Quantitative evaluation of the phenolic profile in fruits of six avocado (Persea americana) cultivars by ultra-high-performance liquid chromatography-heated electrospray-mass spectrometry

Figures & data

Figure 1. SIM traces of several compounds found in avocado samples, gallic acid and 4-idrossibenzoic acids have lower retention times (7.48 and 4.72 min, respectively), are not shown.

Table 1. Formula, retention time and exact mass of studied compounds in avocado fruits analyzed by UHPLC-HESI-MS.

Standard number	Compound identification	Formula	Measured mass [M-H]^−	Delta mm
1	Protocatechuic acid	C7H6O4	153.0174	–0.495
2	Gallic acid	C16H12O8	169.0134	2.143
3	Gentisic acid	C7H6O4	153.0174	–0.785
4	4-hydroxybenzoic acid	C7H6O3	137.0230	–0.261
5	Vanillic acid	C8H8 O4	167.0332	–0.615
6	Chlorogenic acid	C16H18O9	353.0867	0.041
7	Caffeic acid	C9H8O4	179.0337	–0.155
8	Homovanillic acid	C9H10O4	181.0492	–0.245
9	Syringic acid	C9H10O5	197.0444	0.030
10	Epicatechin	C15H14O6	289.0714	0.575
11	Vanillin	C8H8O3	151.0385	–0.881
12	p-coumaric acid	C9H8O3	163.0379	–0.991
13	Ferulic acid	C10H10O4	193.0496	–0.135
14	Sinapinic acid	C11H12O5	223.0603	0.240
15	3-hydroxycinnamic acid	C9H8O3	163.0379	–0.991
16	Rutin	C27H30O16	609.1446	–0.501
17	Taxifolin	C15H12O7	303.0504	0.481
18	Benzoic acid	C7H6O2	121.0280	–0.426
19	Narirutin	C27H32O14	579.1711	0.178
20	Naringin	C27H32O14	579.1711	0.178
21	Isorhamnetin	C16H12O7	315.0142	–1.965
22	Myricetin	C15H10O8	317.0294	0.186
23	Neohesperidin	C28H34O15	609.1818	0.453
24	Quercetin	C15H10O7	301.0346	0.461
25	Luteolin	C15H10O6	285.0399	0.536
26	Trans-cinnamic acid	C9H8O2	147.0433	–0.806
27	Poncirin	C28H34O14	593.1865	0.152
28	Naringenin	C15H12O5	271.0606	0.560
29	Apigenin	C15H10O5	269.0451	0.555
30	Kaempferol	C15H10O6	285.0399	0.536
31	Chrysin	C15H10O4	253.0501	0.565
32	Galangin	C15H10O5	269.0451	0.555

Table 2. Concentration (mg analyte/kg fresh sample) of phenolic compounds in the pulp of unripe (green) and ripe fruit from six avocado cultivars.

