The results showed that “maturity date” or “ripening stages” effects were detected, but these are different for each individual component as well as for each of the two grape varieties studied.

 

In general, the dimer and trimer flavan-3-ol derivatives reached higher levels in the unaged wine made from the grapes collected on the later harvest dates which indicated that the degree of flavanol polymerization increased with the degree of grape ripening. However, this was only true in the CS. The TF had its peak in the middle ripening stage. There seemed to be only small differences between ripening stage 2 and 3, and certain compounds were even statistically higher in stage 2 than in stage 3. No difference in total phenols existed between stages 2) and 3).

 

WINE AGEING: “No clear trends with grape ripening were observed. In fact, the CS wines with the highest color intensity values were the wines made from the grapes collected on the 2nd harvest date.” The wines made from more mature grapes had higher levels of flavanols and their derivatives. The free anthocyanin content decreased sharply during aging, the greatest losses taking place in the first months of aging. After 18 months of ageing, any initial differences in anthocyanins and its derivatives (termed ‘new pigments’) due to ripening stage were virtually erased. However, color intensity differences were maintained after 18 months and in all cases the percentage of blue increased as ‘new pigments’ increased (i.e. anthocyanin products that are not antho-tannin complexes). Wines made from ripening 2) 3) showed higher levels in these ‘new pigments’, in both TF and CS wines.

 

Summarizing: delaying harvest date between 1 and 2 weeks produced grapes with greater color intensity and a higher percentage of blue pigment. This increase in anthocyanin derivative levels contributes to color stability by maintaining color intensity and increasing the blue component.

 

Additionally, the results showed that the amount of time the grapes are left on the vines may need to be limited, because wines made from the grapes collected on the 3rd harvest date did not exhibit better color quality characteristics than the wines made from the grapes collected on the 2nd harvest date.

 

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