L-ascorbic acid and α-tocopherol content in apple pulp: a comparison between 24 cultivars and annual variations during three harvest seasons

Figures & data

Figure 1. α-tocopherol content (n = 3 technical replicates) in ‘Cripps Pink/Pink Lady®’ apple pulp extracted using three procedures: methanolic extraction of freeze-dried material, extraction with n-hexane of fresh apple pulp and saponification of fresh apple pulp.

Table 1. Validation parameters of the HPLC-DAD method for the determination of α-tocopherol in apple pulp.

Linearity	Intraday precision	Interday precision		Detection Limits		Average Recovery
r2 0.99	RSD (%) (5 replicates)	RSD (%) (day 2)	RSD (%) (day 3)	LOD (mg/100 g FW)	LOQ (mg/100 g FW)	(%)
	1.5	1.7	1.9	0.003	0.009	98

Figure 2. Chromatograms of α-tocopherol at 300 nm (a) and L-ascorbic acid (AsA) at 260 nm (b) of the sample LB 04852 (‘Elstar’ x ‘Braeburn’). Insert: UV/VIS spectra of the α-tocopherol and AsA peak of the apple pulp sample (in blue) and a reference standard solution (in red), respectively.

Table 2. Average content of L-ascorbic acid (AsA) and α-tocopherol (mg/100 g FW) in apple pulp and relative standard deviation (RSD in %) between the amount found in 10 apple samples for each of 24 cultivars from season 2010.

Cultivar	Average content of AsA (mg/100 g FW)	Average content of α-tocopherol (mg/100 g FW)	RSD (%) AsA	RSD (%) α-tocopherol
Brixner Plattling	2.28 ± 0.38	0.33 ± 0.04	17	10
Cripps Pink Pink Lady®	4.90 ± 0.63	0.19 ± 0.02	13	9.0
Gala	0.43 ± 0.13	0.22 ± 0.03	29	12
Golden Delicious	1.22 ± 0.10	0.28 ± 0.03	8.4	10
Weißer Rosmarin	2.64 ± 0.73	0.24 ± 0.01	28	5.6
Champagner Renette	2.56 ± 0.6	0.22 ± 0.01	23	3.3
Gelber Bellefleur	2.17 ± 0.42	0.25 ± 0.03	19	10
CIVG 198 Modì®	2.47 ± 0.29	0.31 ± 0.02	12	6.8
Nicoter Kanzi®	4.77 ± 0.84	0.24 ± 0.03	18	13
Pinova	2.20 ± 0.45	0.24 ± 0.02	20	6.6
Kaiser Wilhelm	4.95 ± 0.88	0.32 ± 0.02	18	5.6
Boznerapfel	2.38 ± 0.60	0.29 ± 0.03	25	9.0
Scifresh Jazz®	3.64 ± 0.78	0.31 ± 0.02	21	5.2
Stayman Winesap	2.58 ± 0.40	0.32 ± 0.02	16	6.6
Morgenduft	2.24 ± 0.47	0.27 ± 0.03	21	12
LB 04852 (‘Elstar’ x ‘Braeburn’)	5.68 ± 0.94	0.18 ± 0.01	17	8.0
LB 05090 (‘Cripps Pink’ x ‘Gala’)	1.55 ± 0.28	0.32 ± 0.03	18	10
Cellini	2.40 ± 0.47	0.16 ± 0.03	20	18
Gravensteiner	1.11 ± 0.44	0.21 ± 0.03	40	12
Roter Herbstkalvill	0.57 ± 0.22	0.18 ± 0.01	39	7.2
Freiherr von Berlepsch	6.22 ± 1.06	0.13 ± 0.02	17	15
Karmelitter Renette	2.23 ± 0.29	0.32 ± 0.02	13	5.4
Steinpepping	1.32 ± 0.72	0.21 ± 0.02	55	7.7
Schweizer Orangenapfel	6.07 ± 1.45	0.21 ± 0.03	24	13
Avarage value among 24 cultivars	2.86	0.25

Figure 3. Box plots of the L-ascorbic acid (AsA) (a) and α-tocopherol (b) content (expressed as mg/100 g FW) in 24 apple cultivars from the 2010 season. Median values are reported (n = 10).

Table 3. Two-way analysis of variance (ANOVA) for the effects of the cultivar and the harvest year on the content of L-ascorbic acid (AsA) and α-tocopherol.

Compound	Cultivar	Harvest year	Cultivar*Harvest year
p value
AsA	< 0.001	0.001	< 0.001
α-tocopherol	< 0.001	< 0.001	< 0.001

Figure 4. Box plots of the L-ascorbic acid (AsA) (a) and α-tocopherol (b) content (expressed as mg/100 g FW) in six varieties harvested over three consecutive seasons (2008 to 2010). Median values are reported (n = 10). Significant differences between the content of vitamins in the apple pulp of the same cultivar collected over three years are indicated by different letters (p < .05).