Pectinesterase orange

Jansen, E.F. Jang, F. Bonner, J. 1960. Orange pectinesterase binding and activity. Food Research 25 64-72. 

The apparent Michaelis constants for pectinesterase are usually given in percentage of pectin, which constitutes a poorly defined substrate, so that the quantitative value of these data is limited. For pectinesterases of various origins, Km values of 0.04-0.24% of pectin were found.36,58-62 For orange pectinesterase, by using pectins having... 

MacDonnell, L. R. Jang, R. Jansen, E. F. Lineweaver, H. Specificity of pectinesterases from several sources with some notes on purification of orange pectinesterase. Arch. Biochem., 1950, 28, 260-273. 

Rombouts, F. M. Wissenburg, A. K. Pilnik, W. A. Chromatographic separation of orange pectinesterase isoenzymes on pectates with different degrees of cross-linking. J. Chromatogr., 1979, 168, 151-161. 

Pectinesterases are quite specific for galacturonide esters, which act on pectin at least 1000 times as fast as on non-galacturonide esters (62). A polygalacturonate chain structure is therefore essential to pectinesterase action. Orange pectinesterase, for example, will not attack the methyl ester of polymannuronic acid (62). 

Other pectins with degree of esterification of about 10, 30 and 40% (Table I) were obtained by enzymic deesterification of the initial preparation. An orange pectinesterase was used and the pH of the reaction was 6 in order to avoid concurrent base-catalyzed saponification. The action of plant pectinesterase is known (16-18) to result in a blockwise arrangement of free carboxyl groups in the pectic molecules. The enzymic preparation does not contain depolymerase activities as shown by the constancy of the intrinsic... 

Van Den Broeck, L, Ludikhuyze, LR., Van Loey, A.M., and Hendrickx, M.E. (2000) Inactivation of orange pectinesterase by combined high-pressure and -temperature treatments a kinetic study. Journal of Agricultural and Food Chemistry, 48, 1960-1970. 

Evans, R. McHale, D. 1968. Multiple forms of pectinesterase in limes and oranges. Phytochemistry 17 1073-1075. 

Rouse, A.H. 1951. Effect of insoluble solids and particle size of pulp on the pectinesterase activity in orange juice. R. State Hort. Soc. Proc. 64 162-166. 

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. 

Versteeg, C. 1979. Pectinesterases from the orange fruit - Their purification, general characteristic and juice cloud destabilizing properties. Ph.D. thesis. Agricultural Univ., The Netherlands. 

Versteeg, C. Rombouts, F.M. Spaansen, C.H. Pilnik, W. 1980. Thermostability and orange juice cloud destabilizing properties of multiple pectinesterases from orange. J. Food Sci. 45 969-973. 

Wicker, L. Vassallo, M. Echeverria, E. 1988. Solubilization of cell-wall-bound, thermostable pectinesterase from Valencia oranges. J. Food Sci. 53 1171-1174 and 1180. 

Data on the pectin content of the initial material (AUAC and DE) is presented in Table 1. It is evident that the main difference between the two lots of oranges was in their anhydrouronic acid content. Observations from previous research (1) were confirmed that microwave heating of the fresh material ensured better drying conditions by inactivating pectolitic enzymes, particularly pectinesterase. Thus a better retention of the degree of esterification of pectin was ensured. 

Relatively less attention has been devoted to the isolation of pectinesterase from oranges.35,36 Jansen and coworkers87 described a purification of pectinesterase by adsorption on the cell walls of oranges this adsorption is not specific, but serves to provide a 7.5-fold increase of specific activity. 

Pectinesterase and limonin D-ring lactonase are the only enzymes known to catalyze reactions that adversely affect the quality of citrus juices. Bruemmer et al. (64) listed other enzymes that have been detected in citrus juices and described some of the reactions that can occur in the juices. None of the reactions appear to noticeably affect the quality of commercial juices. Freshly extracted citrus juices contain esterase (EC 3.1.1.1) (65, 66) and phosphatase (EC 3.1.32) (66, 67) activities. Native substrates in orange juice for peroxidase... 

Versteeg, C. Pectinesterases from the orange fruit - their... 

Termote, F. Rombouts, F. M. Pilnik, W. Stabilization of cloud in pectinesterase active orange juice by pectic acid hydrolysates. J. Food Biochem., 1977, 1, 15-34. 

In the same study the relative activities of pectinesterases from alfalfa, tomato, orange, and a fungal source were compared using commercial pectin, methyl polygalacturonate (fully esterified), and ethyl polygalacturonate (50% esterified) as substrates. The latter two substrates were prepared by HCl-catalyzed esterification (68, 69). The enzymatic attack rate of the pectinesterases on the methyl ester was approximately 50% of that on pectin (except for the fungal enzyme where the rate was 80% of that on the pectin substrate). Kertesz (70)... 

Pasteurization appears to have a major impact on the stability of juice cloud in orange juice concentrates because of the deactivation of pectinesterase enzymes (Chandler and Robertson, 1983). 

Collet et al. (2005) stated that the study of pectinesterase inactivation behavior is important because pectinesterase is responsible for juice cloud stability loss, is composed of several isoenzymes, and occurs naturally in orange. Freshly squeezed juice of Pera orange (Citrus sinensis) was pasteurized at temperatures of 82.5, 85.0, and 87.5°C. At least five runs with different holding times were performed for each temperature. As the isothermal curves obtained showed deviations from the expected first-order kinetics, the data was statistically treated by applying a nonlinear regression, and the estimated best fit was a three-parameter-multicomponent-flrst-order model. At 82.5°C, the isothermal curves showed a nonzero asymptote of inactivation, indicating that at this temperature the most heat-resistant... 

Ingallinera et al. (2005) compared total pectinesterase activity of Sicilian blood oranges (Sanguinello, Moro, and Tarocco) with the blonde Navel cultivar, checking enzyme stability with various pasteurization time and temperature (70-8 5 °C) conditions in order to optimize the heat treatment and increase the shelf life of the pasteurized juice. To do this they stored the juices at 4, 15, and 25°C for times ranging between 10 minutes and 50 days. Decimal reduction time and temperature (D and z) and the kinetic constant k) were established to optimize and increase the shelf life of the pasteurized juiee. Finally, a heat treatment (85°C x 3 minutes) of both microbiological and enzymatic efficacy was developed that does not compromise anthocyanin stability. 

Bayindirli et al (2006) studied the effectiveness of treatment on pectinesterase activity in orange juice, comparing the application of high hydrostatic pressure with a mild heat treatment. The residual pectinesterase activity in the orange juice after treatment at 450 MPa and 50°C for 30 minutes was determined as approximately 7 1.6%. This compares with 12 0.2% after a treatment of 40°C and 450 MPa for 60 minutes. The inactivation was irreversible and the enzyme was not reactivated when stored at 4 and 25 °C for 1 week. 

Goodner, J.K., Braddock, R.J., and Parish, M.E. 1998. Inactivation of pectinesterase in orange and grapefruit juices by high pressure. J. Agric. Food Chem. 46, 1997 2000. 

Ingallinera, B., Barbagallo, R.N., Spagna, G., Pahneri, R., and Todaro, A. 2005. Effects of thermal treatments on pectinesterase activity determined in blood orange juices. Enzyme Microb. Technol. 

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