• Korean Journal of Food Science and Technology
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• v.5 no.4
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• pp.215-223
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• 1973

A potent citric acid producing strain was selected by an extensive screening test of the yeasts isolated from the various sources. These experiments were conducted to identify the selected strain and investigate the cultural conditions for citric acid production. The results obtained were as fellows: 1. The selected strain of yeast was identified to Hansenula anomala var. anomala by a taxnoomic study of Lodder. 2. The optimum conditions for citric acid production in the basal medium containing 10% glucose were: temperature $30^{\circ}C$, the concentration of $CaCO_3$ 3% and the velocity of oscillation 110 oscills/min. 3. As a nitrogen source ol the basal medium $NH_4Cl(0.1%)$ was the most effective for citric acid production. Organic nitrogen sources such as peptone were adequate for growth of the strain but not for citric acid production. 4. The most effective concentration of glucose was 10% in yield ratio of citric acid from sugar. 5. The addition of defatted rape seed, defatted perilla or defatted rice bran to the medium was effective for citric acid production. When 5% extract solution of defatted rape seed was added, the citric acid production was increased as much as 40% as compared with the case of adding yeast extract(0.2%). 6. The most effective concentration of $KH_2PO_4$ and $MgSO_4{\cdot}7H_2O$ in the medium(for citric acid Production) was 0.05% and 0.025% respectively. 7. Under the optimum cultural conditions, the growth of the strain was continued up to 5 days and the increase of citric acid production was continued up to 6 days, showing the yield ratio of 46% to glucose.

• Food Science and Preservation
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• v.22 no.3
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• pp.399-407
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• 2015

Sumaeyaksuk (Artemisia Argyi H.) is one of the original mugwort spices in Namhae-gun, Korea. This study was conducted to investigate the physicochemical characteristics and biological activities of water extracts from dried and aging Sumaeyaksuk samples during the May-July harvest season. One (SD) was dried under shade for 12 days, while the other (AD) was aged for 7 days at $60^{\circ}C$ and then roasted for 220 minutes at over $90^{\circ}C$. Glucose was solely detected as a free sugar, and its SD and AD content were $0.42{\pm}0.02{\sim}0.43{\pm}0.01g/100g$, and $0.41{\pm}0.02{\sim}0.47{\pm}0.04g/100g$, respectively. The total phenolic contents of SD were $1.85{\pm}0.09{\sim}3.45{\pm}0.14g/100g$, which were higher than those of AD ($1.29{\pm}0.08{\sim}2.90{\pm}0.08g/100g$). The antioxidant activities of the water extract powder from each Sumaeyaksuk were assessed by different in vitro methods, such as the DPPH and ABTS radical scavenging activity, FRAP, and decoloration prevention activity in ${\beta}$-carotene linoleic system. The DPPH and ABTS radical scavenging activity of AD extract were significantly higher than those of the SD extract (p<0.05). Moreover, at the concentrations of 31.25, 62.5, 125, 250, $500{\mu}g/mL$, the FRAP of the SD-May extract showed $1.67{\pm}0.58{\sim}489.90{\pm}7.59{\mu}M$, while the AD-July extract showed $9.70{\pm}1.07{\sim}590.40{\pm}7.45{\mu}M$. The ${\beta}$-carotene decoloration prevention activity of the SD-May and AD-July extracts were $25.53{\pm}2.85{\sim}81.43{\pm}2.56%$, $35.98{\pm}2.22{\sim}79.00{\pm}1.42%$, respectively. Based on these results, the extracts of SD-May and AD-July were promising as a functional food source due to their high antioxidant activites.

• The Korean Journal of Mycology
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• v.10 no.2
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• pp.75-83
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• 1982

As a primary study for cell growth and alcohol production of a cider yeast, Saccharomyces sp. R-11, cultural and nutritional characteristics of the strain were investigated. The results obtained were as follows: The optimum culture medium for this strain was a synthetic medium, Henneberg B, and sucrose was the best carbon source for yeast growth and alcohol production. Optimum sugar concentrations for yeast growth and alcohol production were 15% and 25%, respectively. Optimum pH and temperature of the basal medium for growth of this strain were 4.5 and $30^{\circ}C$ respectively. The yeast growth was enhanced by the addition of 100 ppm of $Mg^{2+}$, but significantly inhibited by the addition of 100 ppm of $Co^{2+}$. Lower temperature and maintenance of optimum pH for yeast growth increased the final alcohol concentration. Under optimum condition for cell growth at stationary culture, generation time and specific growth rate of the strain were 7.5 hr and 0.092 $hr^{-1}$, respectively. At 8% initial alcohol concentration, yeast growth was inhibited about 50% and this strain could not be grown at more than 12% initial alcohol. The strain could be grown at less than 125ppm $SO_2$without alcohol addition, and at less than 75 ppm $SO_2$ with 8% initial alcohol. The higher sulfur dioxide concentration of a medium, the longer lag phase in yeast growth was observed. This strain could induced alcoholic fermentation at less than 10% initial alcohol concentration with 0 and 25 ppm $SO_2$, at less than 8% initial alcohol with 50 and 75 ppm $SO_2$, and at less than 6% initial alcohol with 100 and 125 ppm $SO_2$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.11
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• pp.1599-1606
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• 2015

