Food Science and Biotechnology
Korean Society of Food Science and Technology (KOSFOST)
- Monthly
- /
- 1226-7708(pISSN)
- /
- 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 15 Issue 3
-
The study of health promoting and disease preventing compounds in food or by themselves, so called nutraceuticals or functional foods, has become a major field of research in food science. Natural flavor compounds are usually present in food, essential oils, spices, and herbs. These compounds can produce aroma, not only by themselves, but also in combination with other compounds. Today, however, greater interest is being paid to the health promoting properties of natural flavor substances rather than their flavoring properties. In fact, a number of naturally occurring flavor compounds that possess health promoting and disease preventing properties have been extensively studied and identified. The beneficial properties of natural volatile flavor compounds as well as non-volatile substances in spices and herbs discussed in this review include antioxidant, anticarcinogenic, anti-inflammatory, and immune enhancing activities.
-
The pattern of drug resistance and incidence of R-factors were studied in Shigella sonnei as food-borne pathogen strains isolated from chicken meat in Iran. In this study we examined for transferring R-factors of S. sonnei to sensitive Escherichia coli
$k_{12}{\bar{F}}(\lambda)$ . The results showed that 19 out of 57 strains (33.3%) were resistant to one or more drugs and multiple drug resistance was more common than single drug resistance. The most predominant pattern of resistance observed was Tetracycline (Tc), Chloramphenicol (Cm), Streptomycin (Sm), and Sulfonamide (Su). 100% of the strains from the Caspian littoral transferred at least a part of their resistance pattern to sensitive E.coli$k_{12}{\bar{F}}(\lambda)$ . -
Yang, Su-Hyeong;Shim, Sung-Lye;No, Ki-Mi;Gyawalli, Rajendra;Seo, Hye-Young;Song, Hyun-Pa;Kim, Kyong-Su 341
This study was performed to examine the effects of${\gamma}$ -irradiation on the volatile flavor compounds of dried leeks (Alliums tuberosum R.). Volatile compounds of dried leeks were extracted using simultaneous steam distillation and extraction (SDE), and analyzed by gas chromatography/mass spectrometry (GC/MS). Forty-one, 51, 45, and 42 compounds were tentatively identified in control, 1, 3, and 10 kGy irradiated samples, respectively. The constituents of flavor compounds in irradiated dried leeks were similar to non-irradiated samples. However, the intensities of the peaks were clearly different between them. Sulfur-containing compounds were detected as dominant compounds in all samples and their amounts decreased after${\gamma}$ -irradiation.${\gamma}$ -Irradiation reduced the total concentration of volatile compounds from leeks by 23.19, 15.09, and 30.23% at 1, 3, and 10 kGy doses, respectively. -
The objective of this study was to investigate the possible effects of oral administration of single cell products (SCP) of apple on activating peritoneal macrophages. Apples were processed either for cold-pressed juice or SCP, which were produced by incubating sliced apples with a protopectinase, Sumyzyme MC. Both cold-pressed juice and SCP of apple were administered to C57BL/6 mice for 10 days to compare their efficacy, along with the control group, in stimulating peritoneal macrophages. The viability of macrophages was significantly increased by up to 161% of that of the control following the administration of apple SCP, whereas the viability of macrophages was increased to a lesser extent of up to 143% in the apple juice (AJ) administered group. Administration of apple SCP also induced a significantly higher production of
$H_2O_2$ from macrophages (317% of the control) than that of cold-pressed AJ (210%). Although nitric oxide (NO) production was not increased by the administration of either AJ or SCP, the latter slightly but significantly increased tumor necrosis factor-${\alpha}$ ($TNF-{\alpha}$ ) production from macrophages from 560.4 to 579.8 pg/mL. The results of this study suggest that administering SCP is more efficient than administering AJ to stimulate functions of peritoneal macrophages. -
