Browsing by Author "von Baer, Dietrich"

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    Multivariate Bayesian discrimination for varietal authentication of Chilean red wine
    (TAYLOR & FRANCIS LTD, 2011) Gutierrez, Luis; Quintana, Fernando A.; von Baer, Dietrich; Mardones, Claudia
    The process through which food or beverages is verified as complying with its label description is called food authentication. We propose to treat the authentication process as a classification problem. We consider multivariate observations and propose a multivariate Bayesian classifier that extends results from the univariate linear mixed model to the multivariate case. The model allows for correlation between wine samples from the same valley. We apply the proposed model to concentration measurements of nine chemical compounds named anthocyanins in 399 samples of Chilean red wines of the varieties Merlot, Carmenere and Cabernet Sauvignon, vintages 2001-2004. We find satisfactory results, with a misclassification error rate based on a leave-one-out cross-validation approach of about 4%. The multivariate extension can be generally applied to authentication of food and beverages, where it is common to have several dependent measurements per sample unit, and it would not be appropriate to treat these as independent univariate versions of a common model.
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    Prototypes of nutraceutical products from microparticles loaded with stilbenes extracted from grape cane
    (2022) Avendano-Godoy, Javier; Ortega, Elisa; Urrutia, Manuel; Escobar-Avello, Danilo; Luengo, Javiana; von Baer, Dietrich; Mardones, Claudia; Gomez-Gaete, Carolina
    Grape canes (Vitis vinifera L.) are an important source of bioactive stilbenes, but they are considered a pruning residue. Despite the potential advantages for human health, the low aqueous solubility and stability limits their usage in commercial goods.This research aimed to improve knowledge about the solubility and stability of the main stilbenes present in important residues of the wine industry, such as grape canes (V. vinifera L. cv. Pinot Noir), through the formation of inclusion complexes with cyclodextrins (CDs) and subsequent polymeric microencapsulation.The formation of inclusion complexes between stilbenes presents in grape cane extracts and 15 mM hydroxypropyl-fl-cyclodextrin (HP-fl-CD) increased the aqueous solubility of (E)-resveratrol, (E)-e-viniferin and (E)-piceatannol by 2.8, 5.4 and 1.9 times, respectively. The microencapsulation (by spray drying) of the inclusion complexes using maltodextrin (MD) (10% w/v) allowed us to improve the stability of the stilbenes, obtaining a retention percentage of 81.9 +/- 2.2% after 60 min of UV irradiation (254 nm). The lower size microparticles (MPs) formulation was 10.9 +/- 0.9 mu m and had a stilbene loading of 0.61 +/- 0.01 mg/100 mg of MPs. The prototype tablets and capsules made from the MPs presented suitable characteristics for their eventual use.The microencapsulation of inclusion complexes between stilbenes presents in grape cane extracts and HP-fl-CD, using MD as a matrix component, is useful to increase the solubility and stability of stilbenes. The prepared MPs can be used for the development of nutraceutical products.(c) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.