Determination of Color, Antioxidant Activity, and Phenolic Profile of Different Fruit Tissue of Spanish ‘Verde Doncella’ Apple Cultivar

Figures & data

Figure 1 ‘Verde Doncella’ apple peel HPLC chromatograms, measured at different wavelengths (a = 280, b = 320, c = 360, d = 520).

Figure 2 ‘Red Delicious’ apple peel HPLC chromatograms, measured at different wavelengths (a = 280, b = 320, c = 360, d = 520).

Table 1  Color coordinates obtained in the initial characterization of apples.

Cultivar	L*	a*	b*	C^ab*	h^ab
‘Verde Doncella’	76.4 ± 3.9	0.0 ± 3.0	49.8 ± 2.2	49.9 ± 2.3	90.1 ± 3.4
‘Red Delicious’	51.2 ± 5.6	31.5 ± 3.7	33.0 ± 3.0	45.8 ± 1.3	46.3 ± 5.7

The presented values correspond to the average ± standard deviation of 200 measured points per sample. Parameter L* indicates brightness or lightness (0 = black, 100 = white); a* indicates chromaticity on a green (-) to red (+) axis; b* indicates chromaticity on a blue (-) to yellow axis (+). The hue (h_ab) is an angle in a color wheel of 360°, with 0°, 90°, 180°, and 270° representing the hues red-purple, yellow, bluish-green, and blue respectively, while Chroma (C_ab^*) is the intensity or purity of the hue[²⁴].

Table 2  Filters’ commercial name, type of filtration, pore size, and average absorbance of filtrate extracts assayed for filtration optimization.

Filter name	Type of filtration	Pore size (μm)	Average absorbance ± Standard Deviation*
1. Albet 9 cm 88663	Gravity; vacuum	25	0.43 ± 0.01
2. Albet 11 cm DP140110	Gravity	15.5	0.22 ± 0.01
3. Albet 13 cm	Gravity; vacuum	25	0.55 ± 0.01
4. Filter-Lab 1250	Gravity	12	0.25 ± 0.02
5. Filter-Lab M2BL0045142	Gravity	0.45	0.16 ± 0.03
6. Machery-Nagel Co. 9 cm MN640d	Gravity; vacuum	2 to 4	0.17 ± 0.05
7. Pall Life Sci. Corp. Acrodisc Syringe Filter	Syringe	0.2	0.20 ± 0.01
8. Pall Life Sci. Corp. Acrodisc Syringe Filter	Syringe	0.45	0.16 ± 0.03
9. Selex coffee filters No. 4	Gravity	40	0.70 ± 0.08
10. Schleicher & Schuell 0860 Rundfilter	Gravity; vacuum	7 to 12	0.26 ± 0.01
11. Whatman No. 1	Gravity	11	0.34 ± 0.03
12. Whatman No. 2	Gravity	8	0.30 ± 0.01
13. Whatman No. 4	Gravity	20 to 25	0.33 ± 0.02

*Each filter was tested in triplicate (n = 3).

Table 3  Mean and standard deviation (n = 3) of total phenolic content (TPC) and antioxidant activity of ‘Verde Doncella’ and ‘Red Delicious’ fruit extracts using Folin-Ciocalteu and FRAP methods.*

Parameter	VD Peel	RD Peel	VD Pomace	RD Pomace	VD Juice	RD Juice
TPC (mg GAE/g)	12.7 ± 0.4 b	28 ± 0.7 c	3,65 ± 0.1 a	3.9 ± 0.2 a	0.89 ± 0.04 A	0.86 ± 0.05 A
Antioxidant activity (mg GAE/g)	52 ± 1.1 b	143 ± 7.4 c	21 ± 0.5 a	24 ± 1.2 a	6.6 ± 0.3 A	6.6 ± 0.4 A

Data for peel and pomace is expressed in per gram dry weight (DW) apple whereas data for juice is expressed per gram fresh weigh (FW) apple.

*Within columns, values followed by the same letter were not significantly different (p < 0.05).

Figure 3 ‘Verde Doncella’ peel, pomace, and juice HPLC chromatograms read at 280 nm. (1) Gallic acid; (2) Procyanidin B1; (3) Unknown procyanidin dimer; (4) Catechin; (5) Procyanidin B2; (6) Chlorogenic acid; (7) Unknown procyanidin dimer; (8) Caffeic acid; (9) Anthocyanin; (10) Epicatechin; (11) Cyanidin-3-rutinoside; (12) Unknown procyanidin dimer; (13) p-Coumaric acid; (14) Unknown procyanidin dimer; (15) 3-Hydroxyphloretin 2-xyloglucoside; (16) Quercetin 3-galactoside; (17) Rutin; (18) Quercetin 3-glucoside; (19) Quercetin derivative; (20) Unknown phloretin derivative; (21) Phloretin 2’-xyloglucoside; (22) Quercetin 3-rhamnoside; (23) Unknown phloretin derivative; (24) Unknown phloretin derivative; (25) Phloridizin; (26) Unknown; (27) Hyperin; (28) Avicularoside; (29) Quercetin.

