15 bonate at 0.1% (m/v), the final concentration of olive oil was 54% (m/v). The aqueous phase was filtered (HPLC filter membrane 0.2 µm) and injected in High performance liquid chromatograph (HPLC) using the 10 µl loop. No Doubt Nivea Download Free. 2.5 ESM VISUALIZATION OF ELECTRONIC SCAN MICROSCOPY OF THE PET The electronic scan microscopy images were carried out on sweeping electronic microscope with (ESM) environmental models ESEM 200 (Quanta 200 of company FEI), carried out with a detector of gas secondary electrons (GSED) for environmental mode and with a resolution tension of 15 KV and a maximum resolution of 1.5 nm. 2.6 ANALYTICAL QUALITY INDICES OF OLIVE OIL The follow-up of the quality of the virgin olive oil packed in PET bottles during storage was monitored by the determination of acidity, peroxide value and absorption values at 232 nm and 270 nm according to the European community s official methods (Official journal of the European community, 1991). 2.7 STATISTICAL ANALYSIS All the experiments were performed in triplicate and the statistical analysis of the data was done by analysis of variance (ANOVA) using software version 6 and the differences were considered statistically different when p.

16 222 fined olive oil [13]. This deformation corresponds to a known phenomenon called: collapse or weakening of the wall, however, this phenomenon is sometimes disconcerting because it is impossible to envisage the amount of time during which it appears and the way in which it occurs. It is mainly with the imbibition of the plastic during which its flexional rigidity is no longer capable to support the founded tensions and, consequently, tends to bend towards the interior [17]. We can say that the only cause of the bending observed on the PET bottles that underwent a contact with the virgin olive oil is the formed depression. Because of the insufficient permeation of outside towards the interior of the atmospheric gases, this could be related to the permeability of the container to oxygen. According to Del Nobile (2003), the diffusivity/solubility of oxygen in PET at 30 C is 4, cm 2 /s and at 40 C is B1 B2 B3 Figure 2 - Photographs of ESM in the end of experimentation 8, cm 2 /s.

Thus, the temperature plays a crucial role in the speed of diffusion [9]. Perhaps, this is why all the bottles are assigned by this phenomenon at 45 C, this should compensate for the losses due to the consequence of alteration of the contained liquid or replace the volume of gases to the top of the level of the liquid that reacts chemically with the packed product [8], and that this PET macromolecular compound can undergo a spacing of the chains [19] at room temperature. In addition to these observations, the bottles showed brittleness during all the period of experimentation with the appearance of the cracks on the surface of the bottles as seen in Figure 2. The images (Fig.1 and Fig.2) obtained by ESM showed that the contact of the PET with the olive oil can involve the formation of the cracks known under the name of stress-cracking observed on the bottles intended to be used for the packaging of carbonated soft drinks [17]. The Tellers More Mp3 Download on this page. With certain polymers, the plastic polymer deformation is due to two main mechanisms: orientation of the macromolecular chains and formation and multiplication of cracks.

These cracks generate an increase in volume, which represents a large fraction of the total effective deformation. This variation of volume can be measured in situ during a tensile test [20]. Thus, the tensile strength testing was carried out to study the behavior of the PET bottles during the storage to appreciate the influence of the temperature and time contact on their resistance. The parameter taken into account is elongation at break (Fig.