Characterization of Six Cold-Pressed Berry Seed Oils and Their Seed Meals

Abstract

When producing fruit juices, the pomace, containing the seeds, is left as a byproduct. In this study, cold-pressed blackcurrant, raspberry, blackberry, blueberry, strawberry, and sea buckthorn seed oils and their seed meals were characterized to explore possible commercial applications. The fatty acid (FA) composition, sterol content, tocopherol content, total polyphenolic content (TP), color, ferric reducing antioxidant power (FRAP), and free-radical scavenging capacity (DPPH assay) were determined. The levels of TP ranged from 8.9 to 19.3 mg GAE/100 g of oil with the highest TP content observed in blackcurrant oil. Concerning the antioxidative activity, sea buckthorn oil and blackberry oil performed best, both exhibiting high FRAP and DPPH scavenging activities. The fatty acid profiles of all oils showed that the main polyunsaturated fatty acids were linoleic acid (C18:2) and α-linolenic acid (C18:3). When studying the sterol and tocopherol content, the highest total amount of sterols (4500 mg/kg) as well as the highest total amount of tocopherols (1036 mg/kg) were observed in blackberry oil. It can be concluded that the cold-pressed berry seed oils examined in this study exhibit interesting characteristics for further commercialization. Moreover, the seed meal is a valuable byproduct that contains high amounts of polyphenols and has a high level of antioxidant activity.