• Journal of Microbiology and Biotechnology
• /
• v.24 no.10
• /
• pp.1368-1376
• /
• 2014

This article focuses on the effects of glycine betaine on preventing caramelization, and increasing DCW and $\small{L}$-lysine production. The additional glycine betaine not only decreased the browning intensity (decreased 4 times), and the concentrations of 5-hydroxymethylfurfural (decreased 7.8 times) and furfural (decreased 12 times), but also increased the availability of glucose (increased 17.5%) for $\small{L}$-lysine production. The DCW and $\small{L}$-lysine production were increased by adding no more than 20 mM glycine betaine, whereas the DCW and $\small{L}$-lysine production were decreased with the reduction of pH values, although pH had a better response to prevent caramelization than did glycine betaine. For $\small{L}$-lysine production, the highest increase (40%) was observed on the media with 20 mM glycine betaine. The crucial enzymes in glycolysis and $\small{L}$-lysine biosynthesis pathway were investigated. The results indicated that additional glycine betaine increases the activity of enzymes in glycolysis, in contrast to the effect of pH. All the results indicated that glycine betaine can be used to prevent caramelization and increase the $\small{L}$-lysine production. By applying this strategy, glucose would not be have to be separated from the culture media during autoclaving so that factories can save production costs and shorten the fermentation period.

• Journal of the Korean Wood Science and Technology
• /
• v.48 no.3
• /
• pp.303-314
• /
• 2020

Gambir is a non-wood forest product with a potential of being used as wood adhesive, due to about 33% catechin in it. Meanwhile, catechins and sucrose have not been studied as adhesives. Therefore, basic characteristics of gambir-sucrose adhesives were investigated. In this research, adhesives were prepared by dissolving gambir and sucrose in distilled water, at different blending ratios of the gambir/sucrose such as 100/0, 75/25, 50/50, and 25/75 wt%. Furthermore, gas chromatography-mass spectrometry (GC-MS) was employed to determine the gambir chemical compositions, and Fourier transform-infrared (FTIR) spectroscopy was carried out to identify chemical bonds. Particleboards with a target density of 0.8 g/㎤ were then manufactured by hot-pressing for 10 min at 200℃. The internal bond (IB) strength of particleboard was subsequently measured. Based on the GC-MS analysis, 31.11% of catechin was identified. In addition, the viscosity, density, solid content, and gelation time of the adhesives, and insoluble matter content (IMC) in boiling water were 7.30~33.24 mPa.s, 1.2~1.3 g/㎤, 25.56~28.44%, 73~420 min, and 29.75~62.10%, respectively. Adding sucrose to the adhesive was observed to raise the IMC from 49.05 to 62.10%, at 180℃ and 200℃. FT-IR analysis showed that the gambir absorption peaks occurred at approximately 1620 cm^-1, assigned to the C=O stretching of 5-hydroxymethylfurfural, which tended to increase with the addition of sucrose. The reaction between gambir and sucrose was observed in the form of the dimethylene ether bridge. The 25/75 wt% gambir-sucrose adhesives and 200℃ hot-pressed temperature resulted in the highest IB strength (0.89 MPa), and met the requirement of JIS A5908-2003 type 18. Consequently, the gambir-sucrose adhesive could be used as a particleboard adhesive.

• Preventive Nutrition and Food Science
• /
• v.18 no.1
• /
• pp.50-59
• /
• 2013

Black jujube was made by aging dried jujube and its physiochemical characteristics, antioxidant activities and ${\alpha}$-glucosidase inhibitory activities were evaluated. The moisture and sugar contents were increased depending on the period of aging times and the pH was reduced thereby increasing acidity. The color of black jujube extract was changed from red to black resulting in decreases of Hunter color values L, a and b. As the aging progressed, sucrose was decomposed by increasing glucose and fructose, indicating higher contents of the total reducing sugars. Among the six different types of organic acids extracted from dried jujube, the levels of oxalic acid and citric acid were increased as the aging progressed. The total polyphenol contents in ethanol and water extracts of dried jujube were 7.74 and 8.12 mg/g, respectively. The water extract of black jujube aged for 48 hr contained the highest polyphenol contents at 16.82 mg/g. The 5'-hydroxymethylfurfural (5'-HMF) contents of black jujube extract significantly increased by longer aging times, and contained higher contents in the ethanol extract than water extract. The ethanol extract of black jujube showed the highest 5'-HMF content with 338.89 mg% after aging for 3 days. Also, $IC_{50}$ values of black jujube aged for 72 hr evaluated by DPPH and ABTS radical assays were 0.54 and 0.59 mg/mL, respectively. ${\alpha}$-Glucosidase inhibitory activities of black jujube at the concentration of 3.33 mg/mL (ethanol extract) increased from 65 to 80 % after aging for 72 hr.

