• Journal of the Korean Society of Food Science and Nutrition
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• v.22 no.4
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• pp.500-509
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• 1993

Pectins present in the primary cell walls and middle lamellae of plant cell walls are extracted by water, cheating agents, acid or alkali solutions. However, some neutral contaminating components are extracted in conjunction with pectins during the extraction process. Thus, the accurate characterization of physi-cochemical properties of pectins necessitates to get rid of the impurities. In this review, dialysis, alcohol precipitation, ion exchange chromatography and metal precipitation were compared as procedures to purify the pectin extracts. In addition, the chemical methods to analyze pectins are discussed in terms of three major chemical constituents, i.e., anhydrogalacturonic acid, methoxyl groups and neutral sugars.

• The Korean Journal of Food And Nutrition
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• v.9 no.1
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• pp.92-98
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• 1996

Pectic materials, which are widely spread in the plant cell wall as plant carbohydrates, plays a great role in food Industry that acts as a softening agent of fruits and vegetables, and gel forming agents. To study physiochemical properties and industrial applications of pectic enzymes that hydrolyzes pectin, classification, assay method and Industrial application are reviewed based on previous results.

• Food Science and Preservation
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• v.8 no.2
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• pp.131-139
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• 2001

Kiyomi tangor(Citus unshiu x sinensis) was stored at 3$\^{C}$ and 85% relative humidity, and the changes in firmness, pectin degrading enzymes activity and other physicochemical properties of citrus fruits during storage were investigated. Decay ratio and weight loss during 180 days’ storage were increased gradually to 13.0% and 12.9%, respectively. Firmness of fruits with 2 mm probe was decreased gradually from 808.7 g-force to 406.4 g-force, and moisture of peel and flesh were decreased from 76.5% to from 89.6% to 87.6% during storage, respectively. Exo-polygalacturonase activity of peel after 150 days’ storage were increased gradually to 558.09 units/100g. Pectin methylesterase activity of peel and flesh were increased from 14.7 units/g to 2.3 units/g, and from 9.4 units/ml to 2.7 units/ml at 150days’ storage, respectively. Endo-polygalacturonase activities were not changed notably during storage. Alcohol-insoluble solid(AIS) of peel was not changed notably. During storage of the fruits water soluble pectin(WSP) of peel and flesh were increased from 474.49 mg/100g to 614.29mg/100g, and from 66.91mg/100g to 92.74mg/100g as wet basis, respectively. Hexameta-phosphate soluble pectin(HMP) of peel were decreased from 405.5mg/100g to 270.43mg/100g, hydochloric acid soluble pectin(HSP) of peel was also decreased from 544.02mg/100g to 412.64mg/100g during storage. Total pectin substance(TPS) of peel and flesh were decreased from 1,424.01mg/100g to 1,297.36mg/100g, and from 165.51mg/100g to 171.54mg/100g, respectively. Composition ratio of pectin was in order of WSP > HSP > HMP.

• Korean Journal of Environmental Biology
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• v.21 no.1
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• pp.31-35
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• 2003

The effects of different extraction methods on quality of citron juices were investigated in terms of chemical composition and sensory evaluation. Extraction methods employed were press-filtration with 400 mesh sieve, centrifugation, and enzyme pretreatment using pectinase. Enzyme pretreatment method showed the highest yield of juice with 68%, while press-filtration method, the lowest yield of juice with 26.3%. The pH of the juices was relatively similar at 3.29～3.34. Filter-pressed juice showed the highest concentration of soluble solid at 6.0$^{\circ}$Brix, while the juice produced using centrifugation showed the lowest concentration at 4.5$^{\circ}$Brix. In all the juices, fructose was the main soluble sugar. Concentration of organic acid was the highest with the juice produced with centrifugation so that supplementation with higher amount with sugar was needed for overall acceptability.

• Applied Biological Chemistry
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• v.33 no.1
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• pp.34-38
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• 1990

The molecular structural properties of amylopectins of Chunmabyeo(Japonica), Yongmunbyeo($Indica{\times}Japonica$) and Mahatma(Indica) rice were investigated. The intrinsic viscosity of Chunmabyeo, Yongmunbyeo and Mahatma amylopectin were 148.3 ml/g, 156.6 ml/g and 167.5 ml/g, and ${\beta}-amylolysis$ limit(%) were 54.6, 55.4 and 52.9 respectively. Average unit chain length(${\overline{CL}}$) and average inner chain length(${\overline{ICL}}$) of Mahatma amylopectin were longer than other varieties. Elution profiles by Sephadex G-50 chromatography of debranched amylopectins with ${\beta}-amylase$ showed two peaks (void volume, ${\overline{DP}}$3) and the elution profiles of debranched amylopectins with pullulanase showed three peaks(void volume, ${\overline{DP}}$35-45, ${\overline{DP}}$10-20). The ratio of Peak III(${\overline{DP}}$10-20) to Peak II (${\overline{DP}}$ 35-45) of Chunmbyeo, Yongmunbyeo and Mahatma amylopectin were 3.9, 3.4 and 3.3, respectively.

