## 3 Results and Discussion
### Droplet Size Distribution of Emulsions  
The emulsifying properties of the vegetable proteins were investigated, varying the protein concentration in the emulsions. Drop size distributions (DSD) were obtained by image analysis of emulsion microphotographs; the images were captured for the emulsions after 3 h storage time and are reported in Figure 2.  
\begin{table}
\begin{tabular}{|c|c|c|c|c|c|} \hline  & **HS\_SFE** & **HS\_SFE\_10U** & **HS\_SFE\_20U** & **HS\_SFE\_40U** & **HS\_S** \\ \hline Monounsaturated of & 11.74 \(\pm\) 0.04 & 11.8 \(\pm\) 0.2 & 11.71 \(\pm\) 0.07 & 11.54 \(\pm\) 0.04 & 11.5 \(\pm\) 0.2 \\ \hline Oleic acid (C18:1) & 11.74 \(\pm\) 0.04 & 11.8 \(\pm\) 0.2 & 11.71 \(\pm\) 0.07 & 11.54 \(\pm\) 0.04 & 11.5 \(\pm\) 0.2 \\ \hline PUFA sum of & **81.71** & **80.67** & **81.46** & **81.29** & **81.77** \\ \hline Linoleic acid (C18:2) & 59.88 \(\pm\) 0.09 & 59.37 \(\pm\) 0.05 & 59.6 \(\pm\) 0.3 & 59.72 \(\pm\) 0.08 & 59.86 \(\pm\) 0.08 \\ \hline alfa-linolenic gamma-linolenic (C18:3) & 21.8 \(\pm\) 0.2 & 21.3 \(\pm\) 0.2 & 21.8 \(\pm\) 0.2 & 21.51 \(\pm\) 0.06 & 21.91 \(\pm\) 0.01 \\ \hline \(\omega\)-6/\(\omega\)-3 ratio & 2.74 & 2.79 & 2.73 & 2.78 & 2.73 \\ \hline Saturated & 7.18 \(\pm\) 0.03 & 7.5 \(\pm\) 0.1 & 7.18 \(\pm\) 0.04 & 7.28 \(\pm\) 0.07 & 7.28 \(\pm\) 0.05 \\ \hline PUFA sum/saturated & 11.39 & 10.7 & 11.35 & 11.16 & 11.24 \\ \hline \end{tabular}
\end{table}
Table 3: Fatty acid composition of hempseed oil, cultivar Futura 75, extracted by supercritical CO\({}_{2}\) from untreated and ultrasound pre-treated hemp seeds and Soxhlet. Each data represents the mean value of three replicates \(\pm\) standard deviation.  
As it is possible to observe in the microphotographs, the emulsions show a broad distribution of oil droplets. The average droplet diameter (\(d_{\mathrm{s}}\)) and standard deviation (\(\sigma_{\mathrm{s}}\)) of emulsions were evaluated from the lognormal model to investigate the effects of the increased hemp protein isolate fraction in the emulsions as well as the gellan gum effect, which allows for stabilizing the sample with a final quantity of 2% \(w/w\) of hemp protein.  
Experimental data show the mean droplet diameter and the standard deviation for all the tested emulsions. It is possible to point out that both mean diameter and standard deviation increase by increasing the quantity of the protein from 1.5 to higher values in the emulsions. It is possible to observe that emulsions with only protein isolate have an average droplet diameter that goes from 2.1 \(\upmu\)m at 1.5% \(w/w\) up to 2.8 \(\upmu\)m at the highest protein concentration. The value found at the lowest protein level is compatible with the mean droplet diameter found by [PERSON] and coworkers [17], who prepared emulsions with protein isolates from hemp seed meal obtained using two different isolation techniques [17].  
The emulsions with only protein show instability phenomena after about 6 h from the preparation. For this reason, it was necessary to add a stabilizing agent. The gellan gum in the quantity of 0.05% \(w/w\) was found to be suitable for obtaining a stable emulsion, but as seen in Figure 3, the mean diameter and the standard deviation increase after the addition of the gellan gum as compared with the same emulsion without it. The increase in d\({}_{\mathrm{s}}\) after the addition of a polysaccharide had already been observed in the literature [31] and was attributed to the thickening effect of the polysaccharide and to the variations in the adsorption behaviour of proteins at the interface O/W. These phenomena can make it difficult to form small droplets of oil. The polydispersity has also a similar trend after the gellan gum addition.  
Figure 2: Microphotographs of O/W emulsions (dilution 1:10) after a storage time of 3 h (magnification 20\(\times\)).