# Characterization of Six Cold-Pressed Berry Seed Oils and Their Seed Meals
## 3 Results and Discussion
### Total Polyphenols (TP) Content  
Polyphenols are present in different varieties of plants [15] where they fulfil functions related to growth, protection against pathogens and diseases, and reproduction [16]. Different types of polyphenols possess different structural and physicochemical properties. Moreover, they exhibit different stability and reactivity in response to factors such as pH, temperature, oxygen, and light [17]. Phenolic compounds provide stability to edible  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Oil Source** & **L* Value** & **a* Value** & **b* Value** \\ \hline Blackcurrant oil 1 & 4.97 \(\pm\) 0.06 & 5.43 \(\pm\) 0.02 & 21.59 \(\pm\) 0.17 \\ Blackcurrant oil 2 & 9.76 \(\pm\) 0.02 & 4.21 \(\pm\) 0.03 & 32.31 \(\pm\) 0.17 \\ \hline Raspberry oil 1 & 87.56 \(\pm\) 0.02 & \(-\)4.56 \(\pm\) 0.01 & 113.85 \(\pm\) 0.22 \\ Raspberry oil 2 & 88.82 \(\pm\) 0.01 & \(-\)6.00 \(\pm\) 0.02 & 76.92 \(\pm\)0.14 \\ \hline Blackberry oil 1 & 6.86 \(\pm\) 0.01 & 5.11 \(\pm\) 0.01 & 24.81 \(\pm\) 0.06 \\ Blackberry oil 2 & 5.61 \(\pm\) 0.02 & 4.93 \(\pm\) 0.01 & 22.9 \(\pm\) 0.05 \\ \hline Blueberry oil 1 & 42.79 \(\pm\) 0.01 & 5.7 \(\pm\) 0.02 & 78.16 \(\pm\) 0.22 \\ Blueberry oil 2 & 44.49 \(\pm\) 0.02 & 6.81 \(\pm\) 0.02 & 83.78 \(\pm\) 14 \\ \hline Strawberry oil 1 & 53.10 \(\pm\) 0.07 & 8.06 \(\pm\) 0.02 & 93.58 \(\pm\) 0.4 \\ Strawberry oil 2 & 60.79 \(\pm\) 0.08 & 7.86 \(\pm\) 0.01 & 102.48 \(\pm\) 0.17 \\ \hline Sea buckthorn oil 1 & 69.25 \(\pm\) 0.05 & 46.48 \(\pm\) 0.11 & 125.41 \(\pm\) 0.5 \\ Sea buckthorn oil 2 & 57.86 \(\pm\)0.02 & 40.99 \(\pm\)0.14 & 108.87 \(\pm\) 0.4 \\ \hline \hline \end{tabular} Key: Data are reported as mean values \(\pm\) standard deviation of triplicates. Color measurement parameters: D65/2”.  
\end{table}
Table 1: CieLab color measurements in berry seeds oils. The L* value describes the brightness of the color, with values ranging between 0 (dark) and 100 (light); negative a* values stand for green colors, while positive a* values stand for red colors; negative b* values represent blue colors, and positive b* values represent yellow colors.  
oils [18]. The type of oil crop as well as the breeding and harvest conditions determine which types of phenolic compounds are present in the oil [19].  
In this study, the levels of polyphenic compounds were determined in different oil samples. Most of the polyphenols remained in the seed meals, and only a small amount was transferred into the oil (Figure 1). The total polyphenol content of the cold-pressed seed oils ranged from 8.9 to 19.3 mg GAE per 100 g of oil. These levels were higher than the ones described for cold-pressed palm oil (3.12-7.18 mg TP/100 g) and extra virgin olive oil [19]. The TP values were highest for the blackcurrant oils, and the lowest TP amounts were found in the raspberry seed oils. The TP content found in the press cake were 10- to 100-fold higher than those in the seed oils and ranged from 312 to 5500 mg GAE/100 g press cake. Thus, 10% of the polyphenols from seeds were transferred to the oil. This can be explained by the hydrophilic properties of most of the polyphenols.