Figure 4 ‘Red Delicious’ peel, pomace, and juice HPLC chromatograms read at 280 nm. (1) Gallic acid; (2) Procyanidin B1; (3) Unknown procyanidin dimer; (4) Catechin; (5) Procyanidin B2; (6) Chlorogenic acid; (7) Cyanidin-3-galactoside; (8) Caffeic acid; (9) Unknown procyanidin dimer; (10) Epicatechin; (11) Cyanidin-3-rutinoside; (12) Procyanidin dimer; (13) p-Coumaric acid; (14); Procyanidin dimer; (15) 3-Hydroxyphloretin 2’-xyloglucoside; (16) Quercetin 3-galactoside; (17) Rutin; (18) Quercetin 3-glucoside; (19) Quercetin 3-xyloside; (20) 3’-Hydroxyphloretin 2’-glucoside; (21) Quercetin 3-arabinoside; (22) Phloretin 2-xyloglucoside; (23) Quercetin 3-rhamnoside; (24) Phloridizin; (25) Unknown; (26) Quercetin 3-α-L-arabofuranoside; (27) Quercetin.

Table 4  Mean concentrations (μg/g fresh apple) and standard deviations (n = 3) of individual and total polyphenols determined by HPLC.

		μg/g DW apple				μg/g FA
Compound	Optimum λ (nm)	VD peel	RD peel	VD pomace	RD pomace	VD juice	RD juice
Catechin	280	118 ± 7.1 c	160 ± 6.0 d	56 ± 5.6 a	80 ± 4.3 b	19 ± 1.4 A	25 ± 1.1 A
Epicatechin	280	135 ± 6.5 c	273 ± 45 d	38 ± 1.9 a	83 ± 12.7 b	14 ± 3.6 A	22 ± 1.2 B
Total flavanols		253 ± 9.4 c	433 ± 67 d	94 ± 7.2 a	163 ± 8.3 b	33 ± 4.9 A	47 ± 1.9 B
Chlorogenic acid	320	94 ± 1.8 c	133 ± 10 d	26 ± 5.9 a	40 ± 3.0 b	14 ± 3.6 A	20 ± 1.5 B
Caffeic acid	320	19 ± 7.1 ab	73 ± 15 c	6 ± 4.1 a	31 ± 6.3 b	3.3 ± 0.4 A	5.5 ± 0.5 B
p-Coumaric acid	320	59 ± 19.4 c	27 ± 1 b	nd	6 ± 3.7 a	nd	3.9 ± 1.6
Hydroxycinamic acids		171 ± 27.6 c	233 ± 46 c	31 ± 8.1 a	77 ± 10.7 b	17 ± 4.9 A	29 ± 2.8 B
Quercetin	360	49 ± 6.5 a	58 ± 7 a	nd	nd	nd	nd
Quercetin-3-galactoside	360	12 ± 0.6 b	93 ± 5 c	nd	3 ± 1.3 a	nd	nd
Quercetin-3-glucoside	360	42 ± 5.3 a	52 ± 8 a	nd	nd	nd	nd
Quercetin-3-rhamnoside	360	12 ± 1.8 a	29 ± 3 b	nd	nd	nd	nd
Quercetin-3-O-rutinoside (rutin)	360	18 ± 4.7 a	87 ± 8 b	nd	13 ± 1.7 a	nd	nd
Total flavonols		135 ± 14.1 b	333 ± 39 c		17 ± 2.0 a	nd	nd
Phloridzin	280	51 ± 4.1 c	73 ± 1 d	22 ± 0.6 b	13 ± 1.7 a	2.3 ± 0.9 A	1.2 ± 0.3 A
Procyanidin B2	280	118 ± 8.8 d	80 ± 2 c	13 ± 0.9 a	25 ± 1.3 b	6.2 ± 0.2 A	8.0 ± 0.1 B
Gallic acid	280	14 ± 8.8 ab	21 ± 7 b	9 ± 3.1 a	10 ± 1.3 a	60 B	3.1 ± 0.9 A
HPLC total phenols		894 ± 133 c	1173 ± 267 d	169 ± 37.5 a	420 ± 58 b	58 A	89 B

Note: Data for peel and pomace is expressed in per gram dry weight (DW) apple whereas data for juice is expressed in per gram fresh weigh (FW) apple. nd: Not detected.

Within rows, values followed by the same letter were not significantly different (p < 0.05).)

McGuire, R.G. Reporting of objective color measurements. Hort Science 1992, 27, 1254–1255.

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