• Journal of Life Science
• /
• v.25 no.9
• /
• pp.1021-1026
• /
• 2015

Invertase (β-D-fructosfuranosidase, EC 3.2.1.26) catalyzes the hydrolysis of sucrose into D-glucose and D-fructose. Three biochemical subgroups of invertases have been investigated in plants: vacuolar (soluble acid), cytoplasmic (soluble alkaline), and cell wall-bound (insoluble acid) invertases. An isoform of neutral invertase was purified from pea seedlings (Pisum sativum L.) and treated with gibberellic acid (GA) by sequential procedures consisting of ammonium sulfate precipitation, ion-exchange chromatography, absorption chromatography, and reactive green-19 affinity chromatography. The results of the overall insoluble invertase purification were a 430-fold increase. The purified neutral invertase was not glycosylated and had an optimum pH between neutral and alkaline (pH 6.8-7.5). It was inhibited by Tris, as well as by heavy metals, such as Hg²⁺ and Cu²⁺. Typical Michaelis–Menten kinetics were observed when the activity of the purified invertase was measured, with sucrose concentrations up to 100 mM. The K_m and V_max values were 12.95 mM and 2.98 U/min, respectively. The molecular mass was around 20 kDa. The sucrose-cleaving enzyme activity of this enzyme is similar to that of sucrose synthase and fructosyltransferase, but its biochemical characteristics are different from those of sucrose synthase and fructosyltransferase. Based on this biochemical characterization and existing knowledge, neutral INV is an invertase isoform in plants.

• Food Science and Preservation
• /
• v.5 no.3
• /
• pp.270-274
• /
• 1998

In order to enhance the availability of Korean loquat fruit, loquat juice was manufactured and its physicochemical characteristics are measured. The juice of raw fruit and pressed juice after blanching with steam that the pH, sugars, total acids and yields were 3.4, 3.6, and 8.5, 8.0 $^{\circ}$ Brix, and 0.36, 0.34%, and 53.2, 57.4% respectively. Four groups of juices were processed as followed. A ; juice of clarified after filteration, B ; pressed and filtered juice of raw fruit in refrigerated for 50 days, C ; clarified juice of heated at 90$^{\circ}C$ for 2 min., D ; clarified juice of blanched and pressed with raw fruit. Total acids, pH and sugars of A, B, C and D juices were 0.27, 0.35, 0.29 and 0.28%, and 3.80, 3.10, 3.68 and 3.71, and 7.5, 8.5, 8.0 and 8.2 $^{\circ}$Brix, respectively. Juice of B was higher total free sugar and organic acid than others. The chromaticity of D juice was stable than others. In the sensory test of loquat juice, that the product showed excellent result at 11 $^{\circ}$Brix and pH 3.78 when 4% of fructose and 0.05% of citric acid added.

• The Korean Journal of Malacology
• /
• v.18 no.2
• /
• pp.77-82
• /
• 2002

This study was performed to find out the optimal kind of additive and concentration of ethylene glycol (EG) as the cryoprotectant on the D-shaped larvae of arkshell, Scapharca broughtonii. The larvae in straws was carried in the programed freezer set uo at 0$^{\circ}C$, frozen to -12$^{\circ}C$ by the freezing rate of -1$^{\circ}C$/min, held for 10 minutes, seeded at -12$^{\circ}C$, finally refrozen to -35$^{\circ}C$ by the freezing rate of -1$^{\circ}C$/min and then directly plunged into liquid nitrogen. The survival of larvae frozen in 1.0 M and 2.0 M ethylene glycol added with 0.5 M sucrose were high (50.5 ${\pm}$ 1.3% and 51.9 ${\pm}$ 1.7%, respectively) in the early D-shaped larvae cryopreserved in 1 M and 2 M ethylene glycol diluted with 0.2 M and 0.5 M fructose, glucose and sucrose. In the late D-shaped larvae were cryopreserved according to five concentrations of ethylene glycol added with 0.5 M sucrose, the survival of larvae frozen in 2.0 M ethylene glycol was the highest as 51.9 ${\pm}$ 1.7%. The morphological differences in cells between unfrozen and frozen-thawed D-shaped larvae were not found by the scanning and transmission electron microscopy.

