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José Ramos - One of the best experts on this subject based on the ideXlab platform.
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Plasma membrane composition of Debaryomyces Hansenii adapts to changes in pH and external salinity
Microbiology, 2016Co-Authors: Dušan Žigon, Vera Montiel, Ana Plemenitaš, Martina Turk, José RamosAbstract:Debaryomyces Hansenii is a marine yeast that has to cope with different stresssituations. Since changes in membrane properties can play an important function in adaptation, we have examined the fluidity and lipid composition ofpurified plasma membranes of D. Hansenii grown at different external pH values and salt concentrations. Growth at low pH caused an increase in the sterol-to-phospholipid ratio and a decrease in fatty acid unsaturation which was reflected in decreased fluidity of the plasma membrane. High levels of NaCl increased the sterol-to-phospholipid ratio and fatty acid unsaturation, but did not significantly affect fluidity. The sterol-to-phospholipid ratios obtained in D. Hansenii grown under any of these conditions were similar to the ratios that have been reported for halophilic/halotolerant black yeasts, but much smaller than those observed in the model yeast Saccharomyces cerevisiae.
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The halotolerant Debaryomyces Hansenii , the Cinderella of non-conventional yeasts
Yeast, 2016Co-Authors: Catarina Prista, Isabel M. Miranda, Carmen Michán, José RamosAbstract:Debaryomyces Hansenii is a halotolerant yeast with a high biotechnological potential, particularly in the food industry. However, research in this yeast is limited by its molecular peculiarities. In this review we summarize the state of the art of research in this microorganisms, describing both pros and cons. We discuss (i) its halotolerance, (ii) the molecular factors involved in saline and osmotic stress, (iii) its high gene density and ambiguous CUG decoding, and (iv) its biotechnological and medical interests. We trust that all the bottlenecks in its study will soon be overcome and D. Hansenii will become a fundamental organism for food biotechnological processes. Copyright © 2016 John Wiley & Sons, Ltd.
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Salt and oxidative stress tolerance in Debaryomyces Hansenii and Debaryomyces fabryi
FEMS yeast research, 2012Co-Authors: Carmen Michán, Martina Turk, José L. Martínez, María C. Álvarez, Hana Sychrová, José RamosAbstract:We report the characterization of five strains belonging to the halotolerant highly related Debaryomyces Hansenii/fabryi species. The analysis performed consisted in studying tolerance properties, membrane characteristics, and cation incell amounts. We have specifically investigated (1) tolerance to different chemicals, (2) tolerance to osmotic and salt stress, (3) tolerance and response to oxidative stress, (4) reactive oxygen species (ROS) content, (5) relative membrane potential, (6) cell volume, (7) K+ and Na+ ion content, and (8) membrane fluidity. Unexpectedly, no direct relationship was found between one particular strain, Na+ content and its tolerance to NaCl or between its ROS content and its tolerance to H2O2. Results show that, although in general, human origin D.fabryi strains were more resistant to oxidative stress and presented shorter doubling times and smaller cell volume than food isolated D.Hansenii ones, strains belonging to the same species can be significantly different. Debaryomyces fabryi CBS1793 strain highlighted for its extremely tolerant behavior when exposed to the diverse stress factors studied.
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monovalent cations regulate expression and activity of the hak1 potassium transporter in Debaryomyces Hansenii
Fungal Genetics and Biology, 2011Co-Authors: José L. Martínez, Hana Sychrová, José RamosAbstract:Abstract Debaryomyces Hansenii was able to grow in a medium containing residual amounts of K+, indicating the activity of high affinity K+ transporters. Transcriptional regulation analysis of the genes encoding the two potassium uptake systems in D. Hansenii revealed that while DhTRK1 is not regulated at transcriptional level, expression of DhHAK1 required starvation in the absence of K+ and Na+ and was not affected by changes in membrane potential. Rb+ transport in cells expressing DhHAK1 was activated by external Na+ or acidic pH and inhibited by high pH. We propose a K+–H+ symporter that, under certain conditions may work as a K+–Na+ transporter, as the mechanism driving K+ influx mediated by DhHak1p.
