• Korean Journal of Food Science and Technology
• /
• v.32 no.5
• /
• pp.1079-1086
• /
• 2000

Pectinesterase inhibitor(PEI) of ripened kiwi fruit(Actinidia chinensis) was separated with affinity chromatography using CNBr-activated Sepharose 4B being covalently bound by orange pectinesterse(PE). The affinity resin strongly and selectively bound PEI, which could be eluted in high yield as a single peak by pH 9.5 without loss of inhibitory activity. The separated PEI had maintained almost inhibitory activity at $-25^{\circ}C$ and $5^{\circ}C$ during 30 days but lost it at room temperature in 4 weeks. The PEI possessed a molecular weight of 16.6 KDa, as estimated by 12.5% SDS-PAGE. PEI had optimum pH of 7.5, optimum temperature of below $10^{\circ}C$ and stability up to $70^{\circ}C$. Also, optimum inhibitory activity for PEI was obtained in 0.2 M NaCl of substrate solutions. The kind of inhibition on tomato pectinesterase was found to be noncompetitive, using citrus pectin as substrate. Fresh orange juice added with crude PEI extracts maintained almost the same cloud stability as pasteurized juice. In case of apple juice, the addition of crude PEI extracts to apple juice had decrease of L-ascorbic acid with nearly no effect on cloud loss.

• Microbiology and Biotechnology Letters
• /
• v.17 no.5
• /
• pp.510-518
• /
• 1989

Most of orange peels are disposed from orange juice manufacturing process. Thus, our purpose is to utilize these orange peels as fermentation substrate. We have investigated culture conditions and factors influencing citric acid production by an isolated strain, Asp. niger. Citric acid production was much higher in semisolid culture than in submerged culture and the particle size of ground orange peels was favored at 20 mesh in semisolid culture. The optimal pH and temperature were 4.5-5.0 and 3$0^{\circ}C$ respectively and the temperature cycling at 35$^{\circ}C$ for 20 hrs durig exponential phase, 1$0^{\circ}C$ for 4 hrs and 3$0^{\circ}C$ during stationary phase showed higher citric acid production than did at fixed temperature, 3$0^{\circ}C$. The addition of NH$_4$NO$_3$0.2%, MgSO$_4$7$H_2O$ 0.1%, methanol 2.5%, ethanol 1.5%, to culture medium promoted citric acid production but the addition of trace metal ions as nutrients had not effect on the acid production in orange peel medium. Under the optimal culture conditions, maximum yield of citric acid was 80.4% in solid medium. Almost of all original components of citrus peel was consumed by Asp. niger during fermentation.

• Journal of Applied Biological Chemistry
• /
• v.59 no.3
• /
• pp.189-201
• /
• 2016

A processing factor (PF) has been used to define the maximum residue limits of pesticide in a variety of processed fruit products. This study summarizes PF by the stage of fruit processing based on JMPR reports from 2010 to 2014. When we compared PF of 19 pesticides in apple products during the processing of washing, drying, canning, juice, sauce, puree and pomace, PF was higher than 1 only in pomace. In the comparison of 21 pesticides during the process of grape (washing, juice, wine and raisin), PF was higher than 1 in raisin. In the comparison of 19 pesticides during the process of orange (juice, oil and marmalade), PF was higher than 1 in oil. When 27 pesticides were compared during the process of tomato (juice, puree and paste), paste showed the highest PF value except pomace. During the process of plum (washing, drying and puree) with 12 pesticides, PF was higher than 1 in drying. The correlation coefficients between physical characteristics of pesticide (fat-solubility and volatility) and PF were statistically significant in the processes of apple juice, orange juice, tomato puree and paste and strawberry jam.

