Food Science and Biotechnology
Korean Society of Food Science and Technology (KOSFOST)
- Monthly
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- 1226-7708(pISSN)
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- 2092-6456(eISSN)
Domain
- Agriculture, Fishery and Food ＞ Science of Food and Crops
- Agriculture, Fishery and Food ＞ Food Science
Aim & Scope
The Food Science and Biotechnology (Food Sci. Biotechnol.; FSB) was launched in 1992 as the Food Biotechnology and changed to the present name in 1998. It is an international peer-reviewed journal published monthly by the Korean Society of Food Science and Technology (KoSFoST). The FSB journal covers; Food chemistry/food component analysis Food microbiology and biotechnology Food processing and engineering Food hygiene and toxicology Biological activity and nutrition in foods Sensory and consumer science s Consumer perception and sensory evaluation on processed foods are accepted only when they are relevant to the laboratory research work. As a general rule, manuscripts dealing with analysis and efficacy of extracts from natural resources prior to the processing or without any related food processing may not be considered within the scope of the journal. The FSB journal does not deal with only local interest and a lack of significant scientific merit. The main scope of our journal is seeking for human health and wellness through constructive works and new findings in food science and biotechnology field.
http://www.fsnb.or.kr/submission/ KSCI KCI SCOPUS SCI SCIEVolume 14 Issue 3
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Wiesenborn, Dennis;Tostenson, Kristi;Kangas, Nancy;Zheng, Yun-Ling;Hall III, Clifford;Niehaus, Mary;Jarvis, Paul;Schwarz, Jurgen;Twombly, Wesley 305
Flaxseed is outstanding for lignans and oil rich in${\alpha}$ -linolenic acid which protect against several major illnesses. Better understanding of processing and storage characteristics of flaxseed will increase options for food use. Lignans and oil are found in the hull and embryo, respectively. Comparison of pearling and impact-dehulling processes for separation of lignan and oil-rich fractions showed the impact process was less effective, but easier to scale-up. Screw-pressing embryo reduced oil yield compared to whole seed, but doubled productivity and sharply reduced frictional heating of the oil. Flaxseed hull and embryo, also whole, ground and steamed-ground samples, were stable up to 30 weeks in closed containers at$23^{\circ}C$ . Steamed-ground samples in open trays at$40^{\circ}C$ deteriorated markedly (peroxide value > 100 by 22 weeks); yet, whole seed remained stable. Incorporation of 18% flaxseed embryo into yellow perch feed increased${\alpha}$ -linolenic acid to 13 to l4% of muscle and liver lipids, compared to 0.5 to 0.7% in the no-embryo control. Feed conversion ratio, weight gain, and survival were similar. These studies are helping to establish the technological base for processing and utilizing flaxseed and flaxseed fractions to improve human diets. -
This study was performed to investigate the antimicrobial effect of Sophora angustifolia extracts against food-borne pathogens. First, Sophora angustifolia was extracted with methanol at room temperature, and the methanol extracts from Sophora angustifolia were fractionated using petroleum ether, chloroform, ethyl acetate, and methanol. The antimicrobial activity of the Sophora angustifolia extracts was determined using the paper disc method against food-borne pathogens and food spoilage bacteria. The methanol extracts of Sophora angustifolia showed the highest antimicrobial activity against Staphylococcus aureus and Salmonella typhimurium. A synergistic effect was found in the combined extracts of Sophora angustifolia and Portulaca oleracea, compared to the activity of each extract alone. Finally, the growth inhibition curve was determined using the methanol extracts of Sophora angustifolia against Staphylococcus aureus and Salmonella typhimurium. The methanol extract of Sophora angustifolia showed strong antimicrobial activity against Staphylococcus aureus at a concentration of 5,000 ppm. The 5,000 ppm methanol extract from Sophora angustifolia retarded the growth of S. aureus for more than 24 hours and of Salmonella typhimurium for up to 12 hours.