• The Korean Journal of Mycology
• /
• v.31 no.3
• /
• pp.141-147
• /
• 2003

The pileus of Pleurotus cystidiosus was attached at the side and was spatular-shape. It grew to the size of $7.6{\sim}9.8\;cm$ with dark brown color. The length of stem was $1.4{\sim}2.9\;cm$. The individual weight of fruiting-body was 25.4 g in average. This study was conducted to Investigate the physiological characteristics and to develop the artificial cultivation technique of P. cystidiosus. To find out the optimum condition of mycelial growth of P. cystidiosus, physiological conditions such as media, temperature, pH carbon sources and nitrogen sources were investigated. Various cultural media were used for the cultivation of P. cystidiosus and compost dextrose agar was favorable for mycelial growth. The optimal growing temperature and pH were in range of 25 to $30^{\circ}C$, pH $7{\sim}9$, respectively. When different carbon sources were compared, glucose was found to be best. However nitrogen sources were different with each strains. When different C/N ratio were compared, 20:1 of C/N ratio was found to be best.

• Korean Journal of Plant Resources
• /
• v.34 no.2
• /
• pp.177-185
• /
• 2021

The purpose of this study was to compare the chemical properties of the bokbunja distributed in Korea with the content of the bioactive substance ellagic acid. The bokbunja was Rubus coreanus group and Rubus occidentalis group were compared, domestic bokbunja and import bokbunja were compared. In bokbunja, free sugar was 30.89 ± 0.7 mg/g of Rubus coreanus and 29.05 ± 0.87 mg/g of Rubus occidentalis. and 27.28 ± 7.4 mg/g of domestic bokbunja and 21.58 ± 6.73 mg/g of import bokbunja. The free amino acids was 4.50 ± 0.08 mg/g of Rubus coreanus and 5.05 ± 0.08 mg/g of Rubus occidentalis. and 4.13 ± 1.09 mg/g of domestic bokbunja and 3.75 ± 0.31 mg/g of import bokbunja. Validation of the ellagic acid method was confirmed by comparing the retention time and spectrum of the standard and extract using HPLC. The calibration curve (R²) showed linearity of 0.9999. As a result of analyzing the ellagic acid content of each extraction solvent, DMSO and methanol mixture extracts were high, and Rubus coreanus was 2.56 mg/g and Rubus occidentalis was 3.16 mg/g, which was not significantly different (p < 0.05) In addition, the ellagic acid content of domestic bokbunja and import bokbunja was 2.83 mg/g and 2.99 mg/g, which was not significantly different (p < 0.05).

• Horticultural Science & Technology
• /
• v.19 no.4
• /
• pp.521-525
• /
• 2001

This study investigated the effects of conventional predrying and modified atmosphere (MA) on the head quality and storability of Chinese cabbage 'Norang' cultivar. Immediately after harvest, heads were predried for 2 days and MA stored in $50{\mu}m$ PE film packages at $4^{\circ}C$. MA packaging restrained Hunter L and b values of Chinese cabbage more effectively than non-packaging during storage at $4^{\circ}C$. But there was little change between the two treatments. Fresh weight decreased less in heads treated with predrying and MA than non-treatment during storage. Predried Chinese cabbage heads kept a high level of soluble solids in 4 weeks of storage, while non-packaging maintained high contents of soluble solids for 6 weeks of storage period. Chinese cabbage heads contained 7.0 mg/gFW glucose, 6.3 mg/gFW fructose, and 0.6 mg/gFW sucrose as major soluble sugars at harvest. The content of sugars decreased immediately after predrying and increased steadily after 2 weeks storage. It was found inappropriate to assess head quality of Chinese cabbage by investigating was investigated by Hunter a, firmness, dry matters content, pH, and soluble sugars after predrying and MA package. Marketability of Chinese cabbage was lost when heads were stored at room temperature in 2 weeks. It showed poor appearance of heads stored at $4^{\circ}C$ in 7 weeks. Decay occurred in Chinese cabbage stored in MA under excessive relative humidity. Predried head showed good appearance during storage at $4^{\circ}C$ for 7 weeks. As a result, Chinese cabbage heads can be successfully stored for at least 7 weeks with predrying and MA storage.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.44 no.10
• /
• pp.1476-1483
• /
• 2015

This study was conducted in order to compare changes in the quality characteristics and antioxidant activity of mulberries depending on the degree of ripeness between greenhouse (GH) and open field (OF) cultivation. The mulberries were divided into five degrees of ripeness. Quality characteristics such as pH, acidity, antioxidant activity, and contents of free sugar, organic acid, polyphenols, flavonoids, and anthocyanins were investigated. pH level increased slightly while acidity decreased depending on the degree of ripeness. Fructose and glucose were detected in mulberries as the major free sugar. Fructose and glucose increased rapidly during ripening. Citric acid was major acid and decreased considerably during ripening. Contents of total polyphenols, flavonoids, and anthocyanins increased considerably in the last stage of ripening. Contents of polyphenols, and flavonoids in mulberry from OF were higher than from GH. DPPH and ABTS radical scavenging activities increased rapidly in mulberries of the last degree. Contents of functional components were not greatly different between GH and OF, whereas content of free sugar in GH was higher than that in OF.

