ORIGINAL ARTICLE Characterization of Encapsulated Flavor Systems by NIR and Low-field TD-NMR: A Chemometric Approach Leticia Andrade & Imad A. Farhat & Kasia Aeberhardt & Valery Normand & Søren B. Engelsen Received: 22 June 2007 / Accepted: 12 October 2007 / Published online: 9 November 2007 # Springer Science + Business Media, LLC 2007 Abstract A quantitative method for measuring simulta- neously the flavor and water contents in model spray-dried flavor delivery systems was developed using spectroscopic techniques and chemometrics. Nine encapsulated systems were prepared, consisting of a solid carrier (maltodextrin and gum arabic) and varying the amounts of water and flavor. The model flavors used in this work were a hydrophobic (limonene) and a more hydrophilic (2,5-dimethylpyrazine) single components. Near-infrared (NIR) and low-field time- domain nuclear magnetic resonance (low field TD-NMR) data were acquired on each system and analyzed using multivariate chemometric techniques to develop optimal prediction models. Partial least squares regression models showed good predictive ability, with coefficients of deter- mination (R 2 ) between 0.81 and 1.00 and low root mean square error of cross-validation values compared to the range of concentrations. The predictive ability of the chemometric models computed using the NIR spectra improved signifi- cantly when data were pre-processed using multiplicative signal correction. The development of good prediction models (i.e., robust models resulting in accurate predictions for water and flavor content) from the NMR relaxation data spectra was successful only for the hydrophobic limonene systems, yielding prediction models whose performance was better than the models obtained using the NIR data. Overall, NIR spectroscopy and NMR relaxometry were identified as complementary techniques rather than competitive methods in the characterization of encapsulated flavor systems. Keywords Flavor delivery systems . NIR . Low-field TD-NMR . Chemometrics . PCA . PLS Introduction Flavor encapsulation is increasingly gaining importance as it offers several advantages, the principal one being the physical and chemical protection of the flavor during storage and handling (and during critical stages of the food manufacturing process in the case of some encapsulation technologies). Indeed, the loss of some components of a flavor, for example, because of the evaporation of the most volatile species or the oxidation of the most susceptible ones, leads to major deterioration of flavor quality and authenticity. Encapsulation also allows a controlled release of the flavor to modulate its perception. 1 Other advantages include the ease of handling and dosing when using a solid powder vs a liquid, the ability to combine liquids and solids (e.g., acids, taste enhancers, sweeteners, etc.), and creation of visual effects depending on the encapsulation technology used. Flavor encapsulation, which typically consists of entrapping flavor inside a solid carrier or capsule, can be achieved by using different approaches. Whereas spray drying remains the most widely used technology, many approaches Food Biophysics (2008) 3:33–47 DOI 10.1007/s11483-007-9046-3 L. Andrade School of Biosciences, Division of Food Sciences, The University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK I. A. Farhat : K. Aeberhardt : V. Normand Firmenich SA, Route de la Bergère 7, 1217 Meyrin, Switzerland L. Andrade (*) : S. B. Engelsen Faculty of Life Sciences, Department of Food Science, Quality, and Technology, The University of Copenhagen, Rolighedsvej 30, 1958 Frederiksberg C, Denmark e-mail: lman@life.ku.dk