The content and composition of lipids isolated from the seeds of seven apple species from Asturias (Spain) were characterized. The highest content in oil corresponded to Collao (22.73±0.81 g·100 g−1 of seed), followed by Raxao and Riega (20.19±0.74 g·100 g−1 of seed; 19.67±0.85 g·100 g−1 of seed), respectively. The linoleic acid was found to be the main component in Limón Montés (60.78±3.07%) followed by Riega (60.01±3.41%). Solarina seed oil was the one with the highest content in total sterols (558.52±9.42 mg·100 g−1 of oil) while Blanquina was the one that presents the lowest amount (166.55±1.89 mg·100 g−1 of oil). Phosphatidylcholine (70.58±3.85%) was found to be the main constituent in Blanquina followed by Collaos (55.55±2.96%). Raxao presented the highest content in β-tocopherol (125.29±12.62) and α-tocopherol was the most important tocopherol in Limón Montés (84.68±5.61 mg·kg−1 of oil). The main triglycerides were LLP (41.17±1.98-39.32±1.66%) followed by LLL (27.12±1.32-17.80±1.96%). Good separation among specie samples according to the statistical analysis of the principal component (PCs) and linear discriminant analysis (LDA) was obtained.
In the last few years, there has been a considerable interest in finding new food sources that will meet the health and nutritional needs of the world′s population (Maazouzi
The aim of this research was to study the oils of seven different apple seed oils from Asturias (Spain), Blanquina, Raxao, Collaos, Durona, Riega, Solarina and Limón Montés species pertaining to the DO cider from Asturias. The composition in fatty acids, sterols, phospholipids, tocopherols and triglycerides were characterized, as well as the total contents in oil and moisture.
The apple seed species (
Oil (g·100 g−1 seed), moisture (g·100 g−1 seed) and seed yield (g·10 Kg−1 fruit) from the different varieties of apples
Cultivar | Variety | Fruit (kg) | Seed yield (g) | Oil (%) | Moisture (%) |
---|---|---|---|---|---|
A | Blanquina | 10±0.13 | 5.19±0.23 |
18.82±0.62 | 9.26±0.12 |
B | Raxao | 10±0.19 | 4.76±0.32 |
20.19±0.74 | 8.79±0.18 |
C | Collaos | 10±0.14 | 5.56±0.19 | 22.73±0.81 | 8.19±0.13 |
D | Durona | 10±0.16 | 4.56±0.16 |
17.71±0.65 | 8.53±0.11 |
E | Riega | 10±0.12 | 6.43±0.19 | 19.67±0.85 | 7.62±0.10 |
F | Solarina | 10±0.14 | 7.21±0.17 |
16.87±0.61 |
8.12±0.13 |
G | Limón Montés | 10±0.18 | 7.49±0.21 | 18.67±0.66 |
7.13±0.12 |
Mean standard deviation (n=3).
Samples were blanched and ground in an electrical grinder. The oil was extracted in a Soxhlet glass apparatus using hexane as solvent (IUPAC,
Fatty acid methyl-esters (FAME) were analyzed by gas chromatography (GC). FAME were extracted with n-heptane after cold methylation with 2N KOH in methanol (IUPAC,
The unsaponifiable fraction was extracted as described (European Communities
Phospholipids were analyzed by reverse phase analysis of the lipids carried out on a Water Acquity Ultra Performance LC (UPLC) system using an Acquity UPLC-Bech C18 column (2.1×10 mm, 1.5 µm) at 40 °C. The solvent consisted of water/methanol (10/90) and the flow rate of 1 mL min−1, which was coupled to an evaporating light scattering detector (ELSD 2424-Waters). As the nebulizing gas, N2 was used at a flow rate of 1.4 L min−1, and a nebulizing temperature of 80 °C. The injection volume was 10 µL (30 mg 10 mL−1 oil sample). The assignment of chromatographic peaks was carried out by means of standards purchased from Sigma-Aldrich (St.Louis, MO). Tryglycerides were performed on a capillary gas chromatography column (25×0.25 mm) coated with TAB-CB in an HP 5890-II apparatus equipped with a split-splitless injector and a flame ionization detector (Chrompack) according to the procedure described by Alonso,
