Purification and characterization of a β-glucosidase capable of hydrolyzing soybean isoflavone glycosides fromPichia guilliermondii K123-1

Jai-Hyun So, Won-Chan Kim, Jae-Ho Shin, Choon-Bal Yu, In-Koo Rhee

                                                                              

Abstract

A β-glucosidase, efficiently hydrolyzing isoflavone glycoside to isoflavone aglycone, was purified fromPichia guilliermondii K123-1, isolated from Korean soybean paste by ammonium sulfate precipitation, ion exchange column chromatography, gel filtration, and fast protein liquid chromatogram (FPLC). The molecular mass of purified enzyme was estimated to be 45 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDSPAGE). The optimum temperature for enzyme activity was 45°c and it decreased dramatically above 50°c. The maximal activity was at pH 4.5 and more than 80% of the activity was retained for 24 hr in the pH range from 4.0 to 8.0 at 4°C. The N-terminal amino acid sequence of the enzyme was determined to be GLNWDYDNDK. Based on its substrate specificity and catalytic properties, the activity of the purified β-glucosidase was more effective when the sugar moiety of the glycoside was glucose and the size of the aglycone similar to that of the isoflavones. The purified β-glucosidase efficiently converts genistin and daidzin to genistein and daidzein 1.96 and 1.75 times more than almond meal β-glucosidase.

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Keywords :isoflavone ,β-glucosidase ,Pichia guilliermondii K 123-1.

Changes in extractability and antioxidant activity of Jerusalem artichoke (Helianthus tuberosus L.) tubers by various high hydrostatic pressure treatments

Dongyeop Kim, Jiang Ping Fan, Hyun Chae Chung, Gi Dong Han

                                                                                 

Abstract

This study investigated changes in the extraction characteristics of Jerusalem artichoke (Helianthus tuberosus L.) tubers (JA) using high hydrostatic pressure (HHP) treatment alone and in combination with enzymes and/or fermentation. HHP treatment of JA increased the soluble solid content and decreased the turbidity compared to the control group that received hot-water extraction. This indicates improved extractability of JA by HHP treatment alone or in combination. Combined HHP treatment with enzymes increased the contents of non-reducing sugars, fructooligosaccharide (FOS), and free amino acids in the extracts compared to those of control, thus activating browning reaction. Extraction of fermented JA by HHP treatment with or without enzyme showed increased polyphenol content as well as improved 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and superoxide dismutase (SOD) like activity compared to the control group. Taken together, HHP treatment of fermented JA with enzymes significantly improved the extractability of bioactive molecules such as phenolics and FOS compared to conventional water extraction or HHP treatment alone. Our results provide useful information for the improvement of raw material extraction by HHP treatment in combination.

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Keywords :Jerusalem artichoke tuber ,high hydrostatic pressure ,enzyme ,fermentation ,antioxidant.

Influence of altitudinal variation on the antioxidant potential of tartar buckwheat of Western Himalaya

Garima Kishore, Shashi Ranjan, Anjana Pandey, Sanjay Gupta

                                                                                     

Abstract

In the present work, the effect of altitudinal variations on the total phenol, flavonoid, and antioxidant potential of seeds and hull of Tartar buckwheat collected from 15 different locations of Western Himalaya has been investigated. Methanolic and acetonic extracts of seed and hull powder showed significantly increasing amounts of total polyphenol content, and antioxidant potential with rising altitude. Methanolic extract of seed and hull powder were found to have significantly greater polyphenol, and antioxidant potential as compared to acetonic extract. The methanolic seed extract of Inderdhara (3,133 m) showed the maximum total phenolic content 1,651 μg gallic acid equivalent/50 mg of dry weight. The methanolic seed extract of Inderdhara showed the maximum antioxidant activity (77.29±1.2%) and antiradical activity (55.5±0.5%) also. The results of this study exhibited good correlation with total polyphenol and antioxidant potential in all the samples followed by the increasing tendency towards rising altitude.

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Keywords :Tartar buckwheat ,altitudinal variation ,antioxidant potential ,polyphenol ,β-carotene.

