Influenza delle tecniche di preparazione della pasta di olive sulla qualità dell'olio. Nota II. Evoluzione delle sostanze fenoliche e di alcuni parametri di qualità in funzione della maturazione delle drupe in olio d'oliva vergine della cv. Coratina

Some quality parameters have been evaluated in oils defined as bitter-pungency extracted from Coratina olives at different ripening stages, and which had undergone different processing procedures. The content of phenolic substances which at the beginning was very high (with values between 436 - 628 mg/kg) undergoes a 50% decrease as the ripening of the olives advances. Hammer crushers were found to have a greater phenol extraction capacity, than stone mills, that produce increasings which in the course of the drupes ripening lower down (going from 44% to 32%). Data referred to induction time, which are always rather high, show both a trend which can be compared to those of total phenols and a good correlation with one of the components of the complex fraction of phenolic substances performed by means of HPLC. This fraction is particularly high if compared to phenolic simple substances and oleuropeine was never found in any of the oil samples.