Stability of rapeseed oil with horseradish Amorica rusticana L. and lovage Levisticum officinale L. extracts under medium temperature accelerated storage conditions

L. Tomsone* and Z. Krūma

Latvia University of Agriculture, Faculty of Food Technology, Department of Food Technology, Liela iela 2, LV-3001, Jelgava, Latvia *Correspondence: lolita.tomsone@llu.lv

Abstract:

This study examined the antioxidant activity of horseradish leaves and lovage leaves and stems extracts added to crude rapeseed oil, under medium temperature accelerated storage conditions. To evaluate efficiency of plant extracts they were added to oil in different concentrations (0.25, 0.5, 1.0 and 1.5%). As a control rapeseed oil without extracts where analysed. For comparison 0.01% butylatedhydroxytoluene (BHT) were added to oil. Efficiency of extracts in oil where tested at +60 ± 1°C in the dark for 22 days. For all samples peroxide value, acid value and 2,2-diphenyl-1-picrylhydrozyl (DPPH˙) activity were determined. In all steps of the experiments for samples with extract peroxide value was significantly (P < 0.05) lower comparing to the control. The control sample without extract reached 15meq O2 kg-1 oil (maximal allowed value in Latvian legislation) in 3 days. The best results showed the horseradish leaves extract (1%) and the lovage leave extract (1.5%) reaching this value in 8.3 days and 7 days, respectively. DPPH˙ activity of the oil was compared after 3 days (when blank sample reached maximal allowed a peroxide value) and it shown that for all samples it was higher compared to the control sample. The highest activity showed the samples with horseradish leave extracts. A acid value in oil samples changed slightly. Lovage leave as stem and horseradish leave extracts could be successfully used for retarding of oxidation of rapeseed oil and in further experiments their activity in meat products will be tested.

Key words:

Exhaust Emissions from Vehicles Operating on Rapeseed Oil Fuel

I. Dukulis, G. Birzietis, V. Pirs, A. Birkavs and Z. Jesko

Motor Vehicle Institute, Faculty of Engineering, Latvia University of Agriculture,
5 J. Cakstes boulv., Jelgava, LV-3001, Latvia; e-mail: ilmars.dukulis@llu.lv;
gints.birzietis@llu.lv; vilnis.pirs@llu.lv; aivars.birkavs@llu.lv; zanis.jesko@llu.lv

Abstract:

One of the primary incentives for expanding the production and use of biofuels worldwide is the potential environmental benefit that can be obtained from replacing petroleum fuels with fuels derived from renewable biomass resources. The use of straight vegetable oil (SVO) in diesel engines is one of the available alternatives, but its use in existing vehicles usually requires modification of engine or fuel system components. In order to find out the trends in changes of different exhaust emission components using fossil diesel and pure rapeseed oil fuel, the car VW GOLF and the truck MAN 19,464 were modified using one-tank and two-tank conversion kits respectively. To ensure stable driving characteristics, a Mustang Chassis Dynamometer MD-1750 was used and for the determination of the content of different exhaust gas components, the AVL SESAM multicomponent exhaust gas measurement system was used. The analyses of obtained results show that the content of NO_xand SO₂ using rapeseed oil fuel in comparison with fossil diesel decreased with both one-tank and two-tank systems. The content of CO and mechanical particles was higher using rapeseed fuel, but the content of unburned hydrocarbons differs depending on the used engine modification system. Since in the one-tank system original engine nozzles were replaced, the pilot studies of the influence of ignition timing on vehicle power characteristics and exhaust emissions were carried out. It was found out that changing the ignition timing from 10.5 to 18.5 degrees decreases the content of CO, mechanical particles and unburned hydrocarbons by up to 70% without losses in power and torque.

Key words:

biofuels, exhaust emissions, one-tank system, rapeseed oil, straight vegetable oil, two-tank system