# Impact of Atmospheric Pressure Microwave Plasma Treatment on Quality of Selected Spices
## 3 Results and Discussion
### Total Polyphenol Content and Antioxidant Activity
\begin{table}
\begin{tabular}{c c c c c c} \hline \hline
**Material** & **Time [s]** & \(L^{*}\) & \(a^{*}\) & \(b^{*}\) & \(\Delta\)E \\ \hline \multirow{4}{*}{Black pepper seeds} & 0 & 16.81 \(\pm\) 0.39 a & 2.43 \(\pm\) 0.22 a & 3.85 \(\pm\) 0.26 a & 0 \\ \cline{2-6}  & 15 & 15.55 \(\pm\) 0.41 b & 3.04 \(\pm\) 0.31 b & 5.4 \(\pm\) 0.75 b & 4.04 \\ \cline{2-6}  & 30 & 15.06 \(\pm\) 0.42 b & 3.3 \(\pm\) 0.24 b & 6.04 \(\pm\) 0.32 b & 7.28 \\ \cline{2-6}  & 45 & 15.24 \(\pm\) 0.40 b & 3.15 \(\pm\) 0.24 b & 5.86 \(\pm\) 0.40 b & 6.13 \\ \cline{2-6}  & 60 & 14.92 \(\pm\) 0.41 b & 3.14 \(\pm\) 0.29 b & 5.86 \(\pm\) 0.34 b & 6.42 \\ \hline \multirow{4}{*}{Juniper berries} & 0 & 15.57 \(\pm\) 0.59 A & 3.57 \(\pm\) 0.38 A & 4.11 \(\pm\) 0.88 A B & 0 \\ \cline{2-6}  & 15 & 13.4 \(\pm\) 0.73 C D & 4.45 \(\pm\) 0.42 B C & 5.37 \(\pm\) 0.83 B C & 4.52 \\ \cline{2-6}  & 30 & 12.64 \(\pm\) 1.02 B C & 4.42 \(\pm\) 0.6 B C & 4.1 \(\pm\) 0.70 A & 3.66 \\ \cline{2-6}  & 45 & 14.17 \(\pm\) 1.0 D & 4.96 \(\pm\) 0.09 C & 5.88 \(\pm\) 0.55 C & 6.45 \\ \cline{2-6}  & 60 & 11.84 \(\pm\) 0.78 B & 4.15 \(\pm\) 0.56 A B & 3.92 \(\pm\) 0.65 A & 4.1 \\ \hline \multirow{4}{*}{Allspices berries} & 0 & 23.84 \(\pm\) 0.63 [A] & \multirow{2}{*}{6.28 \(\pm\) 0.25 [A]} & \multirow{2}{*}{10.64 \(\pm\) 0.53 [A]} & \multirow{2}{*}{0} \\  & [B] & & & & [C] \\ \cline{2-6}  & 15 & 23.28 \(\pm\) 0.41 [A] & 6.96 \(\pm\) 0.15 [B] & 12.06 \(\pm\) 0.33 [B] & 3.02 \\ \cline{2-6}  & 30 & 23.76 \(\pm\) 0.27 [A] & \multirow{2}{*}{7.06 \(\pm\) 0.21 [B]} & \multirow{2}{*}{12.49 \(\pm\) 0.33 [C]} & \multirow{2}{*}{4.09} \\ \cline{2-6}  & [B] & & & & [B] \\ \cline{2-6}  & 45 & 22.31 \(\pm\) 0.7 [C] & \multirow{2}{*}{6.74 \(\pm\) 0.27 [B]} & \multirow{2}{*}{11.49 \(\pm\) 0.66 [A]} & \multirow{2}{*}{2.46} \\ \cline{2-6}  & 60 & 24.24 \(\pm\) 0.65 [B] & 6.98 \(\pm\) 0.23 [B] & 12.94 \(\pm\) 0.72 [C] & 6.18 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The color of different spices subjected to plasma treatment. The same letters indicate homogenous groups (\(\alpha=0.05\)). enzymatic activity that can be also be affected by plasma treatment [51]. The inactivation of enzymes by plasma treatment has been reported, for instance, for potato polyphenol oxidase [52]. Antioxidant activity, as measured by the ABTS and DPPH assays is presented in Table 2. The highest antioxidant potential was found for black pepper seeds extracts, regardless of plasma exposition time and assay type. The extract from black pepper seeds plasma treated for 60 s scavenged 57.6% and 48.6% of ABTS and DPPH free radicals, respectively. In turn, the extracts prepared from untreated material exhibited antioxidant activity of 47.0 and 45.9%, as measured by ABTS and DPPH assays, respectively. Interestingly, black pepper seeds contained the smallest amount of phenolics among all analyzed materials despite their antioxidant potential being the highest. Such results may be related to the fact that black pepper contains piperine, as discussed further, which also exhibits antioxidant activity [53]. In general, the most efficient plasma radiation protocol, from an antioxidant activity increment point of view, lasted either a short (15 s) or long (60 s) time. Similar to total phenolics content, such a situation may be either related to modification of structure, degradation of antioxidants and formation of new compounds that exhibit free radical scavenging potential. In turn, the differences between antioxidant activity measured by DPPH and ABTS assays are related to different characteristic of synthetic free radicals. It has been reported previously that ABTS is more useful to reflect antioxidant activity from pigmented and hydrophilic food [54].