• Journal of Nutrition and Health
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• v.29 no.7
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• pp.738-746
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• 1996

In order to anticipate the physiological function of dietary fibers, glucose and bile acid retarding effects were experimented by using in vitro methods based on dialysis for commercial fibers and dietary fiber residue of food samples. The glucose retarding effect in commercial fibers increased in the order of alginic acid, guar gum, CM-cellulose, citrus pectin > apple pectin > $\alpha$-cellulose and the effect in food fiber residues increased in the order of sea mustard > Korean cabbage, apple > rice bran, barley, soybean, and tangerine. The bile acid retarding effect in commercial fibers increased in the order of citrus pectin, guar gum > CM-cellulose, alginic acid > apple pectin > $\alpha$-cellulose and the effect in food fiber residues increased in the order of barley, rice bran > sea mustard > tangerine > Korean cabbage, soybean > apple. The higher the retarding effect of glucose movement through the dialysis membrane, the more effective the control of the human blood glucose level. As the retarding effect of bile acid movement across the dialysis membrane increased, the human serum cholesterol level correspondingly reduced. Consequently these in vitro methods can be used as a preceding test before undertaking animal and human experiments to predict the physioloical effects of fiber residues from diverse food samples as well as commercially refined fibers.

• Proceedings of the Korean Society for Applied Microbiology Conference
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• 1978.04a
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• pp.98.3-98
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• 1978

The condition necessary for maximal production of pectin trans-eliminase by culturing Aspergillus D-11 on a moistened wheat bran medium was studied. The maximum production of pectin trans-eliminase was obtained after cultivation for two, days at $29^{\circ}C.$ One tenth milligram of crude pectin trans-eliminase of Aspergillus D-11 having 0.15 units of activity could clarify 15-20 ml of apple juice within 3 hours at $40^{\circ}C.$ Optimal pH and temperature for clarifying apple juice by the crude-enzyme were found to be pH 4.5~5.0 and $45^{\circ}C$ respectively.

• The Korean Journal of Mycology
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• v.22 no.4
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• pp.298-308
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• 1994

The properties of polygalacturonase by Ganoderma lucidum in liquid culture were investigated. The enzyme was composed of an endo- and an exo-polygalacturonase. The endo- and exo-polygalacturonase were purified approximately 56 and 9.2-fold, respectively, through ammonium sulfate fractionation, gel filtration on Biogel P-100, anion exchange chromatography on DEAE-cellulose, gel chromatography on Sephadex G-150 and re-gel chromatography on Sephadex G-150. The endo- and exo-polygalacturonase had higher affinity for apple pectin than for citrus pectin or pectic acid. The Km values of the endo- and exo-polygalacturonase for apple pectin, determined on the Lineweaver-Burk plot, were 1.44 and 10.6 mg $ml^{-1}$ for apple pectin, respectively. Purified endo-polygalacturonase was found to be homogeneous electrophoretically and had a molecular weight of 54,000 estimated on SDS polyacrylamide gel. The optimal pH for the activity of the enzymes was 4.0. The endo- and exo-polygalacturonase were stable in the pH range of 4.0 to 6.0 and 3.5 to 5.5, respectively. The optimal temperatures of the endo- and exo-polygalacturonase were 40 and $60^{\circ}C$, respectively. The exo-polygalacturonase was more resistant to heat than the endo-polygalacturonase, requiring heating for 40 min at $80^{\circ}C$ for complete inactivation. The activity of the endo-polygalacturonase was increased by $Ca^{++}$ and $Mn^{++}\;ions$, while that of the exo-polygalacturonase was increased by $Ca^{++}\;ion$ only, and was not affected by $Mn^{++}\;ion$.

• The Korean Journal of Food And Nutrition
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• v.9 no.4
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• pp.413-418
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• 1996

Two methods were used to extract pectin from apple cell wall by enzyme(Hemicellulase) and by acid. Hemicellulase was used to extract high functional pectin with higher degree of polymerization. The yield of weight of pectin by hemicellulase treatment was slightly higher than that by acid treatment. The optimal condition for extraction was accomplished by providing 1.5 grams of Hemicellulase at 38$^{\circ}C$ for 24 hours. The comparison of the pectin purity and the yield of extracts by the portion of galacturonic acid between two methods showed that the purity of pectin extracted by enzymatic method was lower than that by acid treatment.

• Korean Journal of Food Science and Technology
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• v.31 no.1
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• pp.68-73
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• 1999

In order to overcome same disadvantages of acidic solubilization of pectin from apple pomace, enzymatic selective solubilization with exo-polygalacturonase was developed. According to analyses of the effects of temperature, pH and reaction time on extraction yield, the maximum yield by the enzymatic method, shown under the extraction condition of $45^{\circ}C$, pH 7 and 60 hours, was 31.0%, whereas the yield from an acidic method was 8%. Also the quality of pectin extracted by the enzymatic method was to that from acidic solubilization. The purity and methoxyl content of enzyme-extracted pectin were 80.1% and 6.36%, respectively, which were higher than 75.7% and 2.44% of acid-solubilized pectin. Viscosity average molecular weights of enzymic extracted and acid solubilized pectins were $1.50{\times}10^4\;and\;7.66{\times}10^4$, respectively.

