Integration of nondestructive techniques with destructive analyses to study postharvest water stress of winegrapes

Andrea Bellincontro, Isabella Nicoletti, Massimiliano Valentini, Alejandro Tomas, Diana De Santis, Danilo Corradini, Fabio Mencarelli*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

70 Citations (Scopus)

Abstract

Red Cesanese grapes were harvested at 21 Brix. Berries were destemmed manually and placed in perforated plastic trays inside a small ventilated tunnel at 10°C with 1.5 m/sec of air flow, 10°C with 2.5 m/sec of air flow, and 20°C with 1.5 m/sec of airflow as a control. Relative humidity was 45%. The experiment was stopped at 20% berry weight loss, after 26, 22, and 16 days for 10°C at 1.5 m/sec, 10°C at 2.5 m/sec, and 20°C at 1.5 m/sec, respectively. Sugar content rose to 24-25 Brix. Carbon dioxide production from chilled berries under a higher air flow rate was constantly higher (-30%) than at a lower ventilation, and similar to that of the 20°C sample. Berries lost firmness (higher deformation), increased hue angle, and decreased chroma, regardless of treatment. Berries kept at a higher flow rate had magnetic resonance images similar to those of the berries kept at 20°C, with diffuse dark areas in the mesocarp. Analysis of alcohol dehydrogenase in the direction of the oxidation of ethanol to acetaldehyde revealed significantly higher activity at 20°C than at 10°C at 20% of weight loss, and ethanol was lower. The fluorescence (Fa) pattern confirmed a different stress rate depending on temperature and flow rate. Near-infrared-acousto-optic tunable filter (N1R-AOTF) analysis revealed a different absorbance level at a specific wavelength range depending on the treatment and the rate of weight loss. A significant decrease in polyphenols occurred in 10°C samples. Flavonols and stilbenes increased significantly at 20°C, confirming a supposed higher rate of water stress at 20°C.

Original languageEnglish
Pages (from-to)57-65
Number of pages9
JournalAmerican Journal of Enology and Viticulture
Volume60
Issue number1
Publication statusPublished - 2009

Keywords

  • ADH
  • Air flow
  • Dehydration
  • Grape
  • MRI
  • NIR
  • Polyphenols
  • Temperature

ASJC Scopus subject areas

  • Food Science
  • Horticulture

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