Carbonated drinks

Discriminatory analysis is a technique used to distinguish between and assess the quality of food products, often of the same type which, for example, may have gone through different processes or have different origins. This analysis can be done by a panel of trained people who, using their senses for aroma and taste, can differentiate between different food types. However, as mentioned in an earlier section a sensory panel is an expensive and time-consuming approach for food and drink analysis, as well as being unavoidably subjective. An alternative approach is to use an instrument to detect volatiles followed by an objective statistical analysis. 

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Certain types of equipment are specifically excluded from the scope of the directive. It is self-evident that equipment which is already regulated at Union level with respect to the pressure risk by other directives had to be excluded. That is the case with simple pressure vessels, transportable pressure equipment, aerosols and motor vehicles. Other equipment, such as carbonated drink containers or radiators and piping for hot water systems are excluded from the scope because of the limited risk involved. Also excluded are products which are subject to a minor pressure risk which are covered by the directives on machinery, lifts, low voltage, medical devices, gas appliances and on explosive atmospheres. A further and last group of exclusions refers to equipment which presents a significant pressure risk, but for which neither the free circulation aspect nor the safety aspect necessitated their inclusion. 

You can observe heterogeneous nucleation easily in carbonated drinks like "fizzy" lemonade. These contain carbon dioxide which is dissolved in the drink under pressure. When a new bottle is opened the pressure on the liquid immediately drops to that of the atmosphere. The liquid becomes supersaturated with gas, and a driving force exists for the gas to come out of solution in the form of bubbles. The materials used for lemonade bottles - glass or plastic - are poor catalysts for the heterogeneous nucleation of gas bubbles and are usually very clean, so you can swallow the drink before it loses its "fizz". But ordinary blackboard chalk (for example), is an excellent former of bubbles. If you drop such a nucleant into a newly opened bottle of carbonated beverage, spectacular heterogeneous nucleation ensues. Perhaps it is better put another way. Chalk makes lemonade fizz up. 

With the expiry of the basic ICI patents on poly(ethylene terephthalate) there was considerable development in terephthalate polymers in the early 1970s. More than a dozen companies introduced poly(butylene terephthalate) as an engineering plastics material whilst a polyether-ester thermoplastic rubber was introduced by Du Pont as Hytrel. Polyfethylene terephthalate) was also the basis of the glass-filled engineering polymer (Rynite) introduced by Du Pont in the late 1970s. Towards the end of the 1970s poly(ethylene terephthalate) was used for the manufacture of biaxially oriented bottles for beer, colas and other carbonated drinks, and this application has since become of major importance. Similar processes are now used for making wide-neck Jars. 

A useful property of liquids is their ability to dissolve gases, other liquids and solids. The solutions produced may be end-products, e.g. carbonated drinks, paints, disinfectants or the process itself may serve a useful function, e.g. pickling of metals, removal of pollutant gas from air by absorption (Chapter 17), leaching of a constituent from bulk solid. Clearly a solution s properties can differ significantly from the individual constituents. Solvents are covalent compounds in which molecules are much closer together than in a gas and the intermolecular forces are therefore relatively strong. When the molecules of a covalent solute are physically and chemically similar to those of a liquid solvent the intermolecular forces of each are the same and the solute and solvent will usually mix readily with each other. The quantity of solute in solvent is often expressed as a concentration, e.g. in grams/litre. 

Liquid carbon dioxide is discussed on page 261. Carbon dioxide gas is commonly used for carbonating drinks, in fire extinguishers, for gas-shielding of welding and in shell moulding in foundries. Its physical and toxicological properties are summarized in Tables 8.5, 8.6 and 5.29. 

The main fluids of interest with plastics are oxygen and water vapour (for packaging applications) and CO2 (for carbonated drinks applications). Fig. 1.13 and Fig. 1.14 illustrate the type of behaviour exhibited by a range of plastics. In some cases it is necessary to use multiple layers of plastics because no single plastic offers the combination of price, permeation resistance, printability, etc. required for the application. When multi-layers are used, an overall permeation constant for the composite wall may be obtained from... 