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Oxidative stress sensitivity in Debaryomyces Hansenii
FEMS yeast research, 2009Co-Authors: Clara Navarrete, José L. Martínez, Alicia Siles, Fernando Calero, José RamosAbstract:Debaryomyces Hansenii is an osmotolerant and halotolerant yeast of increasing interest for fundamental and applied research. In this work, we have performed a first study on the effect of oxidative stress on the performance of this yeast. We have used Saccharomyces cerevisiae as a well-known reference yeast. We show that D. Hansenii is much more susceptible than S. cerevisiae to cadmium chloride, hydrogen peroxide or 1,4-dithiothreitol. These substances induced the formation of reactive oxygen species (ROS) in both yeasts, the amounts measured being significantly higher in the case of D. Hansenii. We also show that NaCl exerted a protective effect against oxidative stress in Debaryomyces, but that this was not the case in Saccharomyces because sodium protected that yeast only when toxicity was induced with cadmium. On the basis of the present results, we raised the hypothesis that the sensitivity to oxidative stress in D. Hansenii is related to the high amounts of ROS formed in that yeast and that observations such as low glutathione amounts, low basal superoxide dismutase and peroxidase activities, decrease in ATP levels produced in the presence of ROS inducers and high cadmium accumulation are determinants directly or indirectly involved in the sensitivity process.
Nils Arneborg - One of the best experts on this subject based on the ideXlab platform.
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the utilisation of amino acids by Debaryomyces Hansenii and yamadazyma triangularis associated with cheese
International Dairy Journal, 2021Co-Authors: Ling Zhang, Lene Jespersen, Chuchu Huang, Pernille Greve Johansen, Mikael Agerlin Petersen, Mahesha M Poojary, Marianne N Lund, Nils ArneborgAbstract:Abstract This study explored the amino acid utilisation by Debaryomyces Hansenii and Yamadazyma triangularis grown on cheese agar at 16 °C and 25 °C. The consumption of amino acids was species- and strain-dependent and greatly affected by temperature. For D. Hansenii, the consumption of most amino acids was higher at 25 °C compared with 16 °C, contrary to Y. triangularis. Debaryomyces Hansenii produced more 2- and 3-methyl-butanal, 3-methyl-1-butanol, and 2-phenylethanol, and consumed more of the corresponding amino acids, isoleucine, leucine, and phenylalanine, respectively, than Y. triangularis at 25 °C. Yamadazyma triangularis produced more volatile sulphur compounds, and consumed more of their precursor, methionine, than D. Hansenii at 16 °C. Moreover, Y. triangularis seemed able to markedly consume the volatile sulphur compounds at 25 °C. These results may contribute to the selection of appropriate yeasts to be used in the cheese industry.
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in vitro investigation of Debaryomyces Hansenii strains for potential probiotic properties
World Journal of Microbiology & Biotechnology, 2016Co-Authors: Honeylet Sabas Ochangco, Lene Jespersen, Amparo Gamero, Ida M Smith, Jeffrey E Christensen, Nils ArneborgAbstract:In this study, 23 Debaryomyces Hansenii strains, isolated from cheese and fish gut, were investigated in vitro for potential probiotic properties i.e. (1) survival under in vitro GI (gastrointestinal) conditions with different oxygen levels, (2) adhesion to Caco-2 intestinal epithelial cells and mucin, and (3) modulation of pro- and anti-inflammatory cytokine secretion by human monocyte-derived dendritic cells. As references two commercially available probiotic Saccharomyces cerevisiae var. boulardii (S. boulardii) strains were included in the study. Our results demonstrate that the different D. Hansenii yeast strains had very diverse properties which could potentially lead to different probiotic effects. One strain of D. Hansenii (DI 09) was capable of surviving GI stress conditions, although not to the same degree as the S. boulardii strains. This DI 09 strain, however, adhered more strongly to Caco-2 cells and mucin than the S. boulardii strains. Additionally, two D. Hansenii strains (DI 10 and DI 15) elicited a higher IL-10/IL-12 ratio than the S. boulardii strains, indicating a higher anti-inflammatory effects on human dendritic cells. Finally, one strain of D. Hansenii (DI 02) was evaluated as the best probiotic candidate because of its outstanding ability to survive the GI stresses, to adhere to Caco-2 cells and mucin and to induce a high IL-10/IL-12 ratio. In conclusion, this study shows that strains of D. Hansenii may offer promising probiotic traits relevant for further study.
