• Journal of the Korean Home Economics Association
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• v.34 no.4
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• pp.403-414
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• 1996

The softening of the femented vegetables and the fruits was resulted from the degradation of pectin substances, cellulose, hemicellulose by polygalacturonase(PG), pectinesterase(PE), Cx-cellulase, $\beta$-galctosidase. The conversion of insoluble pectin to soluble pectin in cell wall-middle lamella was a major factor in the changes of firmness. Ca2+ was substantially increased firmness. However, Ca2+ could be removed from cell wall by chelating agents such as oxalic acid and citric acid. And Ca2+ was replaced with Na+ by ion exchange reaction. Ca2+ deficient tissue was vulnerable to attack by PG. Preheating treatment and Ca2+ addition is most effective in inhibiting the vegetable food softening and in increasing middle lamella-cell wall regidity, which PE activation by preheating treatment and Ca2+ addition could created more anionic carboxyl groups for cationic materials binding such as Ca2+ and chitosan and for polypectategel formation. Excessive demethylation by PE was associated with loosening of middle lamella cell wall components and softening.

• Korean Journal of Food Science and Technology
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• v.36 no.2
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• pp.321-328
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• 2004

Raw mulberry (Morus spp.) juice was prepared by minimal processing using several filter aids, fining agents, and clarifying enzymes, followed by filtration, centrifugation, and membrane filtration. Control of browning in minimally processed mulberry juices by anti-browning agents, sodium hydrosulfite, L-ascorbic acid, citric acid, and NaCl, was investigated using quantitative measurements of color changes during storage. Clarification of mulberry juice was improved by adding several filter aids, fining agents, and enzymes, followed by filtration and centrifugation. Several fining agents, including chitosan, chitin, PVPP, gelatin, and casein at a concentration of 1%, and combination of ultrafiltration and centrifugation at 8,000 rpm were not suitable for clarification of juice owing to strong adsorption of anthocyanin pigment. Combination of $0.01\;{\mu}m$ membrane filtration and centrifugation at 8,000 rpm was effective for clarification of mulberry juice. Browning of minimally processed mulberry juice was inhibited significantly by adding 200 ppm sodium hydrosulfite, and 0.1% L-ascorbic acid (L-AsA) and 0,1% citric acid (CA) also showed considerable browning inhibition. Combination of L-AsA and CA, which was moderately effective for browning inhibition of juice, may be useful as a sulfite alternative for mulberry juice. Optimum sugar ($^{\circ}Brix$)/acid ratio and commercial sterilization of minimally processed mulberry juice were approximately 40 and 10 min at $85-90^{\circ}C$, respectively.

• Food Science and Preservation
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• v.9 no.4
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• pp.391-395
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• 2002

Thinned fruits, apple, pear and peach were investigated into chemical components and physiological activities. On proximate compositions, crude protein, crude fat and ash of thinned fruits were higher than those of ripe fruits, showing lower carbohydrate in thinned fruits. The contents of inorganic substance were Ca, Mg, P, Na, K and B in order. On heavy metals, As, Cd, Cr and Hg were not detected and Ge, Mo, Ni and Pb were trace. Organic acid in thinned apple and peach were detected as tartaric acid, citric acid, malic acid and succinic acid, but thinned pear did not contain citric acid. Free sugars in thinned pear and peach were composed of glucose, fructose and sucrose but sucrose was not detected in thinned apple. Contents of insoluble dietary fiber in thinned fruits were higher than soluble dietary fiber. The thinned apple extracts showed high antioxidant activity. Nitrite scavenging activity of thinned apple and pear extracts were 71∼80 e/o and 61∼63% at pH 1.2, respectively. Tyrosinase inhibitory activity of thinned pear extracts was 61.0∼89.4 ％, however peach extinct showed no activity.

• Journal of Environmental Health Sciences
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• v.33 no.5
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• pp.403-407
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• 2007

The inhibitory effect of the food processing agent on growth of Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes was performed with organic acid, and combination of citric acid, acetic acid, propionic acid and vanillic acid. The minimun inhibitory concentration(MIC) of propionic acid was 5,000 ppm in E. coli O157:H7, 2,500 ppm in Salmonella Enteritidis and Listeria monocytogenes. MIC of citric acid was 10,000 ppm in E. coli O157:H7 and Salmonella Enteritidis, 2,500 ppm in Listeria monocytogenes. MIC of acetic acid was 2,500ppm, while in vanillic acid was 5,000 ppm in Escherichia coli O157:H7, Salmonella Enteritidis, and Listeria monocytogenes. MIC of combined organc acid in E. coli O157:H7 were 2,500ppm in PC, 1,250 ppm in PA, PV, CA, CV and AV. MIC of combined organc acid in Salmonella Enteritidis were 2,500 ppm in PC, PA, PV, CA, and CV, 1,250 ppm in AV. MIC of combined organc acid in Listeria monocytogenes were 1,250 ppm in all treatment group. MIC of combined treatment of three organc acid in E. coli O157:H7, S. Enteritidis and L. monocytogenes were 1,250 ppm in PCA, PCV, PAV and CAV. The inhibitory effect of organc acid in E. coli O157:H7, S. Enteritidis and L. monocytogenes could be confirmed from the result of this experiment. Therefore, it was expected that the food process would increase or maintain by using organic acid.