• Applied Biological Chemistry
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• v.36 no.4
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• pp.296-303
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• 1993

Response surface methodology was employed to investigate the conditions for separating water-soluble proteins from egg yolk using sodium alginate, propylene glycol alginate (PGA), sodium carboxymethylcellulose (CMC) and pectin which are approved as food additives. Effects of plysaccharide concentration and pH of the reaction system on protein and lipid contents in the supernatant were evaluated at respectively five and three levels of concentration and pH using rotatable hexagon design. Statistical analysis showed that pH of the system was a more important factor than polysaccharide concentration as it significantly affected all two responses. Separating conditions established by a graphical optimization technique were $0.23{\sim}0.25%$ of sodium alginate at $pH\;5.9{\sim}6.0$, $0.15{\sim}0.17%$ of PGA at $pH\;4.3{\sim}4.5$, $0.30{\sim}0.25%$ of CMC at pH 3.0, and $0.09{\sim}0.10%$ of pectin at $pH\;5.6{\sim}5.8%$.

• Applied Biological Chemistry
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• v.42 no.4
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• pp.317-323
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• 1999

Immature plums(Prunus salicina L.) were coated with edible coatings, calcium-added methyl cellulose(CaMC) and hydroxy propyl methyl cellulose-15(CaHPMC-15). Weight loss and respiration rate of immature plums coated with CaMC and CaHPMC-15 were lower only at the earlier storage period. The titratable acidity of plums was decreased and pH was increased during storage, Soluble pectin, pectinesterase, and polygalacturonase activity as the marker of softening were commonly increased with storage time, but those increases were lower in CaMC and CaHPMC-15-coated plums. Mechanical firmness became significantly soft during storage, while the coated plums were remained harder. As a result of sensory evaluation, softening of plum tissue was found during storage, but the coated plums had the harder texture. These data suggest that the application of CaMC or CaHPMC-15 coatings into immature plums can reduce the postharvest softening during storage.

• Applied Biological Chemistry
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• v.14 no.1
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• pp.1-7
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• 1971

In order to develop an enzyme preparation for clarification of fruit juices, a microbial strain having a strong pectolytic activity was selected and a crude enzyme preparation from this strain was examined for the effects in the preparation of grape juice and wine. The results are summarized as follows: 1) A strain of Aspergillus niger was selected as having the highest productivity of pectolytic enzymes among many species of Aspergillus and Rhizopus. 2) A pectolytic enzyme preparation was purified from this selected strain and the effects of pH and temperature on its enzyme activity and stability were investigated. 3) The use of the enzyme preparation brought about the increase in the free run yield and clarity of grape juice. 4) Whereas the use of the enzyme preparation did not exhibit any effect in the brewing of red wine, its use showed a good effect on the rates of filtration and clarity in the case of white wine.

• Korean Journal of Food Science and Technology
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• v.27 no.5
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• pp.757-761
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• 1995

The relationship between the molecular structure of rice starch and the texture of cooked rice was investigated using hot-water soluble rice starch. The structure of hot-water soluble starch bound amylose which was composed of small molecular weight and amylopectin which was composed of chain length of $\overline{DP}\;10{\sim}20$, and the average composition of amylose : amylopectin was 7 : 3. The molecular weight of amylose was the smaller and super long chain of amylopectin was the fewer, the extractable ratio of hot-water soluble rice starch was the higher. And hot-water solubility of rice starch be responsible for molecular structure of starch. On the texture of cooked rice, the extractable ratio of hot-water soluble rice starch was the higher, the hardness was the lower and the adhesiveness was the higher. The results suggest that the molecular structure of rice starch could be responsible for the texture of cooked rice.

• Korean Journal of Food Science and Technology
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• v.27 no.6
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• pp.928-933
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• 1995

Sensory and instrumental characteristics of mixed starch gels of defatted corn starch and mung bean starch were examined in terms of the effects of various additives such as textured soy protein(TSP), soybean oil(S0), carboxymethyl cellulose(CMC) and pectin(PC). Gels were prepared by storing the paste at room temperature for 24 hrs and 72 hrs. The additives were used 1% or 2% on the starch basis. The ratio of defatted corn starch and mung bean starch was selected 60 : 40(to, w/w), where the acceptability was the highest. The cohesiveness and springiness of the mixed starch gels stored 24 hrs increased, but the brittleness and acceptability decreased with all the additives. Textural characteristics of the mixed gels stored 72 hrs were different according to the type and content of additives, whereas hardness and cohesiveness increased in all case. Unlike the sensory evaluation, the textural properties of mixed gels tested by a Instron Universal Testing Machine showed no difference in hardness, but the cohesiveness and springiness increased.