• The Korean Journal of Food And Nutrition
• /
• v.15 no.2
• /
• pp.97-103
• /
• 2002

Five citrus juices were separated into a ascorbate and phenolic portion using rep-pak C$\_$18/ cartridge, respectively, in order to elucidate the nitrite scavenging effect and N-nitrosodimethylamine(NDMA) formation in model system. The nitrite scavenging effect of ascorbate portion from citrus juices, in the different pH, when added with 5ml were 79.9 ∼98.6% under the condition of pH 2.5. 48.5∼86.3% at pH 4.2 and lower than 35.2% at pH 6.0. The nitrite scavenging effect was excellent phenolic portion rather than ascorbate portion. Particularly, the effect was more 2 times than ascorbate portion under the reaction condition of pH 6.0. When added the phenolic portion in the reaction mixture, NDMA formation was inhibited 92.8% or more in kum quat, mandarin orange and sweet orange juices. But the ascorbate portion was a negative response of the inhibition of NDMA formation. The inhibition on NDMA formation in citrus juice may be due to phenolic compounds were reacted.

• Korean Journal of Food Science and Technology
• /
• v.29 no.3
• /
• pp.571-575
• /
• 1997

In the present study, characterization of fermented carrot juice by Bifidobacterium was performed. When inoculated at the level of $10^6\;CFU/mL$ with various Bifidobacterium strains, cell growth of B. longum, B. adolescentis and B. infantis reached more than $10^8\;CFU/mL$. On the other hand, B. bifidum strains reached less than $10^8\;CFU/mL$. Compared with carrot, grape juice did not allow the growth of Bifidobacterium, while peach juice and orange juice were as good as carrot for the growth of Bifidobacterium. On mixed culture with Lactobacillus, growth of Bifidobacterium decreased and cell death rate increased considerably. On panel test, Bifidobacterium cultured-carrot juice showed high score on sensory test than non-fermented carrot. Therefore, fermentation may lead to the quality improvement of carrot juice by combining health-promoting effect of Bifidobacterium and high nutrition value of carrot.

• Journal of Microbiology and Biotechnology
• /
• v.32 no.4
• /
• pp.464-472
• /
• 2022

An endo-polygalacturonase (endo-PGase) exhibiting excellent performance during acidic fruit juice production would be highly attractive to the fruit juice industry. However, candidate endo-PGases for this purpose have rarely been reported. In this study, we expressed a gene from Penicillium oxalicum in Pichia pastoris. The recombinant enzyme PoxaEnPG28C had an optimal enzyme activity at pH 4.5 and 45℃ and was stable at pH 3.0-6.5 and < 45℃. The enzyme had a specific activity of 4,377.65 ± 55.37 U/mg towards polygalacturonic acid, and the K_m and V_max values of PoxaEnPG28C were calculated as 1.64 g/l and 6127.45 U/mg, respectively. PoxaEnPG28C increased the light transmittance of orange, lemon, strawberry and hawthorn juice by 13.9 ± 0.3%, 29.4 ± 3.8%, 95.7 ± 10.2% and 79.8 ± 1.7%, respectively; it reduced the viscosity of the same juices by 25.7 ± 1.6%, 52.0 ± 4.5%, 48.2 ± 0.7% and 80.5 ± 2.3%, respectively, and it increased the yield of the juices by 24.5 ± 0.7%, 12.7 ± 2.2%, 48.5 ± 4.2% and 104.5 ± 6.4%, respectively. Thus, PoxaEnPG28C could be considered an excellent candidate enzyme for acidic fruit juice production. Remarkably, fruit juice production using hawthorn as an material was reported for the first time.

• Journal of Nutrition and Health
• /
• v.18 no.4
• /
• pp.312-317
• /
• 1985

This study was attempted to investigate the occurrence and the characteristics of ascorbic oxidase in cucumbers. Ascorbic acid oxidase was isolated from cucumbers and concentrated using ammonium sulfate precipitation. The results of this study are as follows ; 1) Ascorbic acid oxidase activity was detected in whole cucumber homogenate. 2) Highest amounts of ascorbic acid destroyed after 10 minutes' incubation of ascorbic acid oxidase with its substrate. 3) The optimum pH and temperature of this enzyme were found to be pH 6.5 and $40^{\circ}C$, respectively. 4) Ascorbic acid content in cucumber juice prepared using the cold water $(4^{\circ}C)$ was higher than that made with water at $30^{\circ}C$. 5) When orange juice ( pH 3.4 )was added, ascorbic acid destruction was completely ceased. (The ascorbic acid oxidase was inactivated at pH 3.9) Decreasing the temperature and pH are recommended to achieve maximum stability of ascorbic acid in preparing cucumber juice.

