• Korean journal of food and cookery science
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• v.11 no.5
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• pp.542-547
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• 1995

Pectinesterase was isolated from the culture medium of Aspergillus japonicus and partially purified by DEAE-Sephadex batchwise, Sephadex G-75 gel filtration and ion exchange chromatography. The purified enzyme solution was completely free from polygalacturonase which depolymerizes pectin molecule. The ability of the pectinesterase to demethylate high methoxyl pectin was investigated. On 20 minute of incubation methoxyl content of low methoxyl pectin decreased from 88％ to 6.93%. In general gel prepared with the pectin containing lower methoxyl content showed the lower value of percent sag, and showed the hieher Bel strength. Textural characteristics of pectin gel determined by Rheometer showed that as the methoxyl content was lowered, hardness and resilience of the gel were increased and cohesiveness was decreased. Apple juice containing HMP and organic acids can be converted into low methoxyl pectin apple jelly by the action of pectinesterase and addition of calcium ion. The strength of low methoxyl pectin apple jelly increased when it stored at room temperature.

• Korean journal of food and cookery science
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• v.6 no.1
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• pp.9-12
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• 1990

This study was carried out in order to investigate the physicochemical properties of isolated pectic substances from Citron, Satsuma mandarin, Marumero, and Natsudaidai. Among varieties, Citron had the highest value of isnoluble pectin and Marumero had the hightest ratio of soluble pection. The total pectin contents isolated by 2% Sodium hexameta-phosphate(SHMP) varied in the range of 1.85% ~ 2.63%. Anhydrogalacturonic acid(AUA) contents were 78.64%~89.14% and were lower than commercial pectin. Isolated pectin contained above 7% methoxyl content and above 50% esterification. The apparent molecular weight of commercial pectin and isolated pectin were 72,000 and 42,000~46,000 respectively. Esterification and ester methoxyl content were the lowest and apparent molecular weight was the highest in Satsuma mandarin. Citron's values were a little higher in esterification and ester methoxyl content and lower in apparent molecular weight than the others.

• Applied Biological Chemistry
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• v.42 no.1
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• pp.1-5
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• 1999

For effective utilization of apple pomace, protopectinase(PPase) produced from Bacillus subtilis IFO 12113 was used for pectin extraction from apple pomace. Optimal conditions for enzyme treatment were found at $60^{\circ}$, pH 7.8, 48 hours with 20 : 1 ratio of substrate to enzyme. The yield of extracted pectin from water-alcohol insoluble pectin by enzyme at optimal condition was 34.3%. The purity and methoxyl content of extracted pectin by PPase at optimal condition were measured as 52.9% and 2.75%, respectively. Intrinsic viscosity and average molecular weight of extracted pectin by enzymatic method were 0.178 ml/g and $4.9{\times}10^3$, respectively.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.257-263
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• 2006

This paper examines the physico-chemical properties and structural features of thio lignin and alcohol lignin preparations extracted from fast-growing poplar wood. The lignin preparations were characterized using UV, IR and alkaline nitrobenzene oxidation methods. The yield was higher in thiolignin due to its preparation from wood under drastic alkaline conditions and almost the total amount of alkaline degraded lignin was precipitated except acid soluble lignin. In case of ethanol lignin, structural modifications were comparatively less and form a cream colored lignin more or less similar to its original natural color. The methoxyl values were higher due to syringyl unit present in hard wood lignin in addition to guaicyl unit present in soft wood. The higher values of methoxyl content of isolated lignin revealed that it was built up of high syringyl units. The elementary analysis, methoxyl group and hydroxyl groups were presented by $C_{9}$ formula indicated that it was made up of phenyl propane monomers. Nitrobenzene oxidation of thio lignin and ethanol lignin yield more or less the chromatograms of similar pattern, except difference in relative percentage. The ultra violet spectra of lignins were quite similar, irrespective of the source and method of isolation. Infrared spectroscopy studies of poplar deltoides, thio and ethanol lignin shown different absorption bands which have been utilized for structural investigations.

• 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.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.

• Korean journal of food and cookery science
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• v.2 no.1
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• pp.65-70
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• 1986

Total pectin content of Korean apple varieties at optimum harvest time was deter-mined by carbazole reaction method and pectin fraction content in each variety was also determined. Properties of pectin extracted ty 2a Sodium hexa metaphesphate were compared with commercial pectin. Among apple varieties, pectin contents varied in the range of 0.26-0.48％ on fresh basis and 1.76-4. 0% on dry basis. Ball's was the highest and then high in order of Spur early blaze, Golden delicious, Fuji. , Jonathan. In each pectin fraction, soluble pectin fractions in Rall's was the lowest and in both Spur early blaze and Golden Delicious were highest but insoluble fractions in the latter were lowest. Thub the changes in poetic substances in Spur early blaze and Golden delicious seem to he occurred: during early ripening. In the analysis of properties of isolated pectin, ash, anhydrogalacturonic arid7(AUA) content and methoxyl content were different among apple varieties. Ash and methoxyl content in all isolated pectin were higher and AUA content lower than in commercial pectin. Degree of esterification (DE) in all apple varieties were above 70％.

• Korean Journal of Food Science and Technology
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• v.23 no.4
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• pp.420-427
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• 1991

The structure of fresh, salted and heated petiole tissue from Chinese cabbage was examined with optical microscope, and the pectin of the tissues was fractionated by successive extraction. The pectin in Chinese cabbage consisted mainly of high methoxyl pectin(pA) and low methoxyl pectin(pB). The pA content was converted to pB markedly by salting and heating at $60{\sim}70^{\circ}C$ for 30 min while heating the cabbage above 80 decreased pB content. The firmness of heated tissue was highly correlated with pB content(r=0.996). Cytorrhysis test showed that pore size of the tissue became smaller by salting and heating at temperature below $80^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.4
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• pp.569-573
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• 2001

A pectic substance from citron peel was extracted with different methods to establish the optimum extraction conditions. The extraction yields of pectin with HCl, citrate and tartrate (concentration : 0.1 N, extraction ratio : 1 : 20) were 17.9%, 15.6% and 11.4%, respectively. Six times of 65% ethanol washing step was followed after first ethanol precipitation of acid extract for pure pectin. The degree of esterification (DE) of pectins was in the range of 43.0~47.6% and intrinsic viscosity was in the range of 0.94~2.63 (η$_{sp}$ /C (dL/g)). The sugar compositions such as rhamnose, xylose, glucuronic acid, galacturonic acid, galactose and glucose were little different in three kinds of pectins except for the content of arabinose.

• Korean Journal of Food Science and Technology
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• v.31 no.4
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• pp.971-976
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• 1999

Exo-polygalacturonase (EPG) from Rhizopus sp. was applied to the extraction of pectin from pear pomace because EPG produces pectin by solubilizing protopectin. The content of total galacturonic acid in water-alcohol insoluble pectin (WAIP) was determined as 34.6%. Pear pomace was solubilized by using EPG, with regarding reaction pH, temperature, time and ratio of enzyme to substrate in order to find optimum condition. While the yield by an acidic treatment was 6.2%, the maximum yield by an enzymatic treatment was 23.4% under the extraction condition of pH 7.8, $60^{\circ}C$, 36 hr and 1/10 of enzyme/substrate. At this condition, the purity and methoxyl content of enzyme-extracted pectin were, respectively, 34.7% and 0.7%, while those of acid-extracted pectin were, respectively, 71.1% and 5.0%. Meanwhile, the average molecular weight of pectin extracted by the enzymatic method was $2.5{\times}10^{3}$ while that of acid-solubilized pectin was $8.4{\times}10^{3}$.