The product is a bread that is required to measure antioxidant activity by the DPPH and ABTS methodologies; However, the product contains phenolic compounds such as flavonoids and hydroxybenzoic acids.
I haven't seen standardized method but it is possible to conduct antioxidant activity test heating is not allowed only for the DPPH section not the antioxidant section. so that conducting using the common spectrophotometric method is possible
If I understood you correctly, then to obtain an extract for the DPPH test, is it possible without using thermal techniques? and still obtain reproducible results with the subsequent reading in the spectrophotometer?