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

Abstract

Berry fruit seeds should be treated as a valuable waste product of the 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 the fatty acid profile was not affected when pressurized liquid extraction was used. The major fatty acids in the studied oils were linoleic acid ranging from 36% for cranberry seed oil to 69% for chokeberry seed oil, followed by α-linolenoic acid in the case of cranberry, strawberry and red currant seed oils or by oleic acid for chokeberry and black currant seed oils. The oxidative stability of fats extracted with the use of pressurized solvent was significantly lower compared to oils obtained using the conventional extraction process, e.g., the 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, which, when combined with high values of hypocholesterolemic index, qualifies them as high nutritional quality oils. However, further studies regarding the process optimization are needed in order to obtain oils with improved quality, especially better oxidative stability.

Keywords

• accelerated solvent extraction
• pressurized liquid extraction
• oil extraction
• fruit seeds
• oxidative stability
• PDSC