Optimization of Citric Acid Production by Immobilized Cells of Novel Yeast Isolates

( Abd El-latif Hesham ),( Yasser S. Mostafa ),( Laila Essa Omar Alsharqi ) 한국균학회 2020 Mycobiology Vol.48 No.2

Citric acid is a commercially valuable organic acid widely used in food, pharmaceutical, and beverage industries. In this study, 260 yeast strains were isolated from soil, bread, juices, and fruits wastes and preliminarily screened using bromocresol green agar plates for their ability to produce organic acids. Overall, 251 yeast isolates showed positive results, with yellow halos surrounding the colonies. Citric acid production by 20 promising isolates was evaluated using both free and immobilized cell techniques. Results showed that citric acid production by immobilized cells (30-40 g/L) was greater than that of freely suspended cells (8-19 g/L). Of the 20 isolates, two (KKU-L42 and KKU-L53) were selected for further analysis based on their citric acid production levels. Immobilized KKU-L42 cells had a higher citric acid production rate (62.5%), while immobilized KKU-L53 cells showed an ~52.2% increase in citric acid production compared with free cells. The two isolates were accurately identified by amplification and sequence analysis of the 26S rRNA gene D1/D2 domain, with GenBank-based sequence comparison confirming that isolates KKU-L42 and KKU-L53 were Candida tropicalis and Pichia kluyveri, respectively. Several factors, including fermentation period, pH, temperature, and carbon and nitrogen source, were optimized for enhanced production of citric acid by both isolates. Maximum production was achieved at fermentation period of 5 days at pH 5.0 with glucose as a carbon source by both isolates. The optimum incubation temperature for citric acid production by C. tropicalis was 32 ℃, with NH₄Cl the best nitrogen source, while maximum citric acid by P. kluyveri was observed at 27 ℃ with (NH₄)₂ SO₄ as the nitrogen source. Citric acid production was maintained for about four repeated batches over a period of 20 days. Our results suggest that apple and banana wastes are potential sources of novel yeast strains; C. tropicalis and P. kluyveri which could be used for commercial citric acid production.

Bonding Performance of Maltodextrin and Citric Acid for Particleboard Made From Nipa Fronds¹

Mahdi Santoso,Ragil Widyorini,Tibertius Agus Prayitno,Joko Sulistyo 한국목재공학회 2017 목재공학 Vol.45 No.4

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 bond-ing 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 × 25 × 1 cm, a target density 800 kg/m³ were prepared by hot-pressing at press temperatures of 180℃ or 200℃, 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℃ 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.

유기산을 이용한 오징어 어유의 어취 개선

장민경(Min-Kyung Jang),이옥희(Ok Hee Lee),김남영(Nam-Young Kim),유기환(Ki Hwan Yu),장혜지(Hye Ji Jang),이승우(Seung Woo Lee),박미라(Mi Ra Park),박정현(Joung- Hyun Park),김미향(Mihyang Kim),하종명(Jong-Myung Ha),배송자(Song-Ja Bae),이상 한국생명과학회 2009 생명과학회지 Vol.19 No.9