• Journal of Veterinary Science
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• v.24 no.2
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• pp.22.1-22.12
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• 2023

Background: Citric acid (CA) and sodium hypochlorite (NaOCl) have been used to disinfect animals to protect them against avian influenza and foot-and-mouth disease. Objectives: We performed a good laboratory practice (GLP)-compliant animal toxicity study to assess the acute toxic effects of CA and NaOCl aerosol exposure in Sprague-Dawley rats. Methods: Groups of five rats per sex were exposed for 4 h to four concentrations of the two chemicals, i.e., 0.00, 0.22, 0.67, and 2.00 mg/L, using a nose-only exposure. After a single exposure to the chemicals, clinical signs, body weight, and mortality was observed during the observation period. On day 15, an autopsy, and then gross findings, and histopathological analysis were performed. Results: After exposure to CA and NaOCl, body weight loss was observed but recovered. Two males died in the CA 2.00 mg/L group and, two males and one female died in the 2.00 mg/L NaOCl group. In the gross findings and histopathological analysis, discoloration of the lungs was observed in the CA exposed group and inflammatory lesions with discoloration of the lungs were observed in the NaOCl exposed group. These results suggest that the lethal concentration 50 (LC50) of CA is 1.73390 mg/L for males and > 1.70 mg/L for females. For NaOCl, the LC50 was 2.22222 mg/L for males and 2.39456 mg/L for females. Conclusions: The Globally Harmonized System is category 4 for both CA and NaOCl. In this study, the LC50 results were obtained through a GLP-based acute inhalation toxicity assessment. These results provide useful data to reset safety standards for CA and NaOCl use.

• Journal of Food Hygiene and Safety
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• v.16 no.1
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• pp.16-20
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• 2001

Microbiological and sensory evaluations of refrigerated chicken (average weight of 500g) legs treated with acetic acid (AA), lactic acid (LA), or citric acid (CA) during between June and August, 1998 were assessed. Chicken legs were immersed in solutions containing 1% individual acids for 10 min. Chicken legs treated with AA for 10 min during storage of 16 days at 4$^{\circ}C$ had a significantly (P<0.05) lower levels of aerobic plate counts (APC) and gram-negative bacterial counts (APC) compared to those of LA or CA. AA had greater antimicrobial activity than LA or CA. Microbiological shelf-life of refrigerated chicken legs treated with AA increased eight-additional days compared to the controls. Sensory scores of chicken legs treated with acidulant were in the “liked less”to typical category during storage of days at 4$^{\circ}C$

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.5
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• pp.681-686
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• 2005

The purpose of this study was to analyze the chemical component of Camellia japonica L. according to picking time. Leaves of Camellia japonica L. were picked in April and May,2003. Free sugars (fructose, glucose and sucrose) and organic acids (citric acid, tartaric acid, succinic acid, acetic acid) were present in the Camellia japonica L. leaf. The contents of total free sugars and organic acids increased as picking time was delayed. The major components of free amino acids were aspartic acid, glutamic acid and histidine, and those of total amino acids were histidine and alanine. The contents of total free amino acids and total amino acids were decreased as picking time was delayed, while the ratio of essential amino acids to the total amino acids increased. The amount of minerals (P, Ca, K, Na and Fe), chlorophyll and total polyphenol increased as picking time was delayed.

• 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.

• The Korean Journal of Food And Nutrition
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• v.13 no.5
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• pp.440-445
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• 2000

To develop a new processed foods with prepersimmon, the contents of approximate composition, free sugar, organic acid, mineral and vitamins in prepersimmon(Diospyros kaki Thumb. cv. Fuyu) were investigated. The approximate composition was 89.08% of moisture, 0.26% of crude ash, 0.56% of crude fat and 0.75% of crude protein respectively. Free sugars were composed of glucose, fructose and sucrose. Glucose(3.34%) and fructose(3.01%) were major free sugars, and sucrose was detected a small quantities. The organic acids were composed of citric acid. maleic acid, fumalic acid and lactic acid. Lactic acid(68.65mg%) was major a organic acid and took 79% of total organic acid amount. Minerals were K, P, Na. Ca, Fe and Zn, and K was a major mineral and detected 126.l2mg%, and Fe and Zn were a small quantities. The content of vitamin A was 33.95 R.E., and less than that in hard persimmon, and the content of vitamin C was 171.01 mg%, 10 times higher in comparison with that in hard persimmon, and vitamin B$_1$ and B$_2$ were detected a small quantities.

• Journal of the Korean Ceramic Society
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• v.38 no.4
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• pp.307-307
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• 2001

Combustion process with citrate was used to produce the LiMn$_2$O$_4$powder. Precursors are pre-ignited in open air followed by post-heating in the range from $600^{\circ}C$ to 80$0^{\circ}C$ for 4h. With varying the molar ratio (R) of ethylene glycol (EG) to citric acid (CA) from 0 to 4, the effect of EG content on powder characteristics is evaluated. Vacuum drying promote the auto-ignition at room temperature. With small addition of EG metal ion was selectively segregated with organic substances and undesired lithium evaporation occurred during post-heating. LiMn$_2$O$_4$phase which is produced by combustion reaction was decomposed back to Mn$_3$O$_4$because the reaction temperature was higher than 95$0^{\circ}C$. With increasing EG content, the homogeneity of LiMn$_2$O$_4$powder increased and specific surface area increased. And lithium evaporation during vacuum drying and/or ignition also increased.