• Korean Journal of Fisheries and Aquatic Sciences
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• v.56 no.2
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• pp.253-258
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• 2023

This study was conducted to inhibit histamine formation in salt-fermented anchovy Engraulis japonicus fish sauce, by lowering the pH using 1% citric acid as food additive during the initial fermentation stage. The fish sauce samples were prepared with fresh anchovies used immediately after being caught (F), and left at ambient temperature for 4 h, and 24 h with 25% salt, 1% citric acid, and without citric acid for a 6-month fermentation period. The content of ammonia nitrogen, total nitrogen, and glutamic acid in fish sauce was unaffected by the addition of citric acid during the fermentation period. The histamine content of F and 4 h samples were 20.5-30.6 and 77.4-119.3 mg/kg, respectively. The histamine content of F and 4 h samples with 1% citric acid was 4.1-8.7 and 50.4-56.1 mg/kg, respectively. Furthermore, addition of citric acid did not inhibit histamine formation in 24 h sample that had lower freshness quality. Additionally, effective inhibition of histamine is observed during manufacturing of salt-fermented anchovy fish sauce on an industrial scale, suggesting that lowering the initial pH using 1% citric acid does not alter the taste and flavor of the fish sauce.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.4
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• pp.595-600
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• 1997

To extend the shelf-life of Kochujang, the effects of anti-browning agents and their optimum concentrations were evaluated using organic acids as synergists. Among the physicochemical analyses, amino nitrogen content exhibited the highest correlation with sensory score. Ascorbic acid and citric acid were selected among the anti-browning agents(ascorbic acid, potassium sorbate, calcium chloride) and organic acids(citric acid, lactic acid, oxalic acid) tested on the basis of the highest amino nitrogen content during storage at 55$^{\circ}C$. The appropriate concentration of ascorbic acid was 0.03% based on amino nitrogen content during storage at 55$^{\circ}C$. Combination of 0.06% citric acid with 0.03% ascorbic acid showed the highest amino nitrogen content during storage at 55$^{\circ}C$. From the results, the 0.03% ascorbic acid and 0.06% citric acid were selected as additives for extending the shelf-life. Control(no additive) and additives(0.03% ascorbic acid and 0.06% citric acid) were tested for physicochemical and sensory analyses during storage at 45$^{\circ}C$ and 55$^{\circ}C$. Amino nitrogen content was also highly correlated with sensory score, The marginal amounts of amino nitrogen for control and additives were 174.9mg% and 173.2mg%, respectively. Degradation rate of amino nitrogen was a first order reaction. Compared to control, the predicted shelf-life for adding additives increased 69% and 56% at 45$^{\circ}C$ and 55$^{\circ}C$, respectively.

• Korean Journal of Food Science and Technology
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• v.42 no.2
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• pp.190-197
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• 2010

Changes in the quality of buckwheat sprout treated with organic acid solutions such as ascorbic, citric and acetic acid were examined during storage in order to judge the feasibility of acid dipping as a pretreatment for extending shelf-life. Quality attributes of buckwheat sprout stored at $5^{\circ}C$ were measured in terms of microbial cell count, moisture content, soluble solids content, chromaticity, and sensory evaluation over different storage times. For microbial growth inhibition, combinations of 0.05% acetic acid and 0.5% citric acid or 1% ascorbic acid and 0.5% citric acid were more effective than other treatments. Slight changes were observed in moisture content among the treatments, whereas soluble solids content of each treatment was increased during storage. In chromaticity, the Hunter's a value of buckwheat sprout treated with acetic acid alone or acetic acid combinations showed the largest increase. Dipping treatment with ascorbic acid and citric acid produced only slight changes in color of the sprout. In the sensory evaluation of discoloration (head, stem and root), wilting and overall quality, ascorbic acid and citric acid treatments gave the highest scores. These results suggest that dipping treatment of buckwheat sprout with citric acid can confer more positive effects on storage stability than others.