• The Korean Journal of Mycology
• /
• v.29 no.1
• /
• pp.1-8
• /
• 2001

To examine the structural properties of the proteoglycan (GMPG, Ganoderma lucidum mycelial proteoglycan) obtained from mycelia in Ganoderma lucidum IY009, we obtained the low and high molecular proteoglycan by ultrafiltration and sepharose CL-4B column chromatography. The physicochemical properties of these fractions were as follows. When the proteoglycan separated by ultrafiltration and sepharose CL-4B column chromatography, its was not fractionated completely. The molecular weight of high molecular proteoglycan by the gel column chromatography (CH) was 250 kD and 2,000 kD, and low molecular proteoglycan was 12kD. The total carbohydrate was consisted of 75.7% (UH) and 96.7% (CH), and the low fraction was 72.7% (UL) and 87.1% (CL), respectively. The sugar of high and low molecular proteoglycan composed of glucose, mannose, fructose, galactose, xylose, ribose and arabinose. Glucose contents of all fraction were ranged from $46.9%{\sim}82.4%$ of the total sugar and the ratio of ${\alpha}$\;and\;{\beta}-glucose$ was $0.84{\sim}1.14$, and its indicated the proteoglycan to be ${\beta}-glucan$. Amino acids pattern showed that the fractions contained a large amount of aspartie acid, glutamic acid, alanine and leucine. These fractions showed the characteristics of IR absorption for ${\beta}-glucan$ at $890\;cm^{-1}\;and\;^{13}C-NMR$ spectroscopy showed the presence of the ${\beta}-1,3-glucan$ and a ${\beta}-1,6-glucan$.

• Journal of Applied Biological Chemistry
• /
• v.60 no.3
• /
• pp.283-291
• /
• 2017

Rice that the half of population in the world eats as a staple food is mostly produced and consumed in Asia. However, its consumption is nowadays decreasing mainly due to diet diversity. Accordingly, some attempts are in demand to enhance the utilization of rice. In this study, profiling of volatile and non-volatile flavor components in rice pastes obtained by ${\alpha}$-amylase was performed and compared according to nine different rice cultivars domestically cultivated in Korea using gas chromatography-mass spectrometry combined by solid phase microextraction and gas chromatography-time of flight-mass spectrometry after a derivatization, respectively. In total, 46 volatile compounds identified included 6 alcohols, 6 aldehydes, 4 esters, 4 furan derivatives, 4 ketones, 1 acid, 1 sulfur-containing compound, 7 hydrocarbons, 5 aromatics and 8 terpenes. The non-volatile flavor components found were composed of 12 amino acids, 6 sugars and 4 sugar alcohols. In principal component analysis, rice paste samples could be discriminated according to cultivars on the score plots of volatile and non-volatile flavor compounds. In particular, some volatile compounds such as pentanal and 4,7-dimethylundecane could contribute to distinguish Senong 17 white and Senong 17 brown, whereas ethanol, 6-methylhep-5-en-2-one, and tridecane could be highly related to the discrimination of Iipum from other cultivars. Among non-volatile compounds, some amino acids such as glycine, serine and ${\gamma}$-aminobutyric acid and some sugars such as sucrose and fructose were mainly responsible for the discrimination of Danmi from the other cultivars. On the other hand, galactose, arabitol and mannose were more closely related to Senong 17 white than Senong 17 brown.

• Food Science and Preservation
• /
• v.23 no.5
• /
• pp.680-688
• /
• 2016

This study analyzed the changes in physicochemical components of Astragalus membranaceus (AM) fermented with Phellinus linteus. Moisture content, pH, total acidity, total reducing sugar content, extraction yield, free sugar content, free amino acid and isoflavonoid (calycosin, formononetin) were investigated. The moisture content was increased during fermentation with Phellinus linteus. The pH level increased while the total acidity significantly decreased during fermentation. The reducing sugar content were in the range of 0.32~0.61%. The extraction yield using water was higher than that using 80% ethanol. The major free sugars were identified as glucose, fructose, sucrose and the content of free sugars decreased through fermentation. However, the glucose and sucrose contents of the water extracts were increased. In addition, the free amino acid increased significantly during fermentation. Finally, calycosin and formononetins contents in water extracts of after 30 days of AM fermentaion with Phellinus linteus were (3.91 mg/100 g) and (1.38 mg/100 g), respectively. These results suggest that fermentation with Phellinus linteus could be used to increase the bioactivity of AM. The mycelium-fermented AM could be a valuable source of functional material and edible resource for industry.