Antioxidant properties and sensory quality of traditional rye bread as affected by the incorporation of flour with different extraction rates in the formulation

Abstract

The sensory quality of breads formulated on dark and brown rye flour incorporation (extraction rate of 100 and 92%, respectively) was compared using descriptive analysis and hedonic test. Two kinds of the respective rye breads were also analysed for total phenolic compounds (TPC), profile of phenolic acids, total flavonoids (TF), tocopherols (T) and tocotrienols (T3), inositol hexaphosphate (IP6) and reduced glutathione (GSH) contents. The antioxidant properties of 80% methanol bread extracts were evaluated as free radical scavenging activities against ABTS•+ radical cation (TEAC) and 2,2-diphenyl-1-picryhydrazyl radical (DPPH RSA) while PBS bread extracts were used for evaluation of free radical scavenging activities against superoxide anion radicals (O2−•) (SOD-like activity). The results showed that profiles of both kinds of bread were similar although the bread made from 100% rye flour was a bit more intense in all sensory attributes except from the acid odour, salty taste and acid taste. Among 13 attributes only the intensity of only one of them described as “honey odour” (2-phenylacetaldehyde) was statistically significant (F = 4.61, P < 0.05). In the overall quality test the bread with extraction rate of 100 and 92% obtained the scores of 7.51 and 6.68 units, respectively (in the scale of ten units). This small difference in the overall quality of bread samples was suggested to be associated with a higher level of TPC, especially caffeic acid, a higher content of T, T3 and IP6 noted in bread based on whole meal flour but not with their free radical scavenging activities. Rye bread based on dark flour showed higher TEAC by 24% than bread based on brown flour. In contrast, bread based on brown flour appeared 33% richer in DPPH RSA in comparison to the DPPH RSA of bread formulated on whole meal flour. No differences were observed in SOD-like activity of the two types of bread.