1 propanol

All chemicals were at least of analytical grade. Toluene, 1-propanol, formic acid, acetic acid, hydrochloric acid (37%) and 4-dimethylaminocinnamaldehyde (DMACA) were from Merck (Darmstadt, Germany). Ethanol, acetone, as well as HPLC grade acetonitrile and mEthanol were purchased from Sigma-Aldrich (St. Louis, MO, USA). LC-MS grade acetonitrile and mEthanol used for MS analyses were from Fluka (Buchs, Switzerland). MilliQ 18.2 MΩ water (Millipore, Bedford, MA, USA) was also used.
Standards of (−)-epicatechin gallate, (−)-epigallocatechin, (−)-epigallocatechin gallate, (−)-catechin gallate, (−)-gallocatechin, (−)-gallocatechin gallate, procyanidin B1, procyanidin B2, procyanidin B3 and procyanidin C1 were obtained from Extrasynthèse (Genay, France), while (−)-epicatechin was from Sigma-Aldrich and (+)-catechin from Carl Roth (Karlsruhe, Germany).

Following fixation in 4% PFA, samples were embedded in 1% agarose by boiling and slowly cooling down to room temperature. Samples processed with BABB were sequentially incubated in 25, 50, 80, and 100% ethanol (Merck Millipore, Burlington, MA, United States) for 8 h each at room temperature. Samples processed with 1-propanol BABB (1P-BABB) were sequentially incubated in 25, 50, 80, and 100% 1-propanol (Merck Millipore, Burlington, MA, United States) for 8 h each at room temperature. Samples processed with tert-butanol BABB (tB-BABB) were sequentially incubated in 25, 50, 80, and 100% tert-butanol (Daejung Chemical & Metals Co. Ltd., Gyeonggi-do, Korea) for 8 h each at room temperature. After alcohol dehydration, the samples were incubated in fresh solutions of either 100% ethanol, 1-propanol, or tert-butanol, as appropriate, for 12 h at room temperature. Subsequently, samples were incubated in dichloromethane (DCM; Sigma-Aldrich Inc., St. Louis, MO, United States) for 1 h at room temperature. Samples were then incubated in BABB solution [1 volume of benzyl alcohol (BA; Sigma-Aldrich Inc., St. Louis, MO, United States) to 2 volumes of benzyl benzoate (BB; Duksan Pure Chemicals, Gyeonggi-do, Korea)] for 1–2 days until they achieved optical transparency.

Lipases from Thermomyces lanuginosus (TLL), Rhizomucor miehei (RML), Candida antarctica lipase B (CALB), FeCl₂.4H₂O, FeCl₃.6H₂O, p-nitrophenyl butyrate (p-NPB), and tetraethyl orthosilicate (TEOS) were purchased from Sigma-Aldrich. Waste cooking oil was also obtained from a local restaurant and the fatty acids composition of waste cooking oil was determined to be 40.6% oleic acid, 17.58% linoleic acid, 32.24% palmitic acid, and 5.23% stearic acid. The molecular weight of the waste cooking oil which was determined from the saponification value of 196.2 mg KOH/g and acid value of 76 mg KOH/g was calculated to be 856.3 g/mol. Water content in the oil measured by Karl Fischer (Verhoef et al. 1978 (link)) titration method was determined to be 0.01% (w/w). Solvents used including n-hexane, methanol, ethanol, 1-propanol, toluene, t-butanol and blue silica gel were prepared from Merck chemicals. Triethylamine (Et₃N) was from Titrachem and 3-aminopropyltrimethoxysilane (3-APTMS) 97% was purchased from Alfa Aesar. All the other chemicals were accessed commercially.

