Ruta chalepensis L. Essential Oil: A New Antisprouting Agent for Potatoes Bioconservation

The main concern of this work was to find a new biological antisprouting product for potatoes during storage. Ruta chalepensis L. essential oil (RCEO) was for the first time used as a potential sprouting inhibitor for potatoes. To confirm RCEO antisprouting effect, evolution of sprout length and weight loss of potato tubers was determined during a storage period of six weeks under three RCEO different treatments (2%, 4%, and 6%). Sprout final weight was also computed. Then, a screening of RCEO chemical composition was performed. An outstanding antisprouting effect of 6% emulsions concentrations was observed as compared to 2% and 4% emulsions concentrations. Final sprout weight (SW) of untreated samples was 4.66%, while 6% treated samples scored 0.98%. These results were endorsed by high Pearson correlation coefficients (>0.9). Indeed, increasing treatment concentration enhanced the sprout growth inhibition. Identification of RCEO major components showed that 2-undecanone represented 87.18% of total identified components suggesting that this component is the possible active agent of RCEO against potatoes sprouting

Effect of the Chemical Composition of Free-Terpene Hydrocarbons Essential Oils on Antifungal Activity

In this study, Carum carvi L. essential oil (CEO) and Origanum majorana L. essential oil (MEO) was steam-distillated under reduced pressure. We henceforth obtained three fractions for each essential oil: CF1, CF2, CF3, MF1, MF2, and MF3. Then, these fractions were characterized using the gas chromatography-mass spectrometry (GC-MS) technique. The results indicated that some fractions were rich in oxygenated compounds (i.e., CF2, CF3, MF2, and MF3) with concentrations ranging from 79.21% to 98.56%. Therefore, the influence of the chemical composition of the essential oils on their antifungal activity was studied. For this purpose, three food spoilage fungi were isolated, identified, and inoculated in vitro, in order to measure the antifungal activity of CEO, MEO, and their fractions. The results showed that stronger fungi growth inhibitions (FGI) (above 95%) were found in fractions with higher percentages of oxygenated compounds, especially with (-)-carvone and terpin-4-ol as the major components. Firstly, this work reveals that the free-terpenes hydrocarbons fractions obtained from MEO present higher antifungal activity than the raw essential oil against two families of fungi. Then, it suggests that the isolation of (-)-carvone (97.15 +/- 5.97%) from CEO via vacuum distillation can be employed successfully to improve antifungal activity by killing fungi (FGI = 100%). This study highlights that separation under reduced pressure is a simple green method to obtain fractions or to isolate compounds with higher biological activity useful for pharmaceutical products or natural additives in formulations.This research was funded by Basque Government (IT 1008-16 and POS-2018-1-0077