Protective effects of extract with phenolics from camellia (Camellia japonica) leaf against oxidative stress-induced neurotoxicity

Chang-Ho Jeong, Ji Hye Kim, Gwi Nam Choi, Ji Hyun Kwak, Dae-Ok Kim, Ho Jin Heo

                                                                                   

Abstract

Antioxidant and neuronal cell protective effects of aqueous extract from camellia (Camellia japonica) leaf (CJLE) were evaluated. The 1,1-phenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric reducing/antioxidant power (FRAP) assays of the CJLE were increased in a dose dependent manner. In neuronal cell viability assay using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazoliumbromide (MTT), the aqueous extract showed protective effect against H₂O₂-induced neurotoxicity and lactate dehydrogenase (LDH) release into medium was also inhibited by CJLE (7.13–43.89%). The cell viability of CJLE was higher than vitamin C (200 μM) by neutral red uptake (NRU) assay at a concentration of 250–1,000 μg/mL. Phenolics of CJLE were 21.75 mg/g, and major phenolic compounds were quercetin (120.20mg/100 g) and kaempferol (88.13 mg/100 g). Therefore these data suggested that the CJLE including above phenolics may be useful in the natural antioxidant substance and reduce the risk of neurodegenerative disease such as Alzheimer’s disease.

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Keywords :camellia leaf ,antioxidant activity ,neuronal cell protective effect ,quercetin ,kaempferol.

Effect of enzyme treatment with β-glucosidase on antioxidant capacity of mulberry (Morus alba L.) leaf extract

Gyo-Nam Kim, Hae-Dong Jang

                                                                                

Abstract

This study was carried out to investigate the effect of enzyme treatment with β-glucosidase on antioxidant capacity of the mulberry leaf extract (MLE) using oxygen radical absorbance capacity (ORAC) and cellular antioxidant capacity (CAC) assay. The MLE was prepared by autoclaving at 121°C for 15 min and treated with β-glucosidase for 9 hr. High pressure liquid chromatography (HPLC) analysis showed that only qercetin-3-β-d-glucose (QT-G) among quercetin (QT) glycosides of MLE, including QT-G, quercetin-3-O-glucose-6″-acetate (QT-GA), and rutin (RT), was converted into QT by 3 hr treatment with β-glucosidase. The in vitro peroxyl radical- and hydroxyl radical scavenging capacity significantly increased after the enzyme treatment using β-glucosidase for 6 and 9 hr, respectively. The metal chelating activity increased after the enzyme treatment using β-glucosidase for 3 hr. The intracellular antioxidant capacity of MLE to protect AAPH- and Cu²⁺-induced oxidative stress in HepG2 cells significantly increased after the enzyme treatment using β-glucosidase for 3 and 6 hr, respectively, indicating that QT may be released from QT-G by β-glucosidase and penetrate into cell membrane so that it can contribute to the intracellular antioxidant capacity of MLE.

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Keywords :ulberry leaf extract ,enzyme treatment ,antioxidant capacity ,oxygen radical absorbance capacity (ORAC) ,cellular antioxidant capacity (CAC).

Effect of the degree of enzymatic hydrolysis on the physicochemical properties and in vitro digestibility of rice starch

Kwang Yeon Lee, Suyong Lee, Hyeon Gyu Lee

                                                                      

Abstract

Rice starch was subjected to enzymatic treatment with pullulanase and the physicochemical properties of the modified rice starch were investigated as a function of the degree of hydrolysis which ranged from 0.9 to 10.2%. The enzymatic hydrolysis of rice starch caused a decrease in the fraction of rapidly digestible starch (RDS) (78.31→44.65%), whereas the levels of slowly digestible starch (SDS) (0.8→22.18%) and resistant starch (RS) (20.79→34.43%) increased, consequently reducing in vitro starch digestibility. In addition, the swelling factor of rice starch decreased with increasing enzyme concentration while an increase in its syneresis was observed. In rapid visco analyser (RVA) measurement, dramatic decreases in the peak viscosity (452.5→12.0 cp), breakdown (307.0→4.5 cp), and setback (207.0→3.0 cp) were observed in the enzyme-treated rice starch of which X-ray diffraction showed that there was the coexistence of A-and V-type crystallinity.

