• 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 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.

• Korean journal of food and cookery science
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• v.9 no.4
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• pp.289-292
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• 1993

The effect of sugar alcohols in the preparation of acceptable low methoxyl pectin(LMP) jellies were studied. Sensory scores analysis, Hunter's color parameters and texture profile analysis using universal testing machine were performed. The composition of sweetners used in this study were 100％ sucrose, 75％ sucrose and 25％ maltitol, 50％ sucrose and 50％ maltitol, and 50% sucrose, 25％ maltitol, 12.5％ sorbitol'and 12.5% mannitol. LMP jellies with 100％ sucrose showed the strongest sweetness among them. Other sensory characteristics of LMP jellies were regarded as same. Hunter's value of lightness, redness and yellowness of 100％ sucrose jellies and jellies substituted with maltitol up to 25％ were not significantly different, but those of LMP jellies substituted with 50％ sugar alcohols were higher(p<0.01) than other 3 types of jellies. As substitution ratio was increased, springiness and chewiness were lower(p<0.01). Fracturability(p<0.01) and hardness(p<0.05) of jellies made of 100% sucrose and 75％, sucrose and 25% maltitol showed higer value than the other jellies. Springiness of jelles sweetened with sucrose and 3 sugar alcohols was the highest(p<0.05). Replacement of sucrose by sugar alcohol did not influenced on gumminess and cohesiveness of LMP jellies.

• Korean Journal of Food Science and Technology
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• v.30 no.1
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• pp.125-131
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• 1998

The change of pectinesterase (PE) activity and pectin substances in fig fruit were investigated and low sugar jams prepared by various methods from fig fruit were compared. Fig fruit PE, which began to show the activity at the harvest time, was not inactivated and had slight activity during frozen storage at $-25^{\circ}C$. The amount of alcohol insoluble solid (AIS) and the degree of esterification (DE) of AIS were reduced by its own PE activity. However the intrinsic PE of fig fruit was not enough to make low-methoxyl pectin below 50% of DE. Fig pulp treated by its own PE and combination of fig PE and orange PE could make low-methoxyl pectin. After PE treatments, fig pulp adjusted below pH 4.0 by addition of citric acid kept red colour. Fig Jams processed by various methods had lower soluble solid $(31{\sim}49^{\circ}Brix)$ compared with conventional fig jam. Five kinds of fig jams out of those showed higher score than others in the sensory evaluation. For preparation of the five jams, the fig pulps with or without 1% pectin were treated at $50^{\circ}C$ for 25 minutes with addition of orange PE (200 units/400 g pulp). The treated pulps were added with 0.25% citric acid, 0.7% calcium and 20% cane sugar. The mixed pulps were prepared for jams containing low sugar by hot plate or microwave or refrigeration (excepting the mixed pulp without pectin).

• Korean journal of food and cookery science
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• v.9 no.4
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• pp.284-288
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• 1993

Replacement of sucrose with sugar alcohols in high methoxyl pectin(HMP) jellies were studied. HMP jellies were sweetened with 100％ sucrose, 75％ sucrose and 25％ maltitol, 50％ sucrose and 50％ maltitol, and 50％ sucrose, 25％ maltitol, 12.5％ sorbitol and 12.5％ mannitol. The effect of sugar alcohols in HMP jellies were investigted. There was only slight differences in sweetness intersity in HMP jellies. Color(p<0.05), texture(p<0.01) and preference(p<0.01) of 100fl sucrose jelly were significantly higher than other Jellies sweetened with sugar and sugar alcohols mixtures. Hunter's L(lightness), a(redness), b(yellowness) values of 100％, sucrose jellies and jellies substituted with maltitol up to 25％ were not signignificantly different. But as the ratio and the number of sugar alcohols used for substition were increased, L, a and b values had been lowered signigicantly(p<0.01). Instru-mental characteristics of jelly texture were examined. Hardness of 100％ sucrose jelly sweetened with sucrose and 3 kind of sugar alcohols were higher than others(p<0.05). As substitution ratio was higher, springiness and chewiness of HMP jellies were lowered(p<0.01). Springiness of HMP jellies indicated positive correlation with general acceptance of sensory scores at 5％ significant level. Brittleness, gum-miness and cohesiveness in all types of jellies were not significantly different.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.17 no.1
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• pp.63-68
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• 1988

The changes of methoxy content. compositional sugars. degree of esterification (DE) and pectic substances such as LMP (low methoxy pectin), HMP (high methoxy pectin) IAP (ionically associated pectin) and CBP (covalently bounded pectin) of Fuji apple were investigated during maturity. The contents of LMP+HMP and IAP+CBP in alcohol insoluble solid(AIS) were 70% and 20%. respectively. These pectic substances were increased slightly during maturity. The reductions of hexose and uronic acid were Iron 20-50% and from 2-4%, respectively, but the inclosed of pentose was from 1-9% in LMP, HMP, IAP and CBP during maturity of Fuji apple. The galactose was decreased significantly among hexose. Whereas the relative ratio of uronic acid in HMP and CBP was increased.

• Korean Journal of Food Science and Technology
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• v.31 no.3
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• pp.651-657
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• 1999

These experiments focused on processing low sugar fig jam having marketability by selected substitute for extracted and purified pectinesterase (PE), colorant for colour improvement, food additive to make texture better, and stabilizer for stable storage. Cherry tomato pulp as PE substitute to hydrolyze pectin substance in fig pulp into low-methoxyl pectin was most effective among used vegetables and fruits pulp. Carmacid-R among natural colorants for imprving colour, addition of 20% starch syrup as sugar substitute for texture and addition of $MULTIPHOSE^{TM}$ for red colour change control at cold storage were effective. The low sugar fig jam processed by using the above selected materials showed higher score than others (typical jam and orange PE low sugar fig jam) for colour in sensory evaluation and did no significant difference in taste, odor, texture and overall acceptability.

• 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.