Fruit drinks

Figure 3.7 shows some early examples of this type of analysis (39), illustrating the GC determination of the stereoisomeric composition of lactones in (a) a fruit drink (where the ratio is racemic, and the lactone is added artificially) and (b) a yoghurt, where the non-racemic ratio indicates no adulteration. Technically, this separation was enabled on a short 10 m slightly polar primary column coupled to a chiral selective cyclodextrin secondary column. Both columns were independently temperature controlled and the transfer cut performed by using a Deans switch, with a backflush of the primary column following the heart-cut. 

Figure 3.7 (a) Chromatograms of (i) the dichloromethane extract of a fruit drink analysed with an apolar primary column, with the heart-cut... 

Trichloroethylene has been detected in dairy products (milk, cheese, butter) at 0.3-10 pg/kg (0.3-10 ppb), meat (English beef) at 12-16 ppb, oils and fats at 0-19 ppb, beverages (canned fruit drink, light ale, instant coffee, tea, wine) at 0.02-60 ppb, fruits and vegetables (potatoes, apples, pears, tomatoes) at 0-5 ppb, and fresh bread at 7 ppb (McConnell et al. 1975). Samples obtained from a food processor in Pennsylvania contained trichloroethylene concentrations of 68 ppb in plant tap water, 28 ppb in Chinese-style sauce,... 

The combined use of a continuous flow system and a spectrophotometer for sample screening to discriminate between synthetic and natural colorants is also available. With a very simple flow system on a column packed with natural materials, one can discriminate natural and synthetic colorants. The natural (not retained) ones can be determined in the first step and the synthetic (retained) ones in the second step after their elution. For yellow, red, green, blue, and brown, natural or synthetic colorants were chosen as models. The specific maximum wavelength for each color (400,530, and 610 mn, respectively) was selected by a diode array system. A complete discrimination of natural and synthetic colorants was obtained for concentrations of natural colorants (in the absence of synthetic ones) up to 2000 (yellow), 2000 (red), and 10,000 (brown) times that of the detection limits (DLs) of synthetic additives. This method was applied to screen fruit drinks and candies. ... 

Mullen W, Marks SC and Crozier A. 2007. Evaluation of phenolic compounds in commercial fruit juices and fruit drinks. J Agric Food Chem 55(8) 3148-3157. 

In young children who cannot swallow capsules, succimer can be administered by separating the capsule and sprinkling the medicated beads on a small amount of soft food or putting them in a spoon and following with a fruit drink. 

Similar to inorganic acids, the reaction of carboxylic acids and bases produces carboxylic acid salts. Several of these salts are commonly used in foods and beverages as preservatives. The most common are salts from benzoic, propionic, and sorbic acids. The salts of these acids have names ending with ate, and can often be found in the list of ingredients of baked goods and fruit drinks. Several common preservatives are shown in Figure 15.11. 

Another very important development was the production of citrus comminutes. These were produced by mixing together, in appropriate proportions, the juice, peel components and essential oils of citrus fruits and comminuting the mixture in a stone mill. The resulting product delivered a more intense flavour and cloud than could be obtained from juice alone and allowed the creation of whole fruit drinks , which have dominated the concentrates market in the United Kingdom over the past 40-50 years. 

Phosphoric acid has a drier, and perhaps sharper, flavour than either citric or tartaric acid, tasting rather of flat sourness , in contrast with the sharp fruitiness of citric acid. It therefore appears to blend better with most non-fruit drinks. 

Although this product was available following the war years, it spawned the development of other products such as whole fruit drinks, squashes and cordials, which became and remain the mainstay of the United Kingdom and Commonwealth dilutables market. 

Table 6.1 1964 UK reserved descriptions for dilutable fruit drinks...

Whole fruit drink 10% w/v comminuted citrus fruit No minimum... 

Finished comminutes are often available at between about 35 and 60°Brix. When used for making whole fruit drinks they deliver, apart from a more intense flesh flavour, cloud and colour. 

Since many fruit drinks require heat processing to ensure microbiological stability, consideration must be given to the packaging material and its tolerance to elevated temperatures. If the product is also carbonated then the choice of packaging material and closure system becomes even more critical because of the required heat processing. As the heat builds up so does the internal pressure. Typical IPP conditions are 65-75°C for 20 min, with a warm-up and cool-down time of 20 min for each phase. 

Stratford M., Hofman P.D. and Cole M.B. (2000) Fruit juices, fruit drinks, and soft drinks, in The Microbiological Safety and Quality of Food, Vol. 1 (eds B.M Lund., T.C Baird-Parker and G.W. Gould), Aspen Publishers, Gaithersburg, pp. 836-69. 

A rigorous hygiene programme must be operated at the outlet with daily cleaning of the dispensing valves and drip trays, and of the disconnects when syrup containers are changed. Periodic sanitation of syrup lines is required. This must be done more often when fruit drinks or juices are dispensed. 

In the empirical approach the ultrasonic parameters of a range of samples with known properties are measured. Empirical relationships are then established between the property of interest and the measurable ultrasonic parameters. A typical example of this approach is the determination of the sugar content of fruit drinks [18]. A series of sugar solutions of different sugar concentration are prepared and their ultrasonic velocities are measured. This data is then used to make up a calibration curve which relates the sugar content to the... 

The flavor of lemon, contributed by the peel oil, is probably second only to orange flavor in overall popularity. The growth in market fcr the powdered soft drink mixes and the fruit drink mixes, particularly for lemon-flavored products, has increased the demand for lemon oil. Added to this is the increasing demand for lemon oils for use in the carbonated and noncar-bonated soft drinks that are increasing in popularity worldwide. 

A beverage emulsion is a concentrate added to sugar and carbonated water to make soda and fruit drinks. The oil-in-water emulsion provides flavor as well as opacity in products such as orange soda. Traditionally, gum arabic has been used to stabilize these emulsions. Interfacial starch derivatives (Section 20.4.2) are used to prevent creaming (phase separation), sedimentation, and loss in flavor and opacity, where desired, both in the concentrate and in the finished beverage. The concentrate is made by homogenizing the oils with an equal amount of the solubilized lipophillic starch, citric acid, sodium benzoate and color. A fine emulsion, typically 1 micrometer or less, is required for stability and for opacity, where desired. 

Pour about 60 mL of a fruit drink that you wish to analyze into a clean, dry 100-mL beaker. The fruit drink should be light colored, apple, orange, or grapefruit, but not dark colored, such as grape. Record the kind of drink on the Report Sheet (1). 

If the fruit drink is cloudy or contains suspended particles, it can be clarified by the following procedure Add Celite, used as a filter aid, to the fruit drink (about 0.5 g). After swirling it thoroughly, filter the solution through a glass funnel, bedded with a large piece of cotton. Collect the filtrate in a 50-mL Erlenmeyer flask (Fig. 50.1). 

Using a 10-mL volumetric pipet and a Spectroline pipet filler, transfer 10.00 mL of the fruit drink into a 125-mL Erlenmeyer flask. Then add 20 mL of distilled water, 5 drops of 3 M HC1 (as a catalyst), and 10 drops of 2% starch solution to the flask. 

Place the flask that contains the vitamin C sample under the buret and add the iodine solution dropwise, while swirling, until the indicator just changes to dark blue. This color should persist for at least 20 sec. Record the final buret reading (3b). Calculate the total volume of iodine solution required for the titration (3c), the weight of vitamin C in the sample (4), and percent (w/v) of vitamin C in the drink (5). Repeat this titration procedure twice more, except using 20- and 30-mL portions of the same fruit drink instead of 10 mL. Record the volumes of iodine solution that are required for each titration. 

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