Seed oils recovered from industrial fruit by‐products are a rich source of tocopherols and tocotrienols: Rapid separation of α/β/γ/δ homologues by RP‐HPLC/FLD

Abstract

The profiles of tocopherols and tocotrienols (vitamin E) in the seed oils recovered from apple (Malus domestica Borkh.), canary melon (Cucumis melo L.), gooseberry (Ribes uva‐crispa L.), grape (Vitis vinifera L.), Japanese quince (Chaenomeles japonica), pomegranate (Punica granatum L.), red currant (Ribes rubrum L.), sea buckthorn (Hippophae rhamnoides L.), and watermelon (Citrullus lanatus) by‐products of the fruit industry were studied. The highest concentration of tocochromanols was found in pomegranate seed oil (398.73 mg/100 g) and the lowest in gooseberry seed oil (69.13 mg/100 g). The γ and α homologues were the predominant forms of tocopherol and tocotrienol in all fruit seed oils studied. The pomegranate, canary melon, watermelon, gooseberry and red currants seed oils contained mainly γ‐tocopherol (382.69, 63.08, 111.01, 60.35, and 156.39 mg/100 g, respectively). In the apple, sea buckthorn and Japanese quince seed oils, α‐tocopherol was the predominant tocochromanol (58.77, 121.79, and 198.94 mg/100 g, respectively). High concentrations of tocotrienol homologes (γ and α) (49.49 and 34.53 mg/100 g, respectively) were found only in grape seed oil. A significant correlation (r = 0.994, p < 0.00001) between the total content of tocochromanols in the seed oils and scavenging of the free radical DPPH was found.Practical applicationsThis study demonstrated that seed oils recovered from industrial fruit by‐products generated by the food industry are valuable source of tocochromanols. Therefore, fruit seed oils may be successfully applied to obtain new products rich in vitamin E for the food, pharmaceutical and cosmetic industries, with environmental sustainability benefits and a more effective use of harvested plant material.The profiles of tocopherols and tocotrienols in the seed oils recovered from apple (Malus domestica Borkh.), canary melon (Cucumis melo L.), gooseberry (Ribes uva‐crispa L.), grape (Vitis vinifera L.), Japanese quince (Chaenomeles japonica (Thunb.) Lindl. ex Spach), pomegranate (Punica granatum L.), red currant (Ribes rubrum L.), sea buckthorn (Hippophae rhamnoides L.) and watermelon (Citrullus lanatus (Thunb.) Matsum. & Nakai) by‐products of the fruit industry were studied. The homologues γ and α were predominant for both, tocopherols and tocotrienols. However, the concentration and composition of tocochromanols varied considerably in seed oils recovered from industrial fruit by‐products.