Influence of different extrusion temperatures on the stability of ellagic acid from raspberry seeds

Abstract

Production of raspberry products leaves large amounts of seeds which are considered as by-product or waste. These seeds are rich source of ellagic acid and about 88% of the total ellagic acid content in raspberries comes from the seeds. This study investigates the influence of extrusion process at different temperatures on the content of ellagic acid in 'Willamette' raspberry seeds. The extrusion was performed on a Brabender singlescrew laboratory extruder and at three temperature regimes: 140, 160 and 200°C. HPLC/DAD analysis was used to determine and quantify the content of ellagic acid in the extruded samples. Ellagic acid content was quantified by calculation using a calibration curve established from standard ellagic acid. The content of ellagic acid in raspberry seeds was found to be 286.54 μg/g. Use of different extrusion temperatures did not have any impact on the stability of ellagic acid from 'Willamete' raspberry seeds, i.e. did not make significant differences in the content of the ellagic acid. These findings indicated that raspberry seeds may be suitable for the high temperature food processing.

Keywords

• extrusion
• raspberry seeds
• ellagic acid
• corn grits
• value-added product