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A simple and convenient method of immobilizing dextransucrase via an affinity interaction is described, along with the use of this system to synthesize leucrose. Dextransucrase was produced in sucrose-free medium by fermenting a constitutive mutant of Leuconostoc mesenteroides NRRL B-512F and was separated using an ultrafiltration membrane. The purified enzyme was free of dextran polymer, which previously was always found with the sucrose-induced enzyme. Therefore, it was possible to immobilize the enzyme on dextran-based resins using an affinity interaction. Sephadex G-200 was the best resin for immobilizing the dextransucrase and gave a fast flow rate through the packed column. The immobilized dextransucrase retained more than 80% of its specific activity after immobilization (
$K_m\;=\;18.1\;mM$ and$k_{cat}\;=\;450\;sec^{-1}$ vs. 13.1 mM and$640\;sec^{-1}$ , respectively, for the free enzyme). The immobilized dextransucrase showed improved stability over a pH range of 4.0 to 6.5 and at moderately high temperatures over$40^{\circ}C$ . When immobilized dextransucrase was used to synthesize leucrose via the transfer reaction with sucrose and fructose, about 74% of the sucrose was converted into leucrose after one day, and the half-life of the enzyme activity was 15 days. Regeneration of the resin by supplementation with dextransucrase enabled the recovery of the initial activity of the system, but both the reaction and the flow rate were lower, probably owing to the accumulation of dextran inside the resin. -
The effects of commercial marinades were evaluated for their influence on heterocyclic aromatic amine (HAA) formation and overall mutagenicity in fried beef steaks. Three different commercial marinades A, B, and C tested individually reduced the total HAA formation in fried beef steaks by 44, 38, and 40%, respectively. Three different commercial marinades were also effective in reducing the overall mutagenicity in fried beef steaks. There was, however, no significant difference in the inhibition achieved with three different commercial marinades. Reduction of overall mutagenicity was related to the decrease in HAA formation in fried beef steaks.
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Finite difference model and dynamic thermal property evaluation system were developed to estimate convection heat transfer coefficient by modeling temperature-time profile of beef cube in continuous flow sterilizing system. As input parameters of the model, specific heat and thermal conductivity values of beef frankfurter meat were independently measured from 20 to
$80^{\circ}C$ . Convection heat transfer coefficient was estimated by comparing simulated and measured temperature-time profiles. Actual temperature-time profiles of meat cube were measured at flow rates of 15, 30, and 45 L/min and viscosities from 0 to 15 cp, and mean values of convection heat transfer coefficients ranged from 792 to$2107\;W/m^2{\cdot}K$ . Convection heat transfer coefficient increased with increase in flow rate and decreased as viscosity increased. -
An instrument using thermal probe method was designed to measure thermal conductivity of liquid and solid foods. Thermal conductivity probe was designed with diameter to length ratio of 100 and diameter of 0.51 mm to minimize axial flow effect on thermal conductivity measurement. Thermal conductivities of distilled/deionized water, glycerin, and beef frankfurter meat were measured at
$20-80^{\circ}C$ . Mean thermal conductivity values of water showed less than 2.0% difference from several reference values without using time correction factor or probe calibration constant. For glycerin, difference was less than 0.7% from reference values at$20-50^{\circ}C$ . Mean values of thermal conductivity for beef frankfurter meat ranged from 0.389 to$0.350\;W/m{\cdot}K$ at$20-80^{\circ}C$ . -
Surimi samples were prepared with the addition of three different sugars (sucrose, glucose, and fructose) at 8% and the thermal gelation of surimi sols was investigated by small-deformation oscillatory measurements of storage (G') and loss (G") moduli. The magnitudes of G' at
$10^{\circ}C$ were much greater than G" over the entire range of frequency (${\omega}$ ), with little dependence on${\omega}$ . In general, G' values of surimi sol containing sucrose during heating (from 10 to$95^{\circ}C$ ) was pronounced than those of glucose and fructose, showing the following order: sucrose>glucose>fructose. The transition peaks of surimi sols containing sugars were in the temperature range of$34.8-37.4^{\circ}C$ . -
Choi, Sung-Won;Yang, Jae-Sung;Jung, Eun-A;Choi, Hak-Jong;Lee, Han-Seung;Shin, Chul-Soo;Kim, Dong-Seob;Hur, Nam-Yun;Baik, Moo-Yeol 344
