Raspberries from juice

The method frequently applied to determine ee values is the enantioselective gas chromatographic analysis of the aroma substance on a chiral phase, e. g., peralkylated cyclodextrins. This method was used, e. g., to test raspberry fruit juice concentrates for unauthorized aromatization with trans-a-ionone. The gas chromatograms of trans-a-ionone from two different samples are shown in Fig. 5.13. The low excesses of the R-enantiomer of ee = 8% (concentrate A) and ee = 24% (B) can probably be put down to the addition of synthetic trans-a-ionone racemate to the fruit juice concentrate because in the natural aroma (C), the ee value is 92.4%. 

Such a method has been used to indicate differences between varieties of raspberries (Figure 1). Samples were blended and centrifuged for 15 to 20 minutes at 2000 r.p.m. in 100-ml. tubes. The clear juice was pipetted off and diluted with 9 parts of water. The pH was adjusted to that of the original undiluted juice, and transmittance curves were run for samples in 2.5-cm. cells. The differences between the varieties are apparent from the curves. 

Fig. 2.106. Separation and identification of various anthocyanin red fruit juices a, grape b, blueberry c, raspberry and d, red currant. Mobile phase water-acetonitrile-formic acid (84 6 10, v/v). Abbreviations Dp delphidin, Cy cyanidin, Pt petunidin, Pn peonidin, Mv malvidin, glu glucose, gala galactose, ara arabinose, ruti rutinose, sopho sophorose, sam sambubiose, xyl xylose. Reprinted with permission from J.-P. Goiffon et al. [241].

Red cabbage as a colorant source has been studied for many years. As of 1990 at least one firm has introduced San Red RC, the first commercially available food color derived from red cabbage. The color can be used alone or in combination with other colors to create strawberry, cherry, raspberry, and blueberry tones. By way of proprietary technology, the new dye is claimed to be free of flavor and odor defects, which in the past have been associated with red cabbage. The dye is pH dependent. The color tones move toward blue-red as the pH value increases. San Red RC ranks between cochineal and grape juice in percent or color retention. 

If juice is to be sold as not from concentrate it is usually screened and pasteurised immediately after pressing - an operation with two main objectives. The first is to control the growth of spoilage micro-organisms that live on the fruit surface (mainly yeasts and moulds). The second is to destroy the pectolytic enzymes that occur naturally in fruit that would otherwise break down the cloudy nature of the juice. If, however, a clear juice is required (e.g. apple or raspberry), enzymes can be added to accelerate this natural process. 

One pragmatic approach to the problem is the flavorese concept (i). A crude enzyme preparation from the fresh food or a closely related species is added to the processed food in the hope that the nonvolatile flavor precursors are still present and will yield the full range of fresh flavor components upon enzymatic treatment. This approach has been applied with some success to watercress (1,2), cabbage 1,2, 3, 4), horseradish 2, 3), onions 2, 3), carrots 2, 3, 5), peas, beans 2,3,6), citrus juice (2, 7), raspberries (8), tomato juice (2, 3, 9), bananas (JO), and various flower fragrances 11). This would seem to be a desirable approach since the products of different enzymatic reactions are probably necessary for full flavor. However the flavor-forming activity of the enzyme preparations was variable (5, 6, 7, 9), and the flavors were not always like that of the fresh vegetable (3). The several enzymes and flavor precursors may not have been present in the normal ratios. Also, to be practical, the enzyme preparation must be inexpensive to prepare and store, the substrates must persist in the processed food, and they must be available to enzyme action. One also wonders how processed foods can be enzymatically treated under sterile conditions. 

Odwalla C Monster—contains orange juice, peach puree, apple juice, guava puree, pineapple juice, acerola juice, and raspberry puree fortified with ten times the daily value for vitamin C (from the acerola) and vitamin K... 

