The Experts below are selected from a list of 252 Experts worldwide ranked by ideXlab platform
Konstantinos Gkatzionis - One of the best experts on this subject based on the ideXlab platform.
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study of the influence of yeast inoculum concentration yarrowia lipolytica and kluyveromyces lactis on Blue Cheese aroma development using microbiological models
Food Chemistry, 2014Co-Authors: Elliott J Price, Konstantinos Gkatzionis, Louise Hewson, Joanne Hort, Robert S. T. Linforth, Christine E. R. Dodd, Carol A PhillipsAbstract:Yarrowia lipolytica and Kluyveromyces lactis occur as part of Stilton Cheese microflora yet are not controlled during production. This study investigated the influence of their inoculum concentration on aroma production. Models of Y. lipolytica and K. lactis, with Penicillium roqueforti, were analysed using instrumental and sensory analysis. Different concentrations of Y. lipolytica produced important changes in the aroma profiles of microbiological models, analysed by solid-phase microextraction (SPME GC–MS). Sensory analysis with discrimination tests showed differences were detectable via human perception but did not concern the similarity to Blue Cheese odour. Increasing the inoculum concentration of K. lactis resulted in decreased variation between replicates. Partial least squares (PLS) regression on Flash profile data showed models inoculated with low concentrations of K. lactis exhibited Blue Cheese-related attributes, associated with increased ketone production. Results suggest that controlling the amount of Y. lipolytica and K. lactis during production offers potential to manipulate Blue Cheese aroma development.
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Effect of Yarrowia lipolytica on Blue Cheese odour development: Flash profile sensory evaluation of microbiological models and Cheeses
International Dairy Journal, 2013Co-Authors: Konstantinos Gkatzionis, Louise Hewson, Joanne Hort, Tracey Hollowood, Christine E. R. Dodd, Robert S. T. LinforthAbstract:Abstract Yarrowia lipolytica is among the most frequently occurring species in the secondary flora of Blue Cheeses. This organism produces a range of important aroma compounds for Blue Cheese flavour when cultured outside of Cheese. However, trends in aroma profiles that are observed with instrumental analysis are not always evident in the perception of the aroma with sensory analysis. The odour perception of microbiological models combining Penicillium roqueforti and Y. lipolytica Blue Cheese isolates were compared with the odour of real Blue Cheeses using the technique of Flash profiling. Assessors (n = 9) ranked the samples according to their Blue Cheese odour intensity and discriminated the P. roqueforti + Y. lipolytica model from the model only containing P. roqueforti which was included as a control. The synergy between Y. lipolytica and the mould appears to be responsible for the production of Blue Cheese odour.
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Flavour production of Stilton Blue Cheese microflora
2010Co-Authors: Konstantinos GkatzionisAbstract:In the Blue Cheese Stilton the starter mould Penicillium roqueforti grows and sporulates during the ripening period and is considered to be responsible for the unique Blue Cheese aroma. However, the sporulation of the mould, which results in the formation of Blue veins, takes place in a fraction of the Stilton matrix which overall is very heterogeneous. Most Blue Cheeses develop a secondary microflora of yeasts which may affect their aroma. The aim of this study was to investigate the yeast flora of Stilton, the aroma profile of the Cheese and the role of the yeasts in the aroma production. The approach in this work was to study individually the different sections of Stilton (the Blue veins, the white core and the outer crust) as previous studies have demonstrated each section has a differing bacterial flora. In addition to the classical microbiology, a series of molecular techniques (Denaturing Gradient Gel Electrophoresis, Restriction Fragment Length Polymorphism and Terminal RFLP) were compared and applied for the screening of the local fungal communities in the Cheese. The results showed that the two approaches were complementary. It was concluded that the structure of the fungal community was different for each section of the Cheese. The aroma profiles of the three different sections of Stilton were studied using solvent extraction Gas Chromatography-Mass Spectrometry (GC-MS), a headspace GC-MS technique (SPME GC-MS) and direct headspace analysis (Atmospheric Pressure Chemical Ionisation [APCI]-MS). The different sections of Stilton presented different aroma profiles. Overall, the Blue and the outer crust had similar profiles. These two sections contained higher amount of ketones while the white contained higher amounts of alcohols and aldehydes. Yeast isolates and the starter Penicillium roqueforti were cultivated alone and in combination in a Cheese model and the aroma production was studied with SPME GC-MS analysis. The co-culture of the starter Penicillium roqueforti and individual yeast isolates resulted in aroma profiles different from those that were produced by the mould or the yeasts individually. The model of Penicillium roqueforti with Yarrowia lipolytica resulted in an aroma more similar to Blue Cheese than produced by the mould alone. Sensory analysis (Flash profile technique) was used in order to compare the aroma of this model with the aroma of Blue Cheeses and the perception of the combined culture was found to be similar to Stilton Cheese, whereas that of the mould alone was not. Yeasts are a significant part of the microflora of Stilton and they are able to affect the aroma production. Selected isolates of Yarrowia lipolytica could be used in combination with Penicillium roqueforti for the production of Blue Cheese aroma e.g. as a starter culture.
