• Food Science of Animal Resources
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• v.35 no.6
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• pp.721-730
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• 2015

The objective of this study was to examine the effect of ginger extract (GE) combined with citric acid on the tenderness of duck breast muscles. Total six marinades were prepared with the combination of citric acid (0 and 0.3 M citric acid) and GE (0, 15, and 30%). Each marinade was sprayed on the surface of duck breasts (15 mL/100 g), and the samples were marinated for 72 h at 4℃. The pH and proteolytic activity of marinades were determined. After 72 h of marination, Warner Bratzler shear force (WBSF), myofibrillar fragmentation index (MFI), pH, cooking loss, moisture content, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and protein solubility were evaluated. There was no significant (p>0.05) difference in moisture content or cooking loss among all samples. However, GE marination resulted in a significant (p<0.05) decrease in WBSF but a significant (p<0.05) increase in pH and MFI. In addition, total protein and myofibrillar protein solubility of GE-marinated duck breast muscles in both WOC (without citric acid) and WC (with citric acid) conditions were significantly (p<0.05) increased compared to non-GE-marinated duck breast muscles. SDS-PAGE showed an increase of protein degradation (MHC and actin) in WC condition compared to WOC condition. There was a marked actin reduction in GE-treated samples in WC. The tenderization effect of GE combined with citric acid may be attributed to various mechanisms such as increased MFI and myofibrillar protein solubility.

• Journal of Plant Biology
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• v.12 no.1
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• pp.31-34
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• 1969

This experimental was undertaken for the purpose to investigate the different chemical composition in developing fruit of Poncirus trifoiata. In the first place, the differences among the content of tannin and qualitative analysis of free sugars and organic acids in the fruit of Poncirus trifoiata fron Kwang-ju are to be investigated and chemical components are analyzed. 1) The differences of the content of tannin are investigated at the four periods of time and gradual decrease in the sample 2 (July 15) take place. 2) In sample 1 (June 20), xylose, mannose and rhamnose are not identified and later, as the fruit age, otehr three sorts of sugars with the former are founded and there is a conspicuous tendency to increase in the content and especially the increase in glucose and rhamnose seems to be related with the decomposition of tannin, while the decrease in the former from sample 2 to sample 4 with the formation of the latter. 3) Tartaric acid, succinic acid and citric acid are appeared and then in sample 1 (June 20( these are not founded and later all of them are identified and gradual increase in the content take place and especially citric acid and succinic acid seems to be increased in the content. These are related with the synthesis of organic materials in plant body.

• Korean Journal of Food Science and Technology
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• v.30 no.2
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• pp.306-312
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• 1998

Free sugar, organic acid, naringin, hesperidin and inorganic elements change of six varities of Cheju citrus fruits; Citrus natsudaidai, C. grandis, C. platymamma., C. sudachi, C. aurantiun and C. unshiu Marc. var. miyagawa by harvest date were investigated. Changes in free sugar of citrus fruits on the different harvesting stages and varieties showed a little differencies. The content of sucrose, glucose and maltose in citrus juice were $44.9{\sim}66.0%,\;15.7{\sim}25.7%\;and\;17.5{\sim}30.1%$, respectively. As the fruits were matured, free sugar was increased, but organic acid was decreased gradually. The major organic acids from the fruit juice were citric acid, malic acid and oxalic acid. Citric acid content exceeded 90%, oxalic acid ranged less than 3.58% and malic acid ranged $0.98{\sim}9.45%$ in total organic acids. Both naringin and hesperidin content showed markedly high in immature fruits, and in rind compare to fruit juice. Naringin and hesperidin content decreased as peel coloration progressed. It was estimated that fully matured fruits would be useful for making processed products, which lead to less turbity and less bitterness.

• Food Science and Preservation
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• v.4 no.1
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• pp.77-85
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• 1997

This study aims to determine the optimal picking time and the favorate variety for Ume processing. The changes of physicochemical components and flavors of 6 varieties of the Ume were investigated during maturing. Average weight of the fruit increased to the range of 151-292% from 70 days to 90 days after blooming. The hardness of fruit decreased during maturing and Koume variety was not suitable for processing among the last harvesting samples. Moisture and ash were reached to 89-91%, 0.57-0.69%, respectively, and the ash content increased during maturing. Among the Ume varieties, relatively high content of total acid was observed in Oshuku and Koume. The major organic acid were malic, citric, succinic, and tartaric acid. The content of malic acid decreased significantly, whereas citric acid increased during maturing. Thirty five kinds of flavor components were identified from the Ume fruit and main components were ethyl acetate, butyl acetate, and organic acid derivatives. Koume contained a large amount of flavor components among the Ume and the content increased during maturing.

