• Journal of Microbiology and Biotechnology
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• v.13 no.5
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• pp.745-750
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• 2003

Zoogloea ramigera produces an extracellular polysaccharide called zooglan, which adsorbs heavy metals. In the current study, Zoogloea ramigera was cultured in media containing various carbon sources. When different carbon sources were included in the cultivation medium, there was a change in the composition of zooglan that is mainly composed of glucose, galactose, and pyruvic acid. The various zooglan compositions were analyzed by HPLC, and changes in the heavy metal (lead (II) and cadmium) adsorption characteristics relative to a change in the composition were examined using an atomic absorption spectrophotometer. A high adsorption capacity was observed at a pH higher than 3.0. The adsorption of metal ions was the highest at $35^{\circ}C$, and a higher adsorption was obtained with a lower flow rate. Changes in the zooglan composition did result in changes in the heavy metal adsorption characteristics. Furthermore, it was also found that the pyruvic acid content was more important than the glucose or galactose content for heavy metal adsorption.

• Preventive Nutrition and Food Science
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• v.21 no.4
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• pp.348-354
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• 2016

This study investigated the physicochemical characteristics of black garlic (BG) after different thermal processing steps. Compared with fresh garlic (FG), the moisture content and pH in BG decreased significantly, while the ash content and browning intensity increased during thermal processing. The total mineral and the free sugar contents were significantly higher than that of the BG2 and BG4 samples, respectively. The free sugar content increased by 16-fold in the BG cloves compared with that of FG, while the amino acid content increased during the first stage of thermal processing, and subsequently decreased. The thiosulfinate content in all samples decreased to during thermal processing. The pyruvic acid content initially increased and then decreased during thermal processing. These results contribute to our understanding of the role of thermal processing in the quality formation of BG.

• Korean journal of food and cookery science
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• v.32 no.6
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• pp.665-676
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• 2016

Purpose: This study was conducted to find the optimal freezing method and storage conditions for welsh onion. Methods: Cut welsh onions (0.3 cm) were packed in nylon/linear low density polyethylene (LLDPE) film bags, and frozen utilizing still-air freezing at -$20^{\circ}C$ (SAF20) and -$40^{\circ}C$ (SAF40), and immersed-liquid freezing at -$40^{\circ}C$ (ILF40); they were then stored at -$20^{\circ}C$ for 7 months. During storage, quality characteristics were measured monthly. Results: Drip loss was the lowest in the ILF40 packaging. Color difference in the stem (white part) did not differ significantly according to freezing conditions and storage time. Color difference in the leaf (green part) and stem was the lowest in SAF20. pH remained unchanged, while total aerobic bacterial count, pyruvic acid and moisture content decreased during storage. Pyruvic acid content of ILF40 was the highest among the freezing treatments. Fructose and glucose contents increased gradually during storage. Citric acid, malic acid, succinic acid and fumaric acid contents were unaffected, regardless of the freezing conditions. Conclusion: The optimal freezing method for welsh onions with the least quality changes was determined to be immersed liquid freezing, following by preservation up to 7 months by freeze-storing.

• Food Engineering Progress
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• v.13 no.4
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• pp.360-364
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• 2009

The onion extractions of MIX treatment (5% $\beta$ cyclodextrin+1% calcium chloride+1% soluble starch mixture solution) using hot water (100${^{\circ}C}$ and 80${^{\circ}C}$) and ultrasonic treatment (25${^{\circ}C}$) incresed L values and decreased a and b values apart from the extraction methods. Extent of the browning reaction as caused by the MIX treatment (0.093) following 100${^{\circ}C}$ water extraction resulted in as low as 31% O.D. level, as compared to the control(0.296). Analysis of the pyruvic acid showed that the control had higher content of pyruric acid than MIX-treated samples. The MIX treatment had lower intensities and higher preferences of browning color and pungency taste compared to the control. The total and coliform microbial counts increased continuously during storage period, while the MIX treatment reduced the number of viable cells. Finally, it was concluded that the MIX treatment was highly effective in suppressing the undesirable browning color and pungent taste after processing, and the microbes increment during storage.

