Oranges juice pectin

Pulp free orange juice % pectin (galacturonic acid)... 

Castaldo, D., Lovoi, A., Quagliuolo, L., Servillo, L., Balestrieri, C. and Giovane, A. 1991. Orange juices and concentrates stabilization by a proteic inhibitor of pectin methylesterase. J. Food Sci. 56 1632-1634. 

Rouse, A.H. Atkins, C.D. 1955. Pectinesterase and pectin in commercial orange juice as determined by methods used at the Citrus Experiment Station. Florida Agric. Exper. Station Bull. 570 1-19. 

Citrus fruits, especially certain of their component parts, constitute one of the richest sources of pectin. On a dry weight basis, as much as 30% of orange fruit albedo may be pectin (8). The rag, comprising the fruit core and segment membranes after juice extraction, is also a rich source. Since pectin is a cell wall component, it follows that comparatively little would be present in juice expressed from fruit. For example, concentrations ranging from 0.01 to 0.13% in orange juice have been reported (15). Much of this would be present as cell wall fragments and particulate material in juice pulp and cloud. 

Gelation became a significant problem with the introduction of frozen orange juice concentrate, which initially was often packed without pasteurization. This product, when not frozen, rapidly developed low ester pectins by virtue of the PE it contained. Much of the research generated in response to this problem has been reviewed by Joslyn and Pilnik (22). Briefly, it has been found that gelation is the result of pectin deesterification (23), and increases as juice pulp (24), PE... 

Interaction of volatile and nonvolatile constituents in foods results in flavor modifications of varying intensities. The effects of 5 -nucleotides on the flavor threshold of octanal (23) and the effects of acid, sugar, and pectin on the flavor threshold of limonene (24) have been studied in orange juice. 

Ahmed, E. M. Dennison, R. A. Dougherty, R. H. Shaw, P. E. Effect of nonvolatile orange juice components, acid, sugar and pectin on the flavor threshold of d limonene in water. 

The chemical composition of dried orange juice sacs is as follows (44) crude fiber (18.9%), protein (9.0%), pectin (20.6%), ash (3.1%), fat 2.07.), moisture (10%), and other mostly carbohydrate material (36.4%). Another report (46), compared dried juice sac composition with whole peel and core material and found the three to be similar in composition. 

When freshly squeezed orange juice is allowed to stand, the suspended pectic compounds ("cloud") separate and settle from the juice. This phenomenon can be prevented by heating the freshly squeezed juice to inactivate the pectin methylesterase, producing a "cooked flavor." Alternatively, additional polygalacturonase can be added to the juice (53). Cloud precipitation is caused by Ca + chelating the pectic acid produced by pectin methylesterase. 

Endogenous pectin esterases play an important role in citrus processing they have therefore been studied intensively. They cause cloud loss in citrus juices, which is due to the calcium precipitation of enzymatically de-esterified pectin. This is desirable in the production of lemon and lime juices but undesirable in the production of orange juice. In orange juice concentrates strong calcium pectate gels may form which cannot be reconstituted... 

In strawberry puree, pressurization above 250 MPa generated a poly-phenoloxidase activity loss of 60%, while peroxidase activity decreased in 25% with pressures above 230 MPa. A combination of temperature and pressure reduced the activity of pectin methyl esterase in orange juice by up to 50% (Cano et al., 1997). As shovm by Basak and Ramaswamy (1996), the inactivation of pectin methyl esterase in orange juice depends on pressure level, time of treatment, pH, and soluble solids content. In Satsuma mandarin juice, 300-400 MPa for 10 min was required to partially inactivate the pectin methyl esterase, which was reactivated neither after treatment nor during storage. This demonstrated that the greater the concentration of soluble solids in the medium the lower the inactivation of the enzyme (Ogawa et al., 1990). 

Basak, S. and Ramaswamy, H.S. Ultra high pressure treatment of orange juice a kinetic study on inactivation of pectin methyl esterase, Food Res. Int., 29, 601,... 

Figure 8. Possibilities for preventing PE-induced calcium pectate precipitation in orange juice by enzymatic pectin degradation. (Reproduced from ref. 53. Copyright 1980 American Chemical Society.)...

Sampedro, R, Rodrigo, D., and Hendrickx, M. 2008. Inactivation kinetics of pectin methyl esterase under combined thermal high pressure treatment in an orange juice milk beverage. Journal of Food Engineering 86 133-139. 

Giner-Segui et al. (2006) studied the evolution of polygalacturonase (PG) (EC 3.2.1.15) activity in aqueous solution of commercial enzyme preparation. Up to 76.5% reduction of the PG activity could be achieved at 38 kV cm and 1100 J,s EF intensity and treatment time, respectively. However, an enhancement of PG activity at soft PEF treatment conditions (up to 110.9% at = 15kV cm and 300 J,s) was observed. A maximum of 80% of pectin methyl esterase activity in orange juice was inactivated at 35 kV cm and 1500 J,s EF strength and treatment time, respectively (Elez-Martinez et al., 2007). 

Citrate-phosphate Mcllvain buffer Beverage formulation (orange juice, water, skimmed milk, sugar, pectin, citric acid) 0.1% NaCl... 

Elez-Martmez, P., Suarez-Recio, M., and Martfn-Belloso, O. 2007. Modeling the reduction of pectin methyl esterase activity in orange juice by high intensity pulsed electric fields. Journal of Food Engineering 78 184—193. 

Yeom, H.W., Streaker, C.B., Zhang, Q.H., and Min, D.B. 2000b. Effects of pulsed electric fields on the activities of microorganisms and pectin methyl esterase in orange juice. Journal of Food Science 65 1359-1363. 

Lacroix, N., Fliss, I., and Makhlouf, J. 2005. Inactivation of pectin methylesterase and stabilization of opalescence in orange juice by dynamic high pressure. Food Res. Int. 38, 569-576. 

Polydera, A.C., Galanou, E., Stoforos, N.G., and Taoukis, P.S. 2004. Inactivation kinetics of pectin methylesterase of Greek Navel orange juice as a function of high hydrostatic pressure and temperature process conditions. J. Food Eng. 62, 291-298. 

Various commercial pectins and pectinesterase-treated pectins have been fractionated according to their degree of esterification in the range 6-70%. These fractions were tested for their ability to destabilize the cloud in orange juice. The juice was clarified by fractions with degrees of esterification between 6 and 14%, but not at all by those with degrees of esterification greater than 21%. 

Ingram and Vas (1950a) studied this reaction with several compounds other than glucose which might be present in orange juice. These included other sugars, other aldehydic and ketonic compounds, and pectin. It was... 

Pectin methylesterase (EC 3.1.1.11) causes the flocculation of pectic acid (cf. 2.7.2.2.13) in orange juices and reduces the consistency of tomato products. In orange juice, irreversible enzyme inactivation reaches 90% at a pressure of 600 MPa. Even though the enzyme in tomatoes is more stable, increasing the temperature to 59-60 °C causes inactivation at 400 MPa and at 100 MPa after the removal of Ca + ions. 

Fresh orange juice contains about the same levels of most of the nutrients present in fresh oranges, except for fiber, pectin, and the bioflavonoids, which are present mainly in the peel and the membranes which surround the segments of fruit... 

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