• Korean Journal of Plant Resources
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• v.33 no.3
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• pp.194-199
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• 2020

This study was carried out to get the information of Plum tree (192 germplasm) collected in Korea, and to evaluate the organic acid contents and fermentation solution. The organic acid content of fruit was 50.9 ± 6.0 mg/g, and which was composed of 55.5% of citric acid, 43.4% of malic acid and 1.1% of oxalic acid, and showed large difference among germplasms. Oxalic acid and malic acid made no differences in organic acid content according to flesh color, whereas citric acid and total organic acid contents were highest in orange color and lowest in whitish green. Malic acid, citric acid and total organic acid contents did not show differences among fruit weight groups, but oxalic acid content was highest at fruit weight of 5.1 ~ 10.0 g and lowest at more than 20.1 g. The sugar content of fermentation solution of fruit was 55.7 ± 1.6 °Brix and the harvest rate was 116.7 ± 8.7%. The correlation coefficients among fruit weight, the sugar content (°Brix) and harvest rate of fermentation solution were very low, and there were correlations of r=-0.551^⁎⁎ between fruit weight and oxalic acid, r=-0.767^⁎⁎ between malic acid and citric acid, and r=0.834^⁎⁎ between citric acid and total organic acid content.

• Journal of Ginseng Research
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• v.33 no.3
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• pp.194-198
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• 2009

The changes that would occur in a content of five phenolic ingredients and eight ginsenosides in acid-treatedred ginseng extracts were measured in this study. Acid-treated-red ginseng was prepared by treating with 1 M ascorbic acid or citric acid for 20 min. As a result, the contents of esculetin and quercetin in citric acid-treated-red ginseng increased by 3.5 times and 2.0 times, respectively, compared with control red ginseng. However, all phenolic ingredients decreased after treatment with ascorbic acid. In addition, the contents of ginsenoside Rg$_3$, Rh$_2$, Rd increased but those of Rb$_1$, Rc, Re, Rf, Rg$_1$ decreased after acid treatment. Although these tendency of results are similar, the rate of change of ginsenosides in citric acid-treated-red ginseng was higher than in ascorbic acid-treated-red ginseng. These results indicated that citric acid is more effective in the conversion of ginseng ingredients than ascorbic acid.

• Journal of the Korean Wood Science and Technology
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• v.46 no.2
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• pp.132-142
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• 2018

An elephant digests only around 30~45% of what it consumes; therefore the undigested material mainly passes as intact fibres. Elephant food is usually composed of grass, leaves, twigs, bark, fruit and seed pods. This research aimed to utilize the elephant dung fibers as material for composite board and citric acid as a bonding agent. Citric acid contents in this research were set at 0 wt% (binderless composite board), 10 wt%, 20 wt%, and 30 wt% based on dry weight particles, while the target density was set at $0.8g/cm^3$. Pressing temperatures were set at $180^{\circ}C$ and $200^{\circ}C$ with the pressing time was 10 minutes. Physical and mechanical properties tests were then performed according to Japanese Industrial Standard A 5905. The result showed that elephant dung fibers could be used as potential materials for composite board. Addition of citric acid and pressing temperature significantly increased the quality of composite board. Infrared analysis indicated that the presence of ester linkages much higher with the increasing of citric acid content and pressing temperature. The optimum properties of composite board made from elephant dung fibers could be achieved at pressing temperature of $200^{\circ}C$ and a citric acid content of 20 wt%.

• Journal of the Korean Ceramic Society
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• v.31 no.2
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• pp.117-128
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• 1994

Hematite particles were obtained by hydrothermal reaction of ferric hydroxide in the presence of small amount of citric acid which is acted as crystal growth controller. The effects of hydrothermal reaction condition son the morphology and crystal structure of powder were investigated using X-ray, TEM and FT-IR. Ellipsoidal or rectangular hematite particles were formed in the range of pH 10.75~11.75 as initial basicity of reactants and 3$\times$10-5 ~9$\times$10-5 mol as citric acid content. Crystallization of hematite was inhibited in the range of pH9. 0~10.5 and above citric acid content of $1.5\times$10-4 mol. Hematite particle length and aspect ratio were decreased gradually with increasing of citric acid content. Hematite particles formed at 14$0^{\circ}C$ exhibited particle properties with the length of 0.7 ${\mu}{\textrm}{m}$ and aspect ratio of 8. Hematite particles having a good acicular-type were not obtained above 22$0^{\circ}C$.