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Keywords :rice starch ,pullulanase ,enzyme modification ,in vitro digestibility.

α-pinene triggers oxidative stress and related signaling pathways in A549 and HepG2 cells

Kyong-Suk Jin, Min-Ji Bak, Mira Jun, Ho-Jin Lim, Wan-Keun Jo, Woo-Sik Jeong

                                                                                       

                                                                                  

Abstract

The volatile organic compounds (VOCs) -dlimonene, α-pinene, and isoprene-are widely used in scented products including food flavorings, air fresheners, and cosmetics. The effects of these VOCs on cell viability, oxidative stress generation, and the related molecular events were investigated in A549 and HepG2 cells. α-Pinene induced cell death, reactive oxygen species (ROS) generation, and reporter gene activities of antioxidant response element (ARE), activator protein 1 (AP-1), and nuclear factor (NF)-κB. α-Pinene stimulated the redoxsensitive transcription factors such as nuclear factor E2-related factor 2 (Nrf2) and NF-κB. Their down stream targets including heme oxygenase 1, inducible nitric oxide synthase, and cyclooxygenase 2 also increased after treatment with α-pinene. Moreover, α-pinene-induced oxidative stress-related signaling pathways could be connected by mitogen-activated protein kinases. Conversely, α-pinene-mediated cell death, ROS formation, and AP-1 induction were inhibited by an antioxidant, N-acetyl-l-cysteine. Thus, α-pinene can induce the cell death possibly by modulating oxidative stress-related signaling pathways which can be reversed by an antioxidant treatment.

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Keywords :volatile organic compound ,α-pinene ,oxidative stress ,cytotoxicity ,activator protein 1.

Determination of primary factors with adhesive property of Lactobacillus brevisFSB-1 to rat colonic mucin

Seong Yeong Kim, Kwang-Soon Shin, Ho Lee

                                                                                   

Abstract

To maintain the valid physiological effects of lactic acid bacteria LAB in large intestine, the adhesive properties of LAB to human colonic mucin HCM is essential. In this study, the primary factors associated with the adhesive property of LAB to rat colonic mucin RCM were investigated, which contains sugar chains similar to those in HCM. Specific lectins bound to RCM were isolated by using the reaction between the surface layer Slayer protein of Lactobacillus brevis FSB-1 and RCM-coated membrane. When the isolated specific lectins of L. brevis FSB-1 analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis SDS-PAGE, 3 bands about 24, 55, and 75 kDa were observed on the electrophoretograms. And the specific sugar chains in glycoprotein of mucin also investigated by using modified colonic mucin-binding assay. The results indicated that Slayer protein of L. brevisFSB-1 bound to sialic acid and GalNAcα1-3Gal. Therefore, it could be concluded that Slayer protein of L. brevis FSB-1 recognized the terminal sugar chains of RCM and bound to it

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Keywords :Lactobacillus brevis FSB-1 ,adhesive property ,rat colonic mucin ,colonic mucin-binding assay .lectin

Anti-allergy effect of marc from silver vine Actinidia polygama prepared by supercritical fluid extraction

Seun-Ah Yang, Eun-Jung Lee, Hee-Don Choi, Mi-Hee Yu, Myun-Ho Bang, In-Seon Lee, Sam-Pin Lee

                                                                       

Abstract

Anti-allergic effect of marc extract after supercritical fluid extraction SFE comparing the crude extract from silver vine was investigated to increase its potential for use as a new source of functional food that reduced non-favorable flavor. The results tested by thiazolyl blue tetrazolium bromide MTT assay indicated that the ethanol extract of silver vine ETOH and ethanol extract of SFE marc SFEM showed no cytotoxic effects on IgE-sensitized rat basophilic leukemia RBL-2H3 cells under the conditions. ETOH, as well as SFEM inhibited antigen-induced degranulation in RBL-2H3 mast cells dose dependently. The morphological change of the cells treated with compound 48/80 was prevented by the extracts. Production of tumor necrosis factor TNF-α on the activated RBL-2H3 cells was also reduced by ETOH and SFEM, similarly. Moreover, the total phenolic content of the extracts seems to correlate with the anti-allergic activity. In conclusion, the results suggest that the flavor-improved SFE marc extract suppressed the antigen-induced allergic reactions in RBL-2H3 mast cells.

