Assessment of the antioxidant and antibacterial activities of different olive processing wastewaters

<div><p>Olive processing wastewaters (OPW), namely olive mill wastewater (OMW) and table-olive wastewaters (TOW) were evaluated for their antibacterial activity against five Gram-positive and two Gram-negative bacteria using the standard disc diffusion and thin layer chromatography (TLC)-bioautography assays. Disc diffusion screening and bioautography of OMW were compared to the phenolic extracts of table-olive brines. Positive activity against <i>S</i>. <i>aureus</i> was demonstrated. The optimization of chromatographic separation revealed that hexane/acetone in the ratio of 4:6 was the most effective for phenolic compounds separation. A HPLC-MS analysis was performed showing that only two compounds, hydroxytyrosol and tyrosol, were the predominant phenolic compounds in all OPW. The phenolic extract of OMW generated by a semi-modern process showed the highest free radical-scavenging activity (DPPH assay) compared to the other phenolic extracts. It is apparent from the present study that OPW are a rich source of antioxidants suitable for use in food, cosmetic or pharmaceutical applications.</p></div

Effect of concentration of OMW and TOW phenolic extracts on their antibacterial activity against <i>S</i>. <i>aureus</i> using the disc diffusion assay.

<p>Effect of concentration of OMW and TOW phenolic extracts on their antibacterial activity against <i>S</i>. <i>aureus</i> using the disc diffusion assay.</p

Total phenolic content, phenolic constituents and antioxidant activity (IC₅₀) of different olive processing wastewaters samples.

<p>The values in the brackets are the proportions to the total phenolic content, TPC.</p

Physicochemical characterization of olive mill wastewater and table-olive brine samples.

<p>Physicochemical characterization of olive mill wastewater and table-olive brine samples.</p

HPLC chromatograms of OMW phenolic extracts.

<p>1. Hydroxytyrosol, 2. 3,4-dihydroxyphenylacetic acid, 3. Tyrosol. 4. Protocatechuic acid derivative, 5. Caffeic acid. 6. <i>p</i>-coumaric acid. 7. Ferulic acid derivative, 8. Ferulic acid, 9. Luteolin derivative, 10. Oleuropein. Peaks 1, 3, 6, 8 and 10 were identified by use of standards. The remaining peaks were tentatively identified by comparison with literature data. (OMW1: olive mill wastewater from semi-modern process, OMW2: olive mill wastewater from modern process, GTOW: green table-olive brine, PTOW: purple table-olive brine and BTOW: black table-olive brine).</p

Cytokine production by mitogen-stimulated PBMC from pigs fed diets containing Bt and isogenic maize (pg/mL)¹.

1<p>Values are given as the median with 25^th to 75^th percentiles in parentheses.</p>2<p>Isogenic: isogenic maize diet for 110 days.</p>3<p>Bt: Bt maize diet for 110 days.</p>4<p>Isogenic/Bt: isogenic maize diet for 30 days followed by Bt maize diet for 80 days.</p>5<p>Bt/isogenic: Bt maize diet for 30 days followed by isogenic maize diet for 80 days.</p

Effects of feeding Bt and isogenic maize on immune cell phenotypes of peripheral blood mononuclear cells.

<p>The CD4⁺, CD8⁺, CD4⁺CD8⁺ immune cell populations are given as proportions of CD3⁺ T cells (%). All values are shown ±SE.</p>1<p>Isogenic: isogenic maize diet for 110 days.</p>2<p>Bt: Bt maize diet for 110 days.</p>3<p>Isogenic/Bt: isogenic maize diet for 30 days followed by Bt maize diet for 80 days.</p>4<p>Bt/isogenic: Bt maize diet for 30 days followed by isogenic maize diet for 80 days.</p>ab<p>Within a row means without a common superscript differ by <i>P</i><0.10 by means separation using Tukey-Kramer adjustment for multiple comparisons.</p

Effects of feeding Bt and isogenic maize on immune cell counts (×1000/µL) ±SE in growing pigs.

1<p>Isogenic: isogenic maize diet for 110 days.</p>2<p>Bt: Bt maize diet for 110 days.</p>3<p>Isogenic/Bt: isogenic maize diet for 30 days followed by Bt maize diet for 80 days.</p>4<p>Bt/isogenic: Bt maize diet for 30 days followed by isogenic maize diet for 80 days.</p>5<p>Normal reference range in pigs = 11,000–22,000/µL <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036141#pone.0036141-Thorn1" target="_blank">[20]</a>.</p>6<p>Normal reference range in pigs = 4,300–13,600/µL <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036141#pone.0036141-Thorn1" target="_blank">[20]</a>.</p>7<p>Normal reference range in pigs = 200–2,200/µL <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0036141#pone.0036141-Thorn1" target="_blank">[20]</a>.</p>xy<p>Within a row means without a common superscript differ by <i>P</i><0.05 by means separation using Tukey-Kramer adjustment for multiple comparisons.</p>abc<p>Within a row means without a common superscript differ by <i>P</i><0.10 by means separation using Tukey-Kramer adjustment for multiple comparisons.</p

Cytokine production by resting PBMC from pigs fed diets containing Bt and isogenic maize (pg/mL)¹.

1<p>Values are given as the median with 25^th to 75^th percentiles in parentheses.</p>2<p>Isogenic: isogenic maize diet for 110 days.</p>3<p>Bt: Bt maize diet for 110 days.</p>4<p>Isogenic/Bt: isogenic maize diet for 30 days followed by Bt maize diet for 80 days.</p>5<p>Bt/isogenic: Bt maize diet for 30 days followed by isogenic maize diet for 80 days.</p>xy<p>Within a row means without a common superscript differ by <i>P</i><0.05 by means separation using Tukey-Kramer adjustment for multiple comparisons.</p

Composition of diets (as is basis, %).

1<p>Isogenic: non-GM parent line maize.</p>2<p>Bt; Bt MON810 maize.</p>3<p>Lactofeed 70 contains 70% lactose, 11.5% protein, 0.5% oil, 7.5% ash and 0.5% fibre (Volac, Cambridge, UK).</p>4<p>Immunopro 35 contains whey protein powder - protein 35% (Volac, Cambridge, UK).</p>5<p>Premix provided per kg of complete diet: Cu, 155 mg; Fe, 90 mg; Mn, 47 mg; Zn, 120 mg, I, 0.6 mg; Se, 0.3 mg; vitamin A, 6000 IU; vitamin D_3, 1000 IU; vitamin E, 100 IU; vitamin K, 4 mg; vitamin B_12, 15 µg; riboflavin, 2 mg; nicotinic acid, 12 mg; pantothenic acid, 10 mg; choline chloride, 250 mg; vitamin B_1, 2 mg; vitamin B_6, 3 mg.</p>6<p>Premix provided per kg of complete diet: Cu, 15 mg; Fe, 24 mg; Mn, 31 mg; Zn, 80 mg, I, 0.3 mg; Se, 0.2 mg; vitamin A, 2000 IU; vitamin D_3, 500 IU; vitamin E, 40 IU; vitamin K, 4 mg; vitamin B_12, 15 µg; riboflavin, 2 mg; nicotinic acid, 12 mg; pantothenic acid, 10 mg; vitamin B_1, 2 mg; vitamin B_6, 3 mg.</p>7<p>Formaxol is a blend of encapsulated formic and citric acids and essential oils (Soda Feed Ingredients, Monaco).</p>8<p>Mycosorb® is an organic mycotoxin adsorbent (Alltech, Dunboyne, Co. Meath, Ireland).</p>9<p>Calculated values.</p>10<p>The starter diet was formulated as meal.</p