In this study, we investigated the effect of adding a 1, 3, or 5% solution of germinated brown rice concentrate (GBRC) to fermented kimchi. During fermentation, the concentration of free amino acids and essential amino acids increased with increasing concentrations of GBRC. In particular, higher levels of free amino acids were associated with a sweet taste compared with controls. The
${\gamma}$ -aminobutyric acid (GABA) content of kimchi containing the 5% GBRC solution was 3 times higher than that of controls. The total phenolic compound content (130 mg%) did not change significantly in the control group, but increased in 10 mg% increments as the GBRC concentration rose from 1 to 3 to 5%. 2,2-diphenyl-1-picryhydrazyl (DPPH) free radical scavenging activity and superoxide radical scavenging activity also increased with the GBRC concentration, with maximum activity during the ripe stage with GBRC measured at 79 to 82% compared with controls (30 to 71 %). The nitrite scavenging activity was 10% higher with GBRC compared with controls and was highest when the pH was 1.2. These results showed that the addition of GBRC is effective in improving the function of kimchi. -
We assessed various antioxidant activities, such as 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, 2,2'-azino-bis 3-ethylbenz-thiazoline-6-sulfonic acid (ABTS) radical, and reactive oxygen species (ROS) radical scavenging effect, along with antioxidant capacity, of soybean oil with added Citrus species peel extracts (CPEs). These extract oils showed higher radical scavenging effects than grape fruit seed extract, the natural antioxidant agent, did. When CPEs were added to soybean oil, they showed peroxide value (POV) and acid value (AV) increasing inhibition effects. Furthermore, none of the CPEs showed any cytotoxicity over the tested concentration range of 0.01-100 ppm. The major flavonoid contents of Citrus junos, as determined by HPLC, were naringin (
$7.5\;{\mu}g/mg$ ) and neohesperidin ($7.5\;{\mu}g/mg$ ), and those of Citrus unshiu were narirutin ($3.13\;{\mu}g/mg$ ) and hesperidin ($1.97\;{\mu}g/mg$ ). However, the aglycone form was not found. This study showed that CPEs might be a potent source of natural antioxidant, without any toxic effects. -
Twenty-four different natural food materials extracted with 80% methanol were used to investigate the inhibition of cell-mediated immediate type allergic reactions induced by compound 48/80 in rat peritoneal mast cells (RPMCs). Nine 80% methanol extracts screened at a concentration of
$10\;{\mu}g/mL$ inhibited histamine release from RPMCs induced by compound 48/80. Of these, two materials (Ulmus parvifolia and Liriope platyphylla Wang et Tang) were extracted and fractionated into four different solvent types (chloroform, ethylacetate, butanol, and water), and the fractions with major anti-allergic effects were assessed. The chloroform fraction of U. parvifolia (UP) at$5\;{\mu}g/mL$ and the ethylacetate fraction of L. platyphylla Wang et Tang (LPWT) at$1\;{\mu}g/mL$ showed the greatest inhibition of histamine release induced by compound 48/80. The chloroform fraction of UP and the ethylacetate fraction of LPWT in combination showed a greater inhibition of histamine release than either fraction alone. The cAMP levels in RPMCs treated with UP and LPWT were significantly greater than in cells treated with compound 48/80 alone. Our studies suggest that extracts from UP and LPWT may alleviate immediate type hypersensitivity reactions through the increase of cAMP levels in the mast cells. -
Water extracts obtained from cultured mountain ginseng (CMG) were evaluated for their ability to stimulate immune cells and inhibit cancer cell proliferation. The lymphocyte subpopulation in mouse splenocytes in vivo was significantly increased by the administration of the CMG extract (27.4 mg/mouse). Interleukin-2 and