Aldose reductase catalyzes the conversion of glucose into sorbitol. Inhibiting this enzyme in diabetes mellitus can delay or prevent pathogenic process. Aldose reductase inhibitor was screened from Korean fermented soybean pastes (Doen-jang) and purified via sequential processes of ethanol extraction, HP-20 column chromatography, ethyl acetate extraction, silica gel column chromatography, and crystallization. Aldose reductase inhibitor was identified as genistein with molecular weight of 270 Da and molecular formula of$C_{15}H_{10}O_5$ based on UV spectrometry,$^1H$ and$^{13}C\;NMRs$ , and mass spectrometry. Genistein inhibited aldose reductase of pig lens with$IC_{50}$ level of$20\;{\mu}M$ . Because genistein was effective against aldose reductase of animal source, it may be a potential therapeutic agent for diabetic complications. -
The effect of the essential oil obtained from Chrysanthemum boreale Makino on the apoptosis of KB cells was investigated. Cytotoxicity and cellular DNA content were analyzed by MTT assay, flow cytometry, agarose gel electrophoresis, and Hoechst 33258 staining. The caspase-3 and poly (ADP-ribose) polymerase (PARP) proteins were estimated by Western blotting method. The various cytotoxic effects of the essential oil which are hallmarks of apoptosis, including DNA fragmentation, apoptotic body formation, and sub-G1 DNA content, all progressed in a dose-dependent manner. Treatment with an apoptosis-inducing concentration of the essential oil caused rapid and transient induction of caspase 3 activity. Further, the efficacious induction of PARP cleavage and caspase-3 activation was observed at an essential oil concentration of 0.1 and 0.2 mg/mL for 12 hr.
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This study evaluated the binding abilities of rabbit anti-ovalbumin (OVA) immunoglobulin G (IgG) and egg-allergic patient IgE on gamma-irradiated OVA during proteolysis using pepsin and trypsin. The concentrations of both the intact and the irradiated OVAs decreased during proteolysis when detected with IgG However, when detected by patient IgE the concentration of the intact OVA decreased up to 30 min after the trypsin treatment and increased thereafter. Irradiated OVA detected by patient IgE showed a lower initial concentration (0.16%) than that of the intact OVA, and this reduced concentration was maintained stably. The results indicate that irradiation, rather than enzymatic treatment, could reduce the binding of the irradiated and enzyme-treated OVA. Therefore, gamma irradiation has potential as an effective method to reduce OVA-induced allergy and may enhance the safety of egg-allergic individuals.
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Eudragit E100 microcapsules containing nisin were prepared and employed to control the ripening of kimchi. The recovery yields of microcapsules without/with nisin ranged from 93.53 to 94.61 % and 92.85 to 94.09 %, respectively. The particle size of microcapsules decreased (>200 to
$100\;{\mu}m$ ) as the amount of aluminium tristearate increased from 6.0 to 15 %. The microcapsules were morphologically spherical and possessed rough surface. Nisin was completely released from the microcapsules within a day at pH 3.0 and within two days at pH 4.0, 5.0, and 6.0, respectively, whereas half the amount of nisin was released at pH 7.0 within two days. During fermentation of kimchi with microcapsules containing nisin, the pH decrease was retarded which resulted in a constant pH of approximately 4.2. The pH of 4.2 was optimal for ripening of kimchi for a longer period of time when compared with samples without nisin. -
Although widely applied in the food industry, extrusion cooking has not been applied to the traditional red ginseng process for steaming and drying ginseng. We therefore investigated the change in the effective components in red ginseng (total saponins, ginsenosides and maltol) from extruded raw ginseng. The variables were the drying temperature of the sliced raw ginseng (80 and
$90^{\circ}C$ ) before the extrusion process and the moisture content (15 and 22%, w.b.) during the extrusion process. Ginsenosides Rg1 and Rg2 were detected in dried ginseng at$80^{\circ}C$ , but ginsenoside Rg3, which was contained in red ginseng, was not detected. On the other hand, ginsenosides Rg1, Rg2 and Rg3 were detected in extruded ginseng at moisture contents of 15 and 22%. Total ginsenosides were highest at$90^{\circ}C$ drying temperature and 22% moisture content for the extrusion process. -
Citronellyl valerate was synthesized by a lipase from a Rhizopus sp strain isolated and the lipase produced, at UNICAMP, Brazil. Direct esterification was performed in a solvent-free medium to produce the flavor ester. Response surface methodology was used to optimize the process with respect to the substrate molar ratio and lipase concentration. The results show that the synthesis of citronellyl valerate can be carried out in a solvent-free medium, the maximum ester conversion rate achieved being 91.5% after 48 hours of reaction time.