• Food Science and Biotechnology
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• v.14 no.1
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• pp.28-31
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• 2005

To extract apple pectins, apple pomace (AP) was extruded under 14 different conditions of screw speed (250-350 rpm), feed rate of 30-40 kg/hr, and 20-30% moisture content using twin-screw extrusion. Response surface methodology (RSM), based on three variables by three-level factorial design, was employed to investigate effects of screw speed, feed rate, and moisture on dependent variables of extrudates, soluble dietary fiber (SDF), yield of anhydrogalacturonic acid ($Y_{AGA}$) representing pectin, and intrinsic viscosity ([${\eta}$]). Second order models were used to generate three-dimensional response surface for dependent variables, and their coefficients of determination ($R^2$) ranged from 0.96 to 0.99. Moisture content showed highest effect on solubilization of AP.

• Journal of the Korean Home Economics Association
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• v.19 no.4
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• pp.33-39
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• 1981

This study was attempted to determine the pectin contents of various fruits(Cherry, strawberry, plum, peach, apricot, apple, crabapple) and to investigate the changes in the properties of pectin and pectin gel during crabapple ripening. Methoxyl content, molecular weight and intrinsic viscosity were measured in ripened and unripened crabapples. In order to determine the characteristics of pectin gel, percent sag was measured by exchange Ridgelimeter, hardness and textural characteristics of jellies were measured by a penetrometer and a texturometer. The experimental results are summarized as follows: 1. The pectin contents of various fruits were 1.16% for cherry, 3.17% fir strawberry, 4.29% for plum, 5.51% for apricot, and pectin contents of peaches and apples varies depends on varieties from 4.54% to 5.61% to 6.52, respectively. The pectin contents of unripened and ripened crabapple wee 9.21% and 9.84% respectively, indicating that pectin content increased with fruit maturity. 2. The methoxyl contents, which was 6.61%~6.95%, was very low and it increased significantly during fruit ripening. Further, a decrease in acetyl content, intrinsic viscosity, molecular weight occurred during the ripening of crabapples. 3. The percent sag of crabapple jellies increased with fruit maturity from 5.26% to 5.79%, and the corresponding jelly grade decreased in ripened crabapple. 4. The hardness of jellies determined by a penetrometer was 79.15 pp.U. for ripened crabapple jelly, 90.62 pp.U. for unripe ned crabapple jelly. 5. In the textural characteristics of gels measured by a texturometer, the gels made from unripened crabapple were shown to have the highest values in hardness, cohesiveness, adhesiveness and gumminess.

• Korean Journal of Food Science and Technology
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• v.29 no.1
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• pp.107-114
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• 1997

Various fractions of apple fibers such as crude pulp, total dietary fiber, soluble dietary fiber, and insoluble dietary fiber were prepared and added to the proteose peptone-yeast extract-fildes (PYF) media to see their effects on the growth of type cultures of intestinal bacteria. Most microbes tested in this experiment grew well in PYF media with the soluble dietary fiber of apple than with the insoluble dietary fiber. Especially Bifidobacterium species such as B. adolescentis, B. animalis, B. infantis, B. longum, B. thermophilum showed higher growth in PYF media containing the soluble dietary fiber than other fiber fractions. However, pectin-added media didn't promote the growth of most microbes used in the experiment. In the in vitro mixed culture using rat feces as starter, the addition of the soluble dietary fiber or pectin to the basal medium showed larger proportion of Bifidobacterium species in total bacteria than that of glucose.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.3
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• pp.389-395
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• 1995

The neutral sugar sidechains of apple pectins were hydrolyzed by commercial hemicellulase produced from Aspergillus niger, and the corresponding changes in solution viscosity were investigated in dilute(cc*) pectin solutions. Pectinase activity included in hemicellulases was removed by Epoxy-activated Sepharose 6B affinity chromatography using polygalacturonic acid as a ligand. Enzymatic hydrolysis of sidechains did not affect the specifc viscosity of dilute(0.5%) pectin solutions, while viscosity significantly decreased in concentrated(2.0∼6.0%) region. These results strongly suggest that the sidechains of pectins exists as an entangled state in concentrated solutions. It was also found that in the concentrated region the extent of viscosity reduction was dependent on pectin concentrations.

• Korean Journal of Food Science and Technology
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• v.53 no.2
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• pp.121-125
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• 2021

Very low methoxyl pectin (VLMP) has different physical and rheological properties compared to high and low methoxyl pectins (HMP and LMP). In this study, we produced LMP and VLMP by alkaline de-esterification, and investigated the structural and textural properties. Apple peel pectin was kept at pH 12 using 5.0 M NaOH solution for 3 and 24 h to produce LMP and VLMP, respectively. The molecular weight was decreased due to the removal of an esterified group in the pectin backbones by the alkali treatment, and the VLMP showed a higher calcium ion sensitivity which leads to the production of the gel with increased hardness. The result clearly showed that VLMP has the potential to improve the texture and stability in food products depending on their degree of esterification, and this result can be applied as a functional ingredient in food industrial area application to enhance the current commercial pectins.