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alcohol based quorum sensing plays a role in adhesion and sliding motility of the yeast Debaryomyces Hansenii
Fems Yeast Research, 2011Co-Authors: Klaus Gori, Nils Arneborg, Peter Boldsen Knudsen, Kristian Fog Nielsen, Lene JespersenAbstract:The yeast Debaryomyces Hansenii was investigated for its production of alcohol-based quorum sensing (QS) molecules including the aromatic alcohols phenylethanol, tyrosol, tryptophol and the aliphatic alcohol farnesol. Debaryomyces Hansenii produced phenylethanol and tyrosol, which were primarily detected from the end of exponential phase indicating that they are potential QS molecules in D. Hansenii as previously shown for other yeast species. Yields of phenylethanol and tyrosol produced by D. Hansenii were, however, lower than those produced by Candida albicans and Saccharomyces cerevisiae and varied with growth conditions such as the availability of aromatic amino acids, ammonium sulphate, NaCl, pH and temperature. Tryptophol was only produced in the presence of tryptophane, whereas farnesol in general was not detectable. Especially, the type strain of D. Hansenii (CBS767) had good adhesion and sliding motility abilities, which seemed to be related to a higher hydrophobicity of the cell surface of D. Hansenii (CBS767) rather than the ability to form pseudomycelium. Addition of phenylethanol, tyrosol, tryptophol and farnesol was found to influence both adhesion and sliding motility of D. Hansenii.
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flavour compound production by yarrowia lipolytica saccharomyces cerevisiae and Debaryomyces Hansenii in a cheese surface model
International Dairy Journal, 2011Co-Authors: Louise Marie Sorensen, Lene Jespersen, Klaus Gori, Mikael Agerlin Petersen, Nils ArneborgAbstract:Abstract A simple cheese model mimicking a cheese surface was developed for the detection of cheese flavour formation of yeasts. A total of 56 flavour compounds were detected by dynamic headspace sampling followed by gas chromatography–mass spectrometry analysis. Yarrowia lipolytica CBS 2075 primarily produced sulphides, furans and short-chain ketones; Saccharomyces cerevisiae D7 primarily produced esters and Debaryomyces Hansenii D18335 primarily produced branched-chain aldehydes and alcohols. For several of the detected flavour compounds, an increase in production was observed upon exposure to dairy-relevant environmental stress conditions including high NaCl concentration and low temperature. The predominant yeasts on the cheese surface may be important for development of flavour, and thus the use of yeasts as ripening cultures has the potential to affect the flavour of cheese.
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Intracellular pH Homeostasis Plays a Role in the Tolerance of Debaryomyces Hansenii and Candida zeylanoides to Acidified Nitrite
Applied and environmental microbiology, 2008Co-Authors: Henrik Dam Mortensen, Tomas Jacobsen, Anette Granly Koch, Nils ArneborgAbstract:The effects of acidified-nitrite stress on the growth initiation and intracellular pH (pHi) of individual cells of Debaryomyces Hansenii and Candida zeylanoides were investigated. Our results show that 200 μg/ml of nitrite caused pronounced growth inhibition and intracellular acidification of D. Hansenii at an external pH (pHex) value of 4.5 but did not at pHex 5.5. These results indicate that nitrous acid as such plays an important role in the antifungal effect of acidified nitrite. Furthermore, both yeast species experienced severe growth inhibition and a pHi decrease at pHex 4.5, suggesting that at least some of the antifungal effects of acidified nitrite may be due to intracellular acidification. For C. zeylanoides, this phenomenon could be explained in part by the uncoupling effect of energy generation from growth. Debaryomyces Hansenii was more tolerant to acidified nitrite at pHex 5.5 than C. zeylanoides, as determined by the rate of growth initiation. In combination with the fact that D. Hansenii was able to maintain pHi homeostasis at pHex 5.5 but C. zeylanoides was not, our results suggest that the ability to maintain pHi homeostasis plays a role in the acidified-nitrite tolerance of D. Hansenii and C. zeylanoides. Possible mechanisms underlying the different abilities of the two yeast species to maintain their pHi homeostasis during acidified-nitrite stress, comprising the intracellular buffer capacity and the plasma membrane ATPase activity, were investigated, but none of these mechanisms could explain the difference.
