Detection of Zygosaccharomyces rouxii and Candida tropicalis in a High-Sugar Medium by a Metal Oxide Sensor–Based Electronic Nose and Comparison with Test Panel Evaluation

2015 ◽  
Vol 78 (11) ◽  
pp. 2052-2063 ◽  
Author(s):  
HUXUAN WANG ◽  
ZHONGQIU HU ◽  
FANGYU LONG ◽  
CHUNFENG GUO ◽  
YAHONG YUAN ◽  
...  
Keyword(s):  
Electronic Nose ◽  
Candida Tropicalis ◽  
Solid Phase ◽  
Reference Method ◽  
Test Panel ◽  
Zygosaccharomyces Rouxii ◽  
High Sugar ◽  
Yeast Strains ◽  
Total Yeast ◽  
Panel Evaluation

Osmotolerant yeasts are primarily responsible for spoilage of sugar-rich foods. In this work, an electronic nose (e-nose) was used to diagnose contamination caused by two osmotolerant yeast strains (Zygosaccharomyces rouxii and Candida tropicalis) in a high-sugar medium using test panel evaluation as the reference method. Solid-phase microextraction gas chromatography with mass spectrometry (GC-MS) was used to determine the evolution of the volatile organic compound fingerprint in the contaminated samples during yeast growth. Principal component analysis and linear discriminant analysis revealed that the e-nose could identify contamination after 48 h, corresponding to the total yeast levels of 3.68 (Z. rouxii) and 3.09 (C. tropicalis) log CFU/ml. At these levels, the test panel could not yet diagnose the spoilage, indicating that the e-nose approach was more sensitive than the test panel evaluation. Loading analysis indicated that sensors 8 and 6 were the most important for detection of these two yeasts. Based on the result obtained with the e-nose, the incubation time and total yeast levels could be accurately predicted by established multiple regression models with a correlation of greater than 0.97. In the sensory evaluation, spoilage was diagnosed after 72 h in samples contaminated with C. tropicalis and after 48 to 72 h for samples contaminated with Z. rouxii. GC-MS revealed that compounds such as acetaldehyde, acetone, ethyl acetate, alcohol, and 3-methyl-1-butanol contributed to spoilage detection by the e-nose after 48 h. In the high-sugar medium, the e-nose was more sensitive than the test panel evaluation for detecting contamination with these test yeast strains. This information could be useful for developing instruments and techniques for rapid scanning of sugar-rich foods for contamination with osmotolerant yeasts before such spoilage could be detected by the consumer.

Solid-phase radioimmunoassay of human complement fragment C5a.

1988 ◽  
Vol 34 (6) ◽  
pp. 1018-1021 ◽  
Author(s):  
S Chang ◽  
A Leo-Mensah ◽  
J Campbell ◽  
M Stastny ◽  
R A Patrick
Keyword(s):  
Incubation Time ◽  
Solid Phase ◽  
Biological Fluids ◽  
Reference Method ◽  
Human Complement ◽  
Analytical Recovery ◽  
Solid Phase Radioimmunoassay

Abstract In this competitive RIA for determining concentrations of human C5a in biological fluids and in buffers, labeled C5a and sample are allowed to compete for binding to a limited amount of goat antibody to human C5a in solution. Free and bound tracer are then separated by a second antibody (rabbit anti-goat IgG) immobilized on paramagnetic particles. Total incubation time for this assay is 70 min. Sensitivity, precision, and analytical recovery of this assay compare well with those of a reference method.

scholarly journals Discrimination of Volatiles of Shiitakes (Lentinula edodes) Produced during Drying Process by Electronic Nose

2020 ◽  
Vol 16 (1-2) ◽  
Author(s):  
Hui Zhang ◽  
Jing Peng ◽  
Yu-ren Zhang ◽  
Qiang Liu ◽  
Lei-qing Pan ◽  
...  
Keyword(s):  
Electronic Nose ◽  
Lentinula Edodes ◽  
Solid Phase ◽  
Principal Component ◽  
Gas Chromatography Mass Spectrometry ◽  
Support Vector ◽  
Drying Process ◽  
Drying Time ◽  
Discriminant Models ◽  
Accuracy Rates

