Dilutable soft drinks

Whether RTD or dilutable, soft drinks characteristically contain water, a sweetener (usually a carbohydrate, although artificial sweeteners are increasingly important), an acid (citric or malic are the most common), flavouring,... 

Despite the removal of compositional legislation, the descriptions of dilutable soft drinks in the United Kingdom are still widely used today. Consumers and enforcement authorities alike still have an expectation that a product described as a squash will be a cloudy product containing a significant proportion of fruit juice. Similar expectations still apply to the other products mentioned above. 

Other chapters of this volume deal in more detail with the ingredients of all soft drinks, and readers requiring more information should refer to them. However, it is appropriate here to make reference to special issues concerning ingredients insofar as they relate to dilutable soft drinks. The main ingredients of dilutable soft drinks are set out in Table 6.2. 

Concentrated juices. It will be evident from the section on nomenclature that the principal fruit components that are used in dilutable soft drinks are fruit juices (both clear and cloudy) and whole fruit preparations - the so-called comminutes. 

Table 6.2 Principal ingredients of dilutable soft drinks...

Flavourings. Flavourings are widely used in dilutable soft drinks to boost or substitute those occurring naturally. There are other publications that deal with this topic in more detail, but, in brief, it is necessary to ensure that appropriate beverage flavours are selected to produce adequate solubility. Most manufacturers of dilutables will use either natural or nature-identical flavours. 

By far the greatest consumption of pure aqueous phosphoric acid is in the preparation of various salts for use in the food, detergent and tooth-paste industries (p. 524). When highly diluted the free acid is non-toxic and devoid of odour, and is extensively used to impart the sour or tart taste to many soft drinks ( carbonated beverages ) such as the various colas ( 0,05% H3PO4, pH 2,3), root beers ( 0.01% H3PO4, pH 5,0), and sarsaparilla ( 0.01% H3PO4, pH 4.5). 

Chen et al. (1997a) analysed sodium saccharin in soft drinks, orange juice and lemon tea after filtration by injection into an ion-exclusion column with detection at 202 nm. Recoveries of 98-104% were obtained. They reported that common organic acids like citric and malic and other sweeteners did not interfere. Qu et al. (1999) determined aspartame in fruit juices, after degassing and dilution in water, by IC-PAD. The decomposition products of aspartame, aspartic acid and phenylanaline were separated and other sweeteners did not interfere. The recoveries of added aspartame were 77-94%. Chen et al. (1997b) separated and determined four artificial sweeteners and citric acid. 

Fort he determination of preservatives and sweeteners in soft drinks or fruit juices LC analysis with UV detection is widely used. The sample pretreatment, prior to LC analysis, often consists only of degassing, filtration and dilution of the Uqirid [2]. Sometimes a Uqirid-Uqitid extraction, suitable not only for soft drinks but also for more complex matrices, is appUed [3]. Chemometric methods appUed to overlapped spectra offer the advantage of minimizing or eliminating sample preparation by allowing to simirltaneoirsly determining one or more analytes in relatively complex matrices. 

Clarification of extracts can be accomplished with Carrez reagents (44). Purification has been performed by solid phase or partition. Wu et al. (47) absorbed saccharin onto ODS-4 cartridges and then eluted with methanol phosphate buffer. Puttemans et al. (28,50) extracted saccharin from soft drinks and yogurt by ion-pair extraction with tri-n-octylamine and back-extraction to an aqueous phase with perchlorate. Tereda and Sakabe (48) used cetrimide and Sep-Pak Cl8 in the cleanup of saccharin in coffee drink. The column was preconditioned with methanol, water, and 5 mM cetrimide. The sample, diluted in phosphate buffer pH 3.0 containing cetrimide was poured into the cartridge, washed with water, and eluted with acetonitrile water (1 1, v/v). Moriyasu et al. (40) added n-propylammonium bromide to the extract, passed it through a Bond Elut Cl 8 column, and eluted the sweetener with a mixture of methanol-water (4 6, v/v). The eluate was passed through a Bond Elut SAX column and washed with 0.5% phosphoric acid and water, and the sweetener was eluted with 0.3 N hydrochloric acid. 