• Journal of Bio-Environment Control
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• v.14 no.4
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• pp.254-262
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• 2005

This experiment was carried out to select the desirable welsh onion (Allium fistulosum L.) varieties for the year-round cultivation in water culture. Ten varieties were tested, of which five were Korean's and the other five were Japanese's. The germination percentage and germinative energy of most varieties we.e more than 90 percent. The fastest germination speed were 'Geumjanguedaepa', 'Gujopa' and 'Fuyune'. The best growth of the varieties were 'Geumjanguedaepa' and 'Tokyokuro' in spring, 'Geumjanguedaepa', 'Gujopa', 'Saesaeksisilpa' and 'Tokyokuro' in summer, 'Geumjanguedaepa', 'Gujopa' and 'Tokyokuro' in fall, and 'Geumjanguedaepa', 'Midorigawa' and 'Tokyokuro' in winter cultivation. Suitable varieties of growth fur all seasons were 'Geurnjanguedaepa' and 'Tokyokuro', though 'Gujopa' was good in summer and fall. In the view of nutritional content, nitrate content was significantly lower in 'Geumjanguedaepa', 'Tokyokuro' and 'Fuyune' than that in'Saesaeksisilpa' and 'Starziam'. Vitamin C content was higher in 'Aqua Green', 'Midorigawa' and 'Seoulbaekpa' than that of the others. Pyruvic acid content was the highest in 'Geumjanguedaepa' and 'Suckchanguedaepa'. Based on the above results, 'Geumjanguedaepa', 'Gujopa' and 'Tokyokuro' were selected as the most desirable young welsh onion varieties for the year-round water culture.

• Korean journal of food and cookery science
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• v.10 no.1
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• pp.1-7
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• 1994

Major quality parameters(organic acids, alcohols, fusel oil and sensory characteristics) of traditional Ewhaju were investigated during brewing. In organic acid contents at immediately after brewing, lactic acid was 155.1mg％, malonic acid was 5.4mg％, succinic acid was 8.9mg％, acetic acid was 7.6mg％, oxalic arid was 1.3mg％, citric and tartaric acid was 27.8mg％ and pyruvic acid was 4.8mg％ but in 100 days after brewing and one year aged, lactic acid was 1763.3 and 3059.3mg％, malonic acid was 12.3 and 19.3mg％, succinic acid was 11.5 and 23.1mg％, acetic acid was 29.2 and 73.1mg％, oxalic acid was 0.6 and 0.2mg％, citric and tartaric acid was 298.3 and 639.6mg％, and pyruvic acid were 1.1 and 0.3mg％, respectively. All the alcohol contents increased as the fermentation period increased ; the ethyl alcohol was only 0.05fe at immediately after brewing. In the alcohols content of Ewhaju at 100 days after brewing, the ethyl alcohol, methyl alcohol n-propyl alcohol and iso-butyl alcohol were 5.13ft, 47.56 ppm, 37.25 ppm and 19.51 ppm, respectively, Also in the one year aged Ewhaju, the ethyl alcohol was 9.39f), methyl alcohol was 36.34 ppm, Fusel oil was not detected in the first stage of brewing, but it was detected 1.12mg％ at 100 days after brewing and 1.18mg％ at one year stored sample. A general trend in change of color was almost white immediatly after brewing but a increase in Hunter "b" value and "a" value were observed depending on brewing time prolonged. Taste and overall palatability of Ewhaju after 100 days of brewing were significantly superior(p<0.05, p<0.01).

• Journal of Bio-Environment Control
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• v.4 no.2
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• pp.144-151
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• 1995

This experiment was carried out to investigate the effect of different nutrient solution temperatures on the growth and quality of welsh onion in winter season. The fresh weight increased with the increase of temperature within the range of 13-23$^{\circ}C$. The top length was longer 18 and 23$^{\circ}C$ than at 13$^{\circ}C$, the dry weight was the highest at 18$^{\circ}C$. The potassium content in plant was the highest at 18$^{\circ}C$, calcium and magnesium contents were higher at 13 and 18$^{\circ}C$ than at 23$^{\circ}C$. The vitamin C content decreased with the increase of nutrient solution temperature, but there was no statistical significance within treatments. The pyruvic acid was higher at 13 and 18$^{\circ}C$ than at 23$^{\circ}C$, while nitrate content was lower at 13 and 18$^{\circ}C$ than 23$^{\circ}C$. Therefore, for growth and quality of welsh onion, it was concluded that 18$^{\circ}C$ may be suitable nutrient solution temperature in winter season.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.5
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• pp.786-790
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• 1996

