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Tilmann D. Märk - One of the best experts on this subject based on the ideXlab platform.
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Gas chromatography-olfactometry (GC-O) and proton transfer reaction-mass spectrometry (PTR-MS) analysis of the flavor profile of Grana Padano, Parmigiano Reggiano, and Grana Trentino cheeses
Journal of Agricultural and Food Chemistry, 2003Co-Authors: Elena Boscaini, Saskia M Van Ruth, Flavia Gasperi, Franco Biasioli, Tilmann D. MärkAbstract:Gas chromatography−olfactometry (GC-O) and proton transfer reaction−mass spectrometry (PTR-MS) techniques were used to deduce the profile of odor-active and volatile compounds of three Grana cheeses: Grana Padano (GP), Parmigiano Reggiano (PR), and Grana Trentino (GT). Samples for GC-O analysis were prepared by dynamic headspace extraction, while a direct analysis of the headspace formed over cheese was performed by PTR-MS. The major contributors to the odor profile were ethyl butanoate, 2-heptanone, and ethyl hexanoate, with fruity notes. A high concentration of mass 45, tentatively identified as acetaldehyde, was found by PTR-MS analysis. Low odor threshold compounds, e.g., methional and 1-octen-3-one, which contributed to the odor profile but were not detected by FID, were detected by PTR-MS. Principal component analysis on both GC-O and PTR-MS data separated the three cheese samples well and showed specific compounds related to each sample. Keywords: GC-O; PTR-MS; Grana cheese; odor profile; volatile...
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Gas chromatography-olfactometry (GC-O) and proton transfer reaction-mass spectrometry (PTR-MS) analysis of the flavor profile of Grana Padano, Parmigiano Reggiano, and Grana Trentino cheeses
Journal of Agricultural and Food Chemistry, 2003Co-Authors: Elena Boscaini, Saskia Van Ruth, Flavia Gasperi, Franco Biasioli, Tilmann D. MärkAbstract:Gas chromatography-olfactometry (GC-O) and proton transfer reaction-mass spectrometry (PTR-MS) techniques were used to deduce the profile of odor-active and volatile compounds of three Grana cheeses: Grana Padano (GP), Parmigiano Reggiano (PR), and Grana Trentino (GT). Samples for GC-O analysis were prepared by dynamic headspace extraction, while a direct analysis of the headspace formed over cheese was performed by PTR-MS. The major contributors to the odor profile were ethyl butanoate, 2-heptanone, and ethyl hexanoate, with fruity notes. A high concentration of mass 45, tentatively identified as acetaldehyde, was found by PTR-MS analysis. Low odor threshold compounds, e.g., methional and 1-octen-3-one, which contributed to the odor profile but were not detected by FID, were detected by PTR-MS. Principal component analysis on both GC-O and PTR-MS data separated the three cheese samples well and showed specific compounds related to each sample.
Erasmo Neviani - One of the best experts on this subject based on the ideXlab platform.
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can the development and autolysis of lactic acid bacteria influence the cheese volatile fraction the case of Grana Padano
International Journal of Food Microbiology, 2016Co-Authors: Camilla Lazzi, F Locci, Erasmo Neviani, Valentina Bernini, Milena Povolo, Monica GattiAbstract:Abstract In this study, the relationship between the dynamics of the growth and lysis of lactic acid bacteria in Grana Padano cheese and the formation of the volatile flavor compounds during cheese ripening was investigated. The microbial dynamics of Grana Padano cheeses that were produced in two different dairies were followed during ripening. The total and cultivable lactic microflora, community composition as determined by length heterogeneity-PCR (LH-PCR), and extent of bacterial lysis using an intracellular enzymatic activity assay were compared among cheeses after 2, 6 and 13 months of ripening in two dairies. The evolution of whole and lysed microbiota was different between the two dairies. In dairy 2, the number of total cells was higher than that in dairy 1 in all samples, and the number of cells that lysed during ripening was lower. In addition, at the beginning of ripening (2 months), the community structure of the cheese from dairy 2 was more complex and was composed of starter lactic acid bacteria (Lactobacillus helveticus and Lactobacillus delbrueckii) and NSLAB, possibly arising from raw milk, including Lactobacillus rhamnosus/Lactobacillus casei and Pediococcus acidilactici. On the other hand, the cheese from dairy 1 that ripened for 2 months was mainly composed of the SLAB L. helveticus and L. delbrueckii. An evaluation of the free-DNA fraction through LH-PCR identified those species that had a high degree of lysis. Data on the dynamics of bacterial growth and lysis were evaluated with respect to the volatile profile and the organic acid content of the two cheeses after 13 months of ripening, producing very different results. Cheese from dairy 1 showed a higher content of free fatty acids, particularly those deriving from milk fat lipolysis, benzaldehyde and organic acids, such as pGlu and citric. In contrast, cheese from dairy 2 had a greater amount of ketones, alcohols, hydrocarbons, acetic acid and propionic acid. Based on these results, we can conclude that in the first cheese, the intracellular enzymes that were released from lysis were mainly involved in aroma formation, whereas in the second cheese, the greater complexity of volatile compounds may be associated with its more complex microbial composition caused from SLAB lysis and NSLAB (mainly L. rhamnosus/L. casei) growth during ripening.
