• Korean Journal of Food Science and Technology
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• v.29 no.4
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• pp.716-721
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• 1997

In order to improve the quality of sikhe, Korean traditional sweat rice drink, wheat malt, covered barley malt and naked barley malt were used to prepare sikhe. The optimum temperature of amylase was $60^{\circ}C$ in malt extract. After heat treatment of amylase for 2 hr at $70^{\circ}C$, residual activity of amylase was less than 20% in malt extract. Amylase activity during sikhe preparation was decreased gradually. The sikhe saccharifyed for 6 hr had $6250{\sim}25029$ units of amylase acitivity. The contents of glucose, maltose and maltotriose were increased with increasing time. Maltose content was the highest, followed by glucose and maltotriose. The pH and titrable acidity were slightly changed. The sweetness of sikhe prepared with wheat was 11.3%, and others were 11.1% and 10.4%. The sikhe prepared with naked barley was evaluated the most palatable sikhe.

• Applied Biological Chemistry
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• v.29 no.3
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• pp.266-272
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• 1986

The contents of water soluble ${\beta}-glucan$ were $1.4{\sim}4.0%$ in grains of 4 recommended varieties, and $0.3{\sim}0.6%$ in their malt. The ${\beta}-glucan$ content was subject to environmental factors such as cultivating region and nitrogen fertilizer level. The ${\beta}-glucan$ content of grains was positively correlated with the viscosity, but negatively with the protein and total gum contents. The ${\beta}-glucanase$ activity was $11.0{\sim}20.0$ sec as the reduced flow time in malt of 4 recommended varieties and was also subject to environmental factors. ${\beta}-Glucanase$ activity showed the highest level after the 6th day during malting. The ${\beta}-glucanase$ activity in malt was positively correlated with malt extract, but negatively with the residual ${\beta}-glucan$ content. The protein content in malt was negatively correlated with malt extract, but positively with the diastatic power.

• Horticultural Science & Technology
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• v.35 no.1
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• pp.121-130
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• 2017

This study was carried out to investigate a method for producing cultured virus - free ovules for breeding high - quality Citrus cultivars. Ovules from the immature fruits of three citrus cultivars native to Jeju (Dongjeongkyool, Cheongkyool, and Jikak) and two cultivars of Citrus unshiu Marc. (Miyagawa wase and Haryejosaeng) that were thought to be infected with Citrus tristeza virus (CTV) were cultured on MS2 medium (Murashige - Skoog [MS] basal medium containing $500mg{\cdot}L^{-1}$ malt extract, $50g{\cdot}L^{-1}$ sucrose, $1.0 mg{\cdot}L^{-1}$ kinetin, and $8g{\cdot}L^{-1}$ agar). After four weeks of culture, 10, 21, 13, 5, and 7 somatic embryos and 2, 4, 2, 4, and 5 white callus cells (surrounding green somatic embryos) were obtained from Dongjeongkyool, Cheongkyool, Jikak, Miyagawa wase, and Haryejosaeng, respectively. After six weeks of culture, somatic embryos were obtained from cultured cells grown on MT basal medium supplemented with malt extract ($500mg{\cdot}L^{-1}$), lactose ($70g{\cdot}L^{-1}$), and agar ($16g{\cdot}L^{-1}$). Over 60% of the somatic embryos from citrus cultivars native to Jeju developed into normal plants on MS basal medium supplemented with malt extract ($500mg{\cdot}L^{-1}$), sucrose ($50g{\cdot}L^{-1}$), and agar ($8g{\cdot}L^{-1}$) after 10 weeks of culture. Normal plants were regenerated from two Citrus unshiu Marc. cultivars on MT basal medium supplemented with sorbitol (1.0 M), galactose (1.0 M), $GA_3$ ($1.0mg{\cdot}L^{-1}$), and Gelrite ($3g{\cdot}L^{-1}$). The absence of virus in plants generated from cultured ovules was confirmed by RT - PCR and antigen - antibody reactions. Therefore, virus - free Citrus cells can be obtained for breeding high - quality citrus cultivars using the biotechnological technique evaluated in this study.