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The compositions and antioxidant activities of tree and hydrolyzed phenolic acids, which are aglycones of esterified phenolic acids, in wild ginseng leaves were investigated. The contents of tree and hydrolyzed phenolic acids in the wild ginseng leaves were
$422.4\;{\pm}\;3.5$ and$319.6\;{\pm}\;5.7\;mg/100\;g$ , respectively, as gallic acid equivalents. Free phenolic acids were composed of 55.3% benzoic acid derivatives and 44.6% phenylpropanoids. The major constituents of free phenolic acids in the ginseng leaves were syringic (139.4 mg/l00 g) and sinapic (131.2 mg/100 g) acids. On the other hand, hydrolyzed phenolic acids in the ginseng leaves were mainly composed of caffeic (59.4 mg/100 g), ferulic (49.5 mg/100 g), and p-coumaric (33.8 mg/100g) acids. Phenylpropanoid content was higher (82.7%) than benzoic acid derivatives (17.3%).$IC_{50}$ values of DPPH radical scavenging activity were$10.2\;{\mu}g/mL$ for tree phenolic acids and 8.0 mg/mL for hydrolyzed phenolic acids, as gallic acid equivalents. Hydrolyzed phenolic acids also exhibited higher hydroxyl and superoxide radical scavenging activities than free phenolic acids did. These results indicated that the antioxidant activities of the wild ginseng leaves were correlated more closely with phenylpropanoid contents than with total amount of phenolics. -
Physicochemical properties, intestinal microbial growth, and inhibitory effects of alcohol-insoluble polysaccharide (AIP) extracted from cucumber peel were investigated. AIP was composed of 14.54% crude protein, 1.04% crude lipid, 13.74 % crude ash, 9.1% soluble dietary fiber, and 41.2% insoluble dietary fiber. AIP showed low bulk density (0.18 g/mL) and water-holding capacity (6.39 g/g), and high oil-holding capacity (3.96 g/g). Pectic substance fractions [water-soluble pectic substance (WSP), ethylenediaminetetraacetic acid-soluble pectic substance (ESP), and alkali-soluble pectic substances (ASP)] and hemicellulose fractions [1 M KOH-soluble hemicellulose (KHP1) and 4 M KOH-soluble hemicellulose (KHP4)] were obtained from sequential chemical fractionation of AIP. WSP showed higher total sugar contents than total uronic acid contents, whereas opposite results were observed in ESP and ASP. Molecular weight distributions of three pectic substance fractions were in order of ASP>ESP>WSP. Ion exchange chromatogram pattern of WSP was different from those of ESP and ASP. Major component of WSP was fraction eluted by 0.05 M ammonium acetate buffer, whereas that of ESP and ASP was fraction eluted by 0.2 M NaOH. WSP and ASP showed growth-promoting activities against Lactobacillus brevis, Bifidobacterium bifidum, and B. longum, whereas B. bifidum and B. longum for ESP. KHP1 and KHP4 fractions had significant growth-promoting activities against B. bifidum.
