## 2 Materials and Methods
### Antioxidant Capacity  
Three methods were used to determine the antioxidant activity of the extracts: the radical scavenging activity by DPPH method, the ABTS radical cation scavenging assay and the FRAP method. The existence of a collection of antioxidant capability determination assays can be understood when considering that, when the oxidation processes develop in vivo, different reactive species and several mechanisms are involved [12]. A combination of methods is convenient for characterising the antioxidant capacity of a sample [13]. All the tests were done in triplicate using a spectrophotometer  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Run** & **Sample Weight (g)** & **Extraction Temperature (\({}^{\circ}\)C)** & **Extraction Time (min)** \\ \hline
1 & 2.0 & 60 & 27.5 \\
2 & 1.25 & 60 & 45 \\
3 & 0.5 & 47.5 & 10 \\
4 & 1.25 & 35 & 45 \\
5 & 1.25 & 35 & 10 \\
6 & 1.25 & 47.5 & 27.5 \\
7 & 2.0 & 47.5 & 10 \\
8 & 1.25 & 47.5 & 27.5 \\
9 & 0.5 & 35 & 27.5 \\
10 & 1.25 & 60 & 10 \\
11 & 2.0 & 35 & 27.5 \\
12 & 0.5 & 60 & 27.5 \\
13 & 1.25 & 47.5 & 27.5 \\
14 & 1.25 & 47.5 & 27.5 \\
15 & 2.0 & 47.5 & 45 \\
16 & 0.5 & 47.5 & 45 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Box–Behnken experimental design showing the levels of each independent factor (sample weight, extraction temperature and extraction time) for the Headspace Solid-Phase Microextraction in combination with Gas Chromatography-Mass-Spectrometry (HS-SPME) extraction of target compounds in Raspberry S1.  
(Biomate-3, Thermospectronic, Mobile, AL, USA). A standard curve was prepared using TROLOX as a standard in a range of concentrations from 0 to 500 \(\upmu\)mol L\({}^{-1}\). The results are expressed as \(\upmu\)mol equivalents of TROLOX per 100 g of sample.  
The DPPH method employed was a slight modification of one previously reported by [PERSON] et al. (2019) [14]. An aliquot of 50 \(\upmu\)L of the raspberry extract was added to 3 mL of an ethanolic solution of DPPH\({}^{\bullet}\) (0.025 g L\({}^{-1}\)). The absorbance at 517 nm was registered every minute for 3 h to evaluate when the reaction reached a plateau, to ensure a stable value of the absorbance. For this application, the reaction time selected was 30 min. Subsequently, all the samples were measured spectrophotometrically after 30 min of incubation in the dark at room temperature (25 \(\pm\) 2 \({}^{\circ}\)C).  
The radical DPPH scavenging capacity (AA%) and the ABTS scavenging activity were determined according to [PERSON] et al. (2016) [15]. The ABTS radical cations were prepared by mixing 25 mL of 7 mM ABTS solution with 88 \(\upmu\)L of potassium persulfate (140 mM) solution. The solution obtained was kept in the dark for 16 h. The ABTS solution was conveniently diluted with 96% ethanol until an absorbance value of 0.80 \(\pm\) 0.02 was obtained at 734 nm. Then, 50 \(\upmu\)L volumes of the extracts (80-100 mg raspberry mL\({}^{-1}\)) were combined with 3 mL of the ABTS solution and vortexed. The reaction mixture was incubated at room temperature (25 \(\pm\) 2 \({}^{\circ}\)C) for 30 min, and then the absorbance was measured at 734 nm against a blank (ABTS solution with 100 \(\upmu\)L of methanol/water (80:20)).  
The reductive capacity of the ferric cations of the methanolic extracts was assessed according to [PERSON] and [PERSON] (1996) with several modifications [16]. The FRAP reagent was prepared freshly every day by mixing a sodium acetate buffer (300 mM, pH 3.6) with a 10 mM solution of 2,4,6-tripyridylo-S-triazine (TPTZ) and a 20 mM FeCl\({}_{3}\cdot\)3H\({}_{2}\)O solution in a volumetric ratio of 10:1:1. An extract aliquot of 40 \(\upmu\)L was mixed with 3 mL of FRAP reagent and incubated for 30 min in the dark at 25 \(\pm\) 2 \({}^{\circ}\)C. Measurements were performed at 593 nm.