized by aqueous NaOH (40%), and the oil formed is extracted with ether. The ether phase is washed with water saturated with NaCI, then it is dried over anhydrous NajS04. 

The crude liquid acid (about 300 g.) is cooled with running water and 15 cc. of concentrated sulfuric acid is added the clear yellow oil becomes cloudy. The acid is esterified by the method described in Org. Syn. 3, 54, with the following changes all three flasks, the alcohol flask, the trap, and the esterification flask are i-l. round-bottom wide-neck flasks. The alcohol flask and the trap are set on adjacent steam baths. The esterification flask is placed in an oil bath which is heated by a free flame. A safety tube leads from the alcohol flask and dips under 7.5 cm. of mercury contained in a side-arm tube. 

The construction of calibration curves is recommended in nephelometric and turbidimetric determinations, since the relationship between the optical properties of the suspension and the concentration of the disperse phase is, at best, semi-empirical. If the cloudiness or turbidity is to be reproducible, the utmost care must be taken in its preparation. The precipitate must be very fine, so as not to settle rapidly. The intensity of the scattered light depends upon the number and the size of the particles in suspension, and provided that the average size of particles is fairly reproducible, analytical applications are possible. 

Purification of photoprotein. The dialyzed photoprotein solution was centrifuged to remove precipitates, and then subjected to fractional precipitation by ammonium sulfate, taking a fraction precipitated between 30% and 50% saturation. The protein precipitate was dissolved in 50 ml of 10 mM sodium phosphate, pH 6.0, containing 0.1 mM oxine ( pH 6.0 buffer ), dialyzed against the same buffer, and the dialyzed solution was adsorbed on a column of DEAE-cellulose (2.5 x 13 cm) prepared with the pH 6.0 buffer. The elution was done by a stepwise increase of NaCl concentration. The photoprotein was eluted at 0.2-0.25 M NaCl and a cloudy substance (cofactor 1) was eluted at about 0.5 M NaCl. The photoprotein fraction was further purified on a column of Sephadex G-200 or Ultrogel AcA 34 (1.6 x 80 cm) using the pH 6.0 buffer that contained 0.5 M NaCl. 

An increased hydrogen ion concentration, that is a considerably greater amount of acid than the theoretical two equivalents of Scheme 2-1, is necessary in the diazotization of weakly basic amines. The classic example of this is the preparation of 4-nitrobenzenediazonium ions 4-nitroaniline is dissolved in hot 5-10 m HC1 to convert it into the anilinium ion and the solution is either cooled quickly or poured onto ice. In this way the anilinium chloride is precipitated before hydrolysis to the base can occur. On immediate addition of nitrite, smooth diazotization can be obtained. The diazonium salt solution formed should be practically clear and should not become cloudy on standing in the dark. Some practice is necessary, and details can be found in the books emphasizing preparative aspects (Fierz-David and Blangey, 1952 Saunders and Allen, 1985 in Houben-Weyl, Vol. E 16a, Part II, the chapter written by Engel, 1990). These books give a series of detailed prescriptions for specific examples and a useful review of the principal variations of the methods of diazotization. Such reviews have also been written by Putter (1965) and Schank (1975). 

TsCl was obtained from Aldrich Chemical Company, Inc. and purified by recrystallization according to the following procedure. p-Toluenesulfonyl chloride (85 g) is dissolved in 150 mL of hot CHC13 and 200 ml. of petroleum ether (room temperature) is added in one portion to the clear, colorless solution. The resulting cloudy solution is clarified by addition of ca. 5 g of charcoal, stirred for 1 min, and filtered on a Buchner funnel. The filtrate is concentrated to ca. l/5th of its original volume by rotary evaporation, and the solid which appears is collected by filtration and dried under reduced pressure (25° C, 0.03 mm) to afford 68 g of TsCl as bright white crystals. 

B. 3-(4,4,5,5-Tetramethyl-[l,3,2]dioxaborolan-2-yl)pyridine. A 250-mL, one-necked, round-bottomed flask equipped with a magnetic stirbar and a Dean-Stark trap fitted with a condenser capped with a nitrogen inlet adaptor is charged with tris(3-pyridyl)boroxin-0.85 H20 (3.0 g, 9.1 mmol), pinacol (4.07 g, 34.4 mmol) (Note 6), and 120 mL of toluene. The solution is heated at reflux for 2.5 hr in a 120°C oil bath. The reaction is complete when the mixture changes from cloudy-white to clear. The solution is then concentrated under reduced pressure on a rotary evaporator to afford a solid residue. This solid is suspended in 15 mL of cyclohexane (Note 7) and the slurry is heated to 85°C, stirred at this temperature for 30 min, and then allowed to cool slowly to room temperature. The slurry is filtered, rinsed twice using the mother liquors, washed with 3 mL of cyclohexane, and dried under vacuum to afford 4.59 g (82%) of 3-pyridylboronic acid pinacol ester as a white solid (Note 8). 

Chitin films can be manufactured from DMAc solutions or by other approaches, for example, blend films of beta-chitin (derived from squid pens) and poly(vinyl alcohol) (PVA) were prepared by a solution casting technique from corresponding solutions of beta-chitin and PVA in concentrated formic acid. Upon evaporation of the solvent, the film having 50/50 composition was found to be cloudy [224]. 

Fig. 16-4 pH sensitivity to SO4- and NH4. Model calculations of expected pH of cloud water or rainwater for cloud liquid water content of 0.5 g/m. 100 pptv SO2, 330 ppmv CO2, and NO3. The abscissa shows the assumed input of aerosol sulfate in fig/m and the ordinate shows the calculated equilibrium pH. Each line corresponds to the indicated amoimt of total NH3 + NH4 in imits of fig/m of cloudy air. Solid lines are at 278 K, dashed ones are at 298 K. The familiar shape of titration curves is evident, with a steep drop in pH as the anion concentration increases due to increased input of H2SO4. (From Charlson, R. J., C. H. Twohy and P. K. Quinn, Physical Influences of Altitude on the Chemical Properties of Clouds and of Water Deposited from the Atmosphere." NATO Advanced Research Workshop Acid Deposition Processes at High Elevation Sites, Sept. 1986. Edinburgh, Scotland.)... 

About 40 millions tons of apples are gathered per year and about 10% are processed mostly to produce clear concentrate but a little part as cloudy juice. The aim of pectinases application is to increase the plants productivity by processing apples quantity as high as possible along the season with high yields (see Table 2). 

The pineapple fruit is mainly processed for canning as slices or cubes. After cutting, the residual pulp is removed from the peel for cloudy juice production. Then, by-products are used to produce clear juice for slices cover or as clear concentrate. In the process of clear juice, by-products are crushed and pressed. The juice is pasteurized, cooled down and depectinized with enzymes at 50°C before ultra-filtration and concentration... 

Pulp from ripe Golden apple was pressed in a mortar and filtered, thus obtaining a cloudy and dense juice. Potassium metabisulphite was added as antioxidant at a final concentration of 0.15 mg/mL. The pH of the prepared apple juices was 4.1 4.3. Depectinisation experiments were carried out loading the juice in the packed bed reactor and recycling for 30 min at 25 "C. The reaction mixture was then collected and the percentage reduction of viscosity measured as above described. The y-alumina spheres were abundantly washed with distilled water before performing the successive batch reaction. 

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