• KSBB Journal
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• v.11 no.5
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• pp.565-571
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• 1996

Medium optimization for ${\beta}$-mannanase production by Aspergillus oryzae ATCC 2114 was performed. Effect of carbon source (locust bean gum) concentration on ${\beta}$-mannanase production was investigated. Above 20 g/L locust bean gum, a lag time for ${\beta}$-mannanase production was appeared because high concentration of locust bean gum caused high viscosity which made the mixing of medium poor. As the locust bean gum concentration in the medium increased, ${\beta}$-mannanase activity and cell growth increased proportionally. Effect of various nitrogen sources on ${\beta}$-mannanase production was also studied. (NH4)2SO4 and malt extract were the most effective for ${\beta}$-mannanase production among the inorganic nitrogenous compounds and organic nitrogen nutrients. Inorganic compounds such as KH2SO4, NaCl, Na2CO3, and MgSO4, on ${\beta}$-mannanase production were optimized for ${\beta}$-mannanase production. Locust bean gum of 10 g/L, malt extract of 3 g/L, (NH4)2SO4 of 2 g/L, KH2SO4, of 10 g/L were selected as the optimal medium. Culture in a fermentor by using the optimal medium was carried out. Lag time of ${\beta}$-mannanase production was shorter due to the better mixing of the fermentor. The maximum ${\beta}$- mannanase activity of 9.7 unit/mL and specific ${\beta}$-mannanase activity of 1.9 unit/mg-cell could be obtained at 27 hours and the productivity of ${\beta}$-mannanase was 0.36 unit/mL$.$h.

• KSBB Journal
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• v.9 no.4
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• pp.436-442
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• 1994

The production of itaconic acid by Aspergillus terreus NRRL 1960 was studied. The optimal culture conditional such as pH, inoculum size and medium composition were established. Maximum production of itaconic acid, $19.18g/\ell$, was obtained when the cultivation was carried out at $37^{\circ}C$ and pH 2.5 for 7days, with medium containing 5%(w/v) glucose, 0.5%(w/v) NH4Cl, 0.2%(w/v) yeast extract 0.1%(w/v) CaC12, 0.1%(w/v) MgSO4 and 0.2%(w/v) NaCl. A proper medium for inoculum culture was found to be 2%(w/v) malt extract. The batch production of itaconic acid with free cells in a stirredtank reactor was not efficient compared to the shake-flask culture.

• Journal of Life Science
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• v.13 no.4
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• pp.498-504
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• 2003

This Study was carried out to investigate the optimal mycelial growth of Pholiota nameko. The optimal medium for the mycelial growth was ME medium. The optimal temperature and pH were $25^{\circ}C$$\pm$1 and 5.5, respectively. The modified optimal medium compositions were glucose 3% (w/v), malt extract 0.25% (w/v), yeast extract 0.25% (w/v), $KH_2PO_4$ 0.046% (w/v), $K_2HPO_4$ 0.1% (w/v), $MgSO_4$ㆍ$7H_2O$ 0.05% (w/v). From the result of experiments on the optimal temperature, pH and nutritional requirements, the mycelial growth of modified optimal medium was higher than that of ME medium.

• Food Science of Animal Resources
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• v.30 no.1
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• pp.66-72
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• 2010

Pediococcus pentosaceus SA131 was isolated from jeotgal, is the bacteriocin producer against bovine mastitis pathogens, Streptococcus uberis E290, Enterococcus gallinarum E362, and Staphylococcus epidermidis ATCC 12228. The medium composition for pediocin SA131 production by P. pentosaceus SA131 was optimized using response surface methodology. Component of medium was studied as carbon source (glucose, fructose, lactose, glycerol, sucrose, maltose, and mannitol), nitrogen source (beef extract, yeast extract, peptone, malt extract, and tryptone), mineral and surfactant ($MgSO_4$, $KH_2PO_4$, $(NH_4)_2SO_4$, $MnSO_4$, NaCl, sodium acetate, and Tween 80). Through one factor-at-a-time experiment, glucose, fructose, yeast extract, malt extract, NaCl, $MgSO_4$, and Tween 80 were determined as the good ingredient. The effects of major factors for pediocin SA131 production were investigated by two-level fractional factorial designs (FFD). By a $2^4$ FFD, fructose, yeast extract, and $MnSO_4$ were found to be the important factors for the bacteriocin production. Subsequently, a $2^3$ central composite design (CCD) was adopted to derive a statistical model for optimizing the composition of the fermentation medium. The estimated optimum composition for the production of pediocin SA131 by P. pentosaceus SA131 was as follows; 0.13% fructose, 1% glucose, 1.8% yeast extract, 2.58% $MnSO_4$, 0.2% NaCl, and 0.2% Tween 80. The pediocin production under optimized medium was increased to 1,000 AU/mL, compared to the 400 AU/mL in MRS medium.