The purpose of this study was to assess the quality characteristics of Moju made with Hovenia dulcis Thunb. and its physiological effects on ICR mice. According to the sensory score, we selected Moju made with 1% Hovenia dulcis Thunb. among Moju made with 0, 0.5, 1, 5, and 10% Hovenia dulcis Thunb. Compared to Moju made without Hovenia dulcis Thunb., Moju made with 1% Hovenia dulcis Thunb. had higher proportions of moisture (86.77 g/100 g) and carbohydrates (11.86 g/100 g). The mean values of the physicochemical analyses were as follows: pH 4.91, acidity 0.28, $^{\circ}Brix$ 12.63, reducing sugar 68.97, alcohol content 0.1, alcohol density 0.998. Moju made with 1% Hovenia dulcis Thunb. did not have effects on DPPH radical scavenging activity; however, superoxide dismutase activity was significantly higher than that of Moju made without Hovenia dulcis Thunb. For assessing physiological activities, 4-week-old male ICR mice were divided into six groups (n=10): normal control group (NC), ethanol-administered group (EC), EC plus low-dose Moju made with 0% Hovenia dulcis Thunb. (MCL), EC plus high-dose Moju made with 0% Hovenia dulcis Thunb. (MCH), EC plus low-dose Moju made with 1% Hovenia dulcis Thunb. (MDL), and EC plus high-dose Moju made with 1% Hovenia dulcis Thunb. (MDH). Serum triglyceride (TG) level was reduced by 11.17% and 19.61% in the MDL and MDH groups, respectively, compared to the EC group. Serum total-cholesterol levels of MDL and MDH groups were significantly lower as compared to the EC group. Serum high-density lipoprotein-cholesterol levels of the MDL and MDH groups were significantly higher than those of the EC group. Liver TG levels were significantly reduced in the MCL and MDL groups. From these results, Moju made with Hovenia dulcis Thunb. demonstrated antioxidant activity and reduction of hyperlipidemia markers. Therefore, Moju made with Hovenia dulcis Thunb. can serve as a non-alcoholic beverage and functional food source.

• Horticultural Science & Technology
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• v.31 no.1
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• pp.56-64
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• 2013

Recent unusual weather due to global warming causes shortage of daily sunlight and constitutes one of the primary reasons for agricultural damages. LED light sources are frequently utilized to compensate for the shortage of sunlight in greenhouse agriculture. The present study is aimed at evaluating formations of phytochemicals as well as growth characteristics of mature strawberry fruits ('Daewang' cultivar) during cultivation in a closed growth chamber equipped with artificial LED light as a sole light source. Each LED light of blue (448 nm), red (634 and 661 nm) or mixed blue plus red (blue:red = 3:7) was separately supplied and the intensity of each light was adjusted to $200{\pm}1{\mu}mol{\cdot}m^{-2}{\cdot}s^{-1}$ at plant level with a photoperiod consisted of 16 hours light and 8 hours darkness. Strawberries grown under mixed LED light of blue and red wavelengths showed a higher production of fruits than those grown under other LED treatments. Fructose, one of the free sugars, increased in mixed LED light-grown fruits. Anthocyanin contents were elevated remarkably in the mixed LED light-grown fruits compared with those in other LED treatments. Contrastingly, contents of total phenolics and flavonoids were not of much different from one another among the fruits treated with various LED lights. On the other hand, ripening of strawberry fruits was found to be faster when grown under blue LED light compared with other LED treatments. Moreover, antioxidant activities of blue or red LED light-grown fruits, respectively, were significantly higher than those of mixed LED light-grown fruits. We suggest that when daylight is in shortage during cultivation in a greenhouse, supplementation of sunlight with LED light, which is composed of blue and red wavelengths, could be useful for the enhancement of productivity as well as of free sugar content in strawberry fruits. In addition, for the strawberry culture in the plant factory, selective adoption of LED light wavelength would be required to accomplish the purpose of controlling fruit maturation time as well as of enhancing contents of sugars and antioxidants of fruits.

• Journal of Bio-Environment Control
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• v.32 no.1
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• pp.23-33
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• 2023

