• International Journal of Industrial Entomology and Biomaterials
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• v.23 no.1
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• pp.183-186
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• 2011

The various molecular weight (MW) regenerated silk fibroins were prepared with different dissolution condition and the effect of MW on the gelation behavior of regenerated aqueous silk fibroin (SF) solution was investigated. The result of gelation time measurement indicated that the gelation of SF aqueous solution was accelerated by the increase of MW and SF concentration. When formic acid was added in SF aqueous solution, the gelation time of SFL and SFC30 aqueous solution showed a significant decreaseat 0.03% formic acid addition. In case of the lowest MW sample, SFC180, SF molecules became aggregated and precipitated without gelation after 28 days storage time. These findings indicate that MW control of SF can be utilized to control the gelation time of SF aqueous solution.

• Membrane Journal
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• v.4 no.3
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• pp.152-162
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• 1994

The photodegradation efficiency of formic acid on $TiO_2$ photocatalytic membranes was investigated. A new titania membrane reactors for purification of water combining microfiltration with photocatalytic degradation of organic compounds were developed. Titania membrane tubes(average pore size of $0.2\mu m$) were prepared by the slip casting, and porous thin films of $TiO_2$ were formed on the tube surface by the sol-gel process to increase the surface area, and consequently to increase photodegradation efficiency of organic compounds. The UV light with the wavelength of 365 nm was used as a light source for photocatalytic reactions. The photodegradation efficiency of the organic compounds was strongly dependent on the flux of the solution, the microstructure of the membrane (sol pH), and the amount of $O_2$ supplied. The effects of the primary oxidant such as $H_2O_2$ and dopants such as $Nb_2O_5$ on the photodegradation efficiency were also investigated. The results showed that more than 80% of formic acid could be degraded using membrane coated with a $TiO_2$ sol of pH 1.45. The photodegradation efficiency could be improved by about 20% when adding $H_2O_2$ in feed solution or doping $TiO_2$ membranes with $Fe_2O_3$.

• Korean Journal of Agricultural Science
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• v.39 no.4
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• pp.569-575
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• 2012

This study was performed to investigate the effect of a sequencial washing of organic acid and distilled water on meat quality and the population of Escherichia coli of pork loin during cold storage. E. coli ATCC25922 was inoculated on the surface of sliced pork loin and 50 mL of 1% or 2% of organic acid and the same amount of distilled water was sprayed on the surface of pork loin. Then, physicochemical and microbial properties of pork loin were analyzed during cold storage. During storage period, lightness, yellowness and lipid oxidation (thiobarbituric acid reactive substances value) was higher than those of not treated control. However, the population of E. coli was decreased significantly in formic acid and distilled water sprayed pork loin samples. From these results, it can be considered that application of combination of washing of formic acid and water in the washing step of pig slaughter may be helpful to control the proliferation of E. coli.

• Korean Journal of Poultry Science
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• v.35 no.1
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• pp.57-62
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• 2008

The study was conducted to evaluate the effects of dietary organic acid mixture(lactic acid 12%, formic acid 9%, citric acid 5%, butyric acid 5% and phosphoric acid 6%) on growth performance, organ weight, blood immunological parameter and intestinal villi morphology in broilers. Dietary treatments included 1) CON (basal diet), 2) OA1 (basal diet + 0.1% organic acid mixture) and 3) OA2 (basal diet + 0.2% organic acid mixture). Four hundred eighty hatched Arbor Acre broiler chickens were housed in 24 pens of 20 birds each. Eight replicate pens were allotted into each treatment by completely randomized design. Daily weight gain, feed intake and feed/gain were not significantly different among the treatments. In organ weight, that of gizzard was significantly heavier in OA2 than CON (Linear effect = 0.034). However, those of spleen and intestine were not significantly different among the treatments. Blood immunological parameters such as RBC, WBC and lymphocyte were not significantly difference. In intestinal villi morphology, villi length was increased in OA1 compared to CON (Quadratic effect = 0.050). In conclusion, 0.2% organic acid mixture was effective to improve gizzard weight of broilers.

• Korean Journal of Food Science and Technology
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• v.29 no.5
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• pp.913-918
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• 1997

Taste components of traditional kochujang prepared with various raw materials, were investigated during 90 days of fermentation. The major free sugars, maltose and glucose, were higher in malt added kochujang than others. The major organic acids of kochujang were succinic and citric acids, followed by formic acid. The contents of succinic acid in the kochujang decreased during fermentation, whereas that of citric acid increased. Purple sweet potato kochujang was highest in total free amino acids. The major free amino acids were glutamic acid, serine and aspartic acid. They remarkably increased during fermentation. Among the nucleotides and their related components in kochujang, cytidine-5-monophosphate was the most abundant component at the beginning of aging period, while hypoxanthine increased remarkably during fermentation. Kochujang prepared with purple sweet potato Chinese matrimony vine contained higher amounts of organic acids and nucleotides than the others.

