Abstract in English:
Many negative effects of mechanical harvesting of grapes are attributed to
damage and subsequent leakage of juice, often accentuated by high time between
harvest and processing as well as high temperature. The presence of must in the
product harvested by machine, which can reach very high levels (25-30% of the total
mass), can cause several negative effects such as oxidation of phenolics, abnormal
fermentation, skins maceration, etc. For that reason, an innovative system of
handling and grapes transporting was developed in order to separate, once
harvested, the liquid part (must) from the solid one (bunch of grapes and single
grape), and then to apply different working processes to each of them. Thanks to
this system, it was possible to isolate the must in a closed tank and thus,
immediately, preserve it by dry ice or liquid carbon dioxide, with the addition of
enological chemicals (sulphur dioxide, ascorbic acid and tannin) to avoid chemical
and microbiological modifications. The evaluation of wines throughout tests and
sensorial analysis highlighted the better quality of the wines obtained by the
proposed technique compared with the traditional one. This was related to the
greater presence of primary fragrances, better color, and a better balanced
structure of the wine preserved against oxidation action. |