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Optimal conditions of ultrafiltration (UF) and nanofiltration (NF) were investigated for separation and concentration of isoflavones and oligosaccharides from Sunmul. Levels of COD, BOD, and suspended solids (SS) in UF and NF permeates were also determined to evaluate effectiveness of these processes for reducing water pollution. Optimal UF operation conditions to achieve minimal fouling and maximal flux were
$33-34^{\circ}C$ operating temperature and 2.3-2.4 bar trans-membrane pressure. Recovery yields of isoflavones and oligosaccharides in UF retentate were 11.49-28.16% and 12.77-27.57%, respectively. Increase in volumetric concentration factor (VCF) resulted in more functional compounds of isoflavones and oligosaccharides passing through UF membrane. Total isoflavone and oligosaccharide yields decreased by 3% as VCF increased from 6.0 to 8.0 and from 8.0 to 10.0, while decreased significantly by 10% as VCF decreased from 4.0 to 6.0. Optimal NF operating conditions were 192-195 psig operating pressure at$30-33^{\circ}C$ . Total yields of isoflavones and oligosaccharides significantly decreased at VCF 8.0, whereas did not decrease up to VCF 6.0 during NF operation. Therefore, VCF 6.0 was recommended for economical process. COD and BOD decreased by more than 98% after NF process, and SS were not detected after UF process. These results indicated sequential filtration process was useful for separation of isoflavones and oligosaccharides from Sunmul and for reducing water contaminants. -
Competitive polymerase chain reaction (cPCR) was used to develop a direct enumeration method of Listeria monocytogenes in pork meat. Pork meat was artificially inoculated with L. monocytogenes and DNA was extracted using guanidine thiocyanate-phenol-chloroform and subjected to PCR amplification. Sixteen primer sets for L. monocytogenes hlyA gene were tested for sensitive detection and the DG69/DG74 primer set was selected. The detection limit achieved with this primer set was as low as 860 colony-forming units (cfu) per 0.1 g of pork meat. When the samples were cultured at
$30^{\circ}C$ for 16 hr in Brain Heart Infusion (BHI) medium, even a single bacterium could be detected with this primer set by PCR. For cPCR, the hlyA gene, which features a 148 bp-deletion, was cloned in the pGEM-4Z vector. A known amount of competitor DNA which has the same primer binding sites was co-amplified with L. monocytogenes total DNA from the artificially inoculated pork meat. The cell-number determined by cPCR was approximately equal to cfu from the Most Probable Number (MPN) method. The whole procedure took only 5 hr. -
Fresh, and sun- and oven-dried red peppers were analyzed for volatile components. Also, their odor-active compounds were determined using gas chromatography-olfactometry (GC-O). More diverse volatile components, such as aldehydes, ketones, acids, and esters, were found in dried samples than in fresh ones. They included hexanal, ethyl acetate,
${\alpha}$ -ionone, and${\beta}$ -ionone. Some Strecker aldehydes, 2-methyl butanal and 3-methyl butanal, were found only in dried red peppers. More hydrocarbons of high volatility and terpene-type components, such as${\gamma}$ -terpinene and aromadendrene, were detected only in fresh red peppers. A considerable amount of naphthalene was formed during sun-drying, whereas 2-furancarboxaldehyde, 1-methyl-1H-pyrrole and benzeneethanol were detected only in oven-dried red peppers. Characteristic odor of fresh ones could be attributed to 3-penten-2-o1, 2-methyl-2-butenal, 2-methoxy phenol, 2-hydroxy-methyl-benzoate, and 2-phenoxy ethanol, whereas some odorants, including 2-pentyl furan, naphthalene, hexyl hexanoate, and${\alpha}$ -ionone, could be responsible for distinctive odor property of sun-dried red peppers. 2-Furancarboxaldehyde, benzeneethanol, 4-vinyl-2-methoxy phenol, and unknown played important roles in odor property of oven-dried red peppers. -
Choi, Je-Min;Ryu, Hyun-Jin;Chung, Jae-Hwan;Park, Jae-Chul;Hwang, Jae-Kwan;Shin, Dong-Bum;Lee, Sang-Kyou;Ryang, Ryung 399
