The effect of hydrolysis conditions on the aroma released from Semillon grape glycosides

• I.L. Francis ^[1] ; M.E. Tate ^[2] ; P.J. Williams ^[1]
  1. [1] Australian Wine Research Institute

     Australian Wine Research Institute

     Australia

     
  2. [2] University of Adelaide

     University of Adelaide

     Australia

     
• Localización: Australian journal of grape and wine research, ISSN 1322-7130, Vol. 2, Nº 2, 1996, págs. 70-76
• Idioma: inglés
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• Resumen

  • A glycoside fraction was isolated from a Semillon juice and hydrolysed in vitro by acid‐catalysis at elevated temperature, or by glycosidase enzyme action, or by a sequence of glycosidase and acid treatments. The hydrolysates were evaluated in a white wine medium by sensory descriptive analysis. To evaluate aroma released by in situ hydrolysis of glycosides, wine prepared from the Semillon juice was also assessed, before and after elevated temperature storage, together with Semillon wines from earlier vintages. Descriptive analysis of these samples showed that enzyme‐catalysed hydrolysates had no detectable effect on aroma, while acid‐hydrolysis produced significant aroma and conferred sensory properties similar to those of bottle‐aged wines, i.e. diminished floral and apple aroma attributes, and enhanced honey, nutty, oak, toasty and tobacco attributes. A similar effect on aroma attributes was found for the heated young Semillon wine, which was not scored significantly differently from a three‐year‐old Semillon wine, except for the lime attribute. The glycosyl‐glucose concentration of the Semillon wines was correlated with the sensory scores of the wines, indicating that the extent of in situ hydrolysis of glycosides in wines relates to the development of flavour as a result of storage or accelerated hydrolysis. This study has demonstrated a close association among the aroma properties of Semillon grape glycosides hydrolysed in vitro at elevated temperature, in situ under natural conditions, and in situ at elevated temperature, and supports acid‐catalysed hydrolysis of grape glycosides as the mechanism of varietal aroma development in wine.