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Keywords :silver vine ,Actinidia polygama ,allergic reaction ,supercritical fluid extraction ,RBL-2H3 cell.

Control of citrus green and blue molds by Chinese propolis

Shuzhen Yang, Litao Peng, Yunjiang Cheng, Feng Chen, Siyi Pan

                                                                                     

Abstract

Green and blue molds, caused by Penicillium digitatum and Penicillium italicum, respectively, are economically important postharvest diseases of citrus fruits. In this study, Chinese propolis ethyl acetate extract (PEAE) was evaluated to control P. digitatum and P. italicum on postharvest citrus fruits. The results indicated PEAE strongly inhibited mycelia growth and induced hyphae prominent abnormal morphological alterations. Also, PEAE had strong detrimental effect on spore germination of the tested pathogens in a concentrationdependent manner. For in vivo tests, PEAE could both reduce decay caused by P. digitatum and P. italicum respectively in wound-inoculated fruit and naturally infected fruit; meanwhile, no negative influences on the overall quality of the citrus fruits were observed with PEAE treatment. Therefore, PEAE could be used as a natural antifungal agent to control citrus blue and green mold.

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Keywords :propolis ,citrus ,green mold ,blue mold ,antifungal activity.

Antioxidant and anticytokine effects of bovine colostrum in intestinal ischemia/reperfusion injured rat model

Oh Young Kwon, Jong Seok Lee, Han Sung Choi, Hoon Pyo Hong, Ki-Hyo Jang, Ji Hoon Paek, Soon Ah Kang, Young Gwan Ko

                                                                     

Abstract

The objective of this study was to examine antioxidant and anticytokine effects of bovine colostrum (BC) in an intestinal ischemia/reperfusion injured rat model. Forty Sprague-Dawley rats were induced intestinal ischemia/reperfusion injury. After reperfusion the rats were given BC, 0.9% saline or low fat milk (LFM) orally. The antioxidative activities using superoxide dismutase (SOD), glutathione peroxidase (GSH-PX), catalase (CAT), and malondialdehyde (MDA) were analyzed in this study. Serum cytokine levels [tumor necrosis factor (TNF)-α, interlukin (IL)-1β, IL-6, and IL-10] were also checked. SOD (1.53±0.23 U/mg of protein), GSH-PX (7.62±0.66 U/mg of protein), and CAT (42.16±3.16 U/mg of protein) activities increased and MDA level (0.58±0.05 mmol/mg of protein) decreased significantly in rats fed BC compared to rats fed saline or LFM (p<0.05). TNF-α (7.63±1.31 pg/mL), IL-1β (49.43±4.43 pg/mL), and IL-6 (62.85±7.60 pg/mL) in rats fed BC were significantly lower than saline or LFM (p<0.005), whereas there was no significant difference in IL-10 (220.3±22.06 pg/mL) between experimental groups. In conclusion, BC may have both antioxidative and anticytokine effects in an intestinal ischemia/reperfusion rat model.

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Keywords :anti-inflammation ,bovine colostrum ,cytokine ,antioxidant ,ischemia/reperfusion.

Relationships between sensory and instrumental hardness and the estimation of hardness specifications for commercial soybean curd

Bue-Young Imm, Jae-Yong Shim, Jee-Young Imm

                                                                 

Abstract

This study was carried out to determine the relationships between variations in sensory hardness intensities and hardness levels of soybean curd. There was no significant relationship between the relative standard deviation (RSD, %) and instrumental hardness data of 93 soybean curd samples, including 45 soft and 48 firm soybean curds, analyzed with a texture analyzer. However, a significant negative correlation (p<0.001) was found between RSD (%) of sensory hardness and hardness level for both trained panelists and consumers. This finding offers a reason for the higher frequency of consumer claims made on the hardness of soft soybean curd compared to that of hard soybean curd. Finally, the regression analysis of RSD (%) and sensory hardness can be used to determine hardness specifications for commercial soybean curds.

