Electronic Nose analysis of milk from cows grazing on two different Alpine vegetation types (original) (raw)
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The electronic nose applied to dairy products: a review
The state-of-the-art and current trends in the development of "aroma" analysis with electronic noses are reviewed with special reference to applications to dairy-products. Some of the reported problems with electronic noses have recently been reduced, e.g. the correction/reduction of signal drift, the influence of humidity and temperature. New promising and reproducible sensor manufacturing techniques are being implemented, e.g. electro-spray for QMB sensor production. The development of more selective and sensitive sensors, especially of QMB and conducting polymer (CP) type, should improve their applicability. Interesting novel sampling techniques, such as SPME or SBSE, offer more possibilities for the analysis of semi-volatile compounds which are generally more odoriferous. However, standard calibration procedures and reference materials are not yet available. Although they are normally less powerful than human noses, electronic noses offer some significant advantages in the analysis of volatiles, for example, in instrumental classifications based on hedonic or sensory analyses and in potentially automated on-line monitoring of volatiles. Several groups have explored the application of different electronic noses in the investigation of various aspects of dairy products. The present review includes as examples the evaluation of Swiss and Cheddar cheese aroma, the assessment of the ripening of Pecorino Toscano cheese (ewe's), the detection of mould in Parmesan cheese, the classification of milk by trademark, by fat level and by preservation process, the classification and the quantification of off-flavours in milk, the evaluation of Maillard reactions during heating processes in block-milk, as well as the identification of single strains of disinfectant-resistant bacteria in mixed cultures in milk.
Journal of Dairy Science, 2007
The detection of markers of identification of the geographical origin of food is an attractive challenge and, as far as dairy products are concerned, this paper represents a contribution to this field. In this research the influence of feed on the volatile compound composition was investigated on milk, 2-mo-old cheese (Caciotta), and whey cheese (ricotta) obtained from the same flock of Sarda ewes, under standardized technological conditions. Three different types of pasture (mixture of Lolium perenne and Trifolium squarrosum; rough pasture; Avena sativa) were studied. Solid-phase microextraction combined with gas chromatography-mass spectrometry was used and principal component analysis was applied for statistical evaluation of the data set. The volatile composition was significantly affected by the type of pasture independently of the type of cheese and the ripening period. Moreover, a marker of rough pasture, tentatively identified as (E,E)-3,7,11-trimethyl-2,4,10-dodecatriene, was detected only in milk and cheeses produced when the ewe flock grazed on that pasture.
Frontiers in Veterinary Science, 2021
Milk obtained from sheep grazing natural pastures and some forage crops may be worth a plus value as compared to milk obtained from stall-fed sheep, due to their apparently higher content of beneficial fatty acids (FAs). Fourier transformed mid-infrared (FT-MIR) analysis of FA can help distinguish milk from different areas and diverse feeding systems. The objective was to discriminate milk from sheep and milk from dairy sheep rotationally grazing Italian ryegrass or berseem clover for 2, 4, or 6 h/day. To test this hypothesis, a data-mining study was undertaken using a database of 1,230 individual milk spectra. Data were elaborated by principal component analysis (PCA) and analyzed by linear discriminant analysis (LDA) with or without the use of genetic algorithm (GA) as a variable selection tool with the primary aim to discriminate grazed forages (grass vs. legume), access time (2, 4, or 6 h/day), grazing day (first vs. last grazing day during the 7-day grazing period), and the mil...