• Korean Journal of Food Science and Technology
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• v.48 no.2
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• pp.147-152
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• 2016

This study was conducted to investigate the physicochemical quality properties and provide basic data for the activation of traditional Kamju of juice type product prepared by mixing malt and extruded rice collet powder. Malt extracts were prepared by extracting the mixture of malt and water at a weight ratio of 25:75 after soaking for 2 h at $45^{\circ}C$. Rice collet powder was prepared by adjusting the barrel temperature to $95^{\circ}C$, screw speed to $3.07{\times}g$, discharge port diameter to 7 mm and a raw material input to 50 kg/h, the powder was then ground to a particle size of 80 mesh. The physicochemical characteristics (pH, color, viscosity, reducing sugars, number of viable cells, free amino acids) and sensory evaluations were conducted at various time points during the saccharification and at different mixing ratios of the extruded rice collet powder to malt extract (5:95, 15:85, 25:75, 35:65, each at $55^{\circ}C$ for 9 h). As a result, with an increase in the proportion of the extruded rice collet powder and saccharification time, the physicochemical properties of traditional Kamju significantly improved (p<0.05). A mixing ratio of 35:65 rice collet powder to malt extract and a saccharification time of 9 h were found to be the most desirable conditions. However, based on the sensory evaluation, a mixing ratio of rice collet powder and malt extract of 25:75 and a saccharification time of 5 h resulted in the most preferable palatability of traditional Kamju (p<0.05). Therefore, the mixing ratio and saccharification time should be determined to provide a better choice with respect to the taste and economic aspects of traditional Kamju.

• Korean Journal of Microbiology
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• v.48 no.1
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• pp.48-51
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• 2012

A novel Chryseobacterium sp. JK1 strain producing extracellular protease had been isolated from soil. The largest clear zones were observed on nutrient agar plates supplemented with 1% skim milk at $30-35^{\circ}C$ along with the growth of Chryseobacterium sp. JK1. The cell growth of JK1 strain was maximal at 24 h and maximum protease activity was reached up to 560 unit/ml at the stationary phase in liquid culture. In the presence of maltose, glucose or mannitol in Nutrient broth, cells grew well, but protease were produced poorly with lower production yields of 64-77% than in NB broth only. Similarly, the addition of skim milk, beef extract, yeast extract, malt extract or tryptone showed good growth and poor enzyme production. On the contrary, the addition of $(NH_4)_2HPO_4$ or $(NH_4)_2SO_4$ gave poor growth and good enzyme production of 121-146%.

• Microbiology and Biotechnology Letters
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• v.42 no.3
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• pp.225-231
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• 2014

In this study about the optimum conditions for the production of laccase, a polyphenol oxidase involved in lignin degradation, from Marasmius scorodonius, a white-rot fungus garlic mushroom, were determined. Amongst the tested media used for the enzyme's production, YM medium (1% dextrose, 0.5% malt extract, 0.3% yeast extract) allowed for the highest activity of the enzyme. Then, to optimize the culture conditions for laccase activity, the influence of various carbon and nitrogen sources was investigated in YM medium. Among various carbon and nitrogen sources, 1% galactose and 0.4% yeast extract resulted in the highest production of the enzyme, respectively. Enzyme production attained its highest level after cultivation for 15 days at $25^{\circ}C$. Zymogram analysis of the culture supernatant showed two isoenzymatic bands with molecular masses of 60-70 kDa. The optimum pH and temperature for enzyme activity were 3.4 and $75^{\circ}C$, respectively.