## 3 Results and Discussion
### OBs Morphological Analysis and Thermal Stability  
Figure 4 shows a typical optical microscope image of the OBs at room temperature in the bright field. The red arrow in Figure 4 indicates one of the OBs, which is clearly visible in the image, and they appear bright compared to the surrounding area due to their far higher capacity to diffuse the incident light of the microscope. Moreover, the OBs appear spherical, as previously reported [5]. These microscope images represent remarkable evidence that the olive paste contains OBs and reveals, for the first time, that they are found in this by-product of olive oil production. Figure 5a-d shows the optical microscope images taken, respectively, after the first, second, third and fourth thermal steps. \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{2}{c}{**OOBC Proximate Composition, \%**} \\ \hline Water & 40.00 \\ Lipid & 26.76 \\ Protein & 5.99 \\ Other & 27.25 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: OOBC percentage composition. \begin{table}
\begin{tabular}{c c} \hline \hline \multicolumn{2}{c}{**OOBC**} \\
**TP, TF and Antioxidant Power** \\ \hline Total polyphenols & 1.11 mgGAE/g\({}_{\text{dry}}\) \\ Total flavonoids & 0.50 mgQE/g\({}_{\text{dry}}\) \\ FRAP & 0.08 millimolife/g\({}_{\text{dry}}\) \\  & 20.04 mgTroloxE/g\({}_{\text{dry}}\) \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Polyphenols, flavonoids and FRAP in OOBC. Figure 4: Image of an optical microscope of the oil bodies taken at room temperature and in the bright field. Figure 5: (**a–d**) Images of optical microscope after heating at 50, 100, 150 and 200 \({}^{\circ}\)C, respectively. The images captured using the optical microscope reveal that the OB is preserved after the thermal steps, regardless of the temperature, as indicated by red arrows that point to the same OB particles (see Figure 5a-d). This is a promising result because it demonstrates that the OBs structures did not burst under thermal treatments, which is of crucial importance for the sterilisation process. However, whereas OB structures apparently do not change shapes, there are some points (indicated by yellow arrows in Figure 5a-d) in the surrounding area which appear to have been dried out or burnt, probably due to the increase in temperature during the thermal phase. Although the streaked OOBC still keeps its state (i.e., solid), Figure 5d shows an increment in yellow arrows, which would indicate an excessive temperature that has resulted in the evaporation of the water, which (as is well known) occurs at 100 \({}^{\circ}\)C, and which is at half the temperature of 200 \({}^{\circ}\)C considered in Figure 5d. Figure 6 shows the sizes of the images as examples of the dimensions observed using the microscope. The OB dimensions are approximately within the range of 1-1.5 \(\upmu\)m. This enables us to extend our investigation to a wider range between 0.7 and 1.7 \(\upmu\)m as reported below. The box plots shown in Figure 7 report data about particle size distributions recorded for each temperature. Figure 6: Images of optical microscope with typical measurements of sizes. Figure 7: Box plots of the particle size distributions after each thermal stage, where Q1 is the 25 th percentile; Q2 is the median; Q3 is the 75 th percentile; the minimum is the lowest range value; the maximum is the highest range value; the cross is the mean. Table 3 reports the means and the standard deviations of the diameters and circularities values after each thermal stage. The average diameters are obtained by considering around one hundred values measured.