The aim of this study was to investigate the in vitro antioxidant profiles of genistein and other isoflavonoids. The reactivity of genistein towards stable radical and reactive oxygen species including${\bullet}\;ABTS^+$ ,${\bullet}{O_2}^-$ ,$H_2O_2$ and HOCl has been investigated, and the effects were compared with other isoflavonoids and antioxidants. All the tested isoflavonoids showed remarkable${\bullet}\;ABTS^+$ scavenging activity and genistein was more potent than BHT and ascorbic acid. Genistein was more effective in scavenging hypochlorous acid than superoxide and hydrogen peroxide. At$10\;{\mu}M$ concentrations of genistein and genistin showed about 90% inhibitory effect on HOCl, while BHT and ascorbic acid showed lower than 50% inhibitory effect. Moreover, genistein could inhibit plasmid DNA cleavage, protein degradation and cell death from HOCl attack, while daidzein, BHT and ascorbic acid could not protect them effectively. These results suggest that genistein is a more potent radical scavenger than other isoflavonoids, and it can remarkably reduce cellular damage induced by HOCl. -
Kim, Ji-Yeon;Lee, Seong-Kyu;Jeong, Do-Won;Hachimura, Satoshi;Kaminogawa, Shuichi;Lee, Hyong-Joo 405
Cellular components of Lactococcus lactis ssp. lactis (heat-killed whole cells, cytoplasm, and cell walls) were tested for their in vivo immunopotentiating activities. Peritoneal macrophages from mice injected intraperitoneally with cell-wall fractions exhibited significantly greater phagocytic activity than groups injected with whole cells or cytoplasm fraction. Cytotoxicity of natural-killer cells was highest in cytoplasm fractions. Production of cytokines (IFN-${\gamma}$ , IL-2, IL-6, and IL-12) in spleen cells was significantly higher when cellular components were injected intraperitoneally, and tended to be higher in whole-cell and cytoplasm groups than in cell-wall group. These results demonstrate lactic acid bacteria whole cells and their cytoplasm and cell-wall tractions have immunopotentiating activities. -
Vibrio parahaemolyticus is a gram-negative bacterium which acts as a causative agent for food poisoning. Studies with respect to specific extracellular proteins of V. parahaemolyticus would be useful for the development of specific detection methods against V. parahaemolyticus. In our present study, outer membrane proteins (OMPs) of V. parahaemolyticus were obtained from insoluble traction of 1% sarkosyl treated-cell wall materials. SDS-PAGE analysis showed the presence of several conserved outer membrane proteins among five strains of V. parahaemolyticus, and three bands were identified as V. parahaemolyticus OMPs through MALDI-TOF analysis. Polyclonal antibodies enriched with anti-OmpU were obtained from immunized rabbits. The antibodies against these proteins may be useful for the development of detection methods for V. parahaemolyticus.
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Time-dependent flow properties of commercial kochujang (hot pepper-soybean paste) were evaluated at various shear rates (5, 15, 25, and
$35\;sec^{-1}$ ) and temperatures (5, 15, and$25^{\circ}C$ ). Flow properties of all samples showed thixotropic behaviors, which were qualitatively evaluated and quantitatively described by the Weltman, Hahn, and Figoni and Shoemaker models. Time-dependent flow properties of kochujang were found to vary over the range of the shear rate and temperature investigated. Time-dependent models of Weltman and Hahn were suitable ($R^2=0.923-0.987$ ) for commercial kochujang. -
Unknown bacterium isolated from garlic was characterized using phenotypic methods, phylogenetic analysis, DNA-DNA hybridization, and cultural methods. The strain was identified as typical leuconostoc; Gram-positive, non-sporeforming, heterofermentative, catalase-negative and spherical. Although its 16S rRNA gene sequence showed high homology to Leuconostoc argentinum DSM
$8581^T$ (99.8%), DNA-DNA hybridization experiments indicated it represents novel genomic species in the genus Leuconostoc. The garlic-specific leuconostoc was more resistant to antimicrobial activity of garlic compared to other common laboratory lactic acid bacteria, and was even stimulated by low concentrations (1-2%) of garlic extract supplemented in trypticase soy broth. Growth stimulation was concentration-dependent when tested with residual aqueous layer after solvent extraction of fresh whole garlic extract. -
Effects of Dasom Valley and Bora Valley on fecal microflora, fecal moisture, and fecal pH of twelve healthy human volunteers were investigated. Numbers of Bifidobacterium, Clostridium perfringens, Escherichia coli, and Lactobacillus of control group were