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survey on the community and dynamics of lactic acid bacteria in Grana Padano cheese
Systematic and Applied Microbiology, 2013Co-Authors: Marcela Santarelli, Camilla Lazzi, Erasmo Neviani, Benedetta Bottari, Monica GattiAbstract:Abstract Grana Padano (GP) is a Protected Designation of Origin cheese made with raw milk and natural whey culture (NWC) that is characterised by a long ripening period. In this study, six GP productions were considered in order to evaluate the trend of microbial dynamics and compare lactic acid bacteria (LAB) population levels in cheeses during the entire cheese-making process. To reach this goal, for each GP production, samples of vat raw milk, NWC and cheeses at 48 h, 2, 6, 9 and 13 months were subjected to plate counts and direct counts by fluorescence microscopy, as well as amplicon length heterogeneity-PCR (LH-PCR). Statistical analysis was applied to the results and ecological indices were estimated. It was demonstrated that the LAB able to grow in the cheese-environment conditions could arise from both raw milk and NWC. Starter lactobacilli (SLAB) from NWC were the main species present during acidification, and non-starter LAB (NSLAB), mainly from milk but also from NWC, were able to grow after brining and they dominated during ripening. The peak areas of LH-PCR profiles were used to determine ecological indices during manufacture and ripening. Among cheese ecosystems with different ageing times, diversity, Evenness and Richness were different, with highest bacterial growth and diversity occurring in cheese ripening at 2 months. At this time point, which seemed to be a crucial moment for GP microbial evolution, cell lysis of both SLAB and NSLAB was also observed. Sampling modality and statistical analysis gave greater significance to the results used to describe the microbiological characteristics of a cheese recognised worldwide.
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Diversity and dynamic of lactic acid bacteria strains during aging of a long ripened hard cheese produced from raw milk and undefined natural starter.
Food microbiology, 2013Co-Authors: Tomislav Pogačić, Erasmo Neviani, Camilla Lazzi, Benedetta Bottari, Marcela Santarelli, Andrea Mancini, Monica GattiAbstract:The aim of this study was to explore diversity and dynamic of indigenous LAB strains associated with a long ripened hard cheese produced from raw milk and undefined natural starter such as PDO Grana Padano cheese. Samples of milk, curd, natural whey culture and cheeses (2nd, 6th, 9th and 13th months of ripening) were collected from 6 cheese factories in northern Italy. DNA was extracted from each sample and from 194 LAB isolates. tRNAAla-23S rDNA-RFLP was applied to identify isolates. Strain diversity was assessed by (GTG)5 rep-PCR and RAPD(P1)-PCR. Finally, culture-independent LH-PCR (V1–V2 16S-rDNA), was considered to explore structure and dynamic of the microbiota. Grana Padano LAB were represented mainly by Lactobacillus rhamnosus, Lactobacillus casei, Lactobacillus paracasei, Lactobacillus delbrueckii, Lactobacillus helveticus and Pediococcus acidilactici, while the structure and dynamic of microbiota at different localities was specific. The strength of this work is to have focused the study on isolates coming from more than one cheese factories rather than a high number of isolates from one unique production. We provided a valuable insight into inter and intraspecies diversity of typical LAB strains during ripening of traditional PDO Grana Padano, contributing to the understanding of specific microbial ecosystem of this cheese.
