Drying processes, water-soluble powders

Water-Soluble Powders Obtained by Drying (Freeze AND Spray Drying) Processes... 

Dry processes.—Here the powdered mineral is mixed with an alkali, and something to keep the mass open and porous while it is roasted by an oxidizing flame, say, in a reverberatory furnace, so as to form alkali chromate 2(Fe0.Cr203) -f4Na2C03- -70=Fe203-f4Na2Cr04-f-4 C02. This is extracted with water and converted into dichromate by treatment with acid the dichromate is then reduced to insoluble chromic oxide and a soluble alkali salt which is removed by lixiviation with water. The reaction was studied by A. J. Sofianopoulos, and H. A. Doerner. Technical details are indicated in the usual handbooks. ... 

Instant tea is manufactured in the United States, Japan, Kenya, Chile, Sri Lanka, India, and China. Production and consumption in the United States is greater than in the rest of the world. World production capacity of instant teas depends on market demand but is in the range of 8,000 to 11,000 t/yr (3). The basic process for manufacture of instant tea as a soluble powder from dry tea leaf includes extraction, concentration, and drying. In practice, the process is considerably more compHcated because of the need to preserve the volatile aroma fraction, and produce a product which provides color yet is soluble in cold water, all of which are attributes important to iced tea products (88). 

Milk from cows contains 3.2% protein, about 80% of which is casein. Casein is isolated by a precipitation process from milk, involving heating, rinsing to remove whey, and drying to a powder. The yield is about 3 kg/ 100 kg skim milk. Rennet casein is obtained when the casein is precipitated by chymosin enzyme, also known as rennet, and acid casein is produced when precipitation is accomplished by acidification. Acid casein is usually found in the form of sodium caseinate or calcium caseinate, which are water-soluble salts. Caseinates are made by reacting NaOH or CaOH with a slurry of casein curd or powder and then spray drying (Southward, 2010). 

Both carmine and cochineal extract are made from the dried female insect, Dactylopius coccus costa, commonly known as cochineal. The cochineal live on specific cacti and the main prodnction is in Pern, bnt cochineal are also produced in Chile, Bolivia and the Canary Islands. There are nsnally two harvests per year, where the cochineal are removed mannally with snitable tools from leaves of the cacti. Following harvest the insects are snn dried before further processing. The cochineal insects are extracted nsing an aqueous alkaline solution. The resnlting cochineal extract can either be formulated to different cochineal products in powder or liquid form or further processed to carmine. Cochineal products are water-soluble and orange in low pH applications. The colour intensity is relatively low. 

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