Valorization of red raspberry (Rubus idaeusL.) seeds as a source of health beneficial compounds: Extraction by different methods

Abstract

Fruit processing by-product, raspberry (Rubus idaeus L.) seeds were utilized to obtain health beneficial oils. Cold pressing (CP) and supercritical CO2 extraction (SFE) were applied to separate oil from seeds. Raspberry seed oils were analyzed in terms of fatty acids (FA) content, tocopherols, and functional quality indices. The residues after extractions were analyzed in terms of free and total ellagic acid content (TEAC). CP provided higher extraction yield than the SFE method. Oils isolated by both methods have a significant amount of ω-3 FA, even though oil obtained by SFE had slightly higher ω-3 FA content. Furthermore, oils obtained with both extraction methods exhibited high values of tocopherol content. In terms of ellagic acid content, residues after SFE had higher values of free and TEAC than residues after CP. Practical applications Raspberry seeds are currently underutilized by-product of the fruit processing industry. These seeds could be further processed to obtain oil with high quantity of essential ω-3 fatty acid and polyphenol extracts with high content of ellagic acid. Isolated oil and phenolic extracts could be used in various food, cosmetic, and nutraceutical products to increase its nutritive composition and functional properties. Utilization of cold pressing (conventional extraction technique) and supercritical CO2 extraction (novel and green extraction technique) for oil recovery in the same study enables a direct comparison of these techniques and reveals the advantages and disadvantages of supercritical CO2 extraction for potential industrial application.