Anhydrous sodium sulfate was purchased from AppliChem GmbH (Darmstad, Germany); dichloromethane (99.9%) was supplied by Honeywell Riedel-de Haën (Steinheim, Germany) and silanized glass wool by Supelco (Steinheim, Germany). 2-Octanol (≥99.5%), used as an internal standard was purchased from Sigma-Aldrich (St. Louis, MO, USA).
GC-FID and GC-MS used standards: acetic acid was purchased from Riedel-de-Haen (Seelze, Germany); isobutanol, 2-methyl-1-butanol, 3-methyl-1-butanol,benzyl alcohol, 2-phenylethanol,propanoic acid, butanoic acid, isovaleric acid, octanoic acid, hexanal, ethyl propanoate, isobutyl acetate, ethyl 2-methylbutyrate, ethyl hexanoate, ethyl decanoate, phenethyl acetate, ethyl dodecanoate, eugenol were acquired from Fluka (Buchs, Switzerland);1-propanol, 2,3-butanediol, 1,2-propanediol, glycerol, isobutyric acid, ethyl butyrate, ethyl octanoate were purchased from Merck (Darmstadt, Germany); e-ethoxy-1-propanol, methional, ethyl isobutyrate, ethyl isovalerate, isoamyl acetate, ethyl hydrogen succinate, furfural were bought from Aldrich (Steinheim, Germany) and 2,3 butanedione was acquired from Sigma-Aldrich (Saint Louis, MO, USA).

All chemicals were at least of analytical grade. Acetic acid, formic acid, hydrochloric acid (37%), toluene, 1-propanol, and 4-dimethylaminocinnamaldehyde (DMACA) were from Merck (Darmstadt, Germany). Acetone, ethanol as well as HPLC grade acetonitrile and methanol were purchased from Sigma-Aldrich (St. Louis, MO, USA). LC–MS grade acetonitrile and methanol used for MS analyses were from Fluka (Buchs, Switzerland). MilliQ 18.2 MΩ water (Millipore, Bedford, MA, USA) was also used.
Standard of (−)-epicatechin was obtained from Sigma-Aldrich and (+)-catechin from Carl Roth (Karlsruhe, Germany). Standards of procyanidin B1, procyanidin B2, procyanidin B3, procyanidin C1, (−)-catechin gallate, (−)-gallocatechin, (−)-gallocatechin gallate, (−)-epicatechin gallate, (−)-epigallocatechin and (−)-epigallocatechin gallate were obtained from Extrasynthèse (Genay, France).

Methanol, acetonitrile (HPLC grade), formic acid, sodium acetate, acetic acid, ethyl acetate, n-hexane, sodium carbonate (anhydrous), dichlorophenolindophenol, chloroform, 96% ethanol, 1-propanol, 4-dimethylaminocinnamaldehyde (DMACA), hydrochloric acid (p.a.), sulfuric acid (p.a.), nitric acid (p.a.), and potassium chloride were obtained from Merck (Darmstadt, Germany). Toluen was purchased from Carlo Erba (Chaussée du Vexin, France).
Acetone, trolox (6-hydroxy-2,5,7,8-tetramethyl-chroman-2-carboxylic acid), ascorbic acid, paraffin oil, Folin–Ciocalteu’s phenol reagent, 2,2-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt (ABTS), aluminum chloride hexahydrate, sodium nitrite, sodium chlorite, potassium persulfate, 2-aminoethyl diphenylborinate, boron trifluoride and standards of phenolic compounds: protocatechuic acid, chlorogenic acid, p-coumaric acid, o-coumaric acid, and (+)-catechin, were purchased from Sigma-Aldrich (St. Louis, MO, USA).
Standards of phenolic compounds, quercetin, gallic acid, ferulic acid, and caffeic acid, were purchased from Merck. Standards of cyanidin-3-O-glucoside chloride, pelargonidin-3-O-glucoside chloride, pelargonidin-3,5-di-O-glucoside chloride, and delphinidin-3-O-glucoside chloride were from Extrasynthese (Genay, France). Aqueous solutions were prepared with Mili-Q water (Millipore, Bedford, MA, USA).