Bong Soo Noh

Listeria monocytogenes inhibition by defatted mustard meal-based edible films

An antimicrobial edible film was developed from defatted mustard meal (Sinapis alba) (DMM), a byproduct from the bio-fuel industry, without incorporating external antimicrobials and its antimicrobial activity against Listeria monocytogenes and physical properties were investigated. The DMM colloidal solution consisting of 184 g water, 14 g DMM, and 2g glycerol was homogenized and incubated at 37°C for 0.2, 0.5, 24 or 48 h to prepare a film-forming solution. The pH of a portion of the film-forming solution (pH 5.5) was adjusted to 2.0 or 4.0. Films were formed by drying the film-forming solutions at 23°C for 48 h. The film-forming solution incubated for 48 h inhibited L. monocytogenes in broth and on agar media. Antimicrobial effects of the film prepared from the 48 h-incubated solution increased with decrease in pH of the solution from 5.5 to 2.0. The film from the film forming solution incubated for 48 h (pH 2.0) initially inhibited more than 4.0 log CFU/g of L. monocytogenes inoculated on film-coated salmon. The film-coating retarded the growth of L. monocytogenes in smoked salmon at 5, 10, and 15°C and the antimicrobial effect during storage was more noticeable when the coating was applied before inoculation than when it was applied after inoculation. The tensile strength, percentage elongation, solubility in watercxu, and water vapor permeability of the anti microbial film were 2.44 ± 0.19 MPa, 6.40 ± 1.13%, 3.19 ± 0.90%, and 3.18 ± 0.63 gmm/kPa hm(2), respectively. The antimicrobial DMM films have demonstrated a potential to be applied to foods as wraps or coatings to control the growth of L. monocytogenes.

Analysis of aroma compounds of commercial cider vinegars with different acidities using SPME/GC-MS, electronic nose, and sensory evaluation

Aroma compounds of commercial cider vinegars according to their acidity (low, moderate, double-strength, and triple-strength) were comparatively investigated. SPME/GC-MS analysis revealed 8 types of aroma compounds commonly existing in the vinegar including acetic acid. A cider vinegar with moderate acidity showed the most volatile profiles. Electronic nose analysis suggested that the peak at 0.40 s was a component related to total acidity of vinegar. Principal component analysis enabled e-nose to discriminate easily by presenting the separated position depending on total acidity. Significant differences with the acidity were observed in the pungent odor intensity and odor preference. According to the results, the moderate acidity vinegar was revealed to retain most volatile profiles and sensory odor. Compared to sensory evaluation, the analysis using SPME/GC-MS and e-nose provided more distinct patterns on their volatile compounds depending on their acidity, which might be a potential tool in determining the volatile profiles of cider vinegars.

Discrimination of the Origin of Commercial Red Ginseng Concentrates Using LC-MS/MS and Electronic Nose Analysis Based on a Mass Spectrometer

The geographical origin of commercial red ginseng concentrates was studied using LC-MS/MS and electronic nose analysis based on mass spectrometry. For LC-MS/MS, the Ra1, Rb1, Rg2 ginsenosides showed large differences between Korean and Chinese varieties. Rh2 and F2 were found only in Chinese red ginseng concentrate. Ion fragments were obtained using an electronic nose. Discriminant function analysis of fragment patterns allowed grouping into Korean, Chinese, and suspect origin concentrates. The mixing ratios of suspect origin specimens were predicted based on analysis of different mixing ratios of known specimens of Korean and Chinese origin. LC-MS/MS and electronic nose analysis together allowed method advantages and disadvantages to complement and compensate.

Analysis of Geographical Origin of Red Ginseng Extract Using Mass Spectrometer-based Electronic Nose

The geographical origin of red ginseng extract (RGE) was studied using a mass spectrometry based electronic nose. Imported RGE and domestic RGE were diluted to 12 o Bx. The treated RGE was analyzed, and discriminant function analysis (DFA) was used for discriminating of geographical origins. The DFA plots indicated a significant separation of imported RGE and domestic RGE. The F-value of discriminant function first score (DF1) was much higher than that of discriminant function second score (DF2), indicating that discrimination was mainly affected by DF1. Based on DF1, the concentration of domestic RGE to imported RGE shifted to the left side of DFA plot, and the mixing ratio highly correlated to DF1 value. Unknown sample (#2) was closely located to the sample of mixed imported : domestic (6:4) RGE. In the bar graph, the DF1 value correlated to the mixing ratio. Unknown samples (#2) were thought to be mixed with the imported RGE. This technique could be used to efficiently differentiate the geographical origin of RGE.

