The Quality Assessment of Oils Obtained From Berry Fruit Seeds Using Pressurized Liquid Extraction

Berry fruit seeds should be treated as a valuable waste product of fruit industry. In the following study oils from cranberry, black currant, red currant, strawberry and chokeberry seeds were extracted by conventional and pressurized liquid extraction. The quality of oils was assessed by determining oxidative stability (onset and maximum time of induction) with the use of pressure differential scanning calorimetry, fatty acids composition by gas chromatography and health indices, such as atherogenicity, thrombogenicity and hypocholesterolemic indexes. Additionally, health-promoting index was calculated. It was found that fatty acid profile was not affected when pressurized liquid extraction was used. Major fatty acid in the studied oils was linoleic acid ranging from 36% for cranberry seed oil to 69% for chokeberry seed oil, followed by α-linolenoic acid in case of cranberry, strawberry and redcurrant seed oils or by oleic acid for chokeberry and blackcurrant seed oils. The oxidative stability of fats extracted with the use of pressurized solvent was significantly lower, comparing to oils obtained in conventional extraction process e.g., maximum induction time for conventionally extracted chokeberry seed oil was 40.74 ± 0.66 min and 9.24 ± 0.57 min when pressurized liquid extraction was applied. The studied oils had low values of atherogenicity and thrombogenicity indexes, what with combination with high values of hypocholesterolemic index allow to qualify them for high nutritional quality oils. However, further studies, regarding process optimization in order to obtain oils with improved quality, mainly better oxidative stability, is needed.