Hexane

α-Farnesene and CTols were extracted, and their content analyzed following the procedure described elsewhere^{59 (link)} with slight modifications. Pear peel was isolated from the equatorial axis of the fruit (3 replicates per treatment/storage/stage and 5 fruits per replicate), and a 10-mm-diameter disk was obtained. Two excised disks/fruit were incubated in 5 mL of hexane (Panreac, Barcelona, Spain) for 10 min at 20 °C. After incubation, the hexane solution was filtered through cellulose filter paper and adjusted to 5 mL with pure hexane. After filtration, the absorbance at 232, 258, 281, and 290 nm was measured with a Uvikon 922 spectrophotometer (Kontron Instruments, Italy). The content of α-farnesene and CTol 281 was calculated as described in previous studies^{15 (link),60 (link)}, and referred to nmol g⁻¹ on a fresh weight basis.

The 2,2′-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,4,6-tripyridyl-s-triazine (TPTZ), potassium persulfate, hydrochloric acid, ferric chloride, iron(II) sulfate heptahydrate, sodium phosphate, sodium hydroxide and ammonium persulfate were purchased from Sigma-Aldrich (Milan, Italy). The phenolic compounds, gallic acid and quercetin, were purchased from Sigma Chemical Co. (St Louis, MO, USA). Analytical grade reagents, such as sodium carbonate, potassium hydroxide, Folin-Ciocalteu reagent, ethanol, methanol and hexane were obtained from Panreac (Barcelona, Spain). Aluminum chloride, potassium ferricyanide, ferric chloride and trichloroacetic acid were from Sigma Chemical Co. (St. Louis, MO, USA). The water was treated in a Milli-Q water purification system (TGI Pure Water Systems, Brea, CA, USA). Coomassie Brilliant blue G250 was purchased from Bio-Rad (Richmond, CA, USA). The spectrophotometer UV-VIS Spectrophotometer 1204 (Shimadzu, Japan) was used. MINOLTA Chromameter CR-300 (Minolta Camera Corp., Meter Division, Ramsey, NJ, USA) equipped with a D65 illuminant, 10° Observer and zero and white calibration was used to measure the color parameters (CIE L*, a*, b*).

All solvents used for HPLC analysis were of liquid chromatography grade and the water was ultrapure. From Sigma-Aldrich (St. Louis, MO, USA), the following products were obtained: Folin–Ciocalteu reagent, α-tocopherol, γ-tocopherol, trolox, butylated hydroxytoluene, 1,1,3,3-tetraethoxy propane and cinnamtannin A2, while acetone, butanol, isopropanol, hexane, acetonitrile and methanol were obtained from Panreac (Castellar del Vallés, Barcelona, Spain). Finally, the following standard compounds were purchased at Extrasynthese (Genay, France): gallic acid, catechin, epicatechin, epicatechin gallate, and procyanidins B1, B2, B3 and C1.

In this study was used: iron (III) acetylacetonate (99%) from Sigma Aldrich (St. Louis, MO, USA), oleic acid (90%) from Panreac (Barcelona, Spain), benzyl ether (99%) from Sigma Aldrich (Madrid, Spain), 4-biphenylcarboxylic acid (99%) from Sigma Aldrich (Madrid, Spain), toluene (99.8%) from Panreac (Barcelona, Spain), hexane (99%) from Panreac (Barcelona, Spain), chloroform (99.9%) from Panreac (Barcelona, Spain), and nitrogen (99%) from Air Liquide (Paris, France). All solutions were made with distilled water.

Analytical-grade chemicals Ethanol, Glacial Acetic Acid and Hexane (99.5%), from Panreac (Barcelona, Spain), sodium hydroxide (NaOH, pellet for analysis), buffer solutions (boric acid/potassium chloride/sodium hydroxide), sodium azide, and phenolphthalein were purchased from Sigma-Aldrich (St. Louis, MO, USA).

The three oils used in this study were coconut oil (Organic extra virgin coconut oil from PLANTIS^®, Barcelona, Spain), rapeseed oil (Organic cold pressed rapeseed oil Terpenic lab S.L., Barcelona, Spain) and grape seed oil (Refined grape seed Terpenic lab S.L., Barcelona, Spain). Three different batches of each type of oil were purchased in a local market.
2-thiobarbituric acid, and fatty acid methyl esters were obtained from Sigma-Aldrich Chemical (Steinheim, Germany). Boron/methanol trifluoride and heptane were purchased from Merck (Whitehouse Station, NJ, USA). Potassium hydroxide, hexane, cyclohexanone, hydrochloric acid, trichloroacetic acid and ammonium sulfate were from Panreac (Barcelona, Spain).
Salmonella typhimurium strains TA97a and TA98 and the Mutazime S9 mix at 10% from livers of Aroclor 1254-induced rats were purchased from Moltox (Boone, NC, USA). Nutrient broth and Phosphate Buffered Saline (PBS) tablets were obtained from Oxoid (Basingtone, UK). 4-nitro-o-phenylenediamine (NPD), 2-aminoanthracene (AA) and 2-aminofluorene (AF), histidine and biotin were obtained from Sigma-Aldrich.