Influence of Different Thermohygrometric Conditions on Changes in Instrumental Texture Properties and Phenolic Composition during Postharvest Withering of ‘Corvina’ Winegrapes (Vitis vinifera L.)

Abstract

‘Corvina’ winegrapes were postharvest withered under three controlled thermohygrometric conditions. Sampling was done on different days of withering and the mechanical properties, technological ripeness parameters, phenolic composition, and anthocyanin profile were determined. Depending on the condition, skin break force and pedicel detachment force significantly decreased during the dehydration process with a maximum variation of −0.258 and −1.306 N, respectively. Instead, total flavonoids of skin and seeds, and proanthocyanidins and low-weight flavanols of seeds increased, with a maximum variation of +1,483, +733, +1,022, and +469 mg/kg, respectively. The skin hardness was confirmed to be an important parameter for the dehydration kinetics.

Keywords:

• Controlled thermohygrometric conditions
• cv. Corvina (Vitis vinifera L.)
• Instrumental texture analysis
• Phenolic composition
• Postharvest withering

ACKNOWLEDGMENT

This work was supported by the project Contratto di Filiera—Territori DIVINI (DM MIPAF August 1, 2003, and s.m.i).

Notes

All data are expressed as average value ± standard deviation (n = 25). Different Latin letters within the same row indicate significant differences ( ^a ) among withering conditions at the same withering time (Tukey B test; p < 0.05). Different Greek letters within the same row indicate significant differences ( ^b ) among withering times under the same withering condition (Tukey B test; p < 0.05).

Sign: *, **, ***, and ns indicate significance at p < 0.05, 0.01, 0.001, and not significant, respectively.

F _sk: berry skin break force; W _sk: berry skin break energy; E _sk: berry skin Young's modulus; Sp _sk: berry skin thickness; F _ped: peduncle detachment force; W _ped: peduncle detachment energy; BH: berry hardness; BCo: berry cohesiveness; BG: berry gumminess; BS: berry springiness; BCh: berry chewiness; BR: berry resilience; subscript norm: normalized according to the respective berry diameter.

F ₀: fresh berries; A: 15°C, 45% RH; B: 8°C, 45% RH; C: 15°C, 80% RH.

All data are expressed as average value ± standard deviation (n = 3). Different Latin letters within the same row indicate significant differences ( ^a ) among withering conditions at the same withering time (Tukey B test; p < 0.05). Different Greek letters within the same row indicate significant differences ( ^b ) among withering times under the same withering condition (Tukey B test; p < 0.05).

Sign: *, **, ***, and ns indicate significance at p < 0.05, 0.01, 0.001, and not significant, respectively.

SSC: total soluble solids content; TA: titratable acidity.

F ₀: fresh berries; A: 15°C, 45% RH; B: 8°C, 45% RH; C: 15°C, 80% RH.

All data are expressed as average value ±standard deviation (n = 3). Different Latin letters within the same row indicate significant differences ( ^a ) among withering conditions at the same withering time (Tukey B test; p < 0.05). Different Greek letters within the same row indicate significant differences ( ^b ) among withering times under the same withering condition (Tukey B test; p < 0.05).

Sign: *, **, and ns indicate significance at p < 0.05, 0.01, and not significant, respectively.

TA: total anthocyanins; TF: total flavonoids; PRO: proanthocyanidins; FRV: flavanols reactive to vanillin; subscript sk: berry skin; subscript s: berry seeds.

F ₀: fresh berries; A: 15°C, 45% RH; B: 8°C, 45% RH; C: 15°C, 80% RH.

All data are expressed as average value ±standard deviation (n = 3). Different Latin letters within the same row indicate significant differences ( ^a ) among withering conditions at the same withering time (Tukey B test; p < 0.05). Different Greek letters within the same row indicate significant differences ( ^b ) among withering times under the same withering condition (Tukey B test; p < 0.05).

Sign: *, **, ***, and ns indicate significance at p < 0.05, 0.01, 0.001, and not significant, respectively.

F ₀: fresh berries; A: 15°C, 45% RH; B: 8°C, 45% RH; C: 15°C, 80% RH.

Reducing sugars: 230 ± 8 g/L. Withering condition C: 15°C, 80% RH. S: soft; H: hard.

All data are expressed as average value ± standard deviation (n = 3).

^a Significant differences among skin hardness at the same withering time.

^b Significant differences among withering times at the same skin hardness.

Sign: **, ***, and ns indicate significance at p < 0.01, 0.001, and not significant, respectively.

SSC: total soluble solids content; TA: titratable acidity.

Reducing sugars: 230 ± 8 g/L. Withering condition C: 15°C, 80% RH. S: soft; H: hard.

All data are expressed as average value ± standard deviation (n = 3).

^a Significant differences among skin hardness at the same withering time.

^b Significant differences among withering times at the same skin hardness.

Sign: *, **, ***, and ns indicate significance at p < 0.05, 0.01, 0.001, and not significant, respectively.

TA: total anthocyanins; TF: total flavonoids; PRO: proanthocyanidins; FRV: flavanols reactive to vanillin; subscript sk: berry skin; subscript s: berry seeds.

Reducing sugars: 230 ± 8 g/L. Withering condition C: 15°C, 80% RH. S: soft; H: hard.

All data are expressed as average value ± standard deviation (n = 3).

^a Significant differences among skin hardness at the same withering time.

^b Significant differences among withering times at the same skin hardness.

Sign: *, ***, and ns indicate significance at p < 0.05, 0.001, and not significant, respectively.

Reducing sugars: 230 ± 8 g/L. Withering condition C: 15°C, 80% RH. S: soft; H: hard.

L. Rolle and S. Giacosa contributed equally to the study.