Monica Flores - One of the best experts on this subject based on the ideXlab platform.
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counteracting the effect of reducing nitrate nitrite levels on dry fermented sausage aroma by Debaryomyces Hansenii inoculation
Meat Science, 2020Co-Authors: Laura Pereasanz, Carmela Belloch, Jose Javier Lopezdiez, Monica FloresAbstract:The reduction of ingoing amounts of nitrate and nitrite in dry fermented sausages was studied together with the impact of Debaryomyces Hansenii inoculation on aroma generation. Three different formulations of sausages were manufactured: control (C), reduced in nitrate and nitrite ingoing amounts (R) and reduced R inoculated with D. Hansenii (RY). Changes in physicochemical and microbiological parameters, volatile compounds and aroma were investigated at different drying times. Nitrite/nitrate reduction did not seem to affect microbial growth but affected their metabolic activity. Moreover, nitrite/nitrate reduction decreased lipid oxidation and generation of derived volatile compounds. Yeast inoculation limited lipid oxidation and prevented nitrite oxidation. Sausage aroma profile was positively affected by D. Hansenii inoculation which contributed to the generation of potent aroma compounds like ethyl ester compounds and 3-methylbutanal. Long drying time impacted sausage aroma profile as well as yeast metabolism. Yeast inoculation counteracted the negative influence of nitrite/nitrate reduction due to its antioxidant capacity, aroma generation and hindered nitrite oxidation.
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Debaryomyces Hansenii metabolism of sulfur amino acids as precursors of volatile sulfur compounds of interest in meat products
Journal of Agricultural and Food Chemistry, 2019Co-Authors: Laura Pereasanz, David Peris, Carmela Belloch, Monica FloresAbstract:The ability of Debaryomyces Hansenii to produce volatile sulfur compounds from sulfur amino acids and the metabolic pathway involved have been studied in seven strains from different food origins. Our results proved that l-methionine is the main precursor for sulfur compound generation. Crucial differences in the sulfur compound profile and amino acid consumption among D. Hansenii strains isolated from different food sources were observed. Strains isolated from dry pork sausages displayed the most complex sulfur compound profiles. Sulfur compound production, such as that of methional, could result from chemical reactions or yeast metabolism, while according to this study, thioester methyl thioacetate appeared to be generated by yeast metabolism. No relationship between sulfur compounds production by D. Hansenii strains and the expression of genes involved in sulfur amino acid metabolism was found, except for the ATF2 gene in the L1 strain for production of methyl thioacetate. Our results suggest a complex...
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screening of Debaryomyces Hansenii strains for flavor production under a reduced concentration of nitrifying preservatives used in meat products
Journal of Agricultural and Food Chemistry, 2017Co-Authors: Monica Flores, Jose Javier Lopezdiez, Daniel Moncunill, Rebeca Montero, Carmela BellochAbstract:A total of 15 Debaryomyces Hansenii strains from different food origins were genetically characterized and tested on a culture medium resembling the composition of fermented sausages but different concentrations of nitrifying preservatives. Genetic typing of the D. Hansenii strains revealed two levels of discrimination: isolation source or strain specific. Different abilities to proliferate on culture media containing different concentrations of nitrate and nitrite, as sole nitrogen sources and in the presence of amino acids, were observed within D. Hansenii strains. Overall metabolism of amino acids and generation of aroma compounds were related to the strain origin of isolation. The best producers of branched aldehydes and ethyl ester compounds were strains isolated from pork sausages. Strains from cheese and llama sausages were good producers of ester compounds and branched alcohols, while vegetable strains produced mainly acid compounds. Nitrate and nitrite reduction affected in different ways the pro...
