The water insoluble fraction from red cabbage and black currant pomace reduces the formation of acrylamide, 5-hydroxymethylfurfural and reactive aldehydes in fried potato-based crisps

Plant food by-products are often characterized by a tight matrix of insoluble polysaccharides entrapping bioactive functional molecules. In this study, we investigated the impact of black currant pomace (BC), red cabbage waste (RC) and their water-insoluble fraction (IBC and IRC, respectively) on the formation of Maillard reaction and lipid oxidation products during thermal treatment of potato-based fried crisps. Results showed that the substitution of 20% potato flake with IBC and IRC significantly reduced the formation of acrylamide (14.7%–66.3%) and 5-hydroxymethylfurfural (15.9%–55.4%). This can be explained both by the inhibition of Maillard reaction by plant polyphenols and by the decrease of asparagine and reducing sugars concentration due to the partial replacement of potato flakes. On the opposite, the addition of BC and RC promoted acrylamide and 5-hydroxymethylfurfural formation, which is related to the high amount of reducing carbohydrate in BC and RC. Besides the higher recoveries of extractable polyphenols in IBC- and IRC-enriched crisps, all the four ingredients significantly inhibited the accumulation of 4-hydroxy-2-nonenal, 4-hydroxy-2-hexenal, malondialdehyde and acrolein. These findings highlighted that the elimination of water-soluble compounds is a potential strategy for using plants by-products as efficient ingredients in fried products to limit the formation of processing contaminants.