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New developments in the study of the microbiota of raw-milk, long-ripened cheeses by molecular methods: the case of Grana Padano and Parmigiano Reggiano
Frontiers in microbiology, 2013Co-Authors: Erasmo Neviani, Camilla Lazzi, Benedetta Bottari, Monica GattiAbstract:Microorganisms are an essential component of cheeses and play important roles during both cheese manufacture and ripening. Both starter and secondary flora modify the physical and chemical properties of cheese, contributing and reacting to changes that occur during the manufacture and ripening of cheese. As the composition of microbial population changes under the influence of continuous shifts in environmental conditions and microorganisms interactions during manufacturing and ripening, the characteristics of a given cheese depend also on microflora dynamics. The microbiota present in cheese is complex and its growth and activity represent the most important, but the least controllable steps. In the past, research in this area was dependent on classical microbiological techniques. However, culture-dependent methods are time-consuming and approaches that include a culturing step can lead to inaccuracies due to species present in low numbers or simply uncultivable. Therefore, they cannot be used as a unique tool to monitor community dynamics. For these reasons approaches to cheese microbiology had to change dramatically. To address this, in recent years the focus on the use of culture-independent methods based on the direct analysis of DNA (or RNA) has rapidly increased. Application of such techniques to the study of cheese microbiology represents a rapid, sound, reliable, and effective way for the detection and identification of the microorganisms present in dairy products, leading to major advances in understanding this complex microbial ecosystem and its impact on cheese ripening and quality. In this article, an overview on the recent advances in the use of molecular methods for thorough analysis of microbial communities in cheeses is given. Furthermore, applications of culture-independent approaches to study the microbiology of two important raw-milk, long-ripened cheeses such as Grana Padano and Parmigiano Reggiano, are presented.
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comparison of natural whey starters for Grana Padano cheese using sunray plots
Annals of Microbiology, 2011Co-Authors: Monica Gatti, Benedetta Bottari, Marcela Santarelli, Erasmo NevianiAbstract:Twenty-one natural whey starters, collected from dairy factories located in six provinces of the Grana Padano production area, were characterized. Basic techniques, such as acidity evaluation and microbial plate count, together with more complex methods such as the Live/Dead® BacLight™ bacterial viability kit, have been used. Seven parameters, including pH, Soxhlet Henkel degrees, microbial plate count in Man Rogosa Sharpe medium and Whey Agar medium, together with count of total, viable and non-viable cells, have been adopted to produce sunray plots. One plot for each natural whey starter sample was obtained by characterizing the status of the microbial culture and compared with three natural whey starters prepared in the laboratory. In this way, a sunray trace is suggested to define the traits of a good natural whey starter. Another multivariate technique, principal component analysis, was applied, and it should be possible to conclude that, for this particular dataset composed of 24 objects and 7 variables, PCA allowed the highlighting of the good and bad samples, while sunray plots, even if remaining only a descriptive and explorative analysis, allowed the better visualizing of the differences among all the samples.
Elena Boscaini - One of the best experts on this subject based on the ideXlab platform.
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Gas chromatography-olfactometry (GC-O) and proton transfer reaction-mass spectrometry (PTR-MS) analysis of the flavor profile of Grana Padano, Parmigiano Reggiano, and Grana Trentino cheeses
Journal of Agricultural and Food Chemistry, 2003Co-Authors: Elena Boscaini, Saskia M Van Ruth, Flavia Gasperi, Franco Biasioli, Tilmann D. MärkAbstract:Gas chromatography−olfactometry (GC-O) and proton transfer reaction−mass spectrometry (PTR-MS) techniques were used to deduce the profile of odor-active and volatile compounds of three Grana cheeses: Grana Padano (GP), Parmigiano Reggiano (PR), and Grana Trentino (GT). Samples for GC-O analysis were prepared by dynamic headspace extraction, while a direct analysis of the headspace formed over cheese was performed by PTR-MS. The major contributors to the odor profile were ethyl butanoate, 2-heptanone, and ethyl hexanoate, with fruity notes. A high concentration of mass 45, tentatively identified as acetaldehyde, was found by PTR-MS analysis. Low odor threshold compounds, e.g., methional and 1-octen-3-one, which contributed to the odor profile but were not detected by FID, were detected by PTR-MS. Principal component analysis on both GC-O and PTR-MS data separated the three cheese samples well and showed specific compounds related to each sample. Keywords: GC-O; PTR-MS; Grana cheese; odor profile; volatile...