• Journal of the Korean Dietetic Association
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• v.12 no.1
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• pp.32-43
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• 2006

The purpose of this study is to find out the optimal mixing ratios of three different amounts of pectin, sugar and citric acid for preparation of garlic jam through response surface methodology(RSM) based on the sweetness, pH, color, sensory and texture test. As the sucrose content increased, the sweetness, cohesiveness, color, flavor, gloss and overall palatability of garlic jam tended to be high and the lightness tended to be low. As the pectin content increased, the adhesiveness of garlic jam tended to increase. As the citric acid content increased, the overall palatability of garlic jam tended to be high and the pH tended to be low. The Pectin levels were included 1.8-2.1g, sucrose levels were included 325-342g and citric acid levels were 5.8-6.1g. The optimal mixing ratios of a pectin, sugar and citric acid for manufacturing the best quality of garlic jam were 2.0g, 334g and 6.0g, respectively.

• Journal of the Korean Wood Science and Technology
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• v.45 no.4
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• pp.432-443
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• 2017

Maltodextrin and citric acid are two types of natural materials with the potential as an eco-friendly binder. Maltodextrin is a natural substance rich in hydroxyl groups and can form hydrogen bonds with lignoselulosic material, while citric acid is a polycarboxylic acid which can form an ester bond with a hydroxyl group at lignoselulosic material. The combination of maltodextrin and citric acid as a natural binder materials supposed to be increase the ester bonds formed within the particleboard. This research determined to investigate the bonding properties of a new adhesive composed of maltodextrin/citric acid for nipa frond particleboard. Maltodextrin and citric acid were dissolved in distillated water at the ratios of 100/0, 87.5/12.5, 75/25 and 0/100, and the concentration of the solution was adjusted to 50% for maltodextrin and 60% citric acid (wt%). This adhesive solution was sprayed onto the particles at 20% resin content based on the weight of oven dried particles. Particleboards with a size of $25{\times}25{\times}1cm$, a target density $800kg/m^3$ were prepared by hot-pressing at press temperatures of $180^{\circ}C$ or $200^{\circ}C$, a press time of 10 minute and board pressure 3.6 MPa. Physical and mechanical properties of particleboard were tested by a standard method (JIS A 5908). The results showed that added citric acid level in maltodextrin/citric acid composition and hot-pressing temperature had affected to the properties of particleboard. The optimum properties of the board were achieved at a pressing temperature of $180^{\circ}C$ and the addition of only 20% citric acid. The results also indicated that the peak intensity of C=O group increased and OH group decreased with the addition of citric acid and an increase in the pressing temperature, suggesting an interreaction between the hydroxyl groups from the lignocellulosic materials and carboxyl groups from citric acid to form the ester groups.

• Food Science of Animal Resources
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• v.24 no.3
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• pp.266-272
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• 2004

The objective of this study was to investigate the physicochemical characteristics of gelatin extracted from pork skin under soaking in various acid solutions (lactic acid, acetic acid, and citric acid). Gelatin sol was extracted at 8$0^{\circ}C$, frozen at -2$0^{\circ}C$ and lyophilized it for 3 days to be completely dried in freeze drying unit. In the evaluation of gelatin quality, gelatin soaked in citric acid showed higher L- and a-values than those of any other gelatin (p<0.05). Gelatin treated by acetic acid showed the highest gel strength, cohesiveness, and brittleness. The content of hydroxyproline amino acid in gelatin treated by acetic acid was larger than one of gelatin treated in lactic and citric acid in order. From the experimental results, the highest quality of gelatin in all of period, which was soaked in acetic acid and lactic acid, has a more good quality than gelatin soaked in citric acid.