FIGURE 3.9 Flow diagram for juice processing by a standard technique. [Source Reprinted with permission from Rommel, A. and Wrolstad, R.E. 1993. Ellagic acid content of red raspberry juice as influenced by cultivar, processing and environmental factors, J. Agric. Food Chem. 41(11) 1951-1960. Copyright 1993 American Chemical Society.]... 

Other fruit spirits are distilled from fresh or frozen fruits or their juices (blueberries, raspberries, strawberries, currants, apricots, peaches and others) while adding alcohol. Pomaceous fruit spirits are made from fresh fermented apples or other pomaceous fruits, from the whole fmit or its juices without the addition of sugar-containing substances, sugar or alcohol of another kind with a minimum alcohol content of approx. 38% by vol. 

In the case of red raspberries the distinctive color and flavor were poorly retained, even on keeping the juice in carbon dioxid in cold storage at from 32 to 35 degrees F. 

Citric acid occurs widely distributed in nature in many fruits. It is present in raspberries, gooseberries, currants, and other acidulous fruits. It is usually obtained from unripe lemons, the juice of which contains about six per cent of the free acid. In isolating the acid, the juice is neutralized at the ordinary tem-perture with calcium carbonate, and filtered. Tricalcium citrate dissolves readily in cold water, but is difficultly soluble in hot water. As a consequence, when the solution of the citrate obtained from the lemon juice is boiled, the calcium salt of the acid precipitates. This is separated and treated with an equivalent quantity of sulphuric acid after the removal of calcium sulphate, citric acid is obtained by evaporation of the solution to crystallization. Citric acid is formed as the result of the fermentation of glucose by citromycetes pfefferianus. It is prepared on the technical scale in this way. 

The above trends are also substantiated by the results shown in T le V for the extraction of black raqrberty pomace sub-H20. The pomace is the substance left over after the removal of the jitice from black raspberries. Here, extraction with ethanol yields an approximately equivalent result to that obtained on dried eldeibeny seeds (Ts le FV). The results for extraction with sub-H20 and 90%+ Sub-H20 yield less total ANC than in the case of the whole dried eldeibeny seeds, but this is due to the reduced levels of ANCs found in all pomaces after Ae juice is etqiressed. 

Fruit Juice concentrates vary widely in price because of differences in raw product cost and processing yield. For example, wholesale 1978 prices for Pacific Northwest produced concentrates varied from 6.25 per gallon for apple and pear to 35> T5, and 110 per gallon for strawberry, blackberry, and black raspberry concentrates, respectively (. ). The readily available, low priced concentrates are obvious potential adulterants for more expensive concentrates and methods are needed for their detection. 

Besides other factors such as color and firmness, soluble solids to acids ratio is a good index to determine harvest time. For prunes, this value has to be 12-15 [13]. A maximum limit was set for citric acid to isocitric acid ratio to reveal the dilution factor of juices 130 for apricot puree and orange juice, 80 for grapefruit juice, and 185 for raspberry juice [14]. The total add content varies widely from <0.2% in papaya and avocado [3] to 8.3% in lemon juice [15]. 

Apple juice phenolic compound extracts have the property to induce apoptosis in HT-29 cells [147]. Quercetin and phloretin dose-dependently induced both caspase-3 activity and DNA cleavage under serum-free conditions. Phloretin at 100 pM induced both the death receptor as well as the mitochondrial pathway of apoptosis induction, detected by activation of the initiator caspases-8 and -9 and the effector caspases-3 and -7 as well as by PARP cleavage. Activation of caspase-9 was accompanied by release of cytochrome c and the mitochondrial protein Smac/DIABLO from the mitochondria to the cytoplasm, and upregulation of proapoptotic Bax levels [43,44,148]. In general, berry extracts have the ability to stimulate apoptosis of the HT-29, COX-2-expressing colon cancer cells. Black raspberry and strawberry extracts showed the most significant proapoptotic effects against this cell line [43] (Tables 1 and 6). 

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