Italian Journal of Agronomy, 2015
The aim of this study, carried out within the NOVOROD project (PSR Campania 2007, was to evaluate the aromatic profile of milk and dairy products of dairy cows supplemented with destoned olive cake (DOC). Two techniques for the headspace aroma profile analysis: the thermal desorption by gas chromatography with a mass selective (GC/MS) detector and the electronic nose were compared. The trial was performed into a dairy cow farm. Ten dairy cows were allotted into two homogenous groups: control and experimental. Animals received the same diet, while in the experimental group the concentrate supplementation (15% dry matter) was replaced with DOC. After two weeks of adaptation, animals were fed with the experimental diet for other 15 days. During the experimental period, the milk was collected and cumulatively processed in
Novel analytical technologies of Quality in the Sheep & Goat Dairy Sector
Journal of Veterinary Science and Animal Husbandry, 2017
France, Greece, Italy, and Spain the major sheep and goat milk producers in Europe, got the initiative through an interim of 30 years (1985-2015), to organize-through IDF-7 symposiums aiming at the upgrade of the Dairy Sector. One major interest was the milk quality. Stepwise, the efforts followed cow milk structural development in organizing the testing laboratory, the definition of quality in composition (fat, protein, lactose, total solids), in Hygienic (Total Bacteria Count, Somatic Cell Count, antibiotics residues and Aflatoxin M1 contamination), adulteration with water and detection of milk species. EU, by Decision 2002/657/EC, defined the rules for the Directive 96/23/EC, enumerated the testing methods, the demands in sampling procedures, the minimum limits of performance, the quality control (ISO 17025) and the interpretation of results. The equivalency of results from different laboratories, through ISO 17025, demanded the application of ISO analytical standards. In a period of 5 years these standards have been reformed in order to cover the needs of sheep and goat milk analysis. Novel development in analytical instrumental methods, like FTIR interferometer working with mid-Infrared region of the spectrum from 3-10 µm corresponding to 1000-5000 cm-1, gives opportunities of collecting data by making measurements for new parameters in complex dairy products, like Urea in milk, FFA profile, casein, pH, etc. Flow Cytometry for Individual Bacteria Count and Somatic Cells Count is opening the road for applications on testing for raw milk in hygienic control of the sheep and goat dairy sector. New developed screening methods are applied to give rapid results for antibiotics or aflatoxin M1 residues. Milk quality in the Central Testing Laboratory of today, is upgraded and promoted through rapid, trustful and traceable systems of LIMS in payments and herd management. Milk species mixtures can today be analysed in milk and dairy products with screening and reference methods. PDO products need today testιng methods for authenticity of animals' breed and geographical region of production.
The use of multi element profiling to differentiate between cowand buffalo milk
Food Chemistry, 2008
The multi element profile of milk from 12 cows and 6 water buffaloes was investigated, to establish whether dairy products derived 11 from the two species could be distinguished. Multi-element data were obtained using ICP-MS. Following assessment against the team's 12 QA/QC criteria, or where the levels were below the LOD for the procedure, 16 elements (P, S, K, 13 Mo, Cs and Ba) were submitted for statistical analysis. Using linear discriminant analysis (LDA) it was possible to differentiate between 14 milk from the two species, produced under identical environmental and animal husbandry conditions, on one farm. The sources of food 15 and water available for consumption by the animals were also analysed and the results showed that there was no correlation between the 16 elemental composition of the dietary components and the profiles observed in the milk.
Food Chemistry, 2010
Rapid measurements of milk properties and discrimination of milk origin are necessary techniques for quality control of milk products. The present study was undertaken to evaluate the potential of using front face fluorescence spectroscopy (FFFS) and synchronous fluorescence spectroscopy (SFS) for monitoring the quality of forty-five ewe's milk samples originating from different feeding systems. Physicochemical analyses and fluorescence spectra were conducted on samples during lactation periods (the first 11 weeks). The principal component analysis (PCA) separately applied to the physico-chemical and fluorescence spectral data showed only small discrimination between milk samples based on lactation periods and diet compositions. Similar results were obtained by separately applying factorial discriminant analysis (FDA) on each technique. In a second step, concatenation technique were applied to FFF spectra acquired after excitation set at 250, 290, 380 nm and emission set at 410 nm. Results obtained showed a good discrimination among milk samples with regard to feeding systems given to the ewes throughout the lactation periods. In addition, a better discrimination was observed with FFFS than with SFS.
A Note on the Tracing of Herbage Contribution to Grazing Sheep Diet Using Milk and Feces Biomarkers
Frontiers in Veterinary Science, 2021
Milk from grazing ruminants is usually rich in beneficial components for human health, but distinguishing milks sourced from grazing is difficult, and this hinders the valuing of the grazing benefit. This study aimed at evaluating the ability of milk biomarkers (1) to trace milks sourced from sheep submitted to different access times (ATs) to pasture and (2) to estimate sheep herbage dry matter intake (HDMI, g DM ewe−1 d−1) and herbage percentage (HP, % DM) in sheep diet. Animal data derive from a published experiment in which six replicated groups of mid-lactation Sarda sheep had ATs of 2, 4, or 6 h d−1 to a ryegrass pasture. Sheep HDMI and HP of each group were measured on four dates in April 2013. Group milk was sampled, and milk fatty acids (FAs) and n-alkanes were determined by gas chromatography. The latter markers were also measured in feces samples bulked by group. The data (N = 24 records) were submitted to Linear Discriminant Analysis (LDA) aimed at distinguishing the AT t...