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Gas chromatography-olfactometry (GC-O) and proton transfer reaction-mass spectrometry (PTR-MS) analysis of the flavor profile of Grana Padano, Parmigiano Reggiano, and Grana Trentino cheeses
Journal of Agricultural and Food Chemistry, 2003Co-Authors: Elena Boscaini, Saskia Van Ruth, Flavia Gasperi, Franco Biasioli, Tilmann D. MärkAbstract:Gas chromatography-olfactometry (GC-O) and proton transfer reaction-mass spectrometry (PTR-MS) techniques were used to deduce the profile of odor-active and volatile compounds of three Grana cheeses: Grana Padano (GP), Parmigiano Reggiano (PR), and Grana Trentino (GT). Samples for GC-O analysis were prepared by dynamic headspace extraction, while a direct analysis of the headspace formed over cheese was performed by PTR-MS. The major contributors to the odor profile were ethyl butanoate, 2-heptanone, and ethyl hexanoate, with fruity notes. A high concentration of mass 45, tentatively identified as acetaldehyde, was found by PTR-MS analysis. Low odor threshold compounds, e.g., methional and 1-octen-3-one, which contributed to the odor profile but were not detected by FID, were detected by PTR-MS. Principal component analysis on both GC-O and PTR-MS data separated the three cheese samples well and showed specific compounds related to each sample.
Giorgio Giraffa - One of the best experts on this subject based on the ideXlab platform.
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Evaluation of bacterial communities of Grana Padano cheese by DNA metabarcoding and DNA fingerprinting analysis
Food microbiology, 2020Co-Authors: Miriam Zago, Lia Rossetti, Domenico Carminati, Tommaso Bardelli, Nelson Nazzicari, A. Galli, Giorgio GiraffaAbstract:Abstract The composition of the bacterial community of Grana Padano (GP) cheese was evaluated by an amplicon-based metagenomic approach (DNA metabarcoding) and RAPD-PCR fingerprinting. One hundred eighteen cheeses, which included 118 dairies located in the production area of GP, were collected. Two hundred fifty-four OTUs were detected, of which 82 were further discriminated between dominant (32 OTUs; > 1% total reads) and subdominant (50 OTUs; between 0.1% and 1% total reads) taxa. Lactobacillus (L.) delbrueckii, Lacticaseibacillus (Lact.) rhamnosus, Lact. casei, Limosilactobacillus fermentum, Lactococcus (Lc.) raffinolactis, L. helveticus, Streptococcus thermophilus, and Lc. lactis were the major dominant taxa (‘core microbiota’). The origin of samples significantly impacted on both richness, evenness, and the relative abundance of bacterial species, with peculiar pattern distribution among the five GP production regions. A differential analysis allowed to find bacterial species significantly associated with specific region pairings. The analysis of pattern similarity among RAPD-PCR profiles highlighted the presence of a ‘core’ community banding pattern present in all the GP samples, which was strictly associated with the core microbiota highlighted by DNA metabarcoding. A trend to group samples according to the five production regions was also observed. This study widened our knowledge on the bacterial composition and ecology of Grana Padano cheese.