	Bacon		Fuerte		Hass		Orotawa		Pinkerton		Rincon
	green	ripe	green	ripe	green	ripe	green	ripe	green	ripe	green	ripe	Regression model	LOD (ppm)	LOQ (ppm)
4-hydroxybenzoic acid	0.29	0.26	nf	0.39	0.29	0.27	0.28	0.36	0.32	0.30	0.32	0.42	Y = (–2.56 × 10^6) + (1.58*10^7)*X; R^2 = 0.999	0.004	0.01
benzoic acid	1.86	nd	nd	2.02	8.07	0.99	0.58	5.83	nd	nd	1.76	nd	Y = (4.57 × 10^6) + (2.07*10^7)*X; R^2 = 0.999	0.02	0.2
Caffeic acid	nf	nf	nf	nf	nf	0.20	nf	0.63	nf	nf	nf	nf	Y = (3.23 × 10^6) + (1.05*10^7)*X; R^2 = 0.998	0.009	0.02
Chlorogenic acid	0.41	0.09	0.13	2.32	0.32	0.06	3.36	3.67	6.28	10.36	0.05	nf	Y = (1.45 × 10^6) + (5.15*10^6)*X; R^2 = 0.995	0.006	0.02
Epicatechin	0.38	nd	8.12	1.64	4.04	6.28	10.46	1.29	49.81	6.23	nd	nd	Y = (1.80 × 10^6) + (8.43*10^6)*X; R^2 = 0.998	0.005	0.01
Ferulic acid	nd	nd	nd	1.29	nd	2.29	nd	0.83	nf	2.02	nf	1.57	Y = (3.36 × 10^6) + (2.24*10^7)*X; R^2 = 0.999	0.005	0.06
Gallic acid	nd	0.56	nd	0.96	nf	nd	nq	2.54	nf	nd	nf	nd	Y = 266815 + (1.24*10^6)*X; R^2 = 0.995	0.02	0.05
Gentisic acid	1.18	2.88	0.35	1.67	1.04	0.24	0.42	4.24	nf	0.42	0.52	nf	Y = 6612.29 + (1.67*10^6)*X; R^2 = 0.999	0.005	0.002
Isoramnetin	nf	nf	nf	nf	nf	0.03	nf	nf	nf	nf	nf	nf	Y = (–1.59264 × 10^6) + (7.18468*10^6)*X; R^2 = 0.999	0.007	0.02
Narirutin	nf	nf	nf	nf	nf	nd	nf	nf	1.72	0.01	nf	nf	Y = (2.38 × 10^6) + (1.40*10^7)*X; R^2 = 0.998	0.005	0.01
p-coumaric acid	nf	nf	nf	12.28	0.02	3.64	nf	7.82	nf	1.69	nf	11.11	Y = (2.59 × 10^6) + (2.73*10^7)*X; R^2 = 0.999	0.006	0.01
Poncirin	nd	nf	nd	nf	nd	nd	nd	nd	1.68	nf	nf	nf	Y = 256990 + (1.01*10^6)*X; R^2 = 0.996	0.06	0.02
Protocatechuic acid	0.24	1.11	nq	0.18	0.18	nq	0.01	1.07	0.04	0.04	0.04	0.02	Y = 255906 + (6.23*10^6)*X; R^2 = 0.998	0.01	0.03
Rutin	nf	nf	nf	nf	nd	0.06	nf	nf	nf	nf	nf	nf	Y = (3.94899+10^6) + (1.13391+10^6)*X; R^2 = 0.996	0.006	0.01
sinapinic acid	nf	nf	nf	0.45	nf	0.43	nf	nf	nf	0.25	nf	nf	Y = (3.56 × 10^6) + (1.32*10^7)*X; R^2 = 0.998	0.004	0.01
Taxifolin	nf	nf	nf	nf	nd	0.05	nf	nf	nf	nf	nf	nf	Y = (4.55072 × 10^6) + (9.14316 × 10^6) × X; R^2=0.995	0.05	0.02
Trans-cinnamic acid	nf	nf	nf	nf	nf	0.05	nf	0.04	nf	nf	nf	nf	Y = (3.57102 × 10^7) + (1.15279 × 10^8)*X; R^2= 0.998	0.008	0.03
vanillin	nd	nd	nd	0.17	nd	0.02	nd	nd	nd	nd	nd	0.06	Y = (2.43 × 10^6) + (2.18*10^7)*X; R^2 = 0.999	0.002	0.004

RSD in all cases ≤5%.

nd: not detectable; nf: not found.

Table 3. Total phenolic compounds (mg/kg of analyte in fresh sample) in green and ripe fruit of the six cultivars in the trial.

	Green	Ripe
Bacon	3.96	6.35
Fuerte	7.10	23.19
Hass	13.97	14.61
Orotawa	15.01	28.32
Pinkerton	58.76	21.22
Rincon	2.68	11.73
HSD	1.69

Significant interaction between cultivar and maturation stage (p < 0.001).

Mean separation by Tukey’s honestly significant difference (HSD) at p = 0.05.

Table 4a. Mahalanobis squared distance between cultivar pairs from linear discriminant analysis.

	Bacon	Fuerte	Hass	Orotawa	Pinkerton	Rincon
Bacon	0
Fuerte	142	0
Hass	138	30	0
Orotawa	32	197	226	0
Pinkerton	272	263	163	395	0
Rincon	159	461	518	88	794	0

Table 4b. Tests of significance of squared Mahalanobis f-tests with 7 and 18 degrees of freedom of the variety separation model, independently from the ripening stage.

	Bacon	Bacon	Fuerte	Fuerte	Hass	Hass	Orotawa	Orotawa	Pinkerton	Pinkerton	Rincon	Rincon
	F	p	F	p	F	p	F	p	F	p	F	P
Bacon
Fuerte	38.1	0.00000
Hass	37.0	0.00000	8.0	0.00019
Orotawa	8.5	0.00012	52.8	0.00000	60.7	0.00000
Pinkerton	72.8	0.00000	70.6	0.00000	43.5	0.00000	105.7	0.00000
Rincon	42.6	0.00000	123.5	0.00000	138.6	0.00000	23.5	0.00000	212.8	0.00000

Figure 2. Avocado discrimination by variety: A: 3D separation using three independent root; and B: root 1 and root 3 separation in a 2D graph.