Fruit juice storage

Measurement of Arabinan. Excess quantities of arabinan in fruit juice can lead (after prolonged storage) to hazy fruit-juice concentrates. This problem can be resolved by ensuring that the pectinase preparation employed contains adequate levels of endo-arabinanase to hydrolyse the amounts of debranched arabinan likely to be present. A limiting factor is that currently, there are no methods available for the measurement of arabinan in fruit juice or juice concentrates. 

Rivastigmine oral solution and capsules may be interchanged at equal doses. Storage/Stability When rivastigmine oral solution is combined with cold fruit juice or soda, the mixture is stable at room temperature for 4 hours. 

Fruit juices processing may seriously affect flavanol content. For example, the preparation of commercial apple juice decreased the flavanol content in a stepwise manner. In particular, crushing and pressing, storage of the concentrated juice at room temperature and decolorization by treatment with activated carbon destroy the flavanols almost entirely [46]. 

Phenolic compounds are of interest due to their potential contribution to the taste (astrin-gency, bitterness, and sourness) and formation of off-flavor in foods, including tea, coffee, and various fruit juices, during storage. Their influence on the appearance of food products, such as haze formation and discoloration associated with browning in apple and grape products, is also significant. Furthermore, analysis of these phenolic compounds can permit taxonomic classification of the source of foods. The importance of each phenolic compound and its association with the quality of various foods is described further in Sec. IV, on food applications. 

For fruits and their products, HPLC techniques for phenolics have been used to study the effect of processing, concentration, and storage on the phenolic composition of juices as well as a potential precursor for an off-flavor compound in juices. Phenolic analysis has been further applied to the detection of economic adulteration and especially to verify the authenticity of fruit juices. This is especially important when cheaper fruits can be added to more expensive ones in a fraudulent manner. In most fruits, the nonanthocyanin flavonoids consist mainly of flavonols and flavanols, with trace amounts of flavones. Glycosides are the predominant forms present. These most often are separated by reversed-phase HPLC on Cl8 columns with gradients consisting of acidified H20 and ACN, MeOH, or EtOH. 

Fruit juices and nectars are highly susceptible to fermentation and other forms of microbial spoilage and with few exceptions it is essential that some form of pasteurisation is employed when these products are packaged. The exceptions that are seen usually relate to freshly squeezed orange (or other) juices that are processed directly from fresh fruit and packaged immediately. These products have a very short shelf life, usually a few days, and are maintained by storage at temperatures between 0 and 5°C. 

For all other fruit juice and nectar products either frozen storage or in-pack pasteurisation will be used, although some manufacturers who employ a hot fill process. 

In a soft drink, or a fruit juice reconstituted from concentrate, the quality of the water is an essential element. Checking the water quality includes assessment to ensure that it does not contain any off-tastes or odour s. It also involves checking that any water-treatment processes have been effective and have not introduced defects into the water. The water should also be assessed to ensure that it does not contain materials that are likely to precipitate from the product on storage. Such precipitates are often called floes . 

Liquid extracts such as infusions will often, over time, produce a fine sediment. There may be a statement to this effect in the specification and on the container label. If the product for which the extract is destined is a cloudy drink or opaque like a fruit juice, then the container can be shaken each time to re-disperse the sediment before weighing out. If it is essential for the extract to be clear, then it must be carefully decanted when weighing out for a production batch. Extracts in storage will often change colour over time. Thus, specifying a colour parameter without a time factor can lead to the situation where a customer s QC accepts the extract on delivery, as it meets colour standards at the time, but rejects it on retesting later after it has spent some time in the raw materials store -particularly if the drum has been opened and is part used. 

The use of citrus fruit, especially oranges, dramatically increased in the U.S. after World War II (1 ) because of the introduction of frozen concentrated orange juice (FCOJ) to the market. Citrus fruits, being subtropical products, did not enjoy the popularity of other fruits, e.g. apples, because the locality of production were usually not near the world population centers and because of perishability of citrus fruits during storage. 

HIGH-TEMPERATURE SHORT-TIME (htst) METHOD. The HTST method is used for two purposes in fruit juice technology to sterilize juices for storage and to precipitate thermolabile protein. 

Under proper processing conditions, fruits lose less than 30% of their original vitamin C content through the entire freezing and frozen storage period (106). Frozen concentrated fruit juices can retain over 90% of their ascorbic acid (38,106). Packing in syrup is generally protective of ascorbic acid. 

It has been known for decades that heat is one of the most destructive factors of anthocyanins in berry fruit juices (Jackman et al., 1987a). With strawberry preserves, it was shown as early as 1953 that the half-life time was 1 h at 100°C, 240 h at 38°C and 1300 h at 20°C. In a storage experiment with concentrates and dry powder of elderberry extracts, the stability increased 6-9 times when the temperature was reduced from 20°C to 4°C (Zajac et al., 1992). Anthocyanin degradation in anthocyanin solutions increased from 30% to 60% after 60 days when storage temperatures were increased from 10°C to 23°C (Cabrita et al., 2000). High-temperature short-time processing is recommended for maximum anthocyanin retention of foods containing anthocyanins (Jackman and Smith, 1996). 

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