오징어 정제어유에 대한 부가적인 탈취과정을 통해 고품질의 제품을 생산하기 위하여 유기산의 일종인 citric acid 및 gluconic acid를 이용한 칼럼을 제작하고 여기에 오징어 정제어유를 통과시키는 방법으로 어취제거 실험을 행하였다. 그 결과, citric acid 및 gluconic acid 칼럼 모두에서 우수한 어취 제거 효과가 나타났으며, 유기산 1 g과 2 g을 사용한 경우보다 3 g을 사용한 경우에 더 우수한 어취제거 효과를 얻을 수 있었다. 또한, citric acid를 사용한 칼럼에서 보다 gluconic acid를 사용한 칼럼에서 더 높은 어취제거 효과를 얻을 수 있었다. 한편, 과산화물가(POV) 및 산가(AV)를 측정한 결과, gluconic acid 칼럼을 통과한 시료는 미처리 대조군에 비해 약간 높은 수치를 나타냈으며, citric acid 칼럼을 통과한 시료는 미처리 대조군과 비슷한 수치를 나타냈다. 결론적으로, gluconic acid 칼럼을 이용한 탈취실험의 경우는 탈취효과는 뛰어난 반면 과산화물가와 산가가 약간 증가하는 결과가 나타났고, citric acid 칼럼을 이용한 탈취실험의 경우는 탈취효과는 약간 떨어졌지만 과산화물가와 산가는 미처리 대조군과 비슷한 수치를 나타냈다. 본 연구에서 유기산 칼럼을 이용하여 성공적인 어취제거효과를 얻을 수 있었으며, 어유의 주요 성분 변화는 거의 관찰되지 않음을 확인할 수 있었다. To produce high quality fish oil products, additional deodorization experiments on purified fish oil from squid using columns filled with citric acid or gluconic acid were performed. A deodorization effect on the fish oil was observed on both the citric acid and gluconic acid columns. These effects were more efficient on the columns packed with 3 g of organic acid than those with 1 g or 2 g of organic acid. In addition, a better effect was observed in the column packed with gluconic acid than that with citric acid. Peroxide value (POV) and acid value (AV) of the sample treated with citric acid was the as same as the non-treated sample. However, POV and AV of the sample treated with gluconic acid were about 10% higher than the non-treated sample. Contents of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) of the samples treated with citric acid or gluconic acid columns were about 0.5% higher than the non-treated sample. In conclusion, deodorization of squid fish oil by organic acid could be an efficient method to produce high quality fish oil products.

유기산 전처리에 따른 메밀 새싹의 저장중 품질변화

장수경(Su-Kyung Chang),이현희(Hyun-Hee Lee),홍석인(Seok-In Hong),한영숙(Young-Sook Han) 한국식품과학회 2010 한국식품과학회지 Vol.42 No.2

메밀 새싹의 유통 중 품질유지를 목적으로 유기산 용액과 염소수에 침지한 후 플라스틱 필름봉투에 밀봉하여 5℃에 저장하면서 여러 가지 품질인자의 변화를 살펴보았다. 미생물학적 측면에서 총균수와 대장균군수의 측정 결과 0.5% citric acid, 0.05% acetic acid의 단독 및 병용처리가 다른 처리구에 비해 미생물 증식제어에 효과적이었다. 수분함량이나 가용성 고형분함량의 경우 6일 저장 중 의미 있는 변화를 관찰할 수 없었다. 색 변화에서도 Hunter L값과 Hunter b값은 처리구별로 유의적인 차이를 보이지 않았으나, Hunter a값의 경우 저장기간이 경과함에 따라 ascorbic acid 및 citric acid 처리구의 변화가 가장 적게 나타났다. 관능평가에 있어서도 저장 중 ascorbic acid 및 citric acid 처리구가 다른 것에 비해 변색, 시듦, 종합적 외관품질 항목 모두에서 유의적으로 구분되어 관능적 품질이 우수한 것으로 평가되었다. 결과적으로 본 연구에서 사용한 유기산 가운데 citric acid를 전처리 침지용액으로 적용할 경우 메밀 새싹의 유통 중 품질유지에 매우 긍정적인 효과가 있음을 확인하였다. 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℃ 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.

파일럿 규모의 실증실험 사례를 통한 구연산의 우라늄 식물 전이 효과 규명

한이경,이민희,Han, Yikyeong,Lee, Minhee 한국지하수토양환경학회 2016 지하수토양환경 Vol.21 No.6

The field feasibility tests for a phytoextraction process were performed to identify the effect of citric acid as a chelate on the uranium (U) transfer into the plant for the naturally U contaminated soil in Duckpyeongri, Korea. For the feasibility tests, lettuce and Chinese cabbage were cultivated for 49 days on four testing grounds ($1m{\times}1m{\times}0.5m$ in each) in 2016. The citric acid solution was added to two testing grounds (one for lettuce and the other for Chinese cabbage) increasing the U transfer in two crop plants and their results were compared to those without the citric acid solution. When without the citric acid solution, the U concentration of plant after the cultivation was low (< $45{\mu}g/kg$ for leaves and < $450{\mu}g/kg$ for roots). However, with the addition of 50 mM citric acid solution, the U concentration of lettuce leaves and roots increased by 24 times and 1.8 times, and the U concentration of Chinese cabbage leaves and roots increased by 86.7 times and 5.4 times. The absolute accumulated U amount (${\mu}g$) in lettuce and Chinese cabbage also increased by 8.7 times and 50 times, compared to those without citric acid solution. Less than 8% of the U amount of exchangeable/carbonate phases was removed by using the lettuce and Chinese cabbage when the citric acid solution was not applied. However 52% and 66% of the U amount in exchangeable/carbonate phases were removed by the lettuce and the Chinese cabbage when the citric acid solution was added. The effect of the citric acid on the U transfer capability into the plants was quantitatively investigated by the field feasibility test, suggesting that U existing as exchangeable/carbonate phase in soil can be successfully removed by the phytoextraction process using Chinese cabbage with citric acid.

