The beneficial effects of whole meal wheat products are mainly attributed to dietary fibre and secondary metabolites related to it, such as phenolic compounds. To date, no studies have investigated the effect of fertilization with sewage sludge on the levels of wheat phenolic compounds. The aim of this study was to point out the effects of increasing doses of composted sewage sludge, also in combination with mineral fertilization, on phenolic compounds and antioxidant activity of durum wheat. Moreover, the effects on productivity and technological quality were verified. A randomized block experimental system with six replicates was adopted and seven treatments were compared: unfertilized control (absence of any fertilization or composted sewage sludge application); four doses of composted sewage sludge (3, 6, 9, and 12 Mg ha-1); mineral fertilization (MF) consisting of 120, 100 and 100 kg ha-1 of N, P2O5 and K2O, respectively; combined fertilization with 6 Mg ha-1 of composted sewage sludge and 60 kg ha-1 of N. There was a significantly positive effect of sewage sludge application on productivity as well as on phenolic compounds, antioxidant activity, and technological quality of durum wheat whole meal. Regarding the productivity, the use of 12 Mg ha-1 of composted sewage sludge can effectively substitute mineral fertilization. Regarding phenolics and antioxidant activity, a further increase can be achieved by employing a combination of composted sewage sludge (at the level of 6 Mg ha-1) and mineral fertilization. The phenolic compounds of whole meal raised from 1.31 mg ferulic acid equivalents (FAE) g-1 (unfertilized control) to 1.93 mg FAE g-1 (combined application of 6 Mg ha-1 of sewage sludge and 60 kg ha-1 N). The antioxidant activity range was 1.89-2.02 μmol 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) g-1 d.m., corresponding to a level of scavenging capacity of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical ranging from 56.26% (unfertilized control) to 62.29% (6 Mg ha-1 of sewage sludge plus 60 kg ha-1 N).

Effect of composted sewage sludge on durum wheat: Productivity, phenolic compounds, antioxidant activity, and technological quality

PASQUALONE, Antonella;LACOLLA, GIOVANNI;SIMEONE, Rosanna;CUCCI, Giovanna
2014-01-01

Abstract

The beneficial effects of whole meal wheat products are mainly attributed to dietary fibre and secondary metabolites related to it, such as phenolic compounds. To date, no studies have investigated the effect of fertilization with sewage sludge on the levels of wheat phenolic compounds. The aim of this study was to point out the effects of increasing doses of composted sewage sludge, also in combination with mineral fertilization, on phenolic compounds and antioxidant activity of durum wheat. Moreover, the effects on productivity and technological quality were verified. A randomized block experimental system with six replicates was adopted and seven treatments were compared: unfertilized control (absence of any fertilization or composted sewage sludge application); four doses of composted sewage sludge (3, 6, 9, and 12 Mg ha-1); mineral fertilization (MF) consisting of 120, 100 and 100 kg ha-1 of N, P2O5 and K2O, respectively; combined fertilization with 6 Mg ha-1 of composted sewage sludge and 60 kg ha-1 of N. There was a significantly positive effect of sewage sludge application on productivity as well as on phenolic compounds, antioxidant activity, and technological quality of durum wheat whole meal. Regarding the productivity, the use of 12 Mg ha-1 of composted sewage sludge can effectively substitute mineral fertilization. Regarding phenolics and antioxidant activity, a further increase can be achieved by employing a combination of composted sewage sludge (at the level of 6 Mg ha-1) and mineral fertilization. The phenolic compounds of whole meal raised from 1.31 mg ferulic acid equivalents (FAE) g-1 (unfertilized control) to 1.93 mg FAE g-1 (combined application of 6 Mg ha-1 of sewage sludge and 60 kg ha-1 N). The antioxidant activity range was 1.89-2.02 μmol 6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid (Trolox) g-1 d.m., corresponding to a level of scavenging capacity of the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical ranging from 56.26% (unfertilized control) to 62.29% (6 Mg ha-1 of sewage sludge plus 60 kg ha-1 N).
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11586/129879
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