ANTIOXIDANT PROPERTIES OF RAPESEED CAN BE MODIFIED BY CULTIVATION AND BIOLOGICAL STRESS R. Amarowicz Institute of Animal Reproduction and Food Research of the Polish Academy of Sciences, Olsztyn, Poland 4 th International Conference and Exhibition on Food Processing & Technology London 10-12 August 2015
Chemical structure of phenolic acids
Sinapic acid Sinapine Glucopyranosyl sinapate
The major objective of the present study was to investigate the effect of cultivation (different level of fertilization) and action of pathogen fangus on the rapessed phenolic compounds present in the extract and their antioxidant properties.
Cultivars: California, Castilla, Nelson F1 Characteristic of the cultivation conditions Fertilization Control Intensive Spare Phosphorus (Autumn) 60 kg 80 kg 40 kg Potassium (Autumn) 120 kg 150 kg 60 kg Nitrogen -Autumn - Spring I -Spring II -Total 30 kg 120 kg 60 kg 210 kg 30 kg 120 kg 80 kg 230 kg 30 kg 120 kg 40 kg 190 kg Sulphur (Spring) 45 kg 60 kg -
Effect of pathogen: Cultivar: Hybryda 1 Green house of the University of Warmia and Mazury Cultivation in the vason (volum of 9 l). During the phase of budding plant plantation was inoculated with spores of fungal Alternaria brassica. The seeds of stage of full maturity were analysed.
Extraction: Phenolic compounds were extracted from the defatted seeds with 80% (v/v) aqueous methanol at 80 o C for 15 min at a solid to solvent ratio of 1: 10 (w/v). Extraction was carried out in dark-colored flakes using a shaking water bath. The extraction was repeated twice more, supernatants combined and acetone evaporated under vacuum at 40 o C in a rotary evaporator. The remaining water solution was lyophilised. Chemical analysis: Total phenolics (Folina Ciocalteu a phenol reagent) Antiradical activity against DPPH radical (Yen i Chen, 1995) Antiradical actiovity against ABTS cation radical (TEAC) (Re et al., 1999) FRAP (Prior et al., 2005) RP-HPLC
HPLC analysis of phenolic compounds A Shimadzu HPLC system was employed: LC-10ADVP pump Controler SCL-10AVP Photodiode array detector UV-VIS SPD-M10AVP, Controler SCL-10AVP Conditiones of separations: Prepacked LUNA C8 column (5μm, 4.6 x 250 mm; Phenomenex) A gradient: A - water-methanol (90:10; v/v) with 1.25% o-phosphoric acid, B - methanol with 0.1% o-phosphoric acid; linear gradient from 0 to 60% B for 50 min. Flow rate 1 ml/min; injection volume 20 μl; the detector was set at 330 nm.
Content of total phenolics in the extracts (mg/g) 70 California 70 Castilla 70 Nelson F1 60 60 60 Total phenolics (mg/g) 50 40 30 20 10 60.9 59.4 57.1 Total phenolics (mg/g) 50 40 30 20 10 48.9 48.3 49.4 Total phenolics (mg/g) 50 40 30 20 10 53.9 49.8 53.2 0 Control Intensive Spare 0 Control Intensive Spare 0 Control Intensive Spare
TEAC of the extracts (mmol Trolox/g) 0.5 California 0.5 Castilla 0.5 Nelson F1 0.4 0.4 0.4 TEAC (mmol Trolox/g) 0.3 0.2 0.468 0.417 0.469 TEAC (mmol Trolox/g) 0.3 0.2 0.366 0.360 0.365 TEAC (mmol Trolox/g) 0.3 0.2 0.411 0.418 0.432 0.1 0.1 0.1 0.0 Control Intensive Spare 0.0 Control Intensive Spare 0.0 Control Intensive Spare
FRAP of the extracts (mmol Fe2+/g) 1.8 1.6 California 1.8 1.6 Castello 1.8 1.6 Nelson F1 FRAP (mmol Fe2+/g) 1.4 1.2 1.0 0.8 0.6 0.4 1.61 1.66 1.43 FRAP (mmol Fe2+/g) 1.4 1.2 1.0 0.8 0.6 0.4 1.34 1.30 1.30 FRAP (mmol Fe2+/g) 1.4 1.2 1.0 0.8 0.6 0.4 1.35 1.15 1.31 0.2 0.2 0.2 0.0 Control Intensive Spare 0.0 Control Intensive Spare 0.0 Control Intensive Spare