압출성형에 의한 ginsenoside의 변환

류재형,이춘영,안문섭,김장원,강위수,이해익 한국응용생명화학회 2008 Journal of Applied Biological Chemistry (J. Appl. Vol.51 No.2

Ginseng treated with several treatment conditions of various acids to search hydrolysates on the basis of increased biological activity and modified structure. In the result of acid treatment, the conversion rate of ginsenoside Rg3, Rk1 and Rg5 was highest when ginseng treated with citric acid. After added citric acid to ginseng extract, boiled at 100oC for 1 hour and add enzyme, which is examined change by time. It compared with group which did not treated acid. Two groups became difference according to enzyme but the generation rate of ginsenoside Rg3, Rk1 and Rg5 did not show difference greatly. Also, the generation rate of ginsenoside Rg3, Rk1 and Rg5 by time passes did not show difference. The generation rate of ginsenoside Rg3, Rk1 and Rg5 increased when increased acid concentration, temperature and time. We did exclusion molding to shorten treatment time. In the result of ginseng treated with citric acid of various concentrations at various temperatures as time passes by extrusion molding, the generation rate of ginsenoside Rg3, Rk1 and Rg5 was highest when ginseng treated with 3% citric acid at 160oC for 20 minutes. In addition, total saponin amount of ginseng treated with 3% citric acid at 160oC for 20 minutes was about 11% higher than ginseng heated at 120oC for 3 hours. These results indicated that our exclusion molding process more effective, compared to traditional red ginseng manufacturing process. Ginseng treated with several treatment conditions of various acids to search hydrolysates on the basis of increased biological activity and modified structure. In the result of acid treatment, the conversion rate of ginsenoside Rg3, Rk1 and Rg5 was highest when ginseng treated with citric acid. After added citric acid to ginseng extract, boiled at 100oC for 1 hour and add enzyme, which is examined change by time. It compared with group which did not treated acid. Two groups became difference according to enzyme but the generation rate of ginsenoside Rg3, Rk1 and Rg5 did not show difference greatly. Also, the generation rate of ginsenoside Rg3, Rk1 and Rg5 by time passes did not show difference. The generation rate of ginsenoside Rg3, Rk1 and Rg5 increased when increased acid concentration, temperature and time. We did exclusion molding to shorten treatment time. In the result of ginseng treated with citric acid of various concentrations at various temperatures as time passes by extrusion molding, the generation rate of ginsenoside Rg3, Rk1 and Rg5 was highest when ginseng treated with 3% citric acid at 160oC for 20 minutes. In addition, total saponin amount of ginseng treated with 3% citric acid at 160oC for 20 minutes was about 11% higher than ginseng heated at 120oC for 3 hours. These results indicated that our exclusion molding process more effective, compared to traditional red ginseng manufacturing process.

Ascorbic acid 및 citric acid 처리에 따른 홍삼추출물의 페놀성 성분 및 ginsenoside 함량 변화

공연희(Yeon Hee Kong),노정해(Jeonghae Rho),조장원(Chang-Won Cho),김미현(Mi Hyun Kim),이영철(Young Chul Lee),김성수(Sung Soo Kim),이평재(Pyeongjae Lee),최상윤(Sang Yoon Choi) 고려인삼학회 2009 Journal of Ginseng Research Vol.33 No.3

