headspace analysis (2)


Dry-cured Iberian ham owes its special flavour because it is produced from pigs which feed on acorns. Spanish researchers have investigated the non-destructive authentication of Iberian ham by analysing the headspace from hams produced from different feeding regimes, and analysing the volatiles using gas chromatography coupled to either a mass spectrometer (GC-MS) or an ion mobility spectrometer (GC-IMS, which separates molecules based on their mass, shape and charge). Both instruments were able to differentiate different pig feeding regimes in hams. GC-IMS was more sensitive detecting more volatiles, but GC-MS gave better in providing quantitative results for the amount of volatiles. Using principal component analyis (PCA), the best authenticity markers for hams produced from different feeding regimes were ethanol, 2-propanol and 3-methylbutanol, 3-methylbutanal and heptane.

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4494264005?profile=RESIZE_400xDNA  methods are available for determining the adulteration of orange juice by mandarin juice. Chinese researchers have developed a different approach by analysing the VOCs in the headspace of orange juice (not from concentrate) and manadarin juice, and using chemometrics to calculate if a sample of orange juice has mandarin juice in it. Juices were extracted from different cultivars of sweet orange and mandarin fruits. After being pasteurised, the VOCs in the juice samples were extracted using headspace solid-phase microextraction, and qualitatively and quantitatively analysed using gas chromatography–mass spectrometry. Thirty-two VOCs identified in both the sweet orange juice and mandarin juice, but at different concentrations, were used as variables, and the identification model for discriminating between the two varieties of juice was established by principal component analysis. Model juice mixtures were made up from different varieties of both mandarins and oranges. The model was able  to identify and quantify a blend of mandarin juice in orange juice at the level of 10% or above.

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