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A Qualified Presumption of Safety approach for the safety assessment of Grana Padano whey starters
International Journal of Food Microbiology, 2009Co-Authors: Lia Rossetti, Miriam Zago, Domenico Carminati, Giorgio GiraffaAbstract:Abstract A Qualified Presumption of Safety (QPS) approach was applied to dominant lactic acid bacteria (LAB) associated with Grana Padano cheese whey starters. Thirty-two strains belonging to Lactobacillus helveticus, Lactobacillus delbrueckii subsp. lactis, Streptococcus thermophilus, and Lactobacillus fermentum, and representing the overall genotypic LAB diversity associated with 24 previously collected whey starters [Rossetti, L., Fornasari, M.E., Gatti, M., Lazzi, C., Neviani, E., Giraffa, G., 2008. Grana Padano cheese whey starters: microbial composition and strain distribution. International Journal of Food Microbiology 127, 168–171], were analyzed. All L. helveticus, L. delbrueckii subsp. lactis, and S. thermophilus isolates were susceptible to four (i.e. vancomycin, gentamicin, tetracycline, and erythromycin) of the clinically most relevant antibiotics. One L. fermentum strain displayed phenotypic resistance to tetracycline (TetR), with MIC of 32 µg/ml, and gentamycin (GmR), with MIC of 32 µg/ml. PCR was applied to this strain to test the presence of genes tet(L), tet(M), tet(S), and aac(6')-aph(2')-Ia, which are involved in horizontal transfer of TetR and GmR, respectively but no detectable amplification products were observed. According to QPS criteria, we conclude that Grana cheese whey starters do not present particular safety concerns.
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Grana Padano cheese whey starters microbial composition and strain distribution
International Journal of Food Microbiology, 2008Co-Authors: Lia Rossetti, Maria Emanuela Fornasari, Monica Gatti, Erasmo Neviani, Camilla Lazzi, Giorgio GiraffaAbstract:Abstract The aim of this work was to evaluate the species composition and the genotypic strain heterogeneity of dominant lactic acid bacteria (LAB) isolated from whey starter cultures used to manufacture Grana Padano cheese. Twenty-four Grana Padano cheese whey starters collected from dairies located over a wide geographic production area in the north of Italy were analyzed. Total thermophilic LAB streptococci and lactobacilli were quantified by agar plate counting. Population structure of the dominant and metabolically active LAB species present in the starters was profiled by reverse transcriptase, length heterogeneity-PCR (RT–LH–PCR), a culture-independent technique successfully applied to study whey starter ecosystems. The dominant bacterial species were Lactobacillus helveticus, Lactobacillus delbrueckii subsp. lactis, Streptococcus thermophilus, and Lactobacillus fermentum. Diversity in the species composition allowed the whey cultures to be grouped into four main typologies, the one containing L. helveticus, L. delbrueckii subsp. lactis, and S. thermophilus being the most frequent one (45% of the cultures analyzed), followed by that containing only the two lactobacilli (40%). Only a minor fraction of the cultures contained L. helveticus alone (4%) or all the four LAB species (11%). Five hundred and twelve strains were isolated from the 24 cultures and identified by M13-PCR fingerprinting coupled with 16S rRNA gene sequencing. Most of the strains were L. helveticus (190 strains; 37% of the total), L delbrueckii subsp. lactis (90 strains; 18%) and S. thermophilus (215 strains; 42%). This result was in good agreement with the qualitative whey starter composition observed by RT–LH–PCR. M13-PCR fingerprinting indicated a markedly low infra-species diversity, i.e. the same biotypes were often found in more than one culture. The distribution of the biotypes into the different cultures was mainly dairy plant-specific rather than correlated with the different production areas.
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cultivability of streptococcus thermophilus in Grana Padano cheese whey starters
Fems Microbiology Letters, 2006Co-Authors: Maria Emanuela Fornasari, Lia Rossetti, Domenico Carminati, Giorgio GiraffaAbstract:The application of a culture-independent approach, that of reverse transcriptase-length heterogeneity-PCR coupled with epifluorescence microscopy, allowed us to observe that Streptococcus thermophilus is metabolically active, but only partially cultivable in Grana Padano cheese whey starters. A short preincubation of the starters in sterile skimmed whey was followed by cultivation in sterile skimmed whey-enriched M17. This procedure restored the cultivability of S . thermophilus and enabled us to detect S. thermophilus at ranges (107–108 CFU mL−1) which have rarely been reported in these cultures. The use of cheese whey as a cultivation-revitalization substrate can be useful to obtain an unbiased picture of the microbial composition of whey starters for Grana Padano cheese, thus avoiding an underestimation of S. thermophilus in these cultures.