${\gamma}$ -interferon in the mice serum increased up to 30% in CMG extract-treated mice. At a concentration of 1.37 mg/mL, nitric oxide increased up to 400% in the macrophage cell line treated with CMG extract. The CMG extract significantly retarded the proliferation of human acute promyelocytic (HL60), human histiocytic (U937), and mouse lymphocytic (L1210) leukemia cell lines in vitro at concentrations over 2.74-13.7 mg/mL. In addition, CMG extract treatments (1.37 mg/mL and 2.74 mg/mL) lead to the increased expression of the p53 gene and protein in cultured U937 leukemia cell lines. These results indicate that water extracts of CMG are capable of both immune cell stimulation and cancer cell growth inhibition. -
This study was carried out to investigate the physicochemical properties of frozen pork muscle which has been thawed using the ohmic thawing process, and to establish the optimal ohmic power intensity. The samples were frozen at
$-40^{\circ}C$ and thawed at 0, 10, 20, 30, and 40 V by ohmic thawing. Increasing ohmic power intensity correlated with increased thawing rates. The relationship between ohmic power intensity and thawing rate can be represented as a polynomial function. The pH value decreased with increasing ohmic power intensity (p<0.05). With regard to color measurement, the$L^*$ , a, and b values of thawing at all ohmic power intensities were not significantly different. The water holding capacity showed a peak value of 41.62% with an ohmic thawing intensity of 30 V. Cooking losses were lowest at the lowest ohmic thawing intensity of 10 V. Thiobarbituric acid reactive substance (TBARS) levels with all thawing processes were slightly higher than that of the control (p<0.05). Increasing ohmic power intensity did not tend to change the total volatile basic nitrogen (TVBN) value. -
Choi, Yun-Kyung;Lee, Chang-Hyun;Lee, Moon-Won;Kwon, Jin;Song, Geun-Seoup;Kim, Young-Soo 380
Sprague-Dawley rats (n=32) were fed a diet containing basal (control), cellulose (5%), or alcohol insoluble residue (AIR) (5%) extracted from the stem and root barks of elm (Ulmus davidiana var. japonica Nakai) for 4 weeks. The effects of the diets, on gastrointestinal functions and morphology were evaluated. The weight gains, food intake, and food efficiencies for the cellulose and AIR diet-fed groups were not significantly different from those of the AIR-free (basal) diet. The gastrointestinal transit times of the stem and root bark AIR diets were significantly reduced (p<0.01) compared to the basal diet, and were slower than those of the cellulose diet. The fecal weights of the stem and root bark AIR diets were significantly increased (p<0.01) up to 4-fold compared to those of the basal diet. The height of the mucosal villi, and mucosal and muscle layer thicknesses of the colon were greater and more developed in the stem and root bark AIR diets (p<0.01) than in the basal diet. The villus heights in the jejunum and the colon mucosal goblet cells were more developed in the order of cellulose > stem bark AIR > root bark AIR diets. -
In Korea, different kinds of genetically modified (GM) crops are under development, including GM-rice expressing insecticidal crystal (Cry) proteins of Bacillus thuringiensis (Bt) modified to change a single amino acid. In this study, amino acid (aa) sequences of modified Cry proteins were compared to that of known allergens, and Cry proteins expressed in GM-rice were identified by using Cry protein specific polyclonal antibody. The antigen-antibody reactions were compared between GM and commercial rice to assess the allergic risk of Cry proteins. This analysis showed no known allergen to have more than 35% aa sequence homology with modified Cry proteins in Bt rice over an 80 aa window or to have more than 8 consecutive identical aa. Sera from allergic patients showed some IgE reactivity via immunoblotting and enzyme-linked immunosorbent assay (ELISA), although no differences were seen between GM and commercial rice. Based on these results we conclude that GM rice with modified Cry proteins has no differences in its protein composition or allergenicity relative to commercial rice.