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Keywords :soybean curd ,ardness ,sensory ,relative standard deviation ,specification.

Microbial evaluation of minimally processed vegetables and sprouts produced in Seoul, Korea

Young-Ho Seo, Ji-Hyun Jang, Kwang-Deog Moon

                                                                      

Abstract

The aim of this study was to evaluate the microbial quality of some minimally processed vegetables. A total of 345 samples of minimally processed vegetables were acquired at a department store, a local supermarket, and a restaurant in Seoul, Korea. Samples were tested for microorganism distributions and for the presence of pathogenic bacteria. The aerobic mesophilic counts ranged between 2.0 and 9.7 log CFU/g, with the highest count recorded from the sprouts. Counts of psychrotrophic microorganisms were as high as those of the mesophilic microorganisms. Total coliform populations between 1.0 and 8.8 log CFU/g were found in 98.3% of the samples. Microbiological counts for fresh-cut fruits were very low. Sprouts were highly contaminated with microorganisms and showed a high incidence of Escherichia coli and Clostridium perfringence. Salmonella species and Listeria monocytogenes were detected in 1.5 and 0.3% of samples, respectively. E. Coli O157:H7 and Yersinia enterocolitica were not detected in any of the samples.

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Keywords :minimally processed vegetable ,sprout ,safety ,microorganism ,foodborne pathogen.

Ginsenoside 20(R)-Rg3 stimulates glucose uptake in C2C12 myotubes via CaMKK-AMPK pathways

Do Yeon Kim, Hai-Dan Yuan, Bo Huang, Hai-Yan Quan, Sung Hyun Chung

                                                                                          

Abstract

Based upon preliminary study showing stimulation of glucose uptake by 20(R)-Rg₃, a stereoisomer of 20(S)-Rg₃ ginsenoside found in red ginseng, we investigated the action mechanism of 20(R)-Rg₃ in differentiated C2C12 myotubes. It was found that 20(R)-Rg₃ stimulated translocation of glucose transporter 4 (GLUT4) and glucose uptake in a concentration-dependent manner. In addition, 20(R)-Rg₃ phosphorylated AMP-activated protein kinase (AMPK) and Ca²⁺/Calmodulin-dependent protein kinase kinase (CaMKK) in time- and concentration-dependent manners. In the meantime, 20(R)-Rg₃-induced glucose uptake and translocation of GLUT4 were attenuated in the presence of compound C (an AMPK inhibitor) or STO-609 (a CaMKK inhibitor). Taken together, this study is the first to demonstrate that 20(R)-Rg₃ stimulated the glucose uptake via translocation of GLUT4 and this effect was seemed to be mediated by CaMKK-AMPK pathways in C2C12 myotubes.

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Keywords :20(R)-ginsenoside Rg3 ,glucose uptake ,C2C12 myotube ,AMP-activated protein kinase ,Ca2+/Calmodulindependent protein kinase kinase.

Study on the flavor contribution of phospholipids and triglycerides to pork

Ye-Chuan Huang, Hong-Jun Li, Zhi-Fei He, Ting Wang, Gang Qin

                                                                               

Abstract

For investigating the flavor contribution of phospholipids and triglycerides to pork, the longissimusmuscle of Rongchang (RC) and PIC (bred by PIC Company of England) pig were selectively removed of intramuscular triglycerides or total intramuscular lipids. After cooking, the flavor of different samples was compared by sensory evaluation, gas chromatographymass spectrometry (GC-MS), and electronic nose. The results showed that removing triglycerides had little effect on the aroma of the cooked meat, but when total intramuscular lipids were removed a remarkable difference was observed. The control samples covaried strongly with some lipid-derived products, and the petroleum ether defatted samples also positively related to these compounds, but to a lesser extent, both of them negatively covaried with chloroform-methanol extracted samples which associated with some Maillard reaction products. Moreover the flavor difference between 2 breeds would decrease when triglycerides were removed, and reduce further when phospholipids and triglycerides were removed simultaneously. These results suggested that intramuscular lipids especially phospholipids contributed significantly to pork flavor, the flavor difference between 2 breeds resulted mainly from different intramuscular lipids content and composition.

