Apple juice processing

From application trials it was clear that addition of RGase containing fiactions when used in combination with other pectinases has a beneficial effect on file apple-juice process. 

Sancho, M.F, Rao, M.A., Aroma Retention and Recovery during Apple Juice Processing, New York Science Agricultural Experiment Station Special Report No.65, October 1992. (see also.Flus-siges Obst/Fruit Processing, 5, 175-177, (1993))... 

Van Buren, J.P. Causes and prevention of turbidity in apple juice. Processed Apple Products, D.L. Downing, ed.. Van Nostrand Reinhold, New York, 1989. 

WaUding-Ribeiro, M., Nod, F., Cronin, D.A., Riener, J., Lyng, J.G., and Morgan, D.J. 2008. Reduction of Staphylococcus aureus and quality changes in apple juice processed by ultraviolet irradiation, pre-heating and pulsed electric fields. Journal of Food Engineering 89 267-273. 

Apple juice processing—Continued sugar composition of alcohol-insoluble solids, 231-232t sugar and glycosidic linkage... 

Rungsardthong V, Wongvuttanakul N, Kongpien N, Chotiwaranon P (2006) Application of fungal chitosan for clarification of apple juice. Process Biochem 41 589-593... 

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

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). 

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. 

A commercial pectinase, immobilised on appropriately functionalised y-alumina spheres, was loaded in a packed bed reactor and employed to depolymerise the pectin contained in a model solution and in the apple juice. The activity of the immobilized enzyme was tested in several batch reactions and compared with the one of the free enzyme. A successful apple juice depectinisation was obtained using the pectinase immobilised system. In addition, an endopolygalacturonase from Kluyveromyces marxianus, previously purified in a single-step process with coreshell microspheres specifically prepared, was immobilised on the same active support and the efficiency of the resulting catalyst was tested. 

Spanos GA, Worlstad RE and Heatherbell DA. 1990. Influence of processing and storage on the phenolic composition of apple juice. J Agric Food Chem 38 1572—1579. 

During processing, affected fruit is generally removed or pressurized-water jets are utilized to remove damaged portions of fruit and contaminations (or both). These processes effectively eliminate patulin. However, if these procedures are not done properly, patulin may remain in the processed apple juice and apple products, where it is very stable. Pasteurization at 90°C only causes a reduction of 10%, however patulin is not stable in the presence of sulfur dioxide or sulfydryl compounds. The fermentation process for cider eliminates 99% of patulin. 

However, in the case of apples and many other fruits the (S)-enantiomer of ethyl 2-methylbutanoate, the impact flavour compound of apples, was identified with high enantiomeric purity, irrespective of the apple variety investigated and was unaffected by processing conditions (e.g. distillation, concentrating) or storage of apple juices. 

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]. 

The phenolic composition of apple consists of cinnamic acids, flavonols, dihydrochalcones, and flavan-3-ols (50,56). In the apple fruit processing industry, hydroxycinnamic acid derivatives and flavan-3-ols are important due to their contribution to the astringency, haze, and browning in apple juice and cider. Chlorogenic acid represents the major hydroxycinnamic acid derivative. The flavan-3-ols (catechins) are present in the monomeric form as well as in oligomeric and polymeric forms (procyanidins) in apple and apple products (56). 

Low, N.H. and Hammond, D.A. (1996) Detection of high fiuctose syrup from inulin in apple juice by capillary gas chromatography with flame ionisation detection . Fruit Processing 4, 135-41. 

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