Defatted strawberry seeds as a source of phenolics, dietary fiber and minerals

- Defatted strawberry seeds are rich in dietary fibre and polyphenols.
- Ellagitannins and flavonols are the main polyphenols in degreased strawberry seeds.
- Proteins represent 1/6th of defatted strawberry seed.
- Defatted strawberry seeds are rich in calcium, potassium, magnesium and iron.
- Kaempferol derivatives are the main polyphenols in defatted strawberry seeds.

Strawberry seeds obtained from industrial press cake from three harvest seasons and defatted by supercritical CO2 were analysed for dry substance, protein, fat, ash, minerals, saccharides, total dietary fiber and polyphenols. The defatted seeds were composed mostly of dietary fibers (on average 728 g/kg dry matter) and proteins (167 g/kg dry matter). The sum of polyphenols determined by HPLC varied from 15.6 to 17.5 g/kg dry matter and did not vary significantly with production year. There are two main groups of polyphenols among determined compounds: ellagitannins and flavanols, which mean content are 8.50 and 5.82 g/kg dry matter, respectively. Total contents of ellagitannins in seeds varied significantly with production year, but not flavanols. High contents of dietary fiber, makes it reasonable to consider the use of degreased seeds in food production, as source of dietary fiber or polyphenol preparations.