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Keywords :pig ,triglycerides ,phospholipids ,flavor ,flavor difference.

Enhancement of immunostimulation and anti-metastasis in submerged culture of bearded tooth mushroom (Hericium erinaceum) mycelia by addition of ginseng extract

Hoon Kim, Jae-Hyeon Jeong, Jong-Hyun Hwang, Heon-Sang Jeong, Hyeon-Yong Lee, Kwang-Won Yu

                                                                           

Abstract

After bearded tooth mushroom (Hericium erinaceum) mycelia were cultivated in mushroom complete medium (MCM) supplemented with ginseng extract (GE, 65°Bx) to enhance immunostimulation and anti-metastasis, the submerged culture containing culture broth and mycelia was lyophilized (SC). Hot-water extract from SC cultivated in MCM supplemented with GE-5% (v/v, a ratio of MCM volume to GE, HE-GE-5-HW) showed significantly higher mitogenic activity (1.74 fold of the control) and IL-2 production (2.10 fold) than those of SC without GE (HEHW) at 100 μg/mL. The intestinal immune modulating activity was also obtained in HE-GE-5-HW (1.82 fold) whereas HE-GE-3-HW (GE-3%) had the most effective macrophage stimulation (1.88 fold) and tumor necrosis factor (TNF)-α production (3.59 fold). In addition, intravenous administration of HE-GE-3- and 5-HW significantly inhibited the experimental lung metastasis of colon 26-M3.1 cells (61.2 and 67.2%). HE-GE-5-HW mainly contained neutral sugar (72.0%) in addition to small amounts of protein (9.2%) and uronic acid (3.9%). Furthermore, the activities of the GE culture were high compared with the culture without GE, indicating that GE helped enhance the physiological activities of bearded tooth mushroom.

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Keywords :bearded tooth mushroom ,ginseng extract ,submerged culture ,immunostimulation ,anti-metastasis.

Antioxidant capacity and phenolic content of different solvent extracts from banana (Musa paradisiaca) and mustai (Rivea hypocrateriformis)

Nataraj Loganayaki, Dharmar Rajendrakumaran, Sellamuthu Manian

                                                                              

Abstract

In the present study, chloroform, acetone, and methanol extracts from stem and flower of banana (Musa paradisiaca) and leaves, stem, and flowers of mustai (Rivea hypocrateriformis) were evaluated for their in vitro antioxidant activity using ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picryl-hydrazyl (DPPH^•), 2,2′azinobis (3-ethylbenzothiozoline-6-sulfonic acid) diammonium salt (ABTS^•+), iron chelation, and antihemolytic activity. Among the solvents used, methanol gave the maximum yield in banana, whereas in night glory acetone was reported to having higher extractive value. The total phenolic content was also higher in these extracts. The antioxidant potential of the extracts was well established with their DPPH^• and ABTS^•+ radical scavenging activities and ferric reducing antioxidant capacity. The potential of multiple antioxidant activity of samples can be further evidenced by inhibition of reactive oxygen mediated erythrocyte cell lysis and metal ion chelating activity. However, this is the first report on the antioxidant property of mustai and this plant is having excellent antioxidant potential over banana. In conclusion, the results implied that the leaves, stem, and flowers of banana, and mustai could be considered as health supplements and nutraceuticals/functional foods.

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Keywords :mustai (Rivea hypocrateriformis) ,banana (Musa paradisiaca) ,ferric reducing antioxidant power (FRAP) ,antihemolytic activity.

