• 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.

• Journal of the Korean Wood Science and Technology
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• v.26 no.3
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• pp.26-32
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• 1998

The chemical composition of differentiating xylem of Populus deltoides M. were investigated and compared with those from sapwood. The cell wall polysaccharides were extracted sequentially from a differentiating xylem and sugar composition was analyzed with G.L.C, H.P.L.C and gel chromatograpy. The pectin substance and hemicellulose are rich in the cell wall of differentiating xylem. The $H_2O$ extract polysaccharides from differentiating xylem were composed with xylose-glucose residues which seem to be xyloglucan and a pectin. The arabinogalactan and the mannan were extracted with $Na_2CO_3$ solution and also the xylan was extracted with KOH solution. Sugar composition of each fractions in gel filteration of purified $H_2O$ polysaccharide suggests that the xyloglucan can be extracted with $H_2O$ from differentiating xylem.

• Korean journal of food and cookery science
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• v.2 no.2
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• pp.55-61
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• 1986

This study was attempted to investigate the occurrence and the partial characteristics of pectinesterase (PE) in cucumbers. And the involvement of endogenous cucumber PE with the formation of insoluble pectic acid, in the presence of endogenous or added calcium ions, was also studied. The results of this study are as follows: 1) PE activity was detected in whole cucumber homogenate. 2) The optimum pH and temperature of this enzyme were found to be 8.5 and $50^{\circ}C$, respectively 3) When PE extract was added to 0.25% pectin solution, pectin gel was formed. The time required for the formation of pectin gel was reduced when the pectin solution was adjusted to the optimum conditions for PE activity(pH 8.5, $50^{\circ}C$) and $CaCl_2$ was added. 4) Cucumber juice which was heated to $100^{\circ}C$ for 10 minutes fatted to form any insoluble pectate precipitate. The formation of precipitate in cucumber juice was accelerated by preheating to $50^{\circ}C$, adjusting to pH 8.5 and addition of $CaCl_2$. 5) These results can be interpreted that endogenous PE in cucumber juice demethylates pectin, allowing interlinking of pectin molecules via divalent cation $(Ca^{++})$ and thus forming insoluble Ca-pectate. Therefore additional firming effects of cucumber can be expected to be obtained through activation of PE in conjunction with calcium ions.

• Culinary science and hospitality research
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• v.20 no.2
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• pp.54-64
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• 2014

In order to enhance the firmness of retorted onion, long time, low temperature blanching(LTLT) in calcium solution was conducted. Pre-heating onion in calcium solution significantly improved its texture after high temperature sterilization as compared to conventional blanching alone. The improvement of the firmness by the LTLT blanching is related to the formation of strongly cross-linkages between carboxyl groups and divalent cations($Ca^{2+}$) by the action of pectin methy-lesterase(PME) in onion. A maximum firmness of retorted onion was obtained at the condition of pre-heating at $70^{\circ}C$ for 120min in 0.5%calcium solution. This result supports that the activity of PME and the content of bonded calcium in onion were highest at $70^{\circ}C$. Additionally, the reaction of alkali calcium with various divalent cations such as $Mg^{2+}$ provided a function to hydrolyze pectin molecules, resulting in firmer retorted onion in various calcium agents. Further investigation should be carried out to determine the optimal condition for prevention of tissue softening of various retorted vegetables.

• Food Science and Preservation
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• v.3 no.1
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• pp.93-104
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• 1996

The cell wall components of fruit include cellulose. hemicellulose, pectin, glycoprotein etc., and the cell wall composition differs according to the kind of fruit. Fruit softening occurs as a result of a change in the cell wall polysaccharides : the middle lamella which links primary cell walls is composed of pectin. and primary cell walls are decomposed by a solution of middle lamella caused due to a result of pectin degradation by pectin degrading enzymes during ripening and softening, During fruit ripening and softening, contents of arabinose and galactose among non-cellulosic neutral sugars are notably decreased, and this occurs as a result of the degradation of pectin during fruit repening and softening since they are side-chained with pectin in the form of arabinogalactan and galactan Enzymes involved in the degradation of the cell wall include polygalacturonase, cellulose, pectinmethylesterase, glycosidase, etc., and various studies have been done on the change in enzyme activities during the ripening and softning of fruit. Among cell wall-degrading enzymes, polygalacturonase has the greatest effect on fruit softening, and its activity Increases during the maturating and softening of fruit. This softening leads to the textural change of fruit as a result of the degradation of cell wall polysaccharides by a cell wall degrading enzyme which exists in fruit.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.33 no.5
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• pp.905-910
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• 2004

