jueves, 30 de enero de 2014

Aplicación del SPI (Indice de Precipitación salival) para la evaluación de la astringencia del vino tinto



APLICACIÓN DEL SPI (INDICE DE PRECIPITACIÓN SALIVAL) PARA LA EVALUACIÓN DE LA ASTRINGENCIA DEL VINO TINTO

Fuente: www.infowine.com

Rinaldi , A.; Gambuti , A.; Moio , L.; 2012, Food Chemistry 135 (4) 2498-2504 (15/1/2014)

El objetivo de este trabajo era evaluar la astringencia de los vinos tintos mediante el método basado en SDS -PAGE. Se llevó a cabo la optimización del ensayo in vitro, llamado SPI (Índice de Precipitación salival) que mide la reactividad de las proteínas salivales frente a los polifenoles del vino.

La optimización incluyó la elección de la saliva: proporción de vino, tipología saliva (saliva en reposo o estimulada) y la temperaturas. También se determinó el LOD (0,05 g / L de tanino condensado ) y LOQ (0,1 g / L de tanino condensado) de la reacción entre las proteínas salivales y taninos adicionados en vino blanco.

Se analizaron cincuenta y siete vinos tintos con el SPI optimizado, índice de Folin - Ciocalteu, índice de gelatina, contenido de taninos totales y evaluación cuantitativa de la sensibilidad a la astringencia.

Se encontró una correlación significativa entre el SPI y la astringencia de los vinos tintos (R2 = 0,969 ), lo que indica que este ensayo puede ser útil como estimador de la astringencia.

APPLICATION OF THE SPI (SALIVA PRECIPITATION INDEX) TO THE EVALUATION OF RED WINE ASTINGENCY

Source: www.sciencedirect.com

Rinaldi , A.; Gambuti , A.; Moio , L.; 2012, Food Chemistry 135 (4) 2498-2504 (15/1/2014)

Abstract:

The aim of this work was to evaluate the astringency of red wines by means of a SDS–PAGE based-method. The optimization of the in vitro assay, named SPI (Saliva Precipitation Index) that measured the reactivity of salivary proteins towards wine polyphenols, has been performed. Improvements included the choice of saliva:wine ratio, saliva typology (resting or stimulated saliva), and temperature of binding. The LOD (0.05 g/L of condensed tannin) and LOQ (0.1 g/L of condensed tannin) for the binding reaction between salivary proteins and tannins added in white wine were also determined. Fifty-seven red wines were analysed by the optimised SPI, the Folin–Ciocalteu Index, the gelatine index, the content of total tannins and the sensory quantitative evaluation of astringency. A significant correlation between the SPI and the astringency of red wines was found (R2 = 0.969), thus indicating that this assay may be useful as estimator of astringency.

Highlights:

- An optimization of the existing method (SPI) based on the binding reaction between human saliva and wine was performed.
- Parameters such as salivary flow, saliva typology, ratio saliva/wine, and temperature of binding were evaluated.
- The method was validated by the LOD and LOQ.
- A good correlation between sensory and analytical data was found.
- Based on a relationship between SPI and wine phenolic content, the SPI can be expressed in gallic acid equivalent.

Keywords:

Astringency; Precipitation; Salivary proteins; SDS–PAGE; Red wines

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