• Korean Journal of Food Science and Technology
• /
• v.31 no.4
• /
• pp.894-898
• /
• 1999

Aroma components of Ookjook tea made from Polygonatum involucratum Maxim roots were collected and identified. The extraction of aroma compounds was accomplished by a simultaneous distillation and extraction method using a Likens and Nickerson's extraction apparatus. The concentrated extract was analyzed and identified by GC and GC-MS. The most abundant aroma components of this tea were furanic compounds including 2-furfural, 2-methyl-dihydro-3(2H)-furanone, 2-acetylfuran and 5-methylfurfural. These compounds seem to be originated from the thermal degradation of carbohydrates during the roasting process. Alkylpyrazines and acids including propionic acid increased slightly during the period of manufacturing process of Ookjook tea. Furanic compounds originated from the thermal degradation of carbohydrates and alkypyrazines from aminocarbonyl reaction seemed to be the important contributors to the aroma of the Ookjook tea.

• Korean Journal of Food Science and Technology
• /
• v.16 no.1
• /
• pp.17-22
• /
• 1984

Quality of five kinds of honey were evaluated. Honey had total soluble sugar above 96% on the dry weight and a little amount of protein. The mineral composition varied with the kinds of honey, but all tested honey showed the highest content of K and Na, and a considerable amount of Fe, Mg, Ca, Zn, and P. Free sugars were mainly composed of fructose and glucose. The fructose/glucose ratio of honey was 1.0-1.39. Buckwheat honey showed comparatively higher content of sucrose and maltose. All tested honey were analyzed to give pH 3.23-4.32, total acid 10.5-23.9 meq/kg, hydroxymethylfurfural 0.58-21.31 mg/kg, diastatic activity 13.95-36.59.

• Journal of Microbiology and Biotechnology
• /
• v.28 no.12
• /
• pp.1999-2008
• /
• 2018

The compound 2,5-furandicarboxylic acid (FDCA), an important bio-based monomer for the production of various polymers, can be obtained from 5-hydroxymethylfurfural (HMF). However, efficient production of FDCA from HMF via biocatalysis has not been well studied. In this study, we report the identification of key genes that are involved in FDCA synthesis and then the engineering of Raoultella ornithinolytica BF60 for biocatalytic oxidation of HMF to FDCA using its resting cells. Specifically, previously unknown candidate genes, adhP3 and alkR, which were responsible for the reduction of HMF to the undesired product 2,5-bis(hydroxymethyl)furan (HMF alcohol), were identified by transcriptomic analysis. Combinatorial deletion of these two genes resulted in 85.7% reduction in HMF alcohol formation and 23.7% improvement in FDCA production (242.0 mM). Subsequently, an aldehyde dehydrogenase, AldH, which was responsible for the oxidation of the intermediate 5-formyl-2-furoic acid (FFA) to FDCA, was identified and characterized. Finally, FDCA production was further improved by overexpressing AldH, resulting in a 96.2% yield of 264.7 mM FDCA. Importantly, the identification of these key genes not only contributes to our understanding of the FDCA synthesis pathway in R. ornithinolytica BF60 but also allows for improved FDCA production efficiency. Moreover, this work is likely to provide a valuable reference for producing other furanic chemicals.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.31 no.1
• /
• pp.27-34
• /
• 2023

In this study, spent mushroom substrate (SMS), which consits of lignocellulosic material, was pretreated by hydrothermal method; the changes of biodegradability and methane production yield of pretreated SMS were determined according to formation of lignocellulosic biomass degrading byproducts formation during thermal pretreatment. Based on the results, all hydrothermal pretreatment temperatures showed improved solubilization performance for biomass, and the optimum pretreatment effect was observed at an pretreatment temperature of 150℃ with the highest methane production yield. However, the induced formation of furan derivatives (i.e., 5-hydroxymethylfurfural and furfural) as byproducts during hydrolysis of hemicellulose and cellulose at severe condition lowered biodegradability and methane yield when the hydrothermal pretreatment temperature was higher than 180℃. Thus, this study revealed that hydrothermal pretreatment could promote anaerobic digestion efficiency of lignocellulosic biomass and is of great importance for preventing byproducts formation through pretreatment condition control.