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effect of fat and salt reduction on the sensory quality of slow fermented sausages inoculated with Debaryomyces Hansenii yeast
Food Control, 2014Co-Authors: Sara Corral, Carmela Belloch, Ana Salvador, Monica FloresAbstract:Abstract The inoculation of a Debaryomyces Hansenii strain in dry fermented sausages with reduced fat and salt contents was evaluated in terms of chemical, microbial and consumer acceptability. The implantation of the inoculated yeast strain was confirmed by RAPDs of M13 minisatellite. A reduction of 17–20% salt and 10–16% fat content was achieved. These reductions affected the sausage quality by producing an increase in aw, hardness and chewiness values and a decrease of staphylococci growth. However, D. Hansenii inoculation compensated these changes although it was not able to modify neither the hardness of reduced fat batches nor the staphylococci growth decrease. In terms of sensory acceptability, different preferences patterns of consumers were found. Yeast inoculation improved the aroma and taste quality when fat or salt reductions were carried out in dry fermented sausages.
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generation of aroma compounds in a fermented sausage meat model system by Debaryomyces Hansenii strains
Food Chemistry, 2014Co-Authors: Liliana Canogarcia, Carmela Belloch, Silvia Riverajimenez, Monica FloresAbstract:The ability of seven Debaryomyces Hansenii strains to generate aroma compounds in a fermented sausage model system was evaluated. The presence of the yeast, in the inoculated models, was confirmed by PCR amplification of M13 minisatellite. Volatile compounds production was analysed using Solid Phase Micro-Extraction and gas chromatography/mass spectrometry. Forty volatile compounds were detected, quantified and their odour activity values (OAVs) calculated. All volatile compounds increased during time in the inoculated models although significant differences were found amongst them. Ester and sulphur production was strongly dependent on the strain inoculated. D. Hansenii P2 and M6 strains were the highest producers of sulphur compounds where dimethyl disulphide and dimethyl trisulfide were the most prominent aroma components identified by their OAVs whereas, M4 showed the highest OAVs for ester compounds followed by the P2 strain. The meat model system has been useful to show the real ability of yeast strains to produce aroma compounds.
Carmela Belloch - One of the best experts on this subject based on the ideXlab platform.
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counteracting the effect of reducing nitrate nitrite levels on dry fermented sausage aroma by Debaryomyces Hansenii inoculation
Meat Science, 2020Co-Authors: Laura Pereasanz, Carmela Belloch, Jose Javier Lopezdiez, Monica FloresAbstract:The reduction of ingoing amounts of nitrate and nitrite in dry fermented sausages was studied together with the impact of Debaryomyces Hansenii inoculation on aroma generation. Three different formulations of sausages were manufactured: control (C), reduced in nitrate and nitrite ingoing amounts (R) and reduced R inoculated with D. Hansenii (RY). Changes in physicochemical and microbiological parameters, volatile compounds and aroma were investigated at different drying times. Nitrite/nitrate reduction did not seem to affect microbial growth but affected their metabolic activity. Moreover, nitrite/nitrate reduction decreased lipid oxidation and generation of derived volatile compounds. Yeast inoculation limited lipid oxidation and prevented nitrite oxidation. Sausage aroma profile was positively affected by D. Hansenii inoculation which contributed to the generation of potent aroma compounds like ethyl ester compounds and 3-methylbutanal. Long drying time impacted sausage aroma profile as well as yeast metabolism. Yeast inoculation counteracted the negative influence of nitrite/nitrate reduction due to its antioxidant capacity, aroma generation and hindered nitrite oxidation.
