viernes, 15 de junio de 2012

Análisis no destructivo para identificar vinos en botella con defectos


ANÁLISIS NO DESTRUCTIVO PARA IDENTIFICAR VINOS EN BOTELLA CON DEFECTOS

El problema de la variabilidad de la calidad de las botellas de vino durante su comercialización debido a unas condiciones de conservación inadecuadas o a la variabilidad durante el embotellado puede provocar importantes daños a nivel económico y de imagen de la bodega. A veces una porción significativa de botellas pertenecientes al mismo lote pueden presentar defectos debido a unos niveles particularmente altos de SO2, contaminación microbiológica, excesivo desarrollo de color o características sensoriales de oxidación.

El AWRI (Austrtalian Wine Research Institute) ha estudiado una nueva tecnología para la evaluación e identificación de las botellas de vino que aleatoriamente presentan problemas de oxidación durante el almacenamiento. Gracias a esta tecnología, denominada BevScanTM, el AWRI consiguió identificar las botellas de vino que presentaban unas características correctas para su comercialización.

El BevScanTM es una herramienta analítica no destructiva que puede ser utilizada para identificar diferencias espectrales entre botellas de vino. Aplicando la espectroscopía vis-Nir es posible analizar el vino embotellado e identificar, clasificar y cuantificar rápidamente diferencias entre las matrices.

Fuente: AWRI (The Australian Wine Research Institute)

NON-INVASIVE SPECTROSCOPIC SCREENING: A NEW APPROACH TO ASSESSING DAMAGED WINES INTRODUCTION

Introduction:
This case study presents an example of using BevScan’s classification mode to screen and sort bottles of a red wine affected by variable bottle oxidation.
More general information about BevScan and about variable oxidation can be found in the following two AWRI fact sheets, available from www.awri.com.au
- Introducing BevScan - a new tool for non-destructive wine analysis and classification.
- In-bottle measurement of variable bottle oxidation.

Background: The Australian Wine Research Institute (AWRI) receives a number of enquiries each year from wine producers who have issues with the variability of their products due to inadequate storage conditions, insufficient care taken by distributors and retailers through the supply chain and variability during bottling. Sometimes, a large proportion of bottles are unsaleable due to high sulfur dioxide (SO2) depletion, microbiological contamination, elevated colour development or oxidative sensory characteristics.

Summary: The AWRI, in conjunction with Angove Family Winemakers, used its BevScanTM technology to screen samples of a commercial red wine that were exhibiting random patterns of oxidation during storage and identify those bottles that had acceptable development characteristics.

A spectral classification model was built using samples of the wine that were exhibiting random patterns of oxidation. This calibration model was then used to screen approximately 700 cases of wine and identify those bottles that had acceptable development characteristics, allowing the mobilisation of stock for overseas markets.

Assessing the Problem: Six cases of the wine were supplied to the AWRI for spectral screening. All 72 samples were analysed using the BevScanTM instrument and spectral data was transferred to Unscrambler (CAMO, version 10.1) to undertake principal component analysis (PCA) and identify any differences/similarities among the samples. The spectral range was trimmed to 600-1000 nm for analysis and two groups of samples became apparent, as shown in the PCA plot below, with PC1 appearing to be related to the oxidised state of the wine. This appeared to offer an opportunity for discriminating between good and bad samples, non-destructively.

Summary: BevScanTM has been shown to be a valuable tool for screening and classifying wine stock impacted by random patterns of oxidation non-destructively. By using this tool, Angove Family Winemakers has been able to mobilise otherwise worthless stock and supply their customers with wine which tastes the way the winemaker intended.

For additional information:
Industry Applications (Neil Scrimgeour)
Phone: 08 8303 6600 Fax: 08 8303 6601
Email: neil.scrimgeour@awri.com.au

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