• Korean journal of food and cookery science
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• v.19 no.6
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• pp.777-782
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• 2003

This study was carried out to investigate the characteristics of mulberry fruit seolgidduk. Four percent additions of mulberry were evaluated as the most suitable concentration for seolgidduk, in order to improve the color of gum metal gray and sour smell. Therefore, in order to improve the preference, citric acid was added. The acidity of mulberry fruit seolgidduk increased and its pH decreased significantly by increasing the amount of citric acid. The moisture content of mulberry fruit seolgidduk showed no significant difference between the groups with added citric acid and the control group. The L value decreased as the citric acid concentration increased. Color a and b (Ed-define 'a' and 'b') values increased significantly by increasing the mont of citric acid. The hardness, cohesiveness, springiness, gumminess and brittleness decreased as the citric acid was added. From the sensory evaluation, mulberry fruit seolgidduk with 0.01％ citric acid added was the most preferred in taste, chewiness and overall acceptability. These results indicated that mulberry fruit stolgidduk with 0.01％ citric acid added showed the best quality.

• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.231-234
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• 1973

Dried lavers, Porphyra yezoensis Ueda, were stored at $20^{\circ}C$ for 10, 25 and 45 days under a dry and humid conditions respectively, and changes in the contents of organic acids were studied by GLC and supplementary use of GC-MS. 1) Out of eight acids determined, i. e., pyruvic, lactic, oxalic, malonic, fumaric, succinic, malic, and citric acid, relatively abundant ones were oxalic, succinic, malic, and citric acid. 2) Oxalic, malic, and succinic acid did not show any notable changes in their contents under a dry condition, however, under a humid condition the contents of the former tow acids decreased rapidly showing contrast to that of succinic acid, of which content increased markedly. The content of citric acid rapidly· decreased independent of the storage conditions. 3) Among some unidentified components, two of them were presumed to be aromatic acids from their mass spectra. The contents of the two acids decreased slowly under a dry condition, however, rapidly decreased under a humid condition and after 45 days storage almost all of them disappeared. 4) The contents of total volatile acids were increased under the both storage conditions, however, the rate of increment was larger under a humid than under a dry condition.

• Food Science and Preservation
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• v.11 no.3
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• pp.347-351
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• 2004

Physicochemical properties such as proximate components, minerals, amino acids, organic acid and free sugars of Pleurotus eryngii were investigated. Among the proximate components of Pleurotus eryngii contents of crude protein and total sugar were higher than that of others. The contents of magnesium and sodium were higher than that of other minerals. Hypoproline content was the highest in free amino acid. Among the amino acid, the contents of arginine, lycine, glutamic acid and phenylalanine were 509.03, 410.53, 190.05 and 150.63 mg$\%$, respectively. Organic acids such as citric acid, oxalic acid, formic acid and malic acid were analyzed, contents of citric acid and lactic acid were higher than that of others. Among the free sugars, the content of glucose was the highest, followed by fructose, ribose, galactose, lactose, arabinose and maltose.

• Food Science and Preservation
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• v.6 no.4
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• pp.495-499
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• 1999

The free sugars in leaf and root of dandelion were composed of sucrose, glucose and fructose. The contents of total free sugars was higher in root than those in leaf. The oxalic acid, citric acid and malic acid contents of leaf was 45.4, 3.6, 2.7mg/100g-f.w., respectively. And the oxalic acid, citric acid and malic acid contents of root was 34.6, 2.1, 1.6mg/100g-f.w., respectively. Total free organic acid content of leaf was higher than that of root. The major free amino acids of dandelion were aspartic acid, serine, asparagine, glutamic acid, glycine, valine, isoleucine and content of glutamic acid was highest in free amino acids. The contents of vitamin A in leaf and root of dandelion was 135.4 and 34.1$\mu\textrm{g}$/100g-f.w., respectively. The contents of vitamin C in leaf and root of dandelion was 67.4 and 4.6 mg/100g-f.w., respectively.

• Journal of the Korean Society of Food Science and Nutrition
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• v.29 no.1
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• pp.30-34
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• 2000

Salted Chinese cabbage was washed in 1,000 ppm solutions of grapefruit seed extract(GFSE) or citric acid, and used to make kimchi for the retentio of quality characteristics during fermentation at $10^{\circ}C$. Kimchi treated with GFSE or citric acid showed a retarded increase in titratable acidity and decrease in pH and reducing sugar content. Total microbial count and lactic acid bacteria of GFSE treated kimchi were about 1.1 log(CFU/g) lower than those of control and citric acid treated kimchi after making, but the difference was gradually reduced during fermentation.

• Journal of Fisheries and Marine Sciences Education
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• v.27 no.4
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• pp.973-980
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• 2015

This study was done to investigate the quality characteristics of salmon frame with citric acid pretreatment. Sliced salmon frame samples were cured in soy sauce, sugar, pepper, and sodium nitrate for 12 h and then dried at 3 h and then dried at $60^{\circ}C$ for 3 h. As the autoclaving at $130^{\circ}C$ for 15 min, the pH, moisture content, crude ash, crude fat, crude protein, acid value (AV), peroxide value (POV), volatile basic nitrogen (VBN), trimethylamine (TMA), total plate count and E. coli were measured at $4^{\circ}C$, $25^{\circ}C$ and $35^{\circ}C$ of storage days. The AV, POV, VBN, TMA and total plate count for all samples significantly increased as during storage days (p<0.05). All samples of storage, for autoclaving on salmon frame, there were no growth on E.coli. In the making of autoclaving on salmon frame, technologies for more safety from microbial growth should accompany pretreatment with citric acid.