Study of the aging and oxidation processes of vinegar samples from different origins during storage by near-infrared spectroscopy [An article from: An

About Study of the aging and oxidation processes of vinegar samples from different origins during storage by near-infrared spectroscopy [An article from: Analytica Chimica Acta] detail

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Study of the aging and oxidation processes of vinegar samples from different origins during storage by near-infrared spectroscopy [An article from: Analytica Chimica Acta] Description

This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in . The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
Near infrared spectroscopy combined with several chemometrical techniques has been used to control the aging process in vinegar and the changes produced during storage. Several considerations regarding NIR instrument changes, which can add noise to the determinations, were made and a strategy based on the correction of the spectra was used to eliminate the differences between spectra due to instrument variation, in particular to lamp change. Ninety-five different vinegars were measured using a near-infrared spectrometer. The spectrum of each vinegar sample was collected twice: the first time as soon as the bottle was opened and the vinegar had not undergone any oxidation process and the second measurement was taken after a certain period of time. Then, in order to quantify the discrimination between the two groups of spectra recorded in the two occasions and so to estimate the aging effect in the vinegar samples, Linear Discriminant Analysis was used as a classification method. To improve the results, bearing in mind that many of the measured variables could be useless and that the elimination of these wavelengths can help in interpretation, a feature selection technique was applied. For chemical interpretation of the retained wavelengths, the spectral zones correlated with the aging process were isolated and the species and compounds that can absorb in these NIR spectra bands were studied.

Relationship between sensory analysis and near infrared spectroscopy in Australian Riesling and Chardonnay wines [An article from: Analytica Chimica A

About Relationship between sensory analysis and near infrared spectroscopy in Australian Riesling and Chardonnay wines [An article from: Analytica Chimica Acta] detail

• Published on: 2005-05-10
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• Binding: Digital

Relationship between sensory analysis and near infrared spectroscopy in Australian Riesling and Chardonnay wines [An article from: Analytica Chimica Acta] Description

This digital document is a journal article from Analytica Chimica Acta, published by Elsevier in 2005. The article is delivered in HTML format and is available in your Amazon.com Media Library immediately after purchase. You can view it with any web browser.

Description:
The aim of this work was to investigate the relationship between sensory analysis and visible and near infrared spectroscopy in two Australian white wine varieties (namely unwooded Chardonnay and Riesling). A total of 120 samples (2 varietiesx3 replicatesx20 commercial labels) were scanned in transmission mode in the visible and near infrared range (400-2500nm). For the purposes of this study four aroma descriptors generated from a sensory descriptive analysis study: estery, honey, passionfruit, lemon-citrus and two palate properties:overall flavour and sweetness were selected for investigation. Calibration models between sensory properties and spectra were developed using partial least squares regression (PLS1 and PLS2) with cross validation. The correlation coefficients (R"c"a"l) were greater than 0.70 for estery, lemon and honey, and less than 0.50 for passionfruit, overall flavour and sweetness in both calibration and cross validation. Therefore, this work demonstrates that some relationships between sensory data and both visible and near infrared spectra exists to assess sensory properties in the white wine varieties. Further work will be carried out with a larger set of data including additional sensory properties in different white wine varieties in order to validate the method.