AbstractThis study aimed to investigate the potential of electronic nose (E-nose) to differentiate volatiles of shiitakes produced at different drying stages. Shiitakes at different drying time slots were categorized into four groups (fresh, early, middle and late stage) by sensory evaluation. E-nose was used to analyze the volatiles and compared with headspace solid phase micro-extraction combined with gas chromatography-mass spectrometry (HS/GC-MS). The principal component analysis results showed that shiitakes at each stage could be successfully discriminated by E-nose and HS/GC-MS. The differences in volatile organic compounds produced at each stage were mainly caused by sulfurs and alcohols, leading to apparent changes of sensors sensitive to sulfurs, alcohols and aromatic compounds. The discriminant models were established by partial least squares discriminant analysis and support vector machine classification, with accuracy rates of 91.25 % and 95.83 %, respectively. The results demonstrated the potential use of E-nose in classifying and monitoring shiitakes during drying process.

scholarly journals Comparison of flavour fingerprint, electronic nose and multivariate analysis for discrimination of extra virgin olive oils

2019 ◽  
Vol 6 (3) ◽  
pp. 190002
Author(s):  
Qi Zhou ◽  
Shaomin Liu ◽  
Ye Liu ◽  
Huanlu Song
Keyword(s):  
Multivariate Analysis ◽  
Electronic Nose ◽  
Corn Oil ◽  
Solid Phase ◽  
Partial Least Square ◽  
Least Square ◽  
Gas Chromatography Mass Spectrometry ◽  
Virgin Olive Oils ◽  
Olive Oils ◽  
Coefficient Method

Flavour is a special way to discriminate extra virgin olive oils (EVOOs) from other aroma plant oils. In this study, different ratios (5, 10, 15, 20, 30, 50, 70 and 100%) of peanut oil (PO), corn oil (CO) and sunflower seed oil (SO) were discriminated from raw EVOO using flavour fingerprint, electronic nose and multivariate analysis. Fifteen different samples of EVOO were selected to establish the flavour fingerprint based on eight common peaks in solid-phase microextraction–gas chromatography–mass spectrometry corresponding to 4-methyl-2-pentanol, ( E )-2-hexenal, 1-tridecene, hexyl acetate, ( Z )-3-hexenyl acetate, ( E )-2-heptenal, nonanal and α-farnesene. Partial least square discrimination analysis (PLS-DA) was used to differentiate EVOOs and mixed oils containing more than 20% of PO, CO and SO. Furthermore, better discrimination efficiency was observed in PLS-DA than PCA (70% of CO and SO), which was equivalent to the correlation coefficient method of the fingerprint (20% of PO, CO and SO). The electronic nose was able to differentiate oil samples from samples containing 5% mixture. The discrimination method was selected based on the actual requirements of quality control.

scholarly journals Instrumental measurement of odour nuisance in city agglomeration using electronic nose

2018 ◽  
Vol 28 ◽  
pp. 01012 ◽  
Author(s):  
Bartosz Szulczyński ◽  
Tomasz Dymerski ◽  
Jacek Gębicki ◽  
Jacek Namieśnik
Keyword(s):  
Electronic Nose ◽  
Sewage Treatment ◽  
Sewage Treatment Plant ◽  
Treatment Plant ◽  
Reference Method ◽  
Monitoring Network ◽  
Ambient Air ◽  
Processing Plant ◽  
Production Plant ◽  
Oil Processing

The paper describes an operation principle of odour nuisance monitoring network in a city agglomeration. Moreover, it presents the results of investigation on ambient air quality with respect to odour obtained during six-month period. The investigation was carried out using a network comprised of six prototypes of electronic nose and Nasal Ranger field olfactometers employed as a reference method. The monitoring network consisted of two measurement stations localized in a vicinity of crude oil processing plant and four stations localized near the main emitters of volatile odorous compounds such as sewage treatment plant, municipal landfill, phosphatic fertilizer production plant. The electronic nose prototype was equipped with a set of six semiconductor sensors by FIGARO Co. and one PID-type sensor. The field olfactometers were utilized for determination of mean concentration of odorants and for calibration of the electronic nose prototypes in order to provide their proper operation. Mean monthly values of odour concentration depended on the site of measurement and on meteorological parameters. They were within 0 – 6.0 ou/m3 range. Performed investigations revealed the possibility of electronic nose instrument application as a tool for monitoring of odour nuisance.

scholarly journals Characterization and Discrimination of Chinese Marinated Pork Hocks by Volatile Compound Profiling Using Solid Phase Microextraction Gas Chromatography-Mass Spectrometry/Olfactometry, Electronic Nose and Chemometrics

Molecules ◽  
2019 ◽  
Vol 24 (7) ◽  
pp. 1385 ◽  
Author(s):  
Dong Han ◽  
Si Mi ◽  
Chun-Hui Zhang ◽  
Juan Li ◽  
Huan-Lu Song ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Electronic Nose ◽  
Solid Phase Microextraction ◽  
Solid Phase ◽  
Principal Component ◽  
Gas Chromatography Mass Spectrometry ◽  
Active Compounds ◽  
Volatile Constituents ◽  
Chromatography Mass Spectrometry

