Composition and antioxidative activities of supercritical CO2-extracted oils from seeds and soft parts of northern berries

Abstract

The present study investigated the composition and the antioxidative activities of oils from the seeds and the soft parts of a range of northern berries extracted by supercritical CO2. The seed oils of the species of Rubus, Vaccinium, Empetrum, Fragaria and Hippophaë were rich in linoleic (18:2n-6, 34–55% of total fatty acids) and α-linolenic (18:3n-3, 29–45% of total) acids with n-6:n-3 ratios of 1:1–1:2. The seed oils of the species Ribes contained, in addition to linoleic and α-linolenic acids, γ-linolenic (18:3n-6) and stearidonic (18:3n-4) acids. In seed oils from European rowanberry (Sorbus aucuparia L.) and snowball berry (Viburnum opulus L.), linoleic and oleic (18:1n-9) acids together exceeded 90% of the total fatty acids. The sea buckthorn (SB) pulp oil had palmitoleic (16:1n-7), palmitic (16:0) and oleic acids as the major fatty acids. The SB pulp oil and snowball berry seed oil were rich in α-tocopherol (120 and 110mg/100g oil, respectively), whereas raspberry seed oil contained a high level of γ-tocopherol (320mg/100g oil). Seed oils of cranberry (180mg/100g oil), Arctic cranberry (190mg/100g oil) and lingonberry (120mg/100g oil) are rich sources of γ-tocotrienol. The berry seed oils and the SB pulp oil showed varying peroxyl radical scavenging efficacies (300–2300μmol α-tocopherol equivalent per 100g oil) and inhibitory effects on perioxidation of microsomal lipids (250–1200μmol trolox equivalent per 100g oil) in vitro. The peroxyl radical scavenging activity positively correlated with the total content of tocopherols and tocotrienols of the oils (r=0.875, P=0.001). The SB seed oil and pulp oil were active in scavenging superoxide anions produced by xanthine–xanthine oxidase system and inhibited Cu2+-induced LDL oxidation in vitro. The SB oils also protected purified DNA and rat liver homogenate from UV-induced DNA oxidation in vitro. The current research suggests potential of supercritical CO2-extracted oils from northern berries as nutraceuticals and ingredients of functional foods.