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Debaryomyces Hansenii metabolism of sulfur amino acids as precursors of volatile sulfur compounds of interest in meat products
Journal of Agricultural and Food Chemistry, 2019Co-Authors: Laura Pereasanz, David Peris, Carmela Belloch, Monica FloresAbstract:The ability of Debaryomyces Hansenii to produce volatile sulfur compounds from sulfur amino acids and the metabolic pathway involved have been studied in seven strains from different food origins. Our results proved that l-methionine is the main precursor for sulfur compound generation. Crucial differences in the sulfur compound profile and amino acid consumption among D. Hansenii strains isolated from different food sources were observed. Strains isolated from dry pork sausages displayed the most complex sulfur compound profiles. Sulfur compound production, such as that of methional, could result from chemical reactions or yeast metabolism, while according to this study, thioester methyl thioacetate appeared to be generated by yeast metabolism. No relationship between sulfur compounds production by D. Hansenii strains and the expression of genes involved in sulfur amino acid metabolism was found, except for the ATF2 gene in the L1 strain for production of methyl thioacetate. Our results suggest a complex...
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screening of Debaryomyces Hansenii strains for flavor production under a reduced concentration of nitrifying preservatives used in meat products
Journal of Agricultural and Food Chemistry, 2017Co-Authors: Monica Flores, Jose Javier Lopezdiez, Daniel Moncunill, Rebeca Montero, Carmela BellochAbstract:A total of 15 Debaryomyces Hansenii strains from different food origins were genetically characterized and tested on a culture medium resembling the composition of fermented sausages but different concentrations of nitrifying preservatives. Genetic typing of the D. Hansenii strains revealed two levels of discrimination: isolation source or strain specific. Different abilities to proliferate on culture media containing different concentrations of nitrate and nitrite, as sole nitrogen sources and in the presence of amino acids, were observed within D. Hansenii strains. Overall metabolism of amino acids and generation of aroma compounds were related to the strain origin of isolation. The best producers of branched aldehydes and ethyl ester compounds were strains isolated from pork sausages. Strains from cheese and llama sausages were good producers of ester compounds and branched alcohols, while vegetable strains produced mainly acid compounds. Nitrate and nitrite reduction affected in different ways the pro...
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effect of fat and salt reduction on the sensory quality of slow fermented sausages inoculated with Debaryomyces Hansenii yeast
Food Control, 2014Co-Authors: Sara Corral, Carmela Belloch, Ana Salvador, Monica FloresAbstract:Abstract The inoculation of a Debaryomyces Hansenii strain in dry fermented sausages with reduced fat and salt contents was evaluated in terms of chemical, microbial and consumer acceptability. The implantation of the inoculated yeast strain was confirmed by RAPDs of M13 minisatellite. A reduction of 17–20% salt and 10–16% fat content was achieved. These reductions affected the sausage quality by producing an increase in aw, hardness and chewiness values and a decrease of staphylococci growth. However, D. Hansenii inoculation compensated these changes although it was not able to modify neither the hardness of reduced fat batches nor the staphylococci growth decrease. In terms of sensory acceptability, different preferences patterns of consumers were found. Yeast inoculation improved the aroma and taste quality when fat or salt reductions were carried out in dry fermented sausages.
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generation of aroma compounds in a fermented sausage meat model system by Debaryomyces Hansenii strains
Food Chemistry, 2014Co-Authors: Liliana Canogarcia, Carmela Belloch, Silvia Riverajimenez, Monica FloresAbstract:The ability of seven Debaryomyces Hansenii strains to generate aroma compounds in a fermented sausage model system was evaluated. The presence of the yeast, in the inoculated models, was confirmed by PCR amplification of M13 minisatellite. Volatile compounds production was analysed using Solid Phase Micro-Extraction and gas chromatography/mass spectrometry. Forty volatile compounds were detected, quantified and their odour activity values (OAVs) calculated. All volatile compounds increased during time in the inoculated models although significant differences were found amongst them. Ester and sulphur production was strongly dependent on the strain inoculated. D. Hansenii P2 and M6 strains were the highest producers of sulphur compounds where dimethyl disulphide and dimethyl trisulfide were the most prominent aroma components identified by their OAVs whereas, M4 showed the highest OAVs for ester compounds followed by the P2 strain. The meat model system has been useful to show the real ability of yeast strains to produce aroma compounds.