-
Lee, Jin-Hwan;Baek, In-Youl;Kang, Nam-Suk;Ko, Jong-Min;Han, Won-Young;Kim, Hyun-Tae;Oh, Ki-Won;Suh, Duck-Yong;Ha, Tae-Joung;Park, Ki-Hun 392
Four flavonoids 1-4 and one phytosterol 5 were isolated from methanol extract of Taekwangkong, one of the soybean cultivars, and the structures of these compounds were fully characterized by physical and spectral analysis. The content of compounds 1-4 as determined by$C_{18}$ reversed phase HPLC (high-performance liquid chromatography) coupled with diode-array detector were 12.1, 624.6, 18.0, and$219.6\;{\mu}g/g$ , respectively, and the total phenolic content of this cultivar was measured as 3.7 mg gallic acid equivalent per g dry material (GAB/g). Also, compound 1 showed strong radical scavenging activity in the 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) assay ($IC_{50}\;=\;47.6\;{\mu}M$ ), five-fold higher than seen in the 1,1-diphenyl-2-picrylliydrazyl (DPPH) assay. These results lead to the conclusion that soybean not only has many phytoestrogens but also has potent antioxidant activity. -
The effect of flour storage conditions on the lipid oxidation of fried products during storage was studied. Wheat flour was stored at
$60^{\circ}C$ in the dark and at water activity (Aw) of 0.3, 0.5, or 0.8 for 21 days. The square-shaped dough ($2{\times}2{\times}0.1\;cm$ ) made with the stored flour and water was fried in soybean oil at$160^{\circ}C$ for 1 min. The fried products were stored at$60^{\circ}C$ for 15 days in the dark. The degree of lipid oxidation of the fried products was evaluated by conjugated dienoic acid (CDA) content and p-anisidine value (PAV). Both CDA content and PAV of the fried products increased with lengthening storage time of the fried products, suggesting that longer storage of the fried products raised the lipid oxidation. Furthermore, the lipid oxidation of the fried products made with flour that had been stored for a longer time tended to be higher than that of those made with unstored or short-term-stored flour. However, Aw at which the flour was stored did not significantly affect the lipid oxidation of either flour or the fried products during storage. The storage time of flour clearly exerted a greater effect than Aw on the lipid oxidation of the fried products during storage at$60^{\circ}C$ in the dark. This suggests that for the storage stability of fried products, the flour storage time is a more important factor than Aw at which the flour is stored. -
Feasibility of surface plasmon resonance (SPR) method to evaluate soybean frying oil quality was evaluated. Free fatty acid value, p-anisidine value, conjugated dienoic acid content, conjugated trienoic acid content, peroxide value, iodine value, total polar compound (TPC), ratio of unsaturated fatty acid to saturated fatty acid, refractive index, dielectric constant, smoking point, and L, a, and b of Hunter color system were selected as parameters related to conventional evaluation of soybean frying oil quality. SPR scale mapped with conventional quality parameters well described free fatty acid value, conjugated dienoic acid content, dielectric constant, TPC, and b of Hunter color system, as shown by correlation and linear regression analyses.
-
Interrelationship between results of large deformation (texture profile analysis, TPA) test and small deformation (creep) test on ohmic heated surimi gel, water-bath heated surimi gel, and commercial fish gel products (kamabokos) was examined. Creep test revealed ohmic heated gels have higher elastic modulus and viscosity values than water-bath heated ones, with differences of elastic modulus and viscosity between ohmic and water-bath heated gels being 18 and 28.5%, respectively. These differences were reflected in the higher hardness, cohesiveness, and chewiness values of ohmic heated gels in TPA. In TPA test, the differences of hardness and chewiness between ohmic heated gel and water-bath heated gel were 29.3 and 38.7%, respectively. It was concluded that with proper experimental design, the small deformation creep test which gives molecular level deformation data can be related to the large deformation TPA test indicating the sensory textural properties.
