## Materials and Methods
### Analytical Methods
#### 2.2.1 Pineapple Extract Preparation for Total Phenolic Content and Antioxidant Activity  
The pineapple extract preparation was performed following the procedure of [PERSON] (2009) and [PERSON] (1959) [22; 23], with some modifications. The extraction was carried out in the proportion 1: 10 (w: v) of sample and methanol (100%) followed by an Ultra-Turrax homogenizer (IKA LABORTECHNIK T25 basic, Germany) at 8000 rpm for 2 min. The homogenates were incubated overnight (12-24 h) at 4 \({}^{\circ}\)C and then centrifuged at 8000 rpm for 20 min (4 \({}^{\circ}\)C). The supernatants were collected and stored at 4 \({}^{\circ}\)C, protected from light until analysis.  
The total phenolic content (TPC) were determined according to [PERSON] (2009), and [PERSON] and [PERSON] (1959) [22; 23], with some modifications. The extracts aliquots (150 \(\mu\)L) were diluted with nanopure water (2400 \(\mu\)L), and added 150 \(\mu\)L 0.25 mol L\({}^{-1}\) Folin-Ciocalteu reagent (Panreac AppliChem, Darmstadt, Germany). The reaction was stopped by adding 1 mol L\({}^{-1}\) of sodium carbonate (300 \(\mu\)L) and the mixture was incubated (2 h) protected from light; the samples subsequently were read at 725 nm in a spectrophotometer (UNICAM UV/Vis Spectrometer). The total phenolics were quantified by a standard curve of chlorogenic acid equivalents (CAE) and expressed as mg CAE\(\cdot\)g\({}^{-1}\) of dry weight.  
Antioxidant Activity (DPPH Assay)  
The antioxidant activity was analysed by the scavenging ability of the 2,2-diphenyl-1-picrylhydrazyl (DPPH; Sigma-Aldrich, Darmstadt, Germany) radical following the procedure of [PERSON] et al. (1995) [24]. The supernatants of extraction (100 \(\mu\)L) and DPPH solution (3.9 mL) were mixed, and the reaction occurred for 40 min. Subsequently, the absorbance was measured in a spectrophotometer at 515 nm. The antioxidant activity was determined using Trolox (Acros Organics, Geel, Belgium), and the results were expressed by Trolox Equivalent Antioxidant Capacity [TEAC (\(\mu\)mol Trolox\(\cdot\)g\({}^{-1}\) of dry matter)].  
Antioxidant Activity (FRAP Assay)  
The Ferric Reducing Antioxidant Power (FRAP) assay was performed according to [PERSON] and [PERSON] (1996) [25] with some modifications. The reaction started with the mixture of the FRAP solution (2.7 mL), extract samples (90 \(\mu\)L), and nanopure water (270 \(\mu\)L), and subsequently warmed in a water bath at 37 \({}^{\circ}\)C for 30 min. The absorbance of the colored product (ferrous tripyridyltriazine complex) was measured at 595 nm. The antioxidant capacity was calculated using a standard Trolox (Acros Organics, Belgium) curve and the results were expressed as TEAC (\(\mu\)mol Trolox\(\cdot\)g\({}^{-1}\) of dry matter).  
Antioxidant Activity (ABTS-Assay)  
Antioxidant activity was measured using 2,2'-azino-bis(3-ethylbenzothazoline-6-sulphonic acid) (ABTS; Sigma-Aldrich, Germany) method as described by [PERSON] et al. (1999) and [PERSON] et al. (2007) [26; 27] with some modifications. The reaction was performed by sample aliquots (30 \(\mu\)L) mixed with ABTS solution (2970 \(\mu\)L) for 6 min, and the absorbance at 734 nm was measured. The absorbance of the samples was related to the Trolox (Acros Organics, Belgium) standard curve and the results were expressed as TEAC (\(\mu\)mol Trolox\(\cdot\)g\({}^{-1}\) of dry matter).