Antidiabetic activity of nano powdered chitosan in db/db mice

Mi Hwa Seo, Ju Hyun Park, Hae-Soo Kwak

                                                                        

Abstract

Present study was carried out to examine effects of nanopowdered chitosan on antidiabetic activity in db/db mice. Twenty-eight 8-week-old mice were divided into 4 groups: (1) control, nondiabetic control mice; (2) group 1, diabetic control mice with not treated chitosans; (3) group 2, diabetic mice given 2% powdered chitosan; and (4) group 3, diabetic mice given 2% nanopowdered chitosan. The serum glucose in group 3 reduced by 56%, as compared to group 2 (28%). The total serum cholesterol in group 3 decreased by 31.6%, while group 2 reduced by 18.2%. Triglyceride was decreased by 33.6% in group 3 and by 22.5% in group 2. The insulin of group 2 and 3 were significantly increased by 51.7 and 92.9%, respectively. Only group 3 was recovered from the β-cell destruction. Based on the result of the study, it is suggested that nanopowdered chitosan has higher antidiabetic activities than powdered.

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Keywords :nanochitosan ,antidiabetic effect ,glucose ,total serum cholesterol ,triglyceride ,pancreatic islet.

Inhibition of heat resistant molds:Aspergillus fumigatus and Paecilomyces variotii by some plant essential oils

Tuncay Gumus, Ahmet Sukru Demirci, Osman Sagdic, Muhammet Arici

                                                                                          

Abstract

In this study, the inhibitory properties of some essential oils including citrus (Citrus sinensis L. Osbeck), laurel (Laurus nobilis L.), myrtle (Myrtus communis L.), oregano (Origanum vulgare L.), and savory (Satureja thymbra L.) were investigated against the heat resistant molds Aspergillus fumigatus and Paecilomyces variotii isolated from margarine in a previous study in order to assess the potential for using these essential oils as a natural food preservative. In this study, the essential oils of the plants were obtained by steam distillation using Clevenger apparatus and were tested for antifungal activities at 0.25, 0.50, and 1.00% concentrations. Inhibitory effects of the essential oils on the growth of the fungi followed the sequence: oregano=citrus>savory>laurel>myrtle. P. variotiiwas more resistant against the essential oils than A. fumigatus.

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Keywords :heat resistant fungi ,inhibition ,essential oil ,oregano ,citrus ,savory ,laurel ,myrtle.

Correlation of volatiles and fatty acids in thermally oxidized fatty acid model systems using statistical approaches

MinKyu Jeong, JaeMin Lee, Wan-Il Cho, JaeHwan Lee

                                                                                      

Abstract

Distributions of volatiles and fatty acids from thermally oxidized free fatty acids (FFA) at 93°C for 200 min were analyzed and results were statistically compared using principal component analysis (PCA) and multiple factor analysis (MFA). Mixtures of FFA were composed of linoleic (57.54%), oleic (29.99%), linolenic (5.10%), palmitic (2.95%), stearic (0.26%), and arachadic (1.68%) acids. As thermal oxidation increased for 200 min, peak areas of total volatiles increased from 0.497 to 1.619 (1×10⁷ ion counts), the ratio of unsaturated to saturated fatty acids decreased from 21.65 to 17.65, 3 kinds of pattern changes of fatty acids, and 5 types of pattern changes of volatiles were observed. First principal component (PC1) and second principal component (PC2) expressed 77.34 and 10.02% of the data variability for the fatty acids during oxidation, respectively and 73.09 and 15.66% for the headspace volatiles, respectively. PCA and MFA analyses on fatty acids and volatiles showed that 2-heptenal had the highest correlation with the changes of linoleic acid compared to other volatiles under current oxidation conditions.

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Keywords :volatile compound ,free fatty acid ,thermal oxidation ,headspace-solid phase microextration.