$9.24{\pm}0.63$ ,$4.44{\pm}1.21$ ,$7.75{\pm}0.38$ , and$6.98{\pm}0.81$ (Log CFU/g wet feces), respectively. During administration of Dasom Valley, numbers of Bifidobacterium and Lactobacillus were$10.70{\pm}0.44$ and$8.84{\pm}0.77$ , whereas those of C. perfringens and E. coli were$2.96{\pm}1.50$ and$6.69{\pm}0.29$ , respectively. Administration of Dasom Valley significantly increased growth responses of beneficial bacteria, Bifidobacterium and Lactobacillus, whereas those of harmful bacteria, C. perfringens and E. coli, significantly decreased. Moisture content of feces increased and fecal pH decreased with intake of Dasom Valley. Intake of Bora Valley slightly increased numbers of Bifidbacterium and Lactobacillus and slightly decreased those of C. perfringens and E. coli. Results indicate Dasom Valley has greater intestinal-modulating effect than Bora Valley and Atlantic. Daily intake of Dasom Valley may normalize disturbed physiological functions, resulting in improvement of growth and composition of microbial community within intestinal tract. -
The cleavage products formed by the autoxidation of phytofluene were evaluated in order to elucidate possible oxidation products of phytofluene in the oxidative condition. Among a number of oxidation products formed, the following five in the carbonyl compound fraction were identified: 6, 10, 14-trimethylpentadeca-3,5,9,13-tetraen-2-one, phytapentaenal, 5,9,13,17-tetramethyloctadeca-2,4,6,8,12,16-hexaenal, 5,9,13,17-tetramethyloctadeca-2,4,8,12, 16-pentaenal, 2,7,11,15,19-pentamethylicosa-2,4,6,10,14,18-hexaenal and 4,9,13,17,21-pentamethyldocosa-2,4,6,8,12,16,20-heptaenal. In addition, 4,5-didehydrogeranyl geranoic acid was formed by the autoxidation of phytofluene in liposomal suspension. The pig liver homogenate was able to convert phytapentaenal to 4,5-didehydrogeranyl geranoic acid, in a manner comparable to the conversion of all-trans-retinal to all-trans-retinoic acid. These results suggest firstly that phytofluene is cleaved into a series of long-chain and short-chain carbonyl compounds under the oxidative condition in vitro and secondly that phytapentaenal is further enzymatically converted to 4,5-didehydrogeranyl geranoic acid.
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To compare volatile compounds in bulgogi cooked by different heating procedures, bulgogi was prepared by convection oven, electric pan and charcoal grill. A total of 61 volatile compounds, consisting of 4 pyrazines, 10 sulfur-containing compounds, 7 carbonyls, 7 alcohols, 7 aliphatic hydrocarbons, 25 terpene hydrocarbons, and 1 miscellaneous compound, were tentatively identified in bulgogi cooked by the three heating methods. Comparatively, the difference in volatile compounds identified in bulgogi using the three different heating methods was not significant, except for sulfur-containing compounds and carbonyls which were detected at higher levels in the bulgogi cooked by convection oven than in that cooked by the other two heating methods. On the other hand, some compounds, such as furfural, benzaldehyde, and (E,E)-2,4-decadienal, were detected only in the bulgogi cooked by charcoal.
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Chitosans were obtained with varying deacetylation times using the
${\beta}$ -chitin isolated from Todarodes pacificus, and their deacetylation degrees and average molecular weights were determined. Films prepared with the squid chitosans were characterized by estimating their tensile strengths, percent elongations, water vapor permeabilities, degree of swelling, and temperatures of glass transition and thermal decomposition. The results suggest that the squid chitosan films were comparable to common crustacean chitosan films in regard of mechanical, moisture barrier, and thermal properties, although further, multilateral investigations are necessary to make a more definitive conclusion. -
Freshness of stored soybean curd as sensitivity (
$R_{gas}/R_{air}$ ) was evaluated at 48-50 hr intervals using electronic nose at regular sequential square-wave temperatures between$4\;-\;10^{\circ}C$ . Obtained kinetic data from apparent first principal component score$(PC1)_{app}$ and storage time were used for prediction of freshness. Percentage difference between predicted and actual values of stored soybean curd was less than 8.9% under fluctuating temperature condition.