M.a.t. Kerkhoff - One of the best experts on this subject based on the ideXlab platform.
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Erratum to ‘Determination of roquefortine C in Blue Cheese using on-line column-switching liquid chromatography’: [J. Pharm. Biomed. Anal. 17 (1998) 1215–1223]☆
Journal of pharmaceutical and biomedical analysis, 1999Co-Authors: Ebrahim Noroozian, F. Lagerwerf, H. Lingeman, Udo A. Th. Brinkman, M.a.t. KerkhoffAbstract:A method is described for the determination of roquefortine C in (Blue) Cheese. After liquid-liquid extraction with a mixture of hydrochloric acid and methanol, and filtration, an aliquot is analysed using column-switching reversed-phase liquid chromatography. The recovery of roquefortine C in Fetta Cheese is about 85%, the calibration curve is linear from 10 to 2500 ng g(-1) (r2 = 0.998), and the detection limit is about 10 ng g(-1). In different batches of Danish Blue concentrations of 1000-2000 ng g(-1) of roquefortine C are found. As regards the stability of roquefortine C its half-life in diffuse daylight is ca. 50 min, while after irradiation with ultraviolet light, it is about 10 min.
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Determination of roquefortine C in Blue Cheese using on-line column-switching liquid chromatography
Journal of Pharmaceutical and Biomedical Analysis, 1998Co-Authors: Ebrahim Noroozian, F. Lagerwerf, H. Lingeman, Udo A. Th. Brinkman, M.a.t. KerkhoffAbstract:Abstract A method is described for the determination of roquefortine C in (Blue) Cheese. After liquid–liquid extraction with a mixture of hydrochloric acid and methanol, and filtration, an aliquot is analysed using column-switching reversed-phase liquid chromatography. The recovery of roquefortine C in Fetta Cheese is about 85%, the calibration curve is linear from 10 to 2500 ng g−1 (r2=0.998), and the detection limit is about 10 ng g−1. In different batches of Danish Blue concentrations of 1000–2000 ng g−1 of roquefortine C are found. As regards the stability of roquefortine C its half-life in diffuse daylight is ca. 50 min, while after irradiation with ultraviolet light, it is about 10 min.
Robert S. T. Linforth - One of the best experts on this subject based on the ideXlab platform.
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study of the influence of yeast inoculum concentration yarrowia lipolytica and kluyveromyces lactis on Blue Cheese aroma development using microbiological models
Food Chemistry, 2014Co-Authors: Elliott J Price, Konstantinos Gkatzionis, Louise Hewson, Joanne Hort, Robert S. T. Linforth, Christine E. R. Dodd, Carol A PhillipsAbstract:Yarrowia lipolytica and Kluyveromyces lactis occur as part of Stilton Cheese microflora yet are not controlled during production. This study investigated the influence of their inoculum concentration on aroma production. Models of Y. lipolytica and K. lactis, with Penicillium roqueforti, were analysed using instrumental and sensory analysis. Different concentrations of Y. lipolytica produced important changes in the aroma profiles of microbiological models, analysed by solid-phase microextraction (SPME GC–MS). Sensory analysis with discrimination tests showed differences were detectable via human perception but did not concern the similarity to Blue Cheese odour. Increasing the inoculum concentration of K. lactis resulted in decreased variation between replicates. Partial least squares (PLS) regression on Flash profile data showed models inoculated with low concentrations of K. lactis exhibited Blue Cheese-related attributes, associated with increased ketone production. Results suggest that controlling the amount of Y. lipolytica and K. lactis during production offers potential to manipulate Blue Cheese aroma development.
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Effect of Yarrowia lipolytica on Blue Cheese odour development: Flash profile sensory evaluation of microbiological models and Cheeses
International Dairy Journal, 2013Co-Authors: Konstantinos Gkatzionis, Louise Hewson, Joanne Hort, Tracey Hollowood, Christine E. R. Dodd, Robert S. T. LinforthAbstract:Abstract Yarrowia lipolytica is among the most frequently occurring species in the secondary flora of Blue Cheeses. This organism produces a range of important aroma compounds for Blue Cheese flavour when cultured outside of Cheese. However, trends in aroma profiles that are observed with instrumental analysis are not always evident in the perception of the aroma with sensory analysis. The odour perception of microbiological models combining Penicillium roqueforti and Y. lipolytica Blue Cheese isolates were compared with the odour of real Blue Cheeses using the technique of Flash profiling. Assessors (n = 9) ranked the samples according to their Blue Cheese odour intensity and discriminated the P. roqueforti + Y. lipolytica model from the model only containing P. roqueforti which was included as a control. The synergy between Y. lipolytica and the mould appears to be responsible for the production of Blue Cheese odour.