-
Joo, Hee-Jeong;Kang, Ming-Jung;Seo, Tae-Jin;Kim, Hyun-A;Yoo, Sung-Ja;Lee, Soo-Kyung;Lim, Hwa-Jae;Byun, Boo-Hyeong;Kim, Jung-In 413
The purpose of this study was to investigate the hypoglycemic effect of Saururus chinensis Baill in vitro and in vivo. Methanol extract of S. chinensis Baill inhibited yeast${\alpha}$ -glucosidase activity by 49.8%, which was twice as strong as that of acarbose at a concentration of 0.5 mg/mL in vitro. The effect of S. chinensis Baill methanol extract on the postprandial increase in blood glucose levels was studied in streptozotocin-induced diabetic rats using a carbohydrate load test. Oral administration of S. chinensis Baill extract (500 mg/kg) significantly decreased incremental blood glucose levels at 60 and 90 min (p<0.05) after oral ingestion of starch (1 g/kg). The area under the glucose response curve of the S. chinensis Baill group was significantly decreased compared to that of the control group (p<0.05). The effect of prolonged feeding of S. chinensis Baill was studied in an animal model of type 2 diabetes. Three-week-old db/db mice were fed an AIN-93G diet or a diet containing 0.5% S. chinensis Baill extract for 7 weeks after 1 week of adaptation. Plasma glucose, insulin, and blood glycated hemoglobin levels of the mice fed S. chinensis Baill extract were significantly lower than those of the control group (p<0.05). Therefore, we conclude that S. chinensis Baill is effective in controlling hyperglycemia in animal models of diabetes mellitus. -
Egg white powders (EWPs) were produced after pH adjustment (PH 6-9) of fresh egg white, followed by spray-drying, and foaming and gelling properties of EWPs were examined. EWP produced after pH adjustment to 6.5 (EWP-6.5) resulted in significantly higher foaming ability and gel hardness than control and other pH-adjusted EWP. Significant increases in surface -SH content and surface hydrophobicity of EWP-6.5 coincided with improved foaming ability and gel hardness. Significantly higher consistency index for reconstituted EWP-6.5 indicates unfolding of egg white protein was substantially increased in EWP-6.5. Decreased a-helix content in EWP-6.5 was confirmed by circular dichroism spectral analysis. These results indicate pH adjustment prior to spray-drying leads to structural changes in egg white proteins, significantly affecting major functionalities of EWP.
-
Low molecular weight polyphenols were isolated from hot water extracts of radiata pine (Pinus radiata) bark using a Sephadex LH-20 column and characterized by
$^1H$ and$^{13}C$ NMR, UV, FT-IR, and GC-MS analyses. Major compounds isolated and identified were protocatechuic acid, trans-taxifolin, and quercetin. Trans-taxifolin, an important intermediate in biosynthetic route of proanthocyanidin (PA), was isolated in large quantities and indicates that PA is a major component of radiata pine bark. Small amounts of polyphenols were identified by GC-MS analysis. The presence of p-hydroxybenzoic acid, vanillic acid, protocatechuic acid, cis- and trans-feruic acid, p-coumaric acid, trans-caffeic acid, (-)-epicatechin, (+)-catechin, trans- and cis-taxifolin, (+)-gallocatechin, and quercetin was confirmed by comparison of mass fragmentation patterns and retention times (RT) with authentic samples. In addition, the presence of astringenin, astringenin glycoside, trans- and cis-leucodelphinidin was strongly assumed from characteristic mass fragment ions due to their conjugated structure and retro Diels-Alder reaction, and also from biosynthetic route of PA. GC-MS analysis allowed us to detect small amounts of phenolic acids and flavonoids and eventually discriminate trans- and cis-configuration in the identified polyphenols. -
Effects of vacuum packaging and modified atmosphere packaging (MAP) on shelf life of selenium-supplemented chicken meat during refrigerated storage were examined. Body weight and feed efficiency were unaffected by dietary selenium level. Dietary treatments and packaging methods had no significant effects on level of microbial growth, lightness, and metmyoglobin content. MAP decreased purge loss (10.9-34.5%) and lipid oxidation (15.2-15.9%) more efficiently than vacuum packaging. Broiler chicks supplemented with
${\alpha}$ -tocopherol or${\alpha}$ -tocopherol + selenium had similar TBA values. Dietary supplementation of 4 and 8 ppm selenium reduced lipid oxidation, and this effect was less significant in MAP breast meat. -
To explore the possible usefulness of
