Apple juices

The eady juice industry was largely a salvage operation. The principal source of raw material was misshapen, poorly colored, or skin blemished fmit unsuitable for the fresh, canned, or frozen fmit market. In the 1990s, raw materials are selected for suitabiUty for juice production, except for apple juice production which still uses much cull fmit (4). 

Fig. 1. Manufacturing process for citrus (orange) and deciduous (apple) juices.

There are two methods available for aroma recovery. In one method, a portion of the water is stripped from the juice prior to concentration and fractionally distilled to recover a concentrated aqueous essence solution. Apple juice requires 10% water removal, peach 40%, and Concord grape 25—30% to remove volatile flavor as an essence. Fractional distillation affords an aqueous essence flavor solution of 100—200-fold strength, which means the essence is 100 to 200 times more concentrated in flavor than the starting juice. A second method of essence recovery is to condensate the volatiles from the last effect of the evaporator they are enriched in volatile flavor components (18). 

In the production of opalescent or natural-type apple juice, ascorbic acid is added to the fmit pulp before pressing, or to the juice as it comes from the press, to retain more of the apple flavor (4). Ascorbic acid addition and pasteurization of the juice as soon as possible after pressing prevent polyphenol oxidation, which causes browning and contributes to pulp flocculation. 

Use of ultrafiltration (UF) membranes is becoming increasingly popular for clarification of apple juice. AH particulate matter and cloud is removed, but enzymes pass through the membrane as part of the clarified juice. Thus pasteurization before UF treatment to inactivate enzymes prevents haze formation from enzymatic activity. Retention of flavor volatiles is lower than that using a rack-and-frame press, but higher than that using rotary vacuum precoat-filtration (21). 

Natural style juices that contain the cloud are increasing in popularity, especiaHy apple juices, because these retain more fresh flavor if processed carefuUy. Optimum processing conditions chill the fmit to 4°C before milling, add 500 ppm ascorbic acid to retard browning, press under nitrogen, and flash pasteurize the juice as quickly as possible (4). 

The principal fmit juice and beverage markets are the United States, where 12.1 x 10 L is consumed per year followed by Canada, 5.6 x 10 L Western Europe, 1.2 X 10 L andjapan, 0.76 x 10 L. In all significant markets orange juice predominates (Eig. 2). In the United States apple juice is second, followed by grape and then grapefmit juice (12). 

Sorbate combined with mild heat has a synergistic effect with regard to microbial destmction thus, in the presence of 0.025—0.06 wt % sorbate, products such as apple juice, peach and banana sHces, fmit salads, and strawberries can be treated with less severe heat treatments to extend shelf life (119,120). Sorbates increase the heat sensitivity of various spoilage fungi under varying conditions of pH and water activity (121—124). A similar synergistic effect has been reported for the combination of sorbate with irradiation (125). 

Grape and apple juices usually contain all of the trace nutrients required by Saccharomjces for fermentation of sugars to alcohol. Other fmit and diluted honey, as well as barley malt and rice extract, frequendy need additions of nitrogen, phosphoms, and potassium compounds, together with some autolyzed yeast to faciUtate the yeast growth necessary for fermentation. Stimulation oiy4.cetobacter frequendy requires the addition of autolyzed... 

Fermentation of fmit juices other than grapes, principally apple juice, is the same as that in the production of grape wine. For the production of mm, cane molasses is diluted to a sugar concentration of 15—29% the sucrose, glucose, and fmctose is completely fermented within 36 h at 30—32°C. 

The important commercial feature of these juices, especially significant with blackcurrant and tomato juices, is their ascorbic acid (or vitamin C) content, of which loss by oxidation is known to be accelerated both by heat and by metal (particularly copper) contamination. The effect of copper has been carefully investigated for pure ascorbic acid", and more recently ascorbic acid in blackcurrant juice and model systems. There are, however, oxidation inhibitors of different kinds (which may themselves be heat-sensitive) present in various fruits, which give differing results. The presence of metals will also affect flavours", may cause discoloration, and may give rise to clouding effects, as in apple juice. ... 

D. the drug is given mixed witii orange juice or apple juice... 

Oral liquid concentrates are available for use in patients who can more easily swallow a liquid. These concentrates are light sensitive and dispensed in amber or opaque bottles to help protect the concentrate from light. They are administered mixed in liquids such as fruit juices, tomato juice, milk, or carbonated beverages. Semisolid foods, such as soups or puddingy, may also be used. Perphenazine (Trilafon) concentrate should not be mixed with beverages containing caffeine (coffee, cola), tea, or apple juice because of the risk of incompatibility. 

Fig. 2 HPSEC profiles of three RG-II fractions purified from red wine (a), apple juice (b) and tomato juice (c) on Shodex OHpak KB columns. Elution times and Mw (kDa) of the pullulan standards are shown.

Sugar residue Red Wine Apple Juice Tomato Juice... 

This study is the first report of the presence of rhamnogalacturonan n in fruit-derived products with the exception of the RG-n from wine [20]. Our RG-II preparations correspond very closely to the described model [1,13], confirming the conservation of its structure among plant cell walls. The complexity of the structure and composition of RG-II with several rare sugars uneasy to identify may be one possible explanation of why this fascinating molecule remained undetected in apple juices for such a long time. 

Schols HA, Posthumus MA, Voragen AGJ (1990b) Structural features of hairy regions of pectins isolated from apple juice produced by the liquefaction process. Carbohydr Res 206 117-129... 

In this presentation, we will take examples of different fruit juice processes and will try to relate enzyme activities, the role they play and the transformation they occur in terms of finished products. These examples will concern apple juice, french cider, pineapple and wine. 

In conclusion, the use of exogenous pectinases allows to produce a clear and stable apple juice easily concentrated. 

The present paper demonstrates applications of combinations of cloned monocomponent enzymes, including combinations with rhamnogalacturonases, for production of cloud stable apple juice, gelation of fruits, degradation of soy cell walls, production of dietetic soy and production of carrot puree are demonstrated. 

Apples (Red Belle de Boskoop, Jonagold or Mutzu) were cut and milled (1.5 mm) and 5% (w/w) of a 2% ascorbic acid solution was added immediately. Enzyme preparations (25 mg enzyme protein / kg mash) were added and the mash was incubated for 2 hours at 20°C whereafter it was pressed. The resulting apple juice was pasteurised at 85°C to discontinue further enzyme degradation. The cloud was measured as turbidity in EF/F units [15]. The cloud stability was determined by a centrifugation test as the amount of turbidity remaining after centrifugation at 4,200 x g for 15 minutes [15]. 

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