The changes in chemical constituents of onion in Korea and the degree of hydrolysis in onion by-drolysates by treatment of viscozyme L, celluclast 1.5L, pectinex and cereflo were investigated. Proximate compositions of onion in Korea were as follows; The contents of moisture, protein, lipid, carbohydrate and ash were 89~90%, 1.8~1.9%, 0.4~0.5%, 7.1~8.5% and 0.3~0.5%, respectively. Major free sugars were identified to be glucose, fructose and sucrose and major free amino acids were as cysteine, histidine, arginine and glutamic acid. The degree of hydrolysis by treatment of viscozyme L, celluclast 1.5L, pectinex and cereflo was 69%, 71%, 80% and 62%, respectively. During the enzymatic hydrolysis, free sugar and total sugar content increased however, pyruvic acid content decreased significantly.

• Korean Journal of Food Science and Technology
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• v.24 no.3
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• pp.272-278
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• 1992

Takju, a Korean traditional wine, was prepared by using nuruk and Koji which were inoculated with Aspergillus kawachii and Aspergillus shirousamii. Those chemical composition such as alcohols and organic acids were determined with gas chromatography to investigate the variation of its content by the fermentation. Alcohol such as methyl, ethyl, n-propyl, i-butyl, i-amyl alcohol were detected in the most takju mash samples. Alcohol contents in the groups fermented with KNR and SNR were slightly higher than KKR, SKR groups. Lactic acid were concentrated and organic acids such as pyruvic, oxalic, malonic, succinic, maleic, malic, ${\alpha}-keto$ glutaric acid were also detected in the most samples. The pH was lowest in the KKR group. The total acid content was slightly decreased at the later fermentation and was highest in KKR. The content of minerals were highest in the WNR and BNR groups. Throughout fermentation the content of potassium and magnesium varied greatly with the tested groups.

• Horticultural Science & Technology
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• v.28 no.6
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• pp.921-927
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• 2010

The objective of this study was to improve the breeding efficiency and consumption of red onion by analysis of chemical components. The red cultivar S&P5294 ($52.9mg{\cdot}g^{-1}$ F.W.) resulted in the highest sugar content, and sweetness whereas 'Redprime' had the lowest. For the pyruvic acid content the cultivar 'Redsun' showed the highest value, followed by 'Sunpower' (yellow onion) and S&P7270. Breeding lines had higher sugar content and sweetness than 'Redprime' and 'Sunpower', while they had less pyruvic acid value than 'Redsun' and 'Sunpower'. The the same trend was verified for the total phenol and total flavonoid, of which breeding lines were found to have more content than 'Redprime' or 'Sunpower'. Three major flavonoids, rutin (quercetin glycoside), myricetin, and quercetin, were identified and quantified whereas kaempferol was not detected in all cultivars. Rutin was the major flavonoid present in all cultivars (136.9 to $169.9{\mu}g{\cdot}g^{-1}$ F.W.), followed by quercetin (62.5 to $135.7{\mu}g{\cdot}g^{-1}$ F.W.). Relatively smaller amount of myricetin (11.2 to $16.1{\mu}g{\cdot}g^{-1}$ F.W.) was also detected. Among nine cultivars, 'Redsun' exhibited significantly ($p$ < 0.05) higher content of quercetin and rutin (135.7 and $169.9{\mu}g{\cdot}g^{-1}$ F.W., respectively), and S&P5296 had the highest content of myricetin($16.1{\mu}g{\cdot}g^{-1}$ F.W.). Breeding lines had more quercetin, rutin and myricetin contents than the cultivars 'Redprime' and 'Sunpower'. Hampyeong had the highest content for total phenol and total flavonoid, followed by Andong and Changyeong whereas Changyeong had the highest value for rutin, myricetin and quercetin followed by Hampyeong and Andong. Among red onion cultivars, 'Redsun' showed the highest value for anthocyanin, followed by S&P5295 and S&P5296, which the cultivar 'Redprime' had significantly (p<0.05) lower content(35.5 mg%).