This study was carried out to observe the change of oriental melon juice quality during manufacture by heating condition and enzyme treatment. To use over-production oriental melon effectively, oriental melon juice was prepared with change of heating temperature and heating time. The heating conditions for minimum filtration time were 98.57$^{\circ}C$ and 11.29 min. The optimum conditions Predicted for separation ratio of clear solution, filtration time and browning color intensity of oriental melon juice were 98$^{\circ}C$, 13 min. In the pectin-degrading enzyme treatment test, turbidity showed minimum value in 4.40 mg％(pectin-degrading enzyme content)， 39.72 mg％ (gelatin content) and 24.09 min (treatment time)．Browning color intensity showed minimum value in 9.33 mg％ (pectin-degrading enzyme content)，44.70 mg％ (gelatin content) and 115.56 min (treatment time). The optimum conditions predicted for turbidity and browning color intensity of oriental melon concentration Juice were 6.6 mg％ (pectin-degrading enzyme content), 33.6 mg％ (gelatin content) and 70 min (treatment time).

• Journal of the Korean Society of Food Culture
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• v.4 no.1
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• pp.103-108
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• 1989

Effects of different processes or texture of cucumber pickles fermented in 7% NaCl solution were studied. Cucumbers were treated with different processes: control; preheating in 7% NaCl, 0.04M $CaCl_2$ solution ($60^{\circ}C$, 1hr); combination of preheating and post microwave heating (5 min, midium high level, 2450 Mhz); preheating in the solution which was adjusted to pH 8.5. In each process the pH and total acidity of brine solution, total pectin contents in alcohol insoluble solids (AIS), hot water soluble pectin (HWSP) contents and firmness of cucumber pickles were determined at 0, 5, 10, 15 and 25 days of storage periods. Total pectin contents and the firmness of pickles were decreased during 25 days of storage. Control group showed the lowest value and post microwave heating group marked the highest value in total pectin contents and firmness retention of cucumber pickles. The results of this study indicated that total pectin content seems to correlate with the firmness of cucumber pickles. However, HWSP content did not show any correlation with firmness of cucumber pickles. Post microwave heating method could be used to retain firmness of fermented cucumber pickles.

• Korean journal of food and cookery science
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• v.9 no.1
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• pp.19-24
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• 1993

The purpose of this study was to investigate the physicochemical properties of Su Ri Chwi (Synurus Palmatopinnonatifidus var. indivisus KiTAM.) cooked in different solution (distilled water, 1%, salt and 1% sodium bicarbonate added water) and time. The content of crude fiber showed the highest percentage among the alcohol-insoluble solids of cooked Su Ri Chwi. The contents of Ca and Mg were decreased by the addition of 1% sodium bicarbonate. The main neutral sugars of alcohol insoluble solids were arabinose, galactose, and glucose. The content of glucose was increased regardless of method used. The main neutral sugars of crude pectins were rhamnose, arabinose and glucose. Galactose was increased by the cooking. The gel chromatography on Sepharose CL-4B indicated that the pectin extracted from cooked Su Ri Chwi had lower molecular weight distribution than that of the raw Su Ri Chwi. Total pectin was decreased by the cooking method used. The amounts of soluble pectins of Su Ri Chwi cooked in 1% sodium bicarbonate added water were lower than those of raw material.

• Korean Journal of Environmental Agriculture
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• v.32 no.2
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• pp.108-116
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• 2013

BACKGROUND: Certain crop-based waste materials have been recognized as cost-effective and highly efficient adsorbents for removal and recovery of different kind of heavy metals from aqueous solutions. The ability is strongly attributed to the carboxyl functional group of some pectin substances such as galacturonic acid often found in fruit peels. The present manuscript was aimed at assessing the potential applicability of banana peel for metal removal from contaminated waters. METHODS AND RESULTS: As revealed by laboratory investigations, banana peel contains pectin (10-21%), lignin (6-12%), cellulose (7.6-9.6%), and hemicelluloses (6.4-9.4%). The pectin extraction is reported to have glucose, galactose, arabinose, rhamnose, xylose, and galactouroninc acid. Several studies conducted under different conditions proved that banana peel is capable of adsorbing 5.71, 2.55, 28.00, 6.88, 7.97, and 5.80 mg/g of $Cd^{2+}$, $Co^{2+}$, $Cu^{2+}$, $Ni^{2+}$, $Pb^{2+}$, and $Zn^{2+}$, respectively, from aqueous solutions. Adsorption capacity is, however, dependent upon several factors including solution pH, dose of adsorbent and metal concentration, contact time and shaking speed. CONCLUSION(S): Since the annual world production of banana exceeds 100 million tons, about 40 million tons of banana peel (40% of total weight of the fresh fruit) remains vastly unused. Exploring a sound technology with banana peel would therefore, not only address the much needed sustainable tool for cleaning contaminated waters, but of course bring an additional value to the banana industry worldwide.