Olive oils from Algeria: Phenolic compounds, antioxidant and antibacterial activities

The phenolic compositions, antioxidant and antimicrobial activities against six bacteria of phenolic extracts of olive oil varieties from eleven Algerian varieties were investigated. The antioxidant activity was assessed by determining the scavenging effect on the DPPH and ABTS^.+ radicals. The antimicrobial activity was measured as a zone of inhibition and minimum inhibitory concentration (MIC) on human harmful and foodborne pathogens. The results show that total phenols was significantly (p < 0.05) correlated with DPPH (r = 0.72) and ABTS^.+ radicals (r = 0.76). Among the bacteria tested, <em>S. aureus</em> and to a lesser extent <em>B. subtilis</em> showed the highest sensitivity; the MIC varied from 0.6 to 1.6 mg·mL^-1 and 1.2 to 1.8 mg·mL^-1, respectively. The results reveal that Algerian olive oils may constitute a good source of antioxidant and antimicrobial agents.<br><br>Se ha estudiado la composición fenólica y las actividades antioxidante y antimicrobiana, contra seis bacterias, de extractos de aceites de oliva de once variedades argelinas. La actividad antioxidante se evaluó mediante la determinación del efecto captador de radicales de DPPH y ABTS^.+. La actividad antimicrobiana se midió como zona de inhibición y como concentración inhibitoria mínima (MIC) sobre bacterias perjudiciales humanas y agentes patógenos transmitidos por los alimentos. Los resultados mostraron que los fenoles totales está significativamente (p < 0,05) correlacionados con DPPH (r = 0,72) y los radicales ABTS^.+ (r= 0,76). Entre las bacterias ensayadas, <em>S. aureus</em> y, en menor grado <em>B. subtilis</em> mostraron la mayor sensibilidad; el MIC varió de 0,6 a 1,6 mg·mL^-1 y 1,2 a 1,8 mg·mL^-1 respectivamente. Los resultados muestran que los aceites de oliva argelinos pueden constituir una buena fuente de antioxidantes y agentes antimicrobianos

Irrigation with treated wastewater affected the minor components of virgin olive oil from cv. Chemlali in Tunisia

Water limitation for agriculture is a problem in many countries and irrigation with treated wastewater (TWW) can be a tool to face the decreasing availability of water for important domestic crops such as olive. Taking into account this aspect, a research was carried out for 13 years in an olive grove (Chemlali cultivar) located in the area of Sfax (Tunisia). Two different irrigation treatments were applied: (a) irrigation with good quality water (GQW) and (b) irrigation with TWW. The main objective of this 13-year study was to verify the effects of the irrigation with TWW vs. GQW on some minor parameters of the virgin olive oil. Many oil parameters significantly increased in the TWW irrigated plot, in particular lutein, total tocopherols, squalene, campesterol and stigmasterol whereas β-carotene, α-tocopherol, δ-tocopherol, β-sitosterol and total sterols decreased with respect to the GQW treatment. Irrigation with TWW can be a possible tool to irrigate olive groves with two positive effects: saving of freshwater and production of olive oil of good quality