Effect of 1-monocaprin addition on the emulsion stability and the storage stability of mayonnaise

Kyung Min Park, Seung-Yong Lim, Myung Sub Chung, DongHyun Kang, Young Jin Choi, JaeHwan Lee, Pahn-Shick Chang

                                                                                    

Abstract

Emulsifiers are used in various industries, and the functional development of these emulsifiers is necessary. The objective of this study was to determine the effect of addition of 1-monocaprin on the emulsion stability and viscosity of mayonnaise as an index of storage stability. Mayonnaise made of soybean oil, egg yolk, sugar, salt, and vinegar was supplemented with 20, 40, 60, 80, and 100 ppm of 1-monocaprin. The effects of 1-monocaprin addition on storage stability and emulsion stability of mayonnaise were determined by observing changes in the average Δ-backscattering flux (%) after storage at 60°C for 24 hr. The viscosity of each sample was also measured. Mayonnaise containing 60 ppm of 1-monocaprin had the highest emulsion stability followed in order by mayonnaise containing 40, 20, 80, and 100 ppm 1-monocaprin. Analysis showed that apparent viscosity decreased at a slower rate with higher 1-monocaprin concentrations. From the above results, it could be concluded that the optimal concentration of 1-monocaprin added to mayonnaise for the emulsion stability and the storage stability was 60 ppm.

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Keywords :mayonnaise ,storage stability ,viscosit,emulsion stability index ,1-monocaprin.

Combined effects of heating and γ-irradiation on the microbiological and sensory characteristics of Gochujang(Korean fermented red pepper paste) sauce during storage

Jae-Nam Park, Jin-Gyu Park, In-Jun Han, Beom-Seok Song, Jong-il Choi, Jae-Hun Kim, Hee-Sook Sohn, Ju-Woon Lee

                                                                                            

Abstract

This study was conducted to evaluate the combined effect of heating and γ-irradiation on the microbiological and sensory characteristics of gochujang sauce. Gochujang sauces could be sterilized by heating (HT: 121°C for 15 min) or γ-irradiation (IR: 30 kGy), but their sensory qualities were severely decreased. Otherwise, the combined treatment of heat and γ-irradiation could minimize the change of sensory qualities. Combination treatment of γ-irradiation at 17.5 kGy after heating at 100°C for 30 min (HT-IR) would be optimal. During storage the gochujang sauce samples then were analyzed to enumerate total bacterial populations, to measure pH, and Hunter’s color values, and for sensory evaluation. Any growth of total bacterial populations was not observed in HT, IR, and HT-IR (detection limited 1< log CFU/g). The pH values of gochujang sauce ranged from 4.57 to 4.75 during storage. The Hunter’s (L*, a*, and b*) values of gochujang sauce were gradually decreased during storage, regardless of treatment. Sensory characteristics and acceptance of HT and IR were significantly lower (p<0.05) than those of non-treated control and HT-IR, but there was no difference (p⩾0.05) among non-treated control and HT-IR.

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Keywords :gochujang sauce ,heat treatment ,γ-irradiation ,combined effect ,shelf stability.

Application of an in situ bismuth-coated glassy carbon electrode for electroanalytical determination of Cd (II) and Pb (II) in Korean polished rices

Hak-Jin Kim, Dong-Wook Son, Jong-Min Park, Dae Youn Hwang, Chang-Youn Mo, Sang-Won Park, Giyoung Kim, Jong-Bang Eun

                                                                                 

Abstract

Rapid on-site monitoring of heavy metals in plants is necessary to minimize the exposure of humans to the contaminated food. The potential of using anodic stripping voltammetry (ASV) for simultaneous determination of cadimium (Cd) and lead (Pb) in rice was evaluated. Eight different Korean polished rices were digested using concentrated HNO₃ solution in a microwave oven. The peak currents measured with an in situ bismuth-coated electrode were linearly proportional to Cd and Pb concentrations (1.5 to 200 ppb) in 0.1 M HNO₃ (R² ⩾0.98). The electrode was feasible for measuring Pb in acid digests of the tested polished rices with measurement errors of <16.3 ppb. However, even though there was acceptable agreement in 4 of the 8 samples tested for Cd between the ASV and inductively coupled argon plasma (ICP) methods, further studies would be needed to improve the predictive capability of the electrode while reducing the variability in measurement and lowering the detection limit.

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Keywords :heavy metal ,rice ,bismuth ,anodic stripping voltammetry (ASV) ,microwave digestion.