Alberto Martín - One of the best experts on this subject based on the ideXlab platform.
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Application of ISSR-PCR for rapid strain typing of Debaryomyces Hansenii isolated from dry-cured Iberian ham.
Food microbiology, 2014Co-Authors: G. Gallardo, Santiago Ruiz-moyano, Alejandro Hernández, María José Benito, María De Guía Córdoba, Francisco Pérez-nevado, Alberto MartínAbstract:Yeast populations of dry-cured Iberian ham isolated from seven industries in the province of Badajoz were characterized by ISSR-PCR using the (CAG)4 primer and PCR-RFLP of the ITS1-5.8S rRNA-ITS2 fragment, and identified by DNA sequencing. A total of 242 isolates were analyzed, indicating the primary species present was Debaryomyces Hansenii at 80.9% of the isolates followed by Candida zeylanoides at 10.3% of the isolates. The remainders of isolates were identified as Yamadazyma triangularis, Sporobolomyces roseus, Meyerozyma guilliermondii, Rhodotorula slooffiae, and Cryptococcus victoriae. The ISSR-PCR method was a fast and reliable method which was able to discriminate species at a level comparable to restriction analyses of the ITS1-5.8S rRNA-ITS2 region. This method allowed for strain typing of D. Hansenii, yielding 29 different PCR patterns within 196 isolates. Moreover, ISSR-PCR using the (CAG)4 primer indicated that this technique could be a promising tool for rapid discrimination of yeast starter cultures and spoilage species in dry-cured Iberian ham.
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effect of penicillium chrysogenum and Debaryomyces Hansenii on the volatile compounds during controlled ripening of pork loins
International Journal of Food Microbiology, 2003Co-Authors: Alberto Martín, María José Benito, Emilio Aranda, Juan J Cordoba, Miguel A AsensioAbstract:During ripening of meat products such as dry-cured ham, the moulds and yeasts that proliferate on the surface may contribute to flavour development. However, their contribution to volatile components of dry-cured meat products is not known. One strain each of Penicillium chrysogenum and Debaryomyces Hansenii, selected from dry-cured ham by their proteolytic activity, were tested to determine their effect on the volatile compounds during ripening. Sterile pork loins were inoculated and ripened for 106 days. Volatile compounds collected with a Solid Phase Micro-Extraction (SPME) fibre were analysed by GC/MS. Inoculation of pork loins with P. chrysogenum lead to a decrease in compounds attributed to lipid oxidation and to an increase of compounds derived from free amino acids. Inoculation with D. Hansenii seemed to favour the formation of complex alcohols.
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proteolytic activity of penicillium chrysogenum and Debaryomyces Hansenii during controlled ripening of pork loins
Meat Science, 2002Co-Authors: Alberto Martín, María De Guía Córdoba, Miguel A Asensio, M E Bermudez, Emilio Aranda, Juan J CordobaAbstract:The role of micro-organisms on the ripening process of dry-cured ham, particularly with respect to proteolysis, is not clear. This is partially due to the lack of an adequate system to study changes on a sterile control meat product for long ripening times. Using a meat system based on sterile pork loins ripened under aseptic conditions for 106 days, the contribution to the proteolysis of two micro-organisms isolated from dry-cured ham has been established. Changes were studied by SDS-PAGE of sarcoplasmic and myofibrillar proteins, capillary zone electrophoresis (CZE) of low ionic strength-soluble nitrogen compounds, and HPLC of free amino acids. Debaryomyces Hansenii Dh345 did not show any significant proteolytic activity. However, Penicillium chrysogenum Pg222 showed high proteolytic activity on myofibrillar proteins resulting in an increase in soluble nitrogen compounds. For this, P. chrysogenum Pg222 should be considered to be used as starter culture in meat products made using long ripening times.
