Articles scientifiques

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01 mars 2010

Assessment of maple syrup physico-chemistry and typicity by means of fluorescence spectroscopy

Auteurs : Alain Clément, Luc Lagacé et Bernard Panneton.

Cet article est disponible seulement en anglais (Journal of Food Engineering, Volume 97, Issue 1, March 2010, Pages 17–23).  Le numéro de référence (Digital Object Identifier (DOI)) est le : 10.1016/j.jfoodeng.2009.08.029.

Maple syrup is a natural sweetener obtained from the transformation of maple sap collected mostly from sugar maple (Acer saccharum Marsh) in North America. At present, simple physico-chemical tests are used for routine quality control. Inspectors also taste all batches on the market to ensure authenticity. Because of the presence of various aromatic compounds in sap and syrup, intrinsic fluorescence was tested as a means to characterize the physico-chemistry and typicity of maple syrup. Two hundred samples of sap and their corresponding syrup were obtained from various farms in 2003 and 2004. They were analysed by conventional physico-chemical tests and by fluorescence spectroscopy. Two major regions of fluorescence were found, which were mostly the same for sap and syrup. The first one was at 320 nm, excited at 275 nm, and the second one at 460 nm, excited at 360 (syrup) or 370 nm (sap). The first peak diminishes as harvesting season progresses, while the second peak increases, making it possible to predict the harvesting period of syrup from its spectra (r2 = 0.88 in 2003 and 0.81 in 2004). Color of syrup (r2 = 0.91 and 0.88) and bacterial counts in sap (r2 = 0.75 and 0.78) were also predicted from syrup spectra. Results show that sap spectra are related to syrup spectra and could potentially be used as predictor of quality prior to transformation. Discriminant analysis revealed that between 71% and 95% of syrup samples were correctly classified according to the farm of origin in 2003, and between 78% and 100% in 2004. Proximity was not always a factor of explanation of misclassification, suggesting that precise farm location, rather than the broad region of production is the major factor of typicity.

04 janvier 2010

Identification of Volatile Compounds in Maple Syrup using Headspace Solid-Phase Microextraction with Gas Chromatography-Mass Spectrometry

Auteurs : Hassan Sabik, Jacinthe Fortin et Nathalie Martin.

Cet article est disponible seulement en anglais (Chp. 12. from the book: Chromatography types, techniques and Methods. Thoma J. Quintin Ed. Nova Science Publishers, Inc., 2010, p. 417-427.

Headspace solid-phase microextraction (HS-SPME) combined with gas chromatography-mass spectrometry (GC/MS) was applied to identify volatile compounds in four typical maple syrups. Carboxen/polydimethylsiloxane (CAR/PDMS, 85 μm) fibre was selected as the fibre of choice because of its high capacity to extract both volatile and semi-volatile compounds. The following conditions were selected for HS-SPME analysis: 1) extraction temperature of 40°C and extraction time of 44 min for volatile compounds; and 2) extraction temperature of 67°C and extraction time of 60 min for semi-volatile compounds. A 1-g portion of maple syrup, diluted with 1 mL of NaCl solution (6 M), was sufficient to get the desired sensitivity. A total of 204 volatile compounds were identified by comparing their mass spectra and retention times with injected standards and/or by searching the Mass Spectral Library database of the National Institute of Standards and Technology. Of those compounds, 63 were found to be food aromatic compounds belonging to the following chemical families: acids (1), alcohols (3), aldehydes (8), aromatic compounds (2), esters (1), furan derivatives (15), hydrocarbons (3), ketones (10), pyrazines (15) and miscellaneous substances (5). To our knowledge, 50 of those aromatic compounds had not previously been detected in maple syrup. (388)

04 janvier 2010

Identification of Potential Impact Odorants in Four Typical Maple Syrups Using Headspace Solid-phase Microextraction with Gas Chromatography-mass Spectrometry

Auteurs : Sabik, H., Martin, N. et J. Fortin.

Cet article est disponible seulement en anglais (From the book: Recent Advances in Food, Flavor Chemistry, Proceedings of the 12th International Flavor Conference,RSC Publishing, 2010, p. 69-78). (388)
 

 

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