Water dried pears

Water-Sorption Isotherms and Water-Plasticization Effect in Dried Pear... 

The obtained relationships will allow us to know the critical water content (CWC) and the critical water activity (CWA) at which the glass transition in the water-soluble phase occurs at a determined storage temperature of the product. Above these values, this phase in dried pear become sticky and rubber, and the crystallization of the amorphous compounds could take place. At 30°C (temperature at which the isotherms were obtained). 

NUTRITIONAL VALUE. Fresh pears contain 83% water. Additionally, each 100 g (about 3 1/2 oz) provides 61 Calories (kcal) of energy, 130 mg of potassium, and only 2 mg of sodium. The calories in pears are derived primarily from the sugars (carbohydrate) which give pears a sweet taste. Pears canned in a syrup contain more calories due to the addition of sugar. Also, canning decreases the concentration of some mineral sand vitamins. Dried pears contain only 25% water hence, many of the nutrients, including calories, are more concentrated. More complete information regarding the nutritional value of fresh, canned, and dried pears is presented in Food Composition Table F-21. 

The crude ester is cooled, an equal volume of benzene is added, then the free acid is neutralized by shaking with about 250 cc. of a 10 per cent solution of sodium carbonate (Note 4). The benzene solution is poured into 1300 cc. of a saturated solution of sodium bisulfite (about 60 g. of technical sodium bisulfite per 100 cc.), contained in a wide-neck bottle equipped with an efficient stirrer, and the mixture stirred for two and a half hours. The mixture soon warms up a little and becomes semi-solid. It is filtered through a 20-cm. Buchner funnel and carefully washed, first with 200 cc. of a saturated solution of sodium bisulfite, finally with two 150-cc. portions of benzene (Notes 5 and 6). The white pearly flakes of the sodium bisulfite addition product are transferred to a 3-I. round-bottom wide-neck flask equipped with a mechanical stirrer and containing 700 cc. of water, 175 cc. of concentrated sulfuric acid, and 500 cc. of benzene. The flask is heated on a steam bath under a hood, the temperature being kept at 55°, and the mixture is stirred for thirty minutes (Note 7). The solution is then poured into a separatory funnel, the benzene separated and the water layer extracted with a 200-cc. portion of benzene. The combined benzene solution is shaken with excess of 10 per cent sodium carbonate solution to remove free acid and sulfur dioxide (Note 8). The benzene is washed with a little water and then dried over anhydrous potassium carbonate (Note 9). The benzene is distilled at ordinary pressure over a free flame from a 500-cc. Claisen flask, the solution being added from a separatory funnel as fast as the benzene distils. It is advisable to distil the ester under reduced pressure although it can be done under ordinary pressure. The fraction distilling around n8°/5mm., 130710 mm., 138715 mm., 148725 mm., 155735 mm., or... 

Transfer the concentrate from Section 6.1.1 into a 200-niL separatory funnel with a small amount of water and add 10 mL of saturated sodium chloride solution. Extract three times with 50 mL of n-hexane (a free form of fluthiacet-methyl is present in the aqueous layer see Section 8). Dry the n-hexane extract through 80 g of anhydrous sodium sulfate on a glass funnel and transfer the dried extract into a 300-mL separatory funnel. Extract twice with 70 mL of acetonitrile, collect the extract in a 300-mL round-bottom flask, and evaporate the solvent under reduced pressure. Dissolve the residue in 10 mL of n-hexane-ethyl acetate (4 1, v/v), transfer the solution to a Bond Elut LRC SI column and discard the first eluate. Connect a Sep-Pak Plus NH2 cartridge to the outlet of a Bond Elut LRC SI cartridge and elute fluthiacet-methyl with 15 mL of n-hexane-ethyl acetate (2 3, v/v). Collect the eluate in a 50-mL pear-shaped flask, evaporate the solvent under reduced pressure and dissolve the residue in an appropriate volume of acetone for analysis. 

In fruit penetration studies 8 pounds of fruit were first thoroughly scrubbed with warm 10% trisodium phosphate solution and then rinsed thoroughly with distilled water. Citrus fruits, if depth of penetration into the peel was of interest, were peeled in longitudinal sections with a buttonhook peeler and the albedo or white portion was separated from the flavedo or colored portion. The separated peel was placed in pie tins lined with waxed paper and dried in a forced draft oven at 65° C. for 16 hours. The dried peel was then crushed and steeped for 48 hours in a measured volume of benzene sufficient to cover the sample. If, on the other hand, only the total amount of DDT in the peel was of interest, the fruit was halved and juiced on a power juicer. The pulp was removed, the peel sliced, and the sample dried and treated as before. Thin-skinned fruits, such as apples, pears, and avocados, were peeled with a vegetable peeler, cores or seeds were removed, and the pulp was sliced in thin slices. Pulp and peel were then dried and treated in the same way as the citrus peel. The steeping completed, the samples were filtered through Sharkskin filter paper and the volume of benzene recovered was noted. 

Meconic acid forms beautiful pearly crystalline scales, of a harsh sour taste, sparingly soluble in cold, but more readily In hot water and in alcohol. The anhydrous acid consists of Clt nOa, and is denoted by the. symbol Me the acid dried at 212° contains in addi-... 

Sulphur Thiocyanate, S(SCN)2, is formed as colourless, pearly crystals, when a solution of thiocyanogen in ether reacts with dry hydrogen sulphide. It decomposes at atmospheric temperatures. Heated in an open tube on a water-bath it darkens rapidly and then suddenly decomposes, evolving orange fumes. A solution of sulphur thiocyanate in a mixture of ether and benzene does not react with powdered iron, but on the addition of a drop of water the characteristic red colour of ferric thiocyanate develops immediately. By this reaction sulphur thiocyanate can be distinguished from free thiocyanogen.2... 

The electrolysis of the studied systems was carried out in the same cell as voltammetry measurements under the mode of either constant current or voltage. In the constant current mode, the applied current density was in the range of 0.01 0.2 A/ sm2 with reference to the surface area of the cathode before starting the electrolysis. Semi-immersed glassy carbon plate electrodes (cathode area - 5 sm2, anode area - 10 sm2) were used while electrolysis experiments. A powder product was either settled down onto the crucible bottom or assembled on the cathode in the view of electrolytic pear . The deposit was separated from salts by successive leaching with hot water. Thereafter, the precipitate was washed with distilled water by decantation method several times and dried to a constant mass at 100 - 150 °C. The electrolysis products were analyzed by chemical and X-ray phase analyses, methods of electron diffraction and electronic microscopy (transmission and scanning). 

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