• Korean Journal of Food Science and Technology
• /
• v.47 no.1
• /
• pp.95-102
• /
• 2015

The Maillard reaction is a non-enzymatic reaction between amino and carbonyl groups. During milk processing, lactose reacts with milk protein through this reaction. Infant formulas (IFs) are milk-based products processed with heat-treatments, including spray-drying and sterilization. Because IFs contain higher Maillard reaction products (MRPs) than breast milk, formula-fed infants are subject to higher MRP exposure than breast milk-fed ones. In this study, we investigated the optimization of conditions for minimal MRP formation with the addition of $\small{L}$-carnitine ($\small{L}$-car), pyridoxine hydrochloride (PH), and $\small{DL}$-${\alpha}$-tocopheryl acetate (${\alpha}$-T) in an IF model system. MRP formation was monitored by response surface methodology using fluorescence intensity (FI) and 5-hydroxymethylfurfural (HMF) content. The optimal condition for minimizing the formation of MRPs was with $2.3{\mu}M$ $\small{L}$-car, $15.8{\mu}M$ PH, and $20.6{\mu}M$ ${\alpha}$-T. Under this condition, the predicted values were 77.4% FI and 248.7 ppb HMF.

• The Korean Journal of Food And Nutrition
• /
• v.28 no.5
• /
• pp.745-751
• /
• 2015

This study was performed to investigate the quality characteristics such as pH, total acidity, browning index, 5-hydroxymethylfurfural (5-HMF), fructose, S-allyl-L-cysteine (SAC), total polyphenol, and DPPH radical scavenging activity of aged garlic at different aging temperatures and periods. Aging temperature and period had a significant (p<0.05) effect on the quality characteristics of garlic. The pH in aged garlic significantly (p<0.05) decreased with increasing aging temperatures and periods, while the total acidity, browning index, and 5-HMF levels increased. The 5-HMF levels in garlic aged at 60 and $70^{\circ}C$ increased from 0.08~3.30 and from 0.05~106.07 mg/100 g, respectively. The fructose content in garlic aged at $60^{\circ}C$ gradually increased from 0.77 to 14.57%, while that of garlic aged at $70^{\circ}C$ increased from 1.07 to 19.75% until day 30, after which it decreased. The SAC level in raw garlic was 47.09 mg/100 g. The SAC contents of aged garlic differed significantly according to aging temperature and period. The SAC levels in garlic aged at $60^{\circ}C$ and $70^{\circ}C$ were in the range of 15.28~100.5 and 12.41~85.55 mg/100 g, respectively. The total polyphenol contents of garlic aged at $60^{\circ}C$ and $70^{\circ}C$ were 6.01 and 6.67 fold higher, respectively, than those in raw garlic. The DPPH radical scavenging activity of aged garlic also showed a tendency to increase during aging.

• YAKHAK HOEJI
• /
• v.30 no.5
• /
• pp.253-265
• /
• 1986

Among 230 species of herbal drugs screened, thirty one show the anthelmintic activities in vitro against Clonorchis sinensis, the chinese liver fluke. The active substances have been isolated and their structures identified. Some of the active substances and their derivatives have been synthesized, followed by anthelmintic activity tests. The extracts from the active drugs cause damages in organs of the adult worm in the hepatic duct of rabbit. Some fresh water fish, which function as bad hosts for the fluke, excrete defense substances against the cercaria of the fluke. The defense substances have been isolated from Cyprinus carpio and Cyprinus carpio nudus, followed by structural identification. The results are summarized as follows: l) The bark of Machilus thunbergii as well as the seed of Schizandra chinensis contain meso-dihydro-guaiaretic acid as the anthelmintic component. Among derivatives synthesized, 4-phenyl-1-((3, 4-dihydroxyphenyl)-, 4-phenyl-1-(3-hydroxy-4-methoxy phenyl)-and 4-phenyl-1-(4-hydroxy-3-methoxy phenyl)-2, 3-dimethyl butanes show considerable activities. Administration of the bark extract mainly damages the bladder of the adult worm. 2) The active substance from the roasted fruit of Prunus mume is 2-hydroxymethylfurfural. This substance is produced during the roasting process. Administration of the fruitextract causes a damage of the bladder of the adult worm. 3) The active substance from the root of Scutellaria baicalensis is 5.2'-dihydroxy-6, 7, 8, 6'-tetramethoxyflavone. 4) Beside alantolactone, a very strong anthelmintic component is contained in the root of Inula helenium. Administration of the root extract causes irreversible damage on the worm, affecting mainly the reproductive organs. 5) The cercaricidal substances from the epidermis of C. carpio and C. carpio nudus are ethyl linoleate and linoleic acid, respertively. 6) The cercaricidal substances from various kinds of fresh water fish have different $R_f$ values, implying that the defense substances are species-specific. Unexpectedly, the fish with good host function, for example Pseudorasbora parva, excrete the defense substances, too. The defense substances are possibly organ-specific in individual species; the organs essenstial for the existence of the species excrete the defense substances, allowing other parts to be invaded by the cercaria. 7) The cercaricidal fraction of Carassius carassius is detected only in the fish which have been collected during the summer time from May to September, Its secretion is not dependent on water temperature. Thus, it seems to be possible that the secretion of the defense substance would be stimulated through a contact between the fish and cercaria.