Because it only converts to benzoic acid in acidic environments, it is not used for its antimicrobial action unless the pH is 3.6 or below. In the food industry, it is used in items such as jams, salad dressing, juices, pickles, and carbonated drinks. 

Scuba divers experience similar pressure changes. The amount of air dissolved in the blood increases significantly as the diver descends. If a diver returns to the surface too quickly, nitrogen gas dissolved in the blood forms bubbles in the same way as the CO2 in a freshly opened carbonated drink. These bubbles interfere with the transmission of nerve impulses and restrict the flow of blood. The effect is extremely painful and can cause paralysis or death. The bubbles tend to collect in the joints, where they cause severe contractions. This is the source of the name of this dangerous condition—the bends . 

Caramel colors, liquid forms S.S Type IV, E 150d CU = 115 to 120 Ammonia sulfite Brown Carbonated drinks, candies, baked goods, syrups, pet foods... 

Many polymers are used in barrier applications, either to keep contents in or contaminants out. Food packaging is an excellent example of such usage. Plastic films and containers of many types are used to package food. Blow moldedbottles often contain numerous layers, each of which provides specific benefits. Polyethylene layers are excellent water barriers, polyvinyl alcohol is a good oxygen barrier, and polyethylene terephthalate impedes the diffusion of carbon dioxide from carbonated drinks. Other barrier applications include toothpaste tubes, diaper backsheets, tarpaulins, and geomembranes, which are used to line containment ponds and landfill pits. 

Polyethylene terephthalate is injection blow molded to make water and carbonated drink bottles, and other liquid food packages. High stiffness, excellent clarity, and good resistance to carbon dioxide permeation are the principal attributes of these bottles. We carefully control molding conditions to promote transparency and surface gloss, which are prized for food... 

Polyesters, which are a class of engineering thermoplastics, are found in a wide variety of applications including carbonated drink bottles, fibers for synthetic fabrics, thin films for photographic films and food packaging, injection molded automotive parts, and housings for small appliances. In this chapter, we svill explore the synthesis of this class of polymers. We will also look at the typical properties and end uses for the most common of these resins, polyethylene terephthalate and polybutylene terephthalate, which are commonly known as PET and PBT, respectively. 

Because polyethylene terephthalate crystallizes slowly, it can readily be produced in its amorphous state. This is especially true when it is used in packaging materials, such as thin films and carbonated drink bottles. The final products exhibit high clarity and directionally balanced properties because they lack crystalline regions. 

Fig. 4.2 Consumption of carbonated drinks by UK adults and pre-school children.

O A sealed carbonated-drink bottle contains a liquid drink with a space above it. The space contains carbon dioxide at a pressure of about 405 kPa. 

Carbonic acid (HjCO ) is produced by dissolving carbon dioxide in water. When formed under pressure, it is the gas used in carbonated drinks. In nature, it dissolves the limestone in caves, resulting in the formation of stalactites and stalagmites. It is corrosive as are other acids, although it is considered a rather weak acid. 

Carbon dioxide (CO ) is the 18th most frequently produced chemical in the United States. It has numerous uses, including in refrigeration, in the manufacture of carbonated drinks (e.g., soda pop), in fire extinguishers, in providing an inert atmosphere (unreactive environment), and as a moderator for some types of nuclear reactors. 

Phosphoric acid is used as an intermediate in the production of animal feed supplements, water treatment chemicals, metal surface treatments, etching agent, and personal care products such as toothpaste. It is used as a catalyst in the petroleum and polymer industry. Phosphoric acid is used in food as a preservative, an acidulant, and flavor enhancer it acidifies carbonated drinks such as Coca Cola and Pepsi, giving them a tangy flavor. Phosphoric acid is used as a rust remover and metal cleaner. Naval Jelly is approximately 25% phosphoric acid. Other uses for phosphoric acid include opacity control in glass production, textile dyeing, rubber latex coagulation, and dental cements. 

Coffee Carbonated drink Flavoured milk Wine... 

In non-carbonated drinks there may be visible deposits, and sometimes a neck ring in the finished product, caused by agglomeration of smaller particles. Filtration of the incoming water stream is therefore essential. 

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