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A Comparative Study of the Phenolic and Technological Maturities of Red Grapes Grown in Lebanon

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ABSTRACT

Grape harvest date is determined according to the technological and phenolic maturities. These parameters were calculated for different red grape (Vitis vinifera L.) varieties (Cabernet Sauvignon, Merlot, Syrah, Cabernet Franc) over four years (2008, 2009, 2010, and 2011) (642 samples). Titratable acidity and sugar content of the grapes were used to determine the technological maturity, whereas Glories (1 and 2) and ITV (Institut Technique de la Vigne et du Vin) methods were used to monitor their phenolic maturity. The ITV method allows the monitoring of phenolic maturity by the quantification of total polyphenol index and anthocyanins, while the Glories method enables the quantitative evolution of extractable anthocyanins and tannins of the grapes. A correlation was shown between the harvest dates obtained by both ITV and Glories (R2 = 0.7 – 0.93). Phenolic maturity of grapes can, therefore, be optimized by the application of both ITV and Glories. Similarly, a correlation was observed between technological and phenolic harvest dates. The effect of climate on the phenolic content of grapes was also studied. The highest temperatures (up to 25 °C) accompanied by the lowest rainfall ( value), induced the maximal concentration of polyphenols in grapes. Thermal and water stresses were also shown to enhance the grapes’ polyphenolic production.

No MeSH data available.


Anthocyanin content (mg/L) and total polyphenol index (IPT) (calculated by Institut Technique de la Vigne et du Vin (ITV) method) of four plots ITCS41 (a); ITCS42 (b); ITCS51 (c); and ITCS52 (d) of Cabernet Sauvignon grapes as a function of time (day (dd)/month (mm)) over four years (2008, 2009, 2010, and 2011).
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antioxidants-06-00008-f001: Anthocyanin content (mg/L) and total polyphenol index (IPT) (calculated by Institut Technique de la Vigne et du Vin (ITV) method) of four plots ITCS41 (a); ITCS42 (b); ITCS51 (c); and ITCS52 (d) of Cabernet Sauvignon grapes as a function of time (day (dd)/month (mm)) over four years (2008, 2009, 2010, and 2011).

Mentions: Figure 1 shows anthocyanin content (mg/L) and total polyphenol index (TPI) (calculated by ITV method) of four different cabernet sauvignon plots (ITCS41, ITCS42, ITCS51, ITCS52) as a function of time, over four years of study (2008, 2009, 2010, and 2011). The anthocyanin content (mg/L) increases to reach a peak (optimal harvest time) and then decreases. This kinetic was observed in many previous studies [12,13,14,15]. The decrease of anthocyanins after the peak can be due to the combination of anthocyanins and tannins [16]. For the same year, the peak of anthocyanins is almost reached at the same date for all the plots. For example, the optimal harvest time of ITCS41, ITCS42, ITCS51 and ITCS52 was 29 September 2011. Moreover, all the concentrations of anthocyanins (at harvest time) in 2008 and 2010 are higher than those obtained in 2009 and 2011. The values of TPI increase in the beginning of grape maturation to reach a peak, then gradually decrease. This was observed for the four plots of CS and over the four years. Similarly to anthocyanin content, the levels of TPI in 2008 and 2010 are higher than those obtained in 2009 and 2011. Moreover, the TPI peaks were reached at the same time than those of anthocyanin content.


A Comparative Study of the Phenolic and Technological Maturities of Red Grapes Grown in Lebanon
Anthocyanin content (mg/L) and total polyphenol index (IPT) (calculated by Institut Technique de la Vigne et du Vin (ITV) method) of four plots ITCS41 (a); ITCS42 (b); ITCS51 (c); and ITCS52 (d) of Cabernet Sauvignon grapes as a function of time (day (dd)/month (mm)) over four years (2008, 2009, 2010, and 2011).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383968&req=5

antioxidants-06-00008-f001: Anthocyanin content (mg/L) and total polyphenol index (IPT) (calculated by Institut Technique de la Vigne et du Vin (ITV) method) of four plots ITCS41 (a); ITCS42 (b); ITCS51 (c); and ITCS52 (d) of Cabernet Sauvignon grapes as a function of time (day (dd)/month (mm)) over four years (2008, 2009, 2010, and 2011).
Mentions: Figure 1 shows anthocyanin content (mg/L) and total polyphenol index (TPI) (calculated by ITV method) of four different cabernet sauvignon plots (ITCS41, ITCS42, ITCS51, ITCS52) as a function of time, over four years of study (2008, 2009, 2010, and 2011). The anthocyanin content (mg/L) increases to reach a peak (optimal harvest time) and then decreases. This kinetic was observed in many previous studies [12,13,14,15]. The decrease of anthocyanins after the peak can be due to the combination of anthocyanins and tannins [16]. For the same year, the peak of anthocyanins is almost reached at the same date for all the plots. For example, the optimal harvest time of ITCS41, ITCS42, ITCS51 and ITCS52 was 29 September 2011. Moreover, all the concentrations of anthocyanins (at harvest time) in 2008 and 2010 are higher than those obtained in 2009 and 2011. The values of TPI increase in the beginning of grape maturation to reach a peak, then gradually decrease. This was observed for the four plots of CS and over the four years. Similarly to anthocyanin content, the levels of TPI in 2008 and 2010 are higher than those obtained in 2009 and 2011. Moreover, the TPI peaks were reached at the same time than those of anthocyanin content.

View Article: PubMed Central - PubMed

ABSTRACT

Grape harvest date is determined according to the technological and phenolic maturities. These parameters were calculated for different red grape (Vitis vinifera L.) varieties (Cabernet Sauvignon, Merlot, Syrah, Cabernet Franc) over four years (2008, 2009, 2010, and 2011) (642 samples). Titratable acidity and sugar content of the grapes were used to determine the technological maturity, whereas Glories (1 and 2) and ITV (Institut Technique de la Vigne et du Vin) methods were used to monitor their phenolic maturity. The ITV method allows the monitoring of phenolic maturity by the quantification of total polyphenol index and anthocyanins, while the Glories method enables the quantitative evolution of extractable anthocyanins and tannins of the grapes. A correlation was shown between the harvest dates obtained by both ITV and Glories (R2 = 0.7 – 0.93). Phenolic maturity of grapes can, therefore, be optimized by the application of both ITV and Glories. Similarly, a correlation was observed between technological and phenolic harvest dates. The effect of climate on the phenolic content of grapes was also studied. The highest temperatures (up to 25 °C) accompanied by the lowest rainfall ( value), induced the maximal concentration of polyphenols in grapes. Thermal and water stresses were also shown to enhance the grapes’ polyphenolic production.

No MeSH data available.