${\beta}$ -glucans as natural antioxidants, the antioxidant profiles of${\beta}$ -glucan, extracted from Saccharomyces cerevisiae KCTC 7911, and water soluble and insoluble mutant${\beta}$ -glucan, isolated from yeast mutant S. cerevisiae IS2, were examined by five different in vitro evaluation methods: lipid peroxidation value (POV), nitric oxide (NO), 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical, reducing power, and${\beta}$ -carotene diffusion assay. The antioxidant activities of all${\beta}$ -glucans evaluated in POV test were comparable to or better than that of the known antioxidant, vitamin C. Remarkably, the${\beta}$ -glucan and water insoluble mutant${\beta}$ -glucan possessed 2.5-fold more potent activity than vitamin C at a dosage of 2 mg. Although vitamin C showed 100-fold greater activity than all${\beta}$ -glucans in NO and DPPH tests for measuring the radical scavenging capacity, all${\beta}$ -glucans revealed higher radical scavenging activity than the known radical scavenger, N-acetyl-L-cysteine (NAC), in DPPH test. The water insoluble mutant${\beta}$ -glucan had 2.6- and 5-fold greater antioxidative activity than water soluble${\beta}$ -glucan in NO and DPPH tests, respectively, showing that all${\beta}$ -glucans were able to scavenge radicals such as NO or DPPH. While all${\beta}$ -glucans revealed lower antioxidant profiles than vitamin C in both reducing power activity and${\beta}$ -carotene agar diffusion assay, the${\beta}$ -glucan and water insoluble mutant${\beta}$ -glucan did show a marginal reducing power activity as well as a considerable${\beta}$ -carotene agar diffusion activity. These results confirmed the potential usefulness of these${\beta}$ -glucans as natural antioxidants. -
The biological effects of heating and chemical treatment on castor meal were investigated in order to develop a procedure to inactivate its antigenic activity in a way that is suitable for industrial applications. A 1% solution of purified castor bean allergen (CB-1A) was heat-treated with or without exposure to NaOH and NaOCI (250 ppm each). CB-1A exhibited extreme stability when heat-treated alone. In the presence of NaOH and NaOCl, CB-1A showed a drastic decrease in antigenic activity as the temperature surpassed the critical level of
$70^{\circ}C$ . The gradual disappearance of disc gel electrophoresis bands presumably responsible for the allergenicity of CB-1A, along with the significant losses of the amino acids phenylalanine, methionine, arginine, histidine, and cysteine correlated with the loss of CB-1A activity. CB-1A showed a single symmetrical band in SDS acrylamide gel electrophoresis with an estimated molecular weight of 6,000 daltons. The chemical and heat treatments reduced the disulfide bond content of CB-1A by 9.1% with a coincident increase in sulfhydryl bonds. -
To determine the functions of specific cell wall polysaccharides, polysaccharides of three mutants, mur3-1, mur3-2, and mur3-3, obtained from Arabidopsis wild type, underwent structural characterization. Upon sequential separation of pectins (RG-I and RG-II) and cross-linking glycans (xyloglucan, XG), only XG was affected by the mud mutation. Wild-type XG contained a considerable amount of fucose, whereas the fucose level in mur3 XGs was less than 20% that of wild type. Further analysis of XGs by matrix-assisted laser-induced/ionization time-of-flight (MALDI-TOF) mass spectrometry indicated that mud lines considerably or completely lost the fucosylated XG oligosaccharides such as XXFG and XLFG and the double-galactosylated oligosaccharide XLLG
$^1H$ -NMR spectroscopic analyses of the XG oligosaccharides from mur3-3 plant revealed the absence of fucose and a galactose level in the galactosylated side chain that was reduced by 40% compared to that of Arabidopsis wild-type plant. In contrast, 85% less fucose and a slight loss of galactose were observed in the mur3-1 and mur3-2 lines which show normal growth habit. Of the three Arabidopsis mur3 lines studied here, mur3-3 is disrupted by a T-DNA insertion in the exon of MUR3 which encodes XG-specific galactosyltransferase, and exhibits slight dwarfism. These results indicated that the T-DNA insertion at the MUR3 locus did not induce the complete loss of galactose in XG, and that galactose, rather than fucose, in the XG side chains made a major contribution to overall wall strength. -
Activity and stability of kiwifruit actinidine was determined in various conditions of pH, salt, and temperature using N-
${\alpha}$ -CBZ-lysine P-nitrophenyl ester as the substrate. Actinidine activity was low below pH 6, and undetectable below pH 3. The enzyme was stable in a pH range of 6.0-8.5. At$4^{\circ}C$ the enzyme was inactive in the presence of greater than 36% vinegar and in 2 M NaCl. Actinidine at$25^{\circ}C$ was unstable in 24% vinegar but stable in up to 3 M NaCl. With regard to freeze-thaw stability, actinidine retained 85% residual activity after being frozen at$-20^{\circ}C$ for 3 days. Based on Arrenius and Lineweaver-Burk plots, actinidine became unstable at greater than$45^{\circ}C$ with only 30% residual activity remaining after 6 min. The Km, kcat, and kcat/Km values of actinidine were$56\;{\mu}M$ , 67/sec, and$1.2\;{\mu}M/sec$ , respectively. -
