Borage oil (Borago officinalis L): An important source of gamma linolenic acid .2. Tocopherols and chlorophyll content and sensorial analysis of borage oils extracted by different techniques and blended with extra virgin olive oil

Contents in tocopherols and chlorophyll in the unsaponifiable fraction of borage oils extracted with different techniques, extra virgin olive oil and different mixtures of them (10 and 15%), have been evaluated. A panel test (consumer's test, duo-trio test, and classification test) has also been realised with the purpose to determine the organoleptic quality of the different samples. The obtained results put in evidence the presence of alpha-tocopherol in the extra virgin olive oil only (94% of alpha tocopherol on total tocopherols), while the borage oil contains beta, delta and gamma isomers able to explicate a minor antioxidant activity than alpha. The chlorophyll content in borage oils, which depend son the extraction technique used, is not significantly changed during the preservation time considered (four months at room temperature). Sensorial analysis confirms that the off-flavours of pure borage oil are masked in the blends by extra virgin olive oil added till 80%.