Table 2. GC-MS quantitative analysis of the hydrolyzable constituents identified in cutin samples purified using either cholinium hexanoate or BMIM acetate in 2-, 15-, or 170-h reactions.

The reference cutin and the feedstock (i.e. untreated peels) were also analyzed for comparison. Results are given as wt % (n = 3). The identification yields (wt %) and the mass of the nonhydrolyzable fraction (recalcitrance [%]) are indicated.

Compound Name	Compound Abundances
	Untreated Feedstock	Reference Cutin	Cholinium Hexanoate			BMIM Acetate
			2 h	15 h	170 h	2 h	15 h	170 h
	wt %
Fatty acids	2.60 ± 0.13	1.52 ± 0.24	1.27 ± 0.15	0.88 ± 0.13	0.67 ± 0.09	1.96 ± 0.2	0.74 ± 0.1	0.10 ± 0.06
Hexadecanoic acid	1.25 ± 0.04	0.74 ± 0.05	0.64 ± 0.04	0.41 ± 0.11	0.33 ± 0.03	0.63 ± 0.05	0.42 ± 0.03	0.10 ± 0.06
Octadeca-9,12-dienoic acid	0.43 ± 0.15	0.23 ± 0.05	0.20 ± 0.03	0.11 ± 0.01	–	0.74 ± 0.12	–	–
Octadec-9-enoic acid	–	0.24 ± 0.06	0.11 ± 0.02	0.09 ± 0.04	–	0.18 ± 0.03	–	–
Octadecanoic acid	0.91 ± 0.12	0.31 ± 0.10	0.09 ± 0.00	0.13 ± 0.05	0.12 ± 0.02	0.18 ± 0.04	0.13 ± 0.06	–
4-Oxocyclohexane-1-carboxylic acid	–	–	0.23 ± 0.08	0.14 ± 0.12	0.22 ± 0.06	0.23 ± 0.00	0.19 ± 0.02	–
Dicarboxylic acids	10.89 ± 1.08	18.38 ± 0.44	18.64 ± 0.49	19.2 ± 2.16	18.64 ± 0.58	18.45 ± 1.19	19.3 ± 0.21	9.99 ± 2.05
Nonanedioic acida	–	0.43 ± 0.02	0.26 ± 0.02	0.26 ± 0.15	0.36 ± 0.01	0.27 ± 0.02	0.22 ± 0.04	–
Hexadecanedioic acid	0.56 ± 0.02	1.51 ± 0.07	1.30 ± 0.07	1.52 ± 0.10	1.22 ± 0.08	1.47 ± 0.07	1.42 ± 0.15	0.46 ± 0.07
8/9-Hydroxyhexadecanedioic acidb	10.33 ± 1.06	16.43 ± 0.38	17.08 ± 0.55	17.43 ± 2.01	17.06 ± 0.50	16.7 ± 1.14	17.66 ± 0.20	9.53 ± 0.23
ω-Hydroxy acids	11.13 ± 0.35	15.04 ± 0.31	18.42 ± 0.63	17.42 ± 2.22	17.69 ± 1.28	18.95 ± 0.4	18.49 ± 1.06	22.90 ± 1.68
16-Hydroxyhexadecanoic acid	5.38 ± 0.16	8.17 ± 0.21	8.20 ± 0.12	8.50 ± 0.65	8.32 ± 0.21	8.35 ± 0.23	8.48 ± 0.39	15.71 ± 0.68
16-Hydroxy-10-oxohexadecanoic acid	3.02 ± 0.28	2.29 ± 0.14	6.39 ± 0.52	6.21 ± 0.97	6.28 ± 0.61	6.81 ± 0.05	6.62 ± 0.39	1.80 ± 0.12
9, 10-Epoxy-18-hydroxyoctadecanoic acid	1.14 ± 0.24	1.93 ± 0.09	1.73 ± 0.07	1.63 ± 0.38	1.27 ± 0.32	1.67 ± 0.13	1.60 ± 0.14	2.38 ± 0.53
9, 10-Epoxy-18-hydroxyoctadecenoic acid	1.60 ± 0.15	2.65 ± 0.20	2.10 ± 0.25	1.62 ± 0.18	1.82 ± 0.55	2.11 ± 0.09	1.79 ± 0.18	3.01 ± 0.59
Polyhydroxy acids	55.05 ± 2.01	65.06 ± 0.65	61.67 ± 0.28	62.49 ± 4.06	63.01 ± 1.92	60.64 ± 1.69	61.47 ± 1.28	67.01 ± 1.44
10,16-Dihydroxyhexadecanoic acidc	53.22 ± 2.23	63.24 ± 0.98	58.83 ± 0.42	59.68 ± 5.03	61.20 ± 2.16	58.12 ± 1.89	58.97 ± 1.55	63.12 ± 2.42
9,10,18-Trihydroxyoctadecanoic acid	1.00 ± 0.11	0.94 ± 0.06	1.11 ± 0.32	1.19 ± 0.67	0.53 ± 0.00	0.85 ± 0.11	0.90 ± 0.13	1.51 ± 0.45
9,10,18-Trihydroxyoctadec-12-enoic acid	0.84 ± 0.39	0.89 ± 0.36	1.73 ± 0.07	1.63 ± 0.38	1.27 ± 0.32	1.67 ± 0.13	1.60 ± 0.14	2.38 ± 0.53
Sterolsd	20.33 ± 1.07	–	–	–	–	–	–	–
Identification yield (%)	56.38 ± 2.46	50.7 ± 2.38	58.1 ± 0.88	59.34 ± 6.63	56.39 ± 1.20	58.02 ± 2.45	60.35 ± 3.46	82.15 ± 0.20
Recalcitrance (%)	22.14 ± 2.98	13.32 ± 1.39	28.3 ± 4.98	27.47 ± 0.58	33.07 ± 0.56	19.75 ± 0.36	20.21 ± 1.06	18.15 ± 2.48

^aThis compound was overestimated or overlapped with an unknown compound.

^bThis compound was associated with the possible presence of unspecific isomers.

^cThe major species of this compound was 10,16-diOH and minor species were 9,16- and 8,16-diOH.

^dTriterpenoids and sterols identified were β-amyrin (5.69 ± 0.44), α-amyrin (4.44 ± 0.20), δ-amyrin (7.53 ± 1.48), and stigmasterol (2.68 ± 0.49).