Mechanical tests and definition of new indexes of grape berry firmness. Evolution of berry skin hardness during alcoholic fermentation

  • P. Abbal INRAE, UMR SPO, Montpellier, France
  • A. Vernhet L'Institut Agro-Montpellier SupAgro, Montpellier, France
  • E. Abi-Habib L'Institut Agro-Montpellier SupAgro, Montpellier, France
  • S. Carrillo INRAE, UMR SPO, Montpellier, France
  • M. A. Ducasse IFV, UE Pech Rouge, Gruissan, France
  • C. Poncet Legrand INRAE, UMR SPO, Montpellier, France

Abstract

The mechanical strength or firmness of a fruit is considered an important parameter to characterise its state of ripeness or conservation, as well as other parameters such as sugar level or color. The mechanical hardness of grapes influences the integrity and sanitary quality of the harvest. In this study, the mechanical characteristics of grapevine berries were studied at harvest time in order to determine their rheological properties (firmness and hardness of the berry skin) during alcoholic fermentation. Special indexes were defined measuring the energy needed to crush the berries to 50 % of their initial diameter, and applied successively to two different varieties. The entire berry firmness and the skin hardness were both different. Mechanical indexes linked to grape firmness were defined. Using these indexes, a significant effect on the firmness behavior due to variety was recorded: the skin of 'Grenache Noir' was found firmer and harder than 'Carignan Noir'. Furthermore, during the alcoholic fermentation, no change in skin hardness was observed for both varieties, despite changes in the composition of the must. These results give new information on mechanical properties of berries and could be used as an aid in the winemaking process. Indeed, they would probably help the winemaker to better choose the type of fermentation and maceration adapted to his grapes according to the type of wine he wishes to produce.

Author Biographies

P. Abbal, INRAE, UMR SPO, Montpellier, France

Dr Philippe ABBAL

INRAE

UMR Sciences pour l'Oenologie

2, Place Viala

34060 Montpellier

 

E. Abi-Habib, L'Institut Agro-Montpellier SupAgro, Montpellier, France
     
M. A. Ducasse, IFV, UE Pech Rouge, Gruissan, France

 

 

C. Poncet Legrand, INRAE, UMR SPO, Montpellier, France

 

 

Published
2020-10-29
Section
Article