Aim: 

Monitoring the concentration of chemical nutritional parameters, such as palmitic acid, stearic acid, oleic acid, linoleic acid, a-tochopherol, total phenols, hydrophilic antioxidant capacity and lipophilic antioxidant capacity, with different Jaen index values.

Methods: 

The fatty acid composition has been analysed in according to the E.U. Regulations. The a-tochopherol of each oil was extracted and detected by Gas-Chromatografy. The antioxidant capacity of each unsaponifiable fraction was estimated by crocin bleaching inhibition method. The toal phenols has been analysed by spectrophotometer in according to Folin-Ciocolteau method, the amount of total phenols has been detected, comparing, for each sample, the results found with a standard solution of caffeic acid.

Results: 

From our results the fatty acids composition does not change along the Jaen index scale. At high Jaen index value correspond higher a-tochopherol and phenols value. Both hydrophilic and lipophilic antioxidant capacity present positive values and its trend present a shift at Jean index 1.5 and 1.7, It means that the drupaes have suffered an oxidative attack, before in the hydrophilic fraction and after in the lipophilic fraction, but the positive antioxidant capacity values means the anti-oxidative shield has been proof against this attack.

Conclusion: 

In conclusion we can say that the Jaen index is a valuable system in order to test the ripening grade of the drupaes, but it is yet too empiric and in our opinion other studies have been done in other to improve this index, expecially if compared with other system such as the puncture test (data not showed).