Foodstuffs fruit juices

The corrosive effects to be considered (mainly simple corrosion of metals) are, as would be expected from the edible nature of foodstuffs which are not excessively either acidic or basic but which may contain sulphur, less severe than those often encountered with inedible materials containing reactive substances. The importance of corrosive efiects where foodstuffs are concerned lies not so much in the action of the foodstuffs on the metal involved as in the resultant metal contamination of the foodstuff itself, which may give rise to off-flavours, in the acceleration of other undesirable changes (by the Maillard reaction for example), and in the possible formation of toxic metallic salts. Metal ions generally have threshold values of content for incipient taste effect in different liquid foodstuffs. Except in the case of the manufacture of fruit juices and pickles, process plant failure through corrosion must be rare. Nevertheless all foodstuffs, particularly liquid ones, should be regarded as potentially corrosive and capable of metal pick-up which may be undesirable. 

Annex II lists foodstuffs for which only certain of the annex I additives may be used. Such foodstuffs include cocoa products and chocolate products, fruit juices and nectars, jam, jellies and marmalades and partially dehydrated and dehydrated milk, which are the subjects of EU vertical standards, and a number of other foods including frozen unprocessed fmit and vegetables, quick-cook rice, non-emulsified oils and fats, canned and bottled fruit and vegetables, bread made with basic ingredients only, fresh pasta and beer. 

In foods, the simultaneous HPLC analysis of several vitamins is feasible only under special conditions, for example, determination of fortified, free vitamins rather than endogenous ones, which are often bound to other food components, or determination of vitamins in relatively simple foodstuffs, such as fruit juice. The HPLC separation per se of multiple vitamins is not difficult it is their simultaneous, nondegradative extraction from foods that is problematic. Developing a single set of extraction conditions that satisfies the diverse physicochemical properties and stability requirements of several vitamins is a challenge. 

The method is not only applicable to the EU-official aqueous and fatty food simulant but also to foodstuffs such as beverages and soft margarine. Indeed the collaborative trial included fruit juice, wine and sunflower oil. The level of migrated acrylonitrile is determined by headspace gas chromatography, preferably with automated sample injection and using a nitrogen specific detector, for instance an alkali flame ionization detector (AFID). This gives the method the necessary sensivity to meet the... 

Derivative benzoates and parabenzoates have been used primarily in fruit juices, chocolate syrup, pie fillings, pickled vegetables, relishes, horseradish, and cheese (Barbosa-Canovas et al., 2003). Other foodstuffs where sodium benzoate is used include soft drinks, baked goods, and lollipops (Poulter, 2007). Benzaldehyde and benzoic alcohol are better known to be yeast inhibitors. Benzoic acid has been found to release fewer protons than sulphite, nitrite, or acetic acid and it may be speculated that benzoic acid is not a classic weak-acid preservative. However, due to a lower pKa value, benzoic acid releases three to four times more protons than sorbic acid. This is a sizable concentration of protons although not as much as other weak-acid preservatives (Stratford and Anslow, 1998). Inhibition of growth is strongly pH-dependent and most effective under acidic conditions. Under these conditions the protonated form of the acid is predominantly found (Visti, Viljakainen, and Laakso, 2003). Another unexpected discovery was that benzoic acid appears to be a pro-oxidant. This was unexpected as it is a well-known fact 2-hydroxybenzoic acid (or salicylic acid) acts as a scavenger of free radicals in vivo (Piper, 1999). 

Osmotic distillation is unique among concentration processes in that feeds containing thermally labile or shear-sensitive components, and those with appreciable volatility, can be concentrated with little or no loss of product integrity. This characteristic is particularly important for the concentration of fruit juices and other liquid foodstuffs, such as vegetable juices, and tea and coffee extracts. These feeds contain a complex mixture of essential volatile hydrophilic flavor, and fragrance components in very low concentrations. Substantial depletion of these components by direct destruction or evaporation may render the product... 

Furthermore, the author believes that buffer capacity curves, which may be established from neutralization curves, are of value in estimating the composition of liquids containing a mixture of various acids and bases. Examples of such liquids are soil infusions, beer, milk, fruit juices, foodstuffs, etc. A detailed discussion of the subject is beyond the scope of this monograph. ... 

Proton high-field NMR has been shown to be very valuable for the analysis of low molecular weight compounds in fluid foodstuffs. Water suppression can be achieved with great efficiency, and a large dynamic range is available. Examples are applications to fruit juices,12 199 200 vinegars,199 and coffee.201... 

Sodium benzoate, which is obtained by the neutralizing of benzoic acid with NaOH, is used as a preservative in foodstuffs such as sauces, syrups and fruit juices. It also acts as a corrosion inhibitor in glycol-based anti-freeze, for which some 3,5001 were consumed in Western Europe in 1985. 

Polymers are often applied to promote either stabilization or aggregation. Examples of polymer-induced aggregation are found in water purification, clarification of wine and fruit juices, and in papermaking. Stabilization of colloidal particles by polymers is applied in foodstuffs, paints, and dyes, in the dispersion of particles on magnetic tapes and photographic paper, as well as in many cosmetic and medical salves and lotions. A rather recent development is the use of polymers to reduce or prevent the deposition of protein molecules and biological cells on surfaces in order to avoid biofouling and, hence, improve the biocompatibility of these surfaces. 

In acidic foodstuffs, such as fruit juices and cEirbonated beverages, attack of magnesium is slow but measurable. Milk causes attack, particularly when souring. Continuous poultices of wet organic matter have also been noted to cause corrosive attack, as has continuous contact of wet wood products. In both cases the presence of organic acids produced by the decay process has been assumed to be the cause of the attack. 

Electrodialysis has a number of other large-scale applications and these would include the manufacture of pure sodium chloride for table salt (in Japan, electrodialysis is the principal method, production exceeding 10 ton year" ), the demineralization of cows milk (for baby food), cheese whey and sugar solutions, the removal of excess acid from fruit juice, the isolation of organic acids from reaction streams, and the production of low-salt foodstuffs. 

The lacquer thickness varies between 5 and 15 JLm depending on the nature of the foodstuff. It aims at protecting aluminium against prolonged action of aggressive foodsmfifs such as tomato ketchup. In practice, most cans for fruit juice, beer, sodas (beverage cans), etc. are lacquered. 

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