Ebrahim Noroozian - One of the best experts on this subject based on the ideXlab platform.
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Erratum to ‘Determination of roquefortine C in Blue Cheese using on-line column-switching liquid chromatography’: [J. Pharm. Biomed. Anal. 17 (1998) 1215–1223]☆
Journal of pharmaceutical and biomedical analysis, 1999Co-Authors: Ebrahim Noroozian, F. Lagerwerf, H. Lingeman, Udo A. Th. Brinkman, M.a.t. KerkhoffAbstract:A method is described for the determination of roquefortine C in (Blue) Cheese. After liquid-liquid extraction with a mixture of hydrochloric acid and methanol, and filtration, an aliquot is analysed using column-switching reversed-phase liquid chromatography. The recovery of roquefortine C in Fetta Cheese is about 85%, the calibration curve is linear from 10 to 2500 ng g(-1) (r2 = 0.998), and the detection limit is about 10 ng g(-1). In different batches of Danish Blue concentrations of 1000-2000 ng g(-1) of roquefortine C are found. As regards the stability of roquefortine C its half-life in diffuse daylight is ca. 50 min, while after irradiation with ultraviolet light, it is about 10 min.
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Determination of roquefortine C in Blue Cheese using on-line column-switching liquid chromatography
Journal of Pharmaceutical and Biomedical Analysis, 1998Co-Authors: Ebrahim Noroozian, F. Lagerwerf, H. Lingeman, Udo A. Th. Brinkman, M.a.t. KerkhoffAbstract:Abstract A method is described for the determination of roquefortine C in (Blue) Cheese. After liquid–liquid extraction with a mixture of hydrochloric acid and methanol, and filtration, an aliquot is analysed using column-switching reversed-phase liquid chromatography. The recovery of roquefortine C in Fetta Cheese is about 85%, the calibration curve is linear from 10 to 2500 ng g−1 (r2=0.998), and the detection limit is about 10 ng g−1. In different batches of Danish Blue concentrations of 1000–2000 ng g−1 of roquefortine C are found. As regards the stability of roquefortine C its half-life in diffuse daylight is ca. 50 min, while after irradiation with ultraviolet light, it is about 10 min.
Marek Ogryzek - One of the best experts on this subject based on the ideXlab platform.
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growth potential of yersinia enterocolitica in Blue Cheese and in Blue Cheese with probiotic lactobacillus acidophilus la 5
Journal of Food Science and Technology-mysore, 2015Co-Authors: Anna Zadernowska, Wioleta Chajeckawierzchowska, Marek OgryzekAbstract:In the annual reports of the European Food Safety Authority (EFSA), Yersinia enterocolitica (YE) is enumerated as the third most common enteric pathogen responsible for food poisonings. The objective of the paper was to determine the potential for Yersinia enterocolitica growth in Blue Cheese and in Blue Cheese with a probiotic (Lactobacillus acidophilus LA-5®). The experiment was carried out with five different Cheese batches. The potential of YE growth was determined at 3, 6, 9, 12 and 15 °C in ten time intervals up to 480 h of storage. The initial contamination level was set at ~103 cfu/g YE. The studies demonstrated that at lower temperatures there was a systematic increase in the number of cells throughout the storage period, whereas at higher temperatures stationary and die-off phases were observed. By comparing the increase in the number of YE cells in both Cheese varieties, it may be observed that at 6, 9 and 12 °C the number of YE cells was lower in Blue Cheese with probiotic than in Blue Cheese at each stage of the experiment although it did not guarantee the microbiological safety of the product.
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Growth potential of Yersinia enterocolitica in Blue Cheese and in Blue Cheese with probiotic - Lactobacillus acidophilus LA-5®
Journal of Food Science and Technology, 2015Co-Authors: Anna Zadernowska, Wioleta Chajęcka-wierzchowska, Marek OgryzekAbstract:In the annual reports of the European Food Safety Authority (EFSA), Yersinia enterocolitica (YE) is enumerated as the third most common enteric pathogen responsible for food poisonings. The objective of the paper was to determine the potential for Yersinia enterocolitica growth in Blue Cheese and in Blue Cheese with a probiotic (Lactobacillus acidophilus LA-5®). The experiment was carried out with five different Cheese batches. The potential of YE growth was determined at 3, 6, 9, 12 and 15 °C in ten time intervals up to 480 h of storage. The initial contamination level was set at ~103 cfu/g YE. The studies demonstrated that at lower temperatures there was a systematic increase in the number of cells throughout the storage period, whereas at higher temperatures stationary and die-off phases were observed. By comparing the increase in the number of YE cells in both Cheese varieties, it may be observed that at 6, 9 and 12 °C the number of YE cells was lower in Blue Cheese with probiotic than in Blue Cheese at each stage of the experiment although it did not guarantee the microbiological safety of the product.