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Daegu, South Korea

Lee S.-W.,Kyungpook National University | Yoon S.-R.,Biohealth Convergence Center | Kim G.-R.,Kyungpook National University | Woo S.-M.,Keimyung University | And 4 more authors.
Food Science and Biotechnology | Year: 2012

The effects of different nuruk contents and fermentation methods (AV, vinegar fermented in an agitated culture; SV, vinegar fermented in a static culture) on organic acids and volatile compounds in brown rice vinegars were investigated. In the SV, the contents of acetic, oxalic, tartaric, and malic acids increased with hipher contents of nuruk. Acetic, tartaric, and malic acid contents were higher in the SV than those in the AV. Volatile compounds that can affect vinegar quality, including acetic acid, isoamyl acetate, phenethyl acetate, and phenethyl alcohol were present at high concentrations in the AV. With the increase in nuruk contents in the AV, acetic acid content decreased and isoamyl acetate and phenethyl acetate content increased. No significant differences in sensory scores were observed regarding the amount of nuruk and the type of fermentation. However, electronic-nose analysis showed its potential to effectively differentiate different samples. © 2012 The Korean Society of Food Science and Technology and Springer Netherlands.

Akram K.,Kyungpook National University | Ahn J.-J.,Kyungpook National University | Yoon S.-R.,Biohealth Convergence Center | Kim G.-R.,Kyungpook National University | Kwon J.-H.,Kyungpook National University
Postharvest Biology and Technology | Year: 2012

Quality attributes (appearance, color, texture, weight, and volatile compounds) of irradiated (0, 1, 2, and 3) king oyster (Pleurotus eryngii) mushrooms, packed in polystyrene trays and covered with polyvinylchloride (PVC) film, were evaluated over a storage period of 4 weeks at 5 ± 1 °C. Hunter L values (lightness) increased upon irradiation and remained high throughout the storage period in 1. kGy-irradiated samples, whereas a values showed a slight decrease, and b values exhibited an increasing trend following irradiation. Mushroom texture decreased in firmness with increasing dose, but 1. kGy-irradiated samples maintained an overall better texture than all other samples. A similar trend was observed for weight loss during storage. The control samples developed mold, whereas 3. kGy-irradiated mushrooms were soft at the 3rd week of storage. Scanning electron microscopy showed micro-structural changes in the irradiated samples, which were probably the cause for increased weight loss and poor texture at the high 3. kGy dose. A principal component analysis of E-nose data showed dose-dependent differences in volatile profiles of all samples. Irradiation at 1. kGy was most effective for the extension of postharvest storage with added advantages. © 2011 Elsevier B.V..

Hong J.-H.,Catholic University of Daegu | Jung H.K.,Biohealth Convergence Center
Journal of the Korean Society for Applied Biological Chemistry | Year: 2014

β-Glucan isolated from cell wall of fungi not only has low purity and yield, but also causes adverse effects. Consequently, extracellular β-glucan produced by microorganisms is the focus of this study. β-Glucan-rich exopolysaccharides (G-EPSs) with different molecular weights from Paenibacillus polymyxa JB115 were prepared by ultrafiltration and spray-drying. The weight-average molecular masses of the G-EPSs, P-SD-1 (spray-dried G-EPSs powder prepared below 100 kDa) and P-SD-2 (spray-dried G-EPSs powder prepared above 100 kDa), were 7.084×104 and 9.235×105 g/mol, respectively. β-Glucan content was 47.38% in P-SD-1 and 73.12% in P-SD-2. The hydroxyl radical- and superoxide radicalscavenging activities of P-SD-2 at 1 mg/mL (39.45 and 87.34%, respectively) were higher than those of P-SD-1 (30.32 and 53.06%, respectively). Maximal nitric oxide (22.24±1.34 μM) was generated in the presence of P-SD-2 (1 mg/mL) and the antitumor activity of P-SD-2 was higher than P-SD-1 in four tumor cell lines (HeLa, Sarcoma 180, A549, and Hep3B cells). Thus, antioxidant and antitumor activities could be enhanced by regulating the molecular weight of G-EPSs. We anticipate that the food and medicinal use of G-EPSs will follow further characterization of this class of exopolysaccharides. © 2014 The Korean Society for Applied Biological Chemistry.

Jeong Y.S.,Biohealth Convergence Center | Jung H.K.,Biohealth Convergence Center | Hong J.-H.,Catholic University of Daegu
Journal of the Korean Society of Food Science and Nutrition | Year: 2013

We investigated the protective effect of UVB inducing photodamage from mulberry extract (ME) and Lithospermum erythrorhizon extract (LE). The contents of total anthocyanin and shikonin as a color compound of ME and LE were 4.92 mg/g and 9.58 mg/g, respectively. The electron donating ability and superoxide radical scavenging activity of ME were 84.32% and 76.34%, respectively. The oxygen radical absorbance capacity of the ME (545.37 μmoles TE/g) was higher than LE (427.18 μmoles TE/g). MMP-1 production in the HS68 cells were exposed to UVB suppressed by treatment with 200 μg/mL of ME (68.6%) and LE (32.7%). ME and LE were applied to a skin aging mouse model, which was induced by the irradiation of UVB to the backs of hairless mice. The value of skin erythema index, wrinkle depth and thickness, epidermis thickness, and collagenous fiber damage in the experiment groups (MEL: ME 3%, MEM: ME 5%, MEH: ME 7%, LEL: LE 3%, LEM: LE 5%, LEH: LE 7%) were remarkably reduced than in the control group (only UVB exposure group), while water capacity increased. The level of total wrinkles depth in the skin was decreased to be 30% of the control group by MEH and LEM. These results suggest that ME and LE are useful cosmetic materials for skin protection against UVB-inducing.

Jeong Y.S.,Biohealth Convergence Center | Jung H.K.,Biohealth Convergence Center | Hong J.-H.,Catholic University of Daegu
Journal of the Korean Society for Applied Biological Chemistry | Year: 2013

This study presented a multiplex, single-tube, realtime polymerase chain reaction (RTi-PCR) approach for detecting Staphylococcus aureus, Vibrio parahaemolyticus, and Salmonella typhimurium, three of the more frequent foodborne pathogenic bacteria typically investigated in a variety of foods. New primer sequences were designed for detection of specific gene fragments in the 23s ribosomal RNA, transmembrane transcription regulator, and replication origin sequences of S. aureus, V. parahaemolyticus, and S. typhimurium. Simultaneous amplifications were performed under the optimized reaction conditions. Melting curve analysis using SYBR Green I RTi-PCR analysis produced characteristic Tm values for each target amplicon, demonstrating specific and efficient amplification of the three fragments. Addition of an internal amplification control did not affect detection sensitivity for the target pathogen. The analysis of frequent foodborne pathogenic bacteria in artificially inoculated food demonstrated analytical sensitivity for direct detection of each pathogen using the Chelex method rather than a commercial DNA extraction kit. The assay was sensitive to 103 colony-forming units (CFU)/reaction. With enrichment (2 or 4 h), each species could be detected at 101 CFU/g. These results provided that RTi-PCR is a rapid and costeffective procedure to detect foodborne pathogens. This assay could become a valuable tool for routine microbiological analysis in the food industry. © 2013 The Korean Society for Applied Biological Chemistry.

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