TY - JOUR T1 - Must Browning in Relation to the Behavior of Phenolic Compounds During Oxidation JF - American Journal of Enology and Viticulture JO - Am J Enol Vitic. SP - 346 LP - 349 DO - 10.5344/ajev.1990.41.4.346 VL - 41 IS - 4 AU - Véronique Cheynier AU - Jacques Rigaud AU - Jean-Marc Souquet AU - Françous Duprat AU - Michel Moutounet Y1 - 1990/01/01 UR - http://www.ajevonline.org/content/41/4/346.abstract N2 - White musts prepared from 24 Vitis vinifera varieties were supplied with oxygen by diffusion through silicone tubing. The oxygen consumption was followed by means of an oxymeter, the initial glutathione content was determined, and the concentration of hydroxycinnamic acids monitored by HPLC. Tristimulus color values were measured using the CIE 1976 L*a*b* Scale on the crude and filtered oxidized musts. A principal component analysis was performed on the analytical data and tristimulus parameters. The first axis contrasted b*F (yellowness of the filtered musts), a*C (redness of the crude musts), initial concentration of hydroxycinnamic acids, maximum levels of caftaric and GRP o-quinones, and oxygen consumption with b*C (yellowness of the crude musts), L*C and L*F (lightness of the crude and filtered musts). It differentiated light (resistant to oxidation), colored (sensitive to oxidation), and intermediate musts. Must browning susceptibility appeared essentially related to their initial hydroxycinnamic acid content. Yet, each of these three classes showed a characteristic behavior of caftaric acid derivatives during must oxidation, itself depending on the hydroxycinnamic acid to glutathione molar ratio. It seems, however, that other grape components compete with glutathione to trap caftaric acid quinones. ER -