• Horticultural Science & Technology
• /
• v.33 no.3
• /
• pp.390-395
• /
• 2015

The synthesis of chimeras is a breeding approach for horticultural crops. In our breeding program, a new diploid citrus chimera, named 'Hongrou Taoye' (Citrus sinensis [L.] Osbeck + Citrus unshiu Marc.), was found arising at the junction where a 'Taoye' sweet orange (C. sinensis) scion was grafted onto Satsuma mandarin (C. unshiu). As an artificial chimera, its fruit traits derived from the L1 cell layer, with juice color and carotenoid complement, in which ${\beta}$-cryptoxanthin accumulated predominantly, similar to those of Satsuma mandarin. By contrast, traits originating from the L2/L3 cell layer, including pollen, seed, and rind aroma characteristics, were the same as those of 'Taoye' sweet orange (the scion). SSR and cpSSR analyses showed that both nuclear and chloroplast genomes of the chimera were a combination of both donor parents. 'Hongrou Taoye' thus combined the valuable traits of both donor plants, and therefore has good potential in citrus fresh market.

• Applied Biological Chemistry
• /
• v.32 no.4
• /
• pp.416-423
• /
• 1989

In order to produce clear and favorable citrus wine from Citrus unshiu produced in Cheju island, chemical and microbiological processes for alcoholic fermentation were investigated. The ratio of pressed juice passed below 100 mesh sieve and peel of mandarin orange were 55.9% and 25.6% respectively. Orange juice for fermentation source contained 8.85% total sugar, 1.43% total acid and 0.056% volatile acid. Pressed juice was adjusted to 24 degree Brix with cane sugar, and was fermented at $20^{\circ}C$ for one month. Starter screened and selected was Saccharomyces cerevisiae IAM 4274. As principal fermentation proceeded for one week, suspended solids began to precipitate slowly after then. After fermentation, clear citrus wine consisted of about 8 degree Brix residual sugar, $13.3{\sim}14.4%$ ethanol, $0.78{\sim}1.11%$ total acid, $0.05{\sim}0.07%$ methanol and $2.25{\sim}3.29%$ extract, was obtained. Color, flavor and taste of citrus wine found good with panel test. Citrus wine which was treated with fungal enzyme derived from Aspergillus niger CCM-4 was cleared much faster, and could be filtered more rapidly than the untreated. The enzyme-producing strain was isolated from field soil of Cheju island and identified.

• The Journal of the Korean dental association
• /
• v.54 no.7
• /
• pp.521-528
• /
• 2016

Purpose: The aim of this study was to evaluate the erosive potential of several fruit-flavored liquors marketed in Korea by measuring pH, titratable acidity, and variations in pH utilizing an ISO method. Materials and Methods: Six fruit-flavored liquors were investigated. An orange juice and three kinds of soju were selected as the control beverage. The pH and titratable acidity of the beverages were determined by 1 M NaOH until the pH 5.5 and 7.0 (recorded as $TA_{5.5}$ and $TA_{7.0}$, respectively). All measurements were performed in triplicate. The process of ISO 28888 was used for measurement of the pH variation (${\Delta}pH$) using an under-saturated hydroxyapatite solution (screening solution) and determining the difference between the initial and final pH of the screening solution. The average ${\Delta}pH$ was determined based on 4 measurements. Results: All the fruit-flavored liquors tested in this study showed a pH lower than the critical pH for dental erosion (4.5). The average pH of the fruit-flavored liquors was 2.77 and was also lower than the pH of the soju and an orange juice (control drinks). $TA_{5.5}$ and $TA_{7.0}$ values of the fruit-flavored liquors were 4.92ml and 7.13ml, respectively. The fruit-flavored liquors showed an erosive potential capable of damaging the enamel surfaces, whereas the orange juice had the highest titratable acidity. The changes in pH determined using the screening solution confirmed that the fruit-flavored liquors had erosive potential, with ${\Delta}pH$ value of 1.53. Conclusions: The fruit-flavored liquors tested in this study might have a strong potential to erode dental hard tissues.