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evaluation of bacterial communities belonging to natural whey starters for Grana Padano cheese by length heterogeneity pcr
Journal of Applied Microbiology, 2004Co-Authors: Camilla Lazzi, Lia Rossetti, Erasmo Neviani, M Zago, Giorgio GiraffaAbstract:Aims: To detect bacteria present in controlled dairy ecosystems with defined composition by length-heterogeneity (LH)-PCR. LH-PCR allows to distinguish different organisms on the basis of natural variations in the length of 16S rRNA gene sequences. Methods and Results: LH-PCR was applied to depict population structure of the lactic acid bacteria (LAB) species recoverable from Grana Padano cheese whey starters. Typical bacterial species present in the LAB community were evidenced and well discriminated. Small differences in species composition, e.g. the frequent finding of Streptococcus thermophilus and the constant presence of thermophilic lactobacilli (Lactobacillus helveticus, Lact. delbrueckii subsp. lactis/bulgaricus and Lact. fermentum) were reliably highlighted. Specificity of LH-PCR was confirmed by species-specific PCR from total DNA of the cultures. Conclusions: LH-PCR is a useful tool to monitor microbial composition and population dynamics in dairy starter cultures. When present, non-dominant bacterial species present in the whey starters, such as Strep. thermophilus, can easily be visualized and characterized without isolating and cultivating single strains. A similar approach can be applied to more complex dairy ecosystems such as milk or cheese curd. Significance and Impact of the Study: Community members and differences in population structure of controlled dairy ecosystems such as whey starters for hard cheeses can be evaluated and compared in a relative easy, fast, reliable and highly reproducible way.
Franco Biasioli - One of the best experts on this subject based on the ideXlab platform.
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Gas chromatography-olfactometry (GC-O) and proton transfer reaction-mass spectrometry (PTR-MS) analysis of the flavor profile of Grana Padano, Parmigiano Reggiano, and Grana Trentino cheeses
Journal of Agricultural and Food Chemistry, 2003Co-Authors: Elena Boscaini, Saskia M Van Ruth, Flavia Gasperi, Franco Biasioli, Tilmann D. MärkAbstract:Gas chromatography−olfactometry (GC-O) and proton transfer reaction−mass spectrometry (PTR-MS) techniques were used to deduce the profile of odor-active and volatile compounds of three Grana cheeses: Grana Padano (GP), Parmigiano Reggiano (PR), and Grana Trentino (GT). Samples for GC-O analysis were prepared by dynamic headspace extraction, while a direct analysis of the headspace formed over cheese was performed by PTR-MS. The major contributors to the odor profile were ethyl butanoate, 2-heptanone, and ethyl hexanoate, with fruity notes. A high concentration of mass 45, tentatively identified as acetaldehyde, was found by PTR-MS analysis. Low odor threshold compounds, e.g., methional and 1-octen-3-one, which contributed to the odor profile but were not detected by FID, were detected by PTR-MS. Principal component analysis on both GC-O and PTR-MS data separated the three cheese samples well and showed specific compounds related to each sample. Keywords: GC-O; PTR-MS; Grana cheese; odor profile; volatile...
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Gas chromatography-olfactometry (GC-O) and proton transfer reaction-mass spectrometry (PTR-MS) analysis of the flavor profile of Grana Padano, Parmigiano Reggiano, and Grana Trentino cheeses
Journal of Agricultural and Food Chemistry, 2003Co-Authors: Elena Boscaini, Saskia Van Ruth, Flavia Gasperi, Franco Biasioli, Tilmann D. MärkAbstract:Gas chromatography-olfactometry (GC-O) and proton transfer reaction-mass spectrometry (PTR-MS) techniques were used to deduce the profile of odor-active and volatile compounds of three Grana cheeses: Grana Padano (GP), Parmigiano Reggiano (PR), and Grana Trentino (GT). Samples for GC-O analysis were prepared by dynamic headspace extraction, while a direct analysis of the headspace formed over cheese was performed by PTR-MS. The major contributors to the odor profile were ethyl butanoate, 2-heptanone, and ethyl hexanoate, with fruity notes. A high concentration of mass 45, tentatively identified as acetaldehyde, was found by PTR-MS analysis. Low odor threshold compounds, e.g., methional and 1-octen-3-one, which contributed to the odor profile but were not detected by FID, were detected by PTR-MS. Principal component analysis on both GC-O and PTR-MS data separated the three cheese samples well and showed specific compounds related to each sample.
