Use of blackcurrant and chokeberry press residue in snack products

Fruit and vegetable processing by-products, undervalued until recently, are rich sources of nutrients. This study investigated properties of extruded corn puffs with addition (5-20%) of blackcurrant or chokeberry pressings. We assessed expansion rate, water absorption index (WAI) and water solubility index (WSI) of the produced extrudates, the concentration of polyphenols, and antioxidant activity measured by FRAP method and ABTS method. The puffs with addition of chokeberry pressings had higher WSI values, higher phenolic acids, flavonols, and anthocyanins content, and higher antioxidant activity than puffcorn with addition of blackcurrant pressings. The corn puffs with addition of fruit pressings contained much higher concentrations of phenolic compounds and were characterized by much higher antioxidant activity than pure puffcorn. This confirms the usefulness of addition of such fruit processing by-products in order to manufacture functional food.