To determine whether the toxicity of Bacillus cereus would be seen in human cell lines and mice, we screened B. cereus B-38B, B. cereus B-50B, and B. cereus KCCM40935 for genes that coded for 5 enterotoxins using the polymerase chain reaction and cultivated them for 17 hr, by whose time they had grown to
$10^7-10^8$ colony-forming units (CFU) per milliliter. Cell-free supernatant was added to make up 1% of the total reaction solution. Human cells from normal lung, lung carcinoma, embryonic kidney, and cervical adenocarcinoma cell lines were grown in culture. The cytotoxicity induced by adding the reaction solution was indicated by cell death rates of 0 to 70%, depending on the bacterial strain involved and the cell line. A lethality of 20% was observed when B. cereus cultures containing$10^7-10^8$ viable cells were administrated orally to mice. Therefore, the culture of B. cereus containing$10^7-10^8$ viable cells seems to have high cytotoxicity on human cell lines and lethality on mice. -
In order to extend the shelf life of sliced raw flatfish, the antimicrobial effects of natural essential oil from mustard and a mixture of ginger and mustard essential oils were tested at various temperatures. In addition, volatile components of the mixed essential oils were analyzed using gas chromatography and gas chromatography mass spectrometry. The viable cell counts of Vibrio parahaemolyticus treated with mixed essential oils from ginger and mustard was 0.7-1.3 log CFU/g lower than those of other treatments during storage at
$5^{\circ}C$ . During storage at$20^{\circ}C$ , the viable cell counts of V. parahaemolyticus, V. vulnificus 01, and V. vulnificus 02 treated with the essential oils increased slightly from 6.53-6.64 log CFU/g at initial stages to 6.77-7.72 log CFU/g after 24-hr of storage, however they were 1.38-1.97 log CFU/g lower than those of the control group (8.74-9.10 log CFU/g). These results show that the growth of V. parahaemolyticus and V. vulnificus inoculated on sliced raw flatfish could be inhibited by treatment with natural essential oils from ginger and mustard at$5^{\circ}C$ of storage. However, the antibacterial effects of the essential oils on Vibrio species observed in this study were not sufficient to merit their use in sliced raw flatfish at temperatures exceeding$20^{\circ}C$ . -
Kim, Kee-Tae;Moon, Sun-Hee;Yeo, Eun-Ju;Park, Yong-Sun;Han, Ye-Sun;Nah, Seung-Yeol;Lee, Na-Gyong;Paik, Hyun-Dong 466
The antimicrobial effect of a novel flavonoid (7-O-butyl naringenin) on Helicobacter pylori ATCC 26695 and its inhibitory effects on the urease activity of the strain were evaluated by comparing with quercetin and naringenin. H. pylori was cultured with brain heart infusion supplemented with 5% horse serum at$37^{\circ}C$ under 10%$CO_2$ atmosphere and the inhibitory effects of flavonoids against the strain were detected using micro-plate methods. During 12 hr of incubation time, the optical densities of phenol red reduced (pink color) in the urea broth by producing ammonia were detected at 560 nm with a spectrophotometer. The results indicated that both quercetin and 7-O-butyl naringenin were effective against the growth of H. pylori. Moreover, inhibitory effect of 7-O-butyl naringenin on the growth of H. pylori was about two-fold higher than quercetin at the same concentration. With regard to H. pylori urease activity, 7-O-butyl naringenin had a greater inhibitory effect than did naringenin or quercetin at the same concentration. -
Film-forming yeasts generate an undesirable yeasty flavor in fermented vegetables such as kimchi in the presence of oxygen. Antimicrobial materials including garlic oil (GO), heated garlic (HG), and allyl alcohol (AA) were investigated for use as alternative natural food preservatives to inhibit the growth of film-forming yeasts in fermented vegetables. Using the fermentation of cucumber pickles as a model system, GO, HG, and AA were effective in preventing film formation at concentrations of 0.006, 3.0, and 0.02%, respectively. The effectiveness of HG in preventing the growth of a film yeast, Hansenula anomala, was not influenced by pH, while that of potassium sorbate, a typical anti-yeast food preservative, was highly dependent on pH. All tested materials were effective when added at the beginning of fermentation due to their negligible inhibitory activity toward lactic acid bacteria.