The primary aim of this study was to investigate volatile constituents for the differentiation of Chinese marinated pork hocks from four local brands, Dahongmen (DHM), Daoxiangcun (DXC), Henghuitong (HHT) and Tianfuhao (TFH). To this end the volatile constituents were evaluated by gas chromatography-mass spectrometry/olfactometry (GC-MS/O), electronic nose (E-nose) and chemometrics. A total of 62 volatile compounds were identified and quantified in all pork hocks, and 24 of them were considered as odour-active compounds because their odour activity values (OAVs) were greater than 1. Hexanal (OAV at 3.6–20.3), octanal (OAV at 30.3–47.5), nonanal (OAV at 68.6–166.3), 1,8-cineole (OAV at 36.4–133.3), anethole (OAV at 5.9–28.3) and 2-pentylfuran (OAV at 3.5–29.7) were the key odour-active compounds contributing to the integral flavour of the marinated pork hocks. According to principal component analysis (PCA) and partial least squares-discriminant analysis (PLS-DA) of GC-MS/O and E-nose data, the results showed that the marinated pork hocks were clearly separated into three groups: DHM, HHT, and DXC-TFH. Nine odour-active compounds, heptanal, nonanal, 3-carene, d-limonene, β-phellandrene, p-cymene, eugenol, 2-ethylfuran and 2-pentylfuran, were determined to represent potential flavour markers for the discrimination of marinated pork hocks. This study indicated the feasibility of using GC-MS/O coupled with the E-nose method for the differentiation of the volatile profile in different brands of marinated pork hocks.

Growth Properties and Gas Formation by Yeasts Isolated from Processed Fruits in Media with Various Brix Values and Sorbic Acid Contents

1992 ◽  
Vol 55 (3) ◽  
pp. 192-197 ◽  
Author(s):  
ERICH MAIMER ◽  
MARTIN BUSSE
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Candida Parapsilosis ◽  
Sorbic Acid ◽  
Torulaspora Delbrueckii ◽  
Zygosaccharomyces Rouxii ◽  
Gas Formation ◽  
Yeast Strains ◽  
Growth Properties ◽  
Short Time

Growth and gas formation by Saccharomyces cerevisiae (2 strains), Zygosaccharomyces rouxii (2 strains), Hansenula fabianii (2 strains), Torulaspora delbrueckii (1 strain), and Candida parapsilosis (1 strain) were studied in homogenized processed strawberries. These strawberries had 15, 30, 45, and 55° Brix in combination with 0, 50, 100, 200, 400, and 600 ppm sorbic acid. Z. rouxii showed the highest tolerance for sorbic acid, followed by S. cerevisiae and T. delbrueckii; these strains also produced gas within a short time. The highest osmotolerance was observed for Z. rouxii. Processed fruits with 55° Brix and 200 ppm sorbic acid or with 45° Brix and ≥400 ppm sorbic acid did not allow growth and gas formation by any of the yeast strains.

Detection, Isolation and Identification of Osmotolerant Yeasts from High-Sugar Products

1987 ◽  
Vol 50 (6) ◽  
pp. 468-472 ◽  
Author(s):  
MARCO F. G. JERMINI ◽  
OTTO GEIGES ◽  
WILHELM SCHMIDT-LORENZ
Keyword(s):  
Yeast Extract ◽  
Enrichment Culture ◽  
Debaryomyces Hansenii ◽  
Yeast Cells ◽  
Isolation And Identification ◽  
Torulaspora Delbrueckii ◽  
Enrichment Medium ◽  
Zygosaccharomyces Bailii ◽  
Zygosaccharomyces Rouxii ◽  
High Sugar

A simple presence-absence test for detection of small numbers of osmotolerant yeasts in foods was developed. Yeast extract glucose 50 broth [consisting of 0.5% (w/w) yeast extract and 50% (w/w) glucose] was used as enrichment medium and was incubated with agitation at 30°C. The detection was done by (a) microscope and (b) streaking 0.03 ml of enrichment culture on selective yeast extract glucose 50 agar and incubation at 30°C for 5–7 d. If no yeast cells were observed under the microscope within 10 d of incubation, the product sample was judged as “free from osmotolerant yeasts.” In accordance with this method 28 strains of osmotolerant yeasts were isolated from 27 spoiled high-sugar products. Twenty-four strains were identified as Zygosaccharomyces rouxii, 2 Zygosaccharomyces bailii and 1 each as Torulaspora delbrueckii and Debaryomyces hansenii.

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