## 3 Results and Discussion  
### Antioxidant Characterization of OMWW Phenolic Extract (PE) and Basil Leaves  
The antioxidant characterization of OMWW antioxidant extract (AE) is reported in Table 1. Considering the effect of the oleupopein hydrolysis derivatives on the chemical and microbiological stability of enriched food widely reported in the literature [25; 26], the chromatographic analysis focused on the determination of hydroxytyrosol and tyrosol. Analysis revealed an hydroxytyrosol content of 1.03 \(\pm\) 0.09 mg g\({}^{-1}\) and tyrosol content of 0.57 \(\pm\) 0.04 mg g\({}^{-1}\). From the quantitative analysis, AE showed a high content of total phenolic compounds (TPC), about 60.22 mg g\({}^{-1}\), which was higher than those reported by [PERSON] et al. [27] and [PERSON] et al. [28]; however, it was lower than those obtained by [PERSON] et al. [21]. Naturally, the different concentrations of phenolic compounds in vegetal matrices, particularly in olives and derivatives, can be due to several aspects, such as the cultivar, pedoclimatic conditions, olive varieties, degree of maturity and processing,and extraction system [29]. The antioxidant capacity determined through the ABTS assay showed higher values compared with the DPPH assay.  
Basil leaves (FBL) composition may vary depending on the cultivar, growing method, climatic conditions, etc., and for this reason, were subjected to physicochemical analysis to highlight the variations in composition. The results are reported in Table 2. FBL showed a higher level of chlorophyll b (CHLB: 4.67 mg 100 g\({}^{-1}\)) compared with chlorophyll a (CHLA: 2.68 mg 100 g\({}^{-1}\)), while B-carotene was found only in traces.  
The antioxidant capacity of FBL was determined by two different methods: ABTS radical cation decolorization assay and DPPH free radical scavenging activity. The first method (ABTS) allowed us to determine the highest results of total antioxidant activity (79.08 umol TE g\({}^{-1}\)). Regarding the TPC, the basil leaves showed a content of about 34.09 mg GAE 100 g\({}^{-1}\); this value is similar to that reported by [PERSON] et al. [30].  
The analysis of individual phenolic compounds evidenced the following compounds as principal ones: p-cumaric acid (551 mg kg\({}^{-1}\)), chlorogenic acid (254 mg kg\({}^{-1}\)), rosmarinic acid (195 mg kg\({}^{-1}\)), and quercetin (138 mg kg\({}^{-1}\)); while less representative compounds (below 50 mg kg\({}^{-1}\)) were: rutin, caffe acid, and protocatechic acid (Figure 2). Previous studies [31; 32] point out that basil leaves phenolic compounds--for example, rosmarinic acid--could be excellent allies in extending shelf life and reducing oxidation of pesto during storage for their significant radical scavenging and antibacterial properties.  
\begin{table}
\begin{tabular}{c c} \hline \hline
**TPC (mg g\({}^{-1}\))** & 60.22 \(\pm\) 17.47 \\
**Hydroxytyrosol (mg g\({}^{-1}\))** & 1.03 \(\pm\) 0.09 \\
**Tyrosol (mg g\({}^{-1}\))** & 0.57 \(\pm\) 0.04 \\
**DPPH (μmol TE g\({}^{-1}\))** & 154 \(\pm\) 21 \\
**ABTS (μmol TE g\({}^{-1}\))** & 3768 \(\pm\) 66 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Antioxidant characterization of AE.  
\begin{table}
\begin{tabular}{l c} \hline \hline
**L*** & 48.81 \(\pm\) 4.40 \\
**A*** & \(-\)9.17 \(\pm\) 1.12 \\
**B*** & 23.54 \(\pm\) 3.44 \\
**a**w & 0.983 \(\pm\) 0.004 \\
**Moisture (\%)** & 90.64 \(\pm\) 0.02 \\
**CHLA (mg 100 g\({}^{-1}\))** & 2.68 \(\pm\) 0.01 \\
**CHLB (mg 100 g\({}^{-1}\))** & 4.67 \(\pm\) 0.01 \\
**TPC (mg GAE g\({}^{-1}\))** & 3.64 \(\pm\) 0.02 \\
**DPPH (μmol TE g\({}^{-1}\))** & 5.71 \(\pm\) 0.17 \\
**ABTS (μmol TE g\({}^{-1}\))** & 79.08 \(\pm\) 5.61 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Physicochemical and antioxidant characterization of basil leaves.  
Figure 2: Individual phenolic content of fresh basil (mg kg\({}^{-1}\)).