• Journal of the Korea Organic Resources Recycling Association
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• v.2 no.2
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• pp.31-37
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• 1994

For a microbiological study of composting process, screening and assay method for biopolymer degrading enzymes and microorganisms were developed and for the study of the possibility of composting in anaerobic state, distribution of sulfate reducing bacteria which plays a final role in anaerobic degradation was investigated. Substrates used for the development of assay methods for biopolymer degradation are ${\beta}-glucan$, xylan, dextran, CMC(carboxy methly cellulose), casein, and collagen. These substrates were made insoluble by a cross-linking agent and linked with dye to make chromogenic substrates. ${\beta}-glucan$ and xylan substrates could substitute congo-red method for screening of polymer degrading microorganisms without damaging the colonies. Sulfate reducing bacteria contained in the sample sludge showed preference to lactic acid, propionic acid, butyric acid and formic acid and could use acetic acid and valeric acid.

• Asian-Australasian Journal of Animal Sciences
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• v.19 no.2
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• pp.198-202
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• 2006

An experiment was conducted to investigate the effect of phytase, organic acids and their interaction on body weight gain, feed consumption, feed conversion ratio, carcass yield and tibia ash. A total of 680 three-day old Japanese quail chicks (Coturnix coturnix japonica) were assigned to 20 battery brooders, 34 chicks in each. The experimental period lasted 35 days. The treatment groups employed were: 1) a positive control which included 3.5 g available phosphorus (AP)/kg diet and 10 g Ca/kg diet; 2) a negative control which included 2 g AP/kg diet and 8 g Ca/kg diet, 3) negative control diet supplemented with either 300 FTU phytase/kg diet (phytase) or 4) 2.5 g organic acid (lactic acid+formic acid)/kg diet (organic acid); or 5) 300 FTU phytase/kg diet+2.5 g organic acid/kg diet (phytase+organic acid). All birds were fed with the positive control diet for a week and then transferred to the dietary treatments. At the end of the study, there were no differences (p>0.005) among the groups in body weight, weight gain, feed consumption, feed conversion ratio and carcass yield. Tibia ash, however, was reduced (p<0.001) for quails fed the negative control diet containing a low-level of AP compared to the positive control diet containing adequate AP. The addition of phytase, organic acid or phytase+organic acid to the diets containing the low-level of AP improved (p<0.001) tibia ash. On the other hand, an extra synergistic effect of phytase and organic acid on tibia ash was not determined. This study demonstrated that it may be possible to reduce supplemental level of inorganic P with phytase and/or organic acid supplementation for quail diets without adverse effect on performance and tibia ash.

• Journal of the Korean Wood Science and Technology
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• v.21 no.3
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• pp.22-29
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• 1993

나뭇잎으로부터 발생되는 저분자량 유기산을 이온크로마토그래피를 이용하여 분석하였다. 이 방법은 자연상태의 나뭇잎 (needle litter)을 유기용매의 추출 없이 그대로 이용할 수 있어서 사용하기에 편리하다. 본 논문에서는 이온 크로마토그래피의 사용방법과 침엽수잎(Pacific Silver Fir)의 부후정도에 따른 유기산의 종류와 농도의 변이를 간략하게 소개한다. 초기의 침엽수잎 여과액으로부터는 $C_2$에서 $C_4$까지의 아세트산(acetic acid), 프로피온산(propionic acid), 옥살산(oxalic acid) 그리고 포름산(formic acid) 등이 주종을 이루지만 부후정도가 커짐에 따라 방향핵을 가진 방향핵 유기산(aromatic organic acid)이 발생한다.

• Korean Journal of Food Science and Technology
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• v.27 no.1
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• pp.25-29
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• 1995

Organic acids and fatty acids of four different Kochujang prepared with different mashing methods were determined by HPLC and GC. Citrate, malate, lactate, succinate, formate, oxalate and acetate were identified. Citrate was found as a major organic acid ($450{\sim}565$ mg%) followed in decreasing order by lactate and malate. Total organic acid content of Meju Kochujang was the highest at the initial fermentation time, while that of koji Kochujang was higher than any other one after 90 days of fermentation. There was a little change of total acid among the treatments. Oleic acid was a major fatty acid ($68.59{\sim}75.38%$) during the fermentation of Kochujang. There was no significant change of fatty acids during the fermentation and among the treatments.

• Membrane Journal
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• v.6 no.2
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• pp.101-108
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• 1996

The oxidation/degradation efficiency of formic acid through the photoelectrochemical reaction has been investigated as a basic research in order to develope the process for degrading toxic organic compounds dissolved in water. A $TiO_{2}$ photoelectro-membrane reactor for purification of water, in which filtration as well as photoelectrocatalytic oxidation of organic compounds could be carried out simultaneously, was developed. Porous $SnO_{2}$ tubes prepared by slip casting and commercial porous stainless steel tubes, being electrically conductive, were used as not only supports but also working electrodes. The UV light with the wavelength of 365 nm was applied as a light source for photocatalytic reactions. The photoelectrocatatytic composite membranes were prepared by coating the support surface with the $TiO_{2}$ sol of pH 1.45. The oxidation efficiency of formic acid increased with the reaction time and the applied voltage, but was almost independent of the solution flux. The results showed that more than 90% of formic acid could he dograded at 27V using the $TiO_{2}$/stainless steel composite membrane, while about 77% in case of the $TiO_{2}/SnO_{2}$ Composite membrane. It was also concluded that the oxidation efficiencies of formic acid could be significantly improved by about 6~7 times by the photoelectrochemical reaction in comparison with those by the photocatalytic reaction only.