Usually, OAs present in beverages such as wine, beer, soft drinks, and fruit juices can be injected directly into the chromatographic system with no sample pretreatment other than dilution or filtration (5). 

A method is described for the determination of the preservatives SA and BA in foods (including yogurt, soft drinks, and fruit juices) based on HPLC on a hydrogen-sulfonated divinyl-benzene-styrene copolymer column, isocratic elution with 0.01 N sulfuric acid/acetonitrile (75 25) mobile phase and UV detection at 220 nm (for BA) and 258 nm (for SA). Soft drinks and fruit juices merely require dilution and filtration before injection yogurt samples require treatment with potassium ferricyanide (III) and ZnS04 before analysis. Recovery of SA from yogurt was 95-110% the detection limit was 0.01 mg/kg. The recovery of BA from soft drinks and fruit... 

There are two basic types of soft drinks the so-called ready-to-drink (RTD) products that dominate the world market and the concentrated or dilute-to-taste products that are still important in some markets. These include syrups and so-called squashes and cordials. 

Most concentrated beverages contain fruit juice or whole fruit , a term that refers to a comminuted form of citius that includes components of juice, essential oil, peel (flavedo) and pith (albedo). Concentrated soft drinks are usually flash-pasteurised and chemically preserved. Their dilutable form means that they are often held in partially filled bottles for significant lengths of time (often many weeks or even months) and are extremely vulnerable to spoilage by micro-organisms. 

Soft drinks are low-pH beverages that are based mostly around fruit-derived ingredients or incorporate fruit flavours. They are an important source of hydration but are usually selected on the basis of pleasant taste and convenience of use. There are some soft drinks, of which cola-flavoured beverages are the most prominent, which do not rely primarily on fruit flavours. Some of these nonfruit-flavoured products are almost invariably produced only in a carbonated form, whereas others, such as peppermint, almost always appear only in dilutable and non-carbonated form. 

Dilutable beverages have been widely used for many years as a low-cost, convenient means of producing soft drinks on the consumers premises. 

Carbohydrates still feature as important components of many non-carbonated beverages, and they are particularly important in the manufacture of dilutable drinks. Historically, the UK Soft Drinks Regulations of 1964 required dilutable drinks to have a minimum level of 22.5% w/v carbohydrates unless they were declared to be low calorie . The regulations assumed a five times dilution factor (1 part dilutable plus 4 parts water) and thus a minimum carbohydrates level of 4.5% w/v in finished drinks. 

Acidulants. The preferred acidulant for dilutable (and other) soft drinks is citric acid, which is readily available both as a crystalline solid (citric acid anhydrous) and as a 50% w/w solution in bulk. Other acidulants that are used in specific products include malic acid, lactic acid and tartaric acid. Phosphoric acid, until recently permitted only in cola drinks, is now available for use in the United Kingdom but has so far found little, if any, use in dilutable products. Acids other than citric are usually employed only where a slightly different taste profile is needed. Ascorbic acid is usually employed as an antioxidant rather than as a direct acidulant. 

As with all methods, this approach has some limitations it uses acetonitrile, which is toxic, and the separation of glucose from fructose can sometimes be problematic after extended use of the column. However, sample preparation is easy since it requires only dilution to the required level (often 1 10) and filtration prior to analysis to remove particulate materials, which protects and extends the useful life of the column. The degradation of the resolution between glucose and fructose is caused by the partial inactivation of the column by materials in the matrix, but this resolution can be recovered by reducing the acetonitrile concentration in the solvent. The same column can also be used to assay the level of ascorbic acid (vitamin C) in a soft drink or fruit juice, although different detection and solvent systems are used. 

Sulphur dioxide is a widely used preservative for foods and soft drinks, particularly dilutables, and in principle is quite easy to detect and quantify. Owing to the importance of sulphur dioxide as a preservative an extensive review of its chemistry in foods was undertaken in the mid-1980s (Wedzicha, 1984). 

Examples show the effect of 18% (but not 15%) of added water in preventing ignition when glycerol was dripped onto a hypochlorite (79% active chlorine) containing 2% of oil [1]. Ignition with brake fluid is also reported, in this case reaction is accelerated by cola soft drinks - which are dilute acids rather than just water [2]. 

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