Statistical correlation between flavanolic composition, colour and sensorial parameters in grape seed during ripening.
The aim of this work has been to determine the correlations between sensory analysis, colour and content of main flavanols present in seeds. For this, the flavanic composition of grape seeds with different degrees of maturity was analysed by HPLC-DAD-MS and the obtained results were correlated with CIELab colour parameters, perceived colour (C), hardness of the seed (HS), tannic intensity (TI) and astringency (A). Multiple linear regression analysis (MLR) with the variables showing significant correlations (p<0.05) was also performed. Grape seeds undergo important decreases in the content of catechins and procyanidin oligomers during ripening. Epicatechin-(4-8)-epicatechin-3-O-gallate (B2G) and (-)-epicatechin-3-O-gallate (ECG) are the flavanolic compounds whose contents decrease most. The changes in the phenolic composition accompany changes in TI, A and HS. The total content of flavanols in the seed is not the only factor affecting these attributes, since samples containing higher contents in flavanols can exhibit less astringency and tannic intensity than others with lower ones. The qualitative profile of the seeds is, therefore, also responsible for the sensations elicited in the mouth. A and HS parameters are more affected by the presence of galloylated dimeric procyanidins in the molecule than TI. CIELab colour parameters of seeds have high correlation coefficients with many flavanolic compounds. ECG was the compound most related to these parameters.
Ferrer-Gallego
Raúl
R
Grupo de Investigación en Polifenoles, Unidad de Nutrición y Bromatología, Facultad de Farmacia, Universidad de Salamanca, Campus Miguel de Unamuno, E 37007 Salamanca, Spain.
García-Marino
Matilde
M
Hernández-Hierro
José Miguel
JM
Rivas-Gonzalo
Julián C
JC
Escribano-Bailón
M Teresa
MT
D000975:Antioxidants / Q000032:analysis; D002392:Catechin / Q000031:analogs & derivatives / Q000032:analysis; D002851:Chromatography, High Pressure Liquid; D003116:Color; D005419:Flavonoids / Q000032:analysis* / Q000737:chemistry; D056604:Grape Seed Extract / Q000737:chemistry; D013058:Mass Spectrometry; D044945:Proanthocyanidins / Q000032:analysis; D012044:Regression Analysis; D013634:Tannins / Q000032:analysis; D013649:Taste; D027843:Vitis / Q000737:chemistry*
D000975:Antioxidants; D005419:Flavonoids; D056604:Grape Seed Extract; D044945:Proanthocyanidins; D013634:Tannins; D002392:Catechin; C062669:epicatechin gallate