PT  - JOURNAL ARTICLE
AU  - Stéphanie Doumouya
AU  - Marc Lahaye
AU  - Chantal Maury
AU  - René Siret
TI  - Physical and Physiological Heterogeneity within the Grape Bunch: Impact on Mechanical Properties during Maturation
AID  - 10.5344/ajev.2014.13062
DP  - 2014 Feb 28
TA  - American Journal of Enology and Viticulture
PG  - ajev.2014.13062
4099  - http://www.ajevonline.org/content/early/2014/02/25/ajev.2014.13062.short
4100  - http://www.ajevonline.org/content/early/2014/02/25/ajev.2014.13062.full
AB  - Mechanical properties are emerging as a complementary criterion to evaluate grape berry quality for wine making. As texture is evaluated on a berry per berry basis it is important to assess the impact of the within grape heterogeneity on mechanical properties. Evolution of textural maturity of Cabernet Franc was assayed throughout ripening using double compression 20% tests. Instead of using berries randomly picked in the vineyard, berries were sampled from whole grape bunches. Results show coherent and significant evolution of double compression parameters: F1, Grad0, Grad1, W1 and gumminess significantly decreased while cohesiveness significantly increased during maturation. Variations in texture were related with major physiological and physical traits. Mechanical parameters differed significantly according to the berry position. Among these parameters, Grad1 was highly correlated with berry density and ∘Brix (r = −0.91 for both), and W1 was highly correlated with water content (r = 0.87). Within grape bunch heterogeneity was illustrated by different distributions of physical, physiological and texture parameters. A negative gradient was shown from the top to the bottom of bunches for dry weight, density, ∘Brix, cohesiveness, and gumminess. Berries at the distal part of the bunch were more advanced in maturity and were softer compared to the berries at the top. The results are discussed with regard to the sampling strategy in the assessment of grape berry quality based on mechanical properties.