Flavor Analysis of Commercial Korean Distilled Spirits using an Electronic Nose and Electronic Tongue

Department of Food Science and Technology, Korea Christian UniversityAbstract The objective of this study was to analyze the flavor patterns of commercial Korean distilled spirits using amass spectrometry-based electronic nose and an electronic tongue. Thirteen types of domestic distilled spirits were usedfor analysis. The flavor patterns of the distilled spirits were clearly identified through discriminant function analysis of theraw materials. The obtained data of the electronic nose analysis showed that the flavor pattern of the distilled spirits agedin oak barrels was not significantly different from that of the general distilled spirits. According to the results of theelectronic tongue, the distilled spirits made with rice had a stronger flavor than those made with foxtail millet. Comparedto the sensitivity value of each taste sensor, the distilled spirits showed various intensities of sourness and umami.Therefore, an electronic nose and electronic tongue could be successfully used for quality evaluation and new productdevelopment of distilled spirits.Keywords: electronic nose, electronic tongue, distilled spirits, flavor analysis

Analysis of Mitochondrial DNA Sequence and Molecular Marker Development for Identification of Panax Species

This study describes the identification of Panax species using mitochondrial consensus primers. Initially, a total of thirty primers were tested in ten Korean ginseng cultivars and two foreign Panax species, P. quinquefolius and P. notoginseng. In the polymerase chain reaction (PCR) amplification results, three primers (cox1, nad1/2-3 and nad2/1-2) generated co-dominant polymorphic banding patterns discriminating Korean ginseng cultivars from P. quinquefolius and P. notoginseng. However, these primers could not generated polymorphisms among the Korean ginseng cultivars, and simply represented species-specific polymorphisms for P. quinquefolius and P. notoginseng. Primers PQ91 and PN418 were designed from the consensus sequence of nad1/2-3 region. Two banding patterns (A or B) were detected in PQ91. Korean ginseng cultivars and P. notoginseng shared the same banding pattern (A type) and P. quinquefolius was identified another banding pattern (B type). In the case of PN418, two banding patterns (A or B) were detected in the Korean ginseng cultivars and two foreign Panax species. Korean ginseng cultivars and P. quinquefolius shared the same banding pattern (A type) and P. notoginseng was identified another banding pattern (B type). The combination banding patterns of three Panax species, Korean ginseng cultivars (Panax ginseng C. A. Mey.), P. quinquefolius and P. notoginseng, was identified as `AA`, `BA` and `AB`, respectively. Consequently, PQ91 and PN418 primer sets can be used to distinguish among Panax species.

Comparison of volatile compounds from vegetable oils under light emitting diode irradiation using MS-based electronic nose

The objective of this study is to analyze volatile compounds from different types of vegetable oils under light emitting diode (LED) irradiation during 12 weeks. Yellow, red, blue, and fluorescent light were treated by LED equipment. Samples stored under dark conditions were also conducted at the same time. A MS-based electronic nose and discriminant function analysis (DFA) were used to determine the amount of volatiles from various oils under LED irradiation. As the exposure time of LED treatment increased, volatile compounds in sesame oil and perilla oil increased considerably under blue light. Under fluorescent, red, and yellow light, the volatile compounds from extra virgin olive oil increased significantly.

Analysis of Off-flavor Generated from a Polyethylene Terephthalate Water Bottles and Caps by Using an Electronic Nose

The objective of the study was to investigate the off-flavor generated from PET water bottles and their caps by using a mass spectrometry-based electronic nose. The ion fragment data obtained from the electronic nose were used for discriminant function analysis (DFA). In the case of increased concentrations of the contamination of water, the off-flavor pattern depended on the discriminant function second score instead of the discriminant function first score. To identify the cause of off-flavor in polyethylene terephthalate (PET) bottled water, the PET bottle and its cap were analyzed by DFA. The results showed that the cap generated more volatile compounds than the bottle or mineral water did. The substances causing the off-flavor were predicted to be 2,4-di-tert-butylphenol (2,4-DTBP), nonanal, and decanal when the main peak of the mass spectrum was compared with the major ion fragments of the electronic nose. Thus, using this method, we could determine whether the PET water bottle was contaminated and whether the off-flavor resulted from contamination of the bottle cap.

Physicochemical properties and volatile components of wine vinegars with high acidity based on fermentation stage and initial alcohol concentration

High acidity vinegar using grape concentrate was manufactured by fed-batch fermentation without additional chemical nutrients. Physicochemical properties and volatile components were investigated at different wine vinegar fermentation stages (stages 1–4) and at different initial alcohol concentrations (IAC, 6–9%). Acetic acid production showed a high yield and a rapid increase with an IAC=6%. The contents of reducing sugar, free amino acids, total phenolics, and overall volatiles increased during stage 4 (high acidity vinegar) most likely due to addition of a feeding solution. High acidity vinegar produced using a fed-batch culture at an IAC of 6% is a source of functional constituents with improved physicochemical and volatile properties, compared to moderate acidity vinegar.

Authentication of Rapeseed Oil Using an Electronic Nose Based on Mass Spectrometry

To determine mixing ratios for mixtures of rapeseed oil and other oils, an electronic nose (E-nose) based on a mass spectrometer system was used. Rapeseed oil was blended with soy bean oil or corn oil at ratios of 100:0, 97:3, 94:6, 91:9, 88:12, 85:15, and 80:20, respectively. The intensities of each fragment from the mixed rapeseed oil by E-nose based on MS were completely different from those of the soy bean oil and corn oil. The obtained data were used for discriminant function analysis (DFA). DFA plots indicated a significant separation of pure rapeseed oil and soy bean oil or corn oil and their mixtures. The added concentration of soy bean oil or corn oil to rapeseed oil was highly correlated to the first discriminant function score (DF1). When soy bean oil was added to rapeseed oil, it was possible to predict the following equation: DF1