Antiradical activity of the extracts against DPPH radical Absorbance at 517 nm 1.2 1.0 0.8 0.6 0.4 Control California 0.2 Intensive Spare 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Content (mg/assay) Absorbance at 517 nm 1.2 1.0 0.8 0.6 0.4 Control Absorbance at 517 nm 1.2 1.0 0.8 0.6 0.4 Nelson F1 Control Intensive 0.2 Spare 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Content (mg/assay) Castilla Intensive 0.2 Spare 0.0 0.0 0.2 0.4 0.6 0.8 1.0 Content (mg/assay)
HPLC chromatograms of the extracts
Content of individual phenolic compounds in the extracts of California (mg/g) Compound Control Intensive Spare 1 2 3 4 5 6 80.1 ± 1.4 8.4 ± 0.3 5.6 ± 0.3 6.3 ± 0.4-8.5 ± 0.5 81.9 ± 5.1 7.7 ± 0.6 5.1 ± 0.2 6.2 ± 0.3-8.3 ± 0.2 76.2 ± 4.0 7.6 ± 0.6 5.1 ± 0.3 6.1 ± 0.3-7.6 ± 0.5
Content of individual phenolic compounds in the extracts of Castilla (mg/g) Compound Control Intensive Spare 1 2 3 4 5 6 76.3 ± 3.4 7.1 ± 0.9 5.9 ± 0.5 5.9 ± 0.7-6.0 ± 0.7 73.0 ± 5.6 7.1 ± 1.2 5.9 ± 1.0 5.2 ± 0.6-5.7 ± 0.2 70.1 ± 1.4 6.4 ± 0.2 5.4 ± 0.5 5.5 ± 0.1-6.4 ± 1.5
Content of individual phenolic compounds in the extracts of Nelson F1 (mg/g) Compound Control Intensive Spare 1 2 3 4 5 6 65.8 ± 3.0 4.0 ± 0.1 5.2 ± 0.1 3.8 ± 0.2 18.3 ± 0.5 3.8 ± 0.4 64.5 ± 3.3 2.5 ± 0.2 4.9 ± 0.2 3.9 ± 0.5 16.9 ± 1.0 3.2 ± 0.4 70.8 ± 5.3 3.1 ± 0.8 5.0 ± 0.6 4.4 ± 0.8 17.3 ± 0.9 3.5 ± 0.8
Content of total phenolics in the extracts and seeds 70 10 Total phenolics (mg/g of extract) 60 50 40 30 20 10 57.6 45.9 Total phenolics (mg/g of defatted seeds) 8 6 4 2 8.38 9.68 0 Control Inoculated Incubated 0 Control Incubated Inoculated
TEAC of the extracts and seeds 0.4 0.06 TEAC (mmol Trolox/g of extract) 0.3 0.2 0.1 0.338 0.246 TEAC (mmol Trolox/g of defatted seeds) 0.05 0.04 0.03 0.02 0.01 0.049 0.051 0.0 Control Inoculated Incubated 0.00 Control Incubated Inoculated
FRAP of the extracts and seeds 800 120 FRAP (umol Fe2+/g of extract) 700 600 500 400 300 200 100 747 507 FRAP (umol Fe2+/g of defatted seeds) 100 80 60 40 20 108 107 0 Control Incubated Inoculated 0 Control Inoculated Incubated
Antiradical activity of the extracts aginst DPPH radical 1.2 Absorbance at 517 nm 1.0 0.8 0.6 0.4 0.2 Control Incubated Inoculated 0.0 0.0 0.4 0.8 1.2 1.6 2.0 Content (mg/assay)
HPLC chromatograms of the extracts
Content of individual phenolic compounds in rapeseed extracts (mg/g of extract) Compound Control Inoculated 1 (sinapine) 2 3 4 5 6 7 8 58.2 ± 2.2 3.3 ± 0.2 1.7 ± 0.2 1.6 ± 0.2 3.1 ± 0.2 11.2 ± 0.8 2.0 ± 0.1 2.1 ± 0.1 37.9 ± 1.8 2.3 ± 0.2 1.4 ± 0.1 0.7 ± 0.1 2.2 ± 0.1 7.0 ± 0.5 1.0 ± 0.1 1.1 ± 0.1
Content of individual phenolic compounds in rapeseeds (mg/g of defatted seeds) Compound Control Inoculated 1 (sinapine) 2 3 4 5 6 7 8 8.49 ± 0.41 0.48 ± 0.03 0.25 ± 0.01 0.24 ± 0.01 0.45 ± 0.02 1.63 ± 0.05 0.29 ± 0.01 0.30 ± 0.01 8.00 ± 0.39 0.48 ± 0.03 0.29 ± 0.01 0.16 ± 0.01 0.46 ± 0.02 1.47 ± 0.05 0.21 ± 0.01 0.23 ± 0.01
Conclusions: All the rapeseed extracts were characterized by the high content of phenolic compound (phenolic acids). Strong antioxidant activities of the rapeseed extracts were observed and assayed using different chemical methods. In the seeds of Nelson F1 we found sinapic acid derivative which was absent in the seeds of California and Castilla. The weak effect of fertilization on the antioxidant properties was observed. However, it was different for the individual rapeseed cultivars and the chemical methods used for the measure the antioxidant activity. In the extract of the seeds treated by Alternaria brassica the content of phenolic compounds as well as antioxidant activity were lower than in the extracts of the untreated seeds.
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