본 연구에서는 수삼을 식품에 쓰이는 산화 방지제인 ascorbic acid와 citric acid로 처리하여 홍삼을 제조한 후 활성성분인 페놀화합물과 진세노사이드의 추출물내 함량 변화를 HPLC를 이용하여 살펴보았다. 분석결과 citric acid 처리 홍삼에서 esculetin과 quercetin 함량이 무처리 홍삼에 비하여 각각 3.5 배, 2.0 배 증가하였고 ginsenoside 함량 역시 citric acid 처리시의 Rg₃, Rd, Rh₂ 증가량이 ascobic acid 처리시에 비하여 높았다. 따라서 인삼추출물의 이들 특정활성성분 강화를 위하여는 citric acid 처리가 효과적인 것으로 판단된다. 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 Rg₃, Rh₂, Rd increased but those of Rb1, Rc, Re, Rf, Rg₁ 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.

Combined Effect of Lactic Acid Bacteria and Citric Acid on Escherichia coli O157:H7 and Salmonella Typhimurium

서승우,Day Jung,Xiaoyu Wang,서동주,이민화,이복희,최창순 한국식품과학회 2013 Food Science and Biotechnology Vol.22 No.4

Lactic acid-producing bacteria (LAB) and organic acids can inhibit the growth of pathogenic bacteria and spoilage organisms. Here, synergistic effect of LAB and citric acid was examined. Escherichia coli O157:H7 or Salmonella Typhimurium were treated with a 1% citric acid, 2% citric acid, LAB mixture, LAB mixture+1% citric acid, and LAB mixture+2% citric acid for 10, 20, 30, and 60 min, respectively. While LAB only, the addition of 1 or 2% citric acid caused 0.28-0.57 log reductions of E. coli O157:H7 or S. Typhimurium within 60 min, the treatment of LAB mixture+2% citric acid showed 1.96 and 6.24 log reductions of E. coli O157:H7 and S. Typhimurium,respectively. In conclusion, LAB and citric acid act synergistically and the combination showed its potential of an effective hurdle for the inactivation of foodborne pathogens.

Enhanced concentrations of citric acid in spring aerosols collected at the Gosan background site in East Asia

Jung, J.,Kawamura, K. Pergamon Press ; Elsevier [distribution] 2011 Atmospheric environment Vol.45 No.30

In order to investigate water-soluble dicarboxylic acids and related compounds in the aerosol samples under the Asian continent outflow, total suspended particle (TSP) samples (n = 32) were collected at the Gosan site in Jeju Island over 2-5 days integration during 23 March-1 June 2007 and 16-24 April 2008. The samples were analyzed for water-soluble dicarboxylic acids, ketocarboxylic acids, and α-dicarbonyls using a capillary gas chromatography technique. We found elevated concentrations of atmospheric citric acid (range: 20-320 ng m<SUP>-3</SUP>) in the TSP samples during mid- to late April of 2007 and 2008. To specify the sources of citric acid, dicarboxylic acids and related compounds were measured in the pollen sample collected at the Gosan site (Pollen_Gosan), authentic pollen samples from Japanese cedar (Cryptomeria) (Pollen_cedar) and Japanese cypress (Chamaecyparis obtusa) (Pollen_cypress), and tangerine fruit produced from Jeju Island. Citric acid (2790 ng in unit mg of pollen mass) was found as most abundant species in the Pollen_Gosan, followed by oxalic acid (2390 ng mg<SUP>-1</SUP>). Although citric acid was not detected in the Pollen_cedar and Pollen_cypress as major species, it was found as a dominant species in the tangerine juice while malic acid was detected as major species in the tangerine peel, followed by oxalic and citric acids. Since Japanese cedar trees are planted around tangerine farms to prevent strong winds from the Pacific Ocean, citric acid that may be directly emitted from tangerine is likely adsorbed on pollens emitted from Japanese cedar and then transported to the Gosan site. Much lower malic/citric acid ratios obtained under cloudy condition than clear condition suggest that malic acid may rapidly decompose to lower molecular weight compounds such as oxalic and malonic acids (<C4) via aqueous phase reaction in cloud during the atmospheric transport.

Citric Acid에 의한 원료 멸치(Engraulis japonicus) pH가 발효초기 멸치 액젓의 히스타민 생성에 미치는 영향

심길보,이우진,안병규,인정진,한형구,손승아 한국수산과학회 2023 한국수산과학회지 Vol.56 No.2

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.