Sucrose (suc) is a disaccharide that consists of glucose (glu) and fructose (fru). It is a carbohydrate source that acts as a nutrient molecule and a molecular signal that regulates gene expression and alters metabolites. This study aimed to evaluate whether suc-specific signaling induces an increase in bioactive compounds by exogenous suc absorption via roots or whether other factors, such as osmotic stress or biotic stress, are involved. To compare the osmotic stress induced by suc treatment, 4-week-old cultured mugwort plants were subjected to Hoagland nutrient solution with 10 mM, 30 mM, and 50 mM of suc or mannitol (man) for 3 days. Shoot fresh weight in suc and man treatments was not significantly different from the control. Both man and suc treatments increased the content of bioactive compounds in mugwort, but they displayed different enhancement patterns compared to the suc treatments. Mugwort extract treated with suc 50 mM effectively protected HepG2 liver cells damaged by ethanol and t-BHP. To compare the biotic stress induced by suc treatment, 3-week-old mugwort plants were subjected to microorganism and/or suc 30 mM with Hoagland nutrient solution. Microorganisms and/or suc 30 mM treatments showed no difference about the shoot fresh weight. However, sugar content in mugwort treated with suc 30 mM and microorganism with suc 30 mM treatment was significantly higher than that of the control. Suc 30 mM and microorganism with suc 30 mM were effective in enhancing bioactive compounds than microorganism treatment. These results suggest that mugwort plants can absorb exogenous suc via roots and the enhancement of bioactive compounds by suc treatment may result not from osmotic stress or biotic stress because of microorganism, but by suc-specific signaling.

• The Korean Journal of Mycology
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• v.7 no.1
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• pp.13-73
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• 1979

These studies were conducted to investigate nutrient sources and supplementary materials of synthetic compost media for Agaricus bisporus culture. Investigation were carried out to establish the optimum composition for compost of Agaricus bisporus methods of out-door fermentation and peakheating with rice straw as the main substrate of the media. The incidence and flora of harmful organisms in rice straw compost and their control were also studied. 1. When rice straw was used as the main substrate in synthetic compost as a carbon source. yields were remarkably high. Fermentation was more rapid than that of barley straw or wheat straw, and the total nitrogen content was high in rice straw compost. 2. Since the morphological and physico-chemical nature of Japonica and Indica types of rice straw are greatly dissimilar. there were apparent differences in the process of compost fermentation. Fermentation of Indica type straw proceeded more rapidly with a shortening the compost period, reducing the water supply, and required adding of supplementary materials for producing stable physical conditions. 3. Use of barley straw compost resulted in a smaller crop compared with rice straw. but when a 50%, barley straw and 50% rice straw mixture was used, the yield was almost the same as that using only rice straw. 4. There were extremely high positive correlations between yield of Agaricus bisporus and the total nitrogen, organic nitrogen, amino acids, amides and amino sugar nitrogen content of compost. The mycerial growth and fruit body formation were severely inhibited by ammonium nitrogen. 5. When rice straw was used as the main substrate for compost media, urea was the most suitable source of nitrogen. Poor results were obtained with calcium cyanamide and ammonium sulfate. When urea was applied three separate times, nitrogen loss during composting was decreased and the total nitrogen content of compost was increased. 6. The supplementation of organic nutrient activated compost fermentation and increased yield of Agaricus bisporus. The best sources of organic nutrients were: perilla meal, sesame meal, wheat bran and poultry manure, etc. 7. Soybean meal, tobacco powder and glutamic acid fermentation by-products which were industrial wastes, could be substituted for perilla meal, sesame meal and wheat bran as organic nutrient sources for compost media. B. When gypsum and zeolite were added to rice straw. physical deterioration of compost due to excess moisture and caramelization was observed. The Indica type of straw was more remarkable in increase of yield of Agricus bisporus by addition of supplementing materials than Japonica straw. 9. For preparing rice straw compost, the best mixture was prepared by 10% poultry manure, 5% perilla meal, 1. 2 to 1. 5% urea and 1% gypsum. At spring cropping, it was good to add rice bran to accelerate heat generation of the compost heap. 10. There was significantly high positive correlation (r=0.97) between accumulated temperature and the decomposition degree of compost during outdoor composting. The yield was highest at accumulated temperatures between 900 and $1,000^{\circ}C$. 11. Prolonging the composting period brought about an increase in decomposition degree and total nitrogen content, but a decrease in ammonium nitrogen. In the spring the suitable period of composting was 20 to 25 days. and about 15 days in autumn. For those periods, the degree of decomposition was 19 to 24%. 12. Compactness of wet compost at filling caused an increase in the residual ammonium nitrogen. methane and organic acid during peak heating. There was negative correlation between methane content and yield (r=0.76)and the same was true between volatile organic acid and yield (r=0.73). 13. In compost with a moisture content range between 69 to 80% at filling. the higher the moisture content, the lower the yield (r=0.78). This result was attributed to a reduction in the porosity of compost at filling the beds. The optimum porosity for good fermentation was between 41 and 53%. 14. Peak heating of the compost was essential for the prevention of harmful microorganisms and insect pests. and for the removal of excess ammonia. It was necessary to continue fer mentatiion for four days after peak heating. 15. Ten species of fungi which are harmful or competitive to Agaricus bisporus were identified from the rice compost, including Diehliomyces microsporus, Trichoderma sp. and Stysanus stemoites. The frequency of occurrance was notably high with serious damage to Agaricus bisporus. 16. Diehliomyces microsporus could be controlled by temperature adjustment of the growing room and by fumigating the compost and the house with Basamid and Vapam. Trichoderma was prevented by the use of Bavistin and Benomyl. 17. Four species of nematodes and five species of mites occured in compost during out-door composting. These orgnanisms could be controlled through peakheating compost for 6 hours at $60^{\circ}C$.