-
Dynamic rheological properties of commercial 0.8, 1.0, and 1.2% gums [carboxylmethylcellulose (CMC), guar gum, hydroxypropylmethylcellulose (HPMC), tara gum, and xanthan gum], which can be dissolved in cold water, were investigated by small-deformation oscillatory measurements. Magnitudes of storage (G') and loss (G") moduli increased with increasing concentration of gum solutions except for xanthan gum. Guar gum exhibited greatest G' and G" values among all gums except for G' value at 0.8% concentration. Slopes of G' and G" decreased with increasing concentration of gum solutions except for xanthan gum. Tan
${\delta}$ (G"/G') values decreased with increasing concentration of gum solutions except for xanthan gum. Tan${\delta}$ values of xanthan gum solutions were much lower than those of other gum solutions, indicating that xanthan gum solutions were predominantly more elastic than viscous. -
Kim, Ki-Myong;Lee, Boo-Yong;Kim, Young-Teck;Choi, Sung-Gil;Lee, Jun-Soo;Cho, Seung-Yong;Choi, Won-Seok 478
This study investigated the antimicrobial activity of soy protein isolate (SPI) film containing green tea extract (GTE, 1-4%, w/w) on dental caries-inducing bacterium (Streptococcus mutans), food pathogenic (Staphylococcus aureus, Escherichia coli 0157, Salmonella typhimurium), and spoilage (Pseudomonas aeruginosa) bacteria. The physical and mechanical properties of the SPI film containing GTE were also studied. The SPI film containing GTE (4%, w/w) exhibited good antimicrobial activity against S. mutans and S. aureus. The antimicrobial activity of the SPI film containing GTE increased against S. mutans as the concentration of GTE increased up to 4%(w/w). SPI films containing GTE showed lower tensile strength and elongation, and higher total soluble matter than those of control SPI film. Therefore, GTE can be used as one of antimicrobial agents for anti-dental caries and food packaging films. -
Kim, Tae-Hoon;Lee, Na-Kyoung;Chang, Kyung-Hoon;Park, Eun-Ju;Choi, Shin-Yang;Paik, Hyun-Dong 482
The antioxidant activity of Bacillus polyfermenticus SCD was studied by partially purified culture extracts using various methods: ammonium sulfate precipitation, adsorption to Diaion HP-20 columns using polar solvents, and extraction using non-polar solvents. The 1,1-diphenyl-2-picyrylhydrazyl (DPPH) radical scavenging activity of these partially purified fractions was then investigated. The precipitate isolated using 75%-saturated ammonium sulfate was shown to contain about 77.2% DPPH radical scavenging activity. Using the Diaion HP-20 resin adsorption method, the fraction obtained using 60% ethanol and 60% methanol possessed 76.7 and 89.5% DPPH radical scavenging activity, respectively. Fractions obtained by extracting with the non-polar solvents 80 mg/mL chloroform, 80 mg/mL n-hexane, 80 mg/mL ethyl acetate, and 80 mg/mL butanol contained 68.4, 75.0, 70.7, and 87.5% DPPH radical scavenging activity, respectively. Further study is needed to characterize the antioxidant substance(s) released by B. polyfermenticus SCD cultures.