Tocopherols were quantified by high performance liquid chromatography (HPLC). The HPLC system consisted of a low pressure quaternary pump HP-1050, a Rheodyne injection valve (20 mL loop), a thermostatic furnace and a fluorescence detector RF-235 (Shimadzu, Kyoto, Japan). Separation was performed in a 250×4 mm particle size 5 µm Lichrospher Si-60 (
In order to determine significant differences among species, the main effects analysis of variance (ANOVA) was performed according to the general lineal model procedure. The data were analyzed using the statistical package CSS: Statistica 8.0 software (StatSoft Inc.,
Fatty acid composition (%) of lipid fractions extracted from apple seed oils
Cultivar | C16:0 | C16:1 | C18:0 | C18:1 | C18:2 | C18:3 | C20:0 | C20:1 | C22:0 |
---|---|---|---|---|---|---|---|---|---|
A | 8.49±0.98 | 0.08±0.01 |
1.90±0.13 | 32.71±2.65 | 53.98±3.16 | 0.30±0.06 | 1.53±0.19 | 0.51±0.08 | 0.28±0.03 |
B | 8.67±0.67 | 0.08±0.01 | 1.98±0.11 | 30.53±1.98 | 56.31±3.25 | 0.25±0.05 | 1.34±0.11 | 0.40±0.07 | 0.25±0.02 |
C | 8.07±0.71 |
0.07±0.02 | 2.30±0.15 |
36.57±2.08 | 50.34±2.91 | 0.25±0.04 |
1.48±1.15 | 0.45±0.09 | 0.25±0.04 |
D | 8.28±0.84 | 0.08±0.01 | 1.90±0.18 | 34.32±2.15 | 52.97±3.29 | 0.28±0.06 | 1.27±0.09 | 0.48±0.08 | 0.25±0.03 |
E | 9.18±0.92 |
0.12±0.03 | 1.75±0.12 |
27.02±1.69 | 60.01±3.41 | 0.34±0.06 | 1.14±0.12 |
0.36±0.06 | 0.17±0.02 |
F | 9.01±0.85 | 0.09±0.02 | 1.97±0.13 | 31.85±2.07 | 54.49±2.91 | 0.40±0.04 |
1.28±1.11 | 0.46±0.08 | 0.23±0.03 |
G | 8.89±0.93 |
0.12±0.02 |
1.75±0.12 |
27.02±1.91 | 60.01±3.07 | 0.34±0.03 | 1.14±0.13 | 0.36±0.07 | 0.17±0.02 |
Mean standard deviation (n=3).
Phospholipid (% of total PL) compositions from apple seed oils
Cultivar | Total PL | LPC | PC | PE | PI |
---|---|---|---|---|---|
A | 0.38±0.06 | 3.75±0.31 | 70.58±3.85 | 8.71±0.52 |
17.16±0.21 |
B | 0.45±0.08 | 4.88±0.39 | 35.78±0.31 |
27.53±0.22 | 31.80±0.25 |
C | 0.41±0.06 | 5.18±0.57 | 55.55±2.96 | 16.95±1.52 |
22.32±1.91 |
E | 0.52±0.07 | 3.10±0.27 |
40.65±2.61 | 31.39±1.69 | 24.85±1.51 |
F | 0.49±0.08 | 3.01±0.19 |
42.59±2.85 | 30.80±1.54 | 23.59±1.32 |
Men standard deviation (n=3).
LPC: Lisophosphatidilcolina; PC: Phosphatidilcolina; PE: Phosphatidylethanolamina; PI: Phosphatidylinositol.
Total sterol (mg·100 g−1 of oil) of lipid fractions extracted from apple seed oils
Cultivar | Cholesterol | Campesterol | Stigmasterol | Chlerosterol | b-Sitosterol | Sitostanol | Δ5Avenasterol- | Δ5,24-Stigmastadienol | Δ7-Stigmastenol |
---|---|---|---|---|---|---|---|---|---|
A | 1.39±8.22 | 17.70±0.22 | 1.61±0.12 | 1.26±0.02 | 166.55±1.89 | 5.21±0.16 | 14.37±0.43 | 1.31±0.12 | 9.85±1.17 |
B | 3.03±2.80 | 28.16±0.75 | 1.78±0.21 | 1.76±0.10 | 225.13±1.89 | 1.34±0.25 | 20.05±0.20 | 2.05±0.22 | 5.05±1.53 |
C | 2.94±2.39 | 22.94±1.78 | 1.58±0.31 | 1.52±0.39 | 231.6±12.39 | 7.9±0.39 | 22.69±1.40 | 2.43±0.79 | 26.65±2.75 |
D | 1.74±8.19 | 21.93±0.65 | 1.98±0.23 | 1.86±0.28 | 254.04±7.64 | 1.93±0.89 |
14.42±1.11 | 6.29±0.70 |
32.22±2.04 |
E | 2.40±0.16 | 39.76±0.62 | 3.19±0.29 | 1.66±0.05 | 392.48±8.92 | 21.58±0.69 | 28.35±1.19 | 2.42±0.27 | 67.51±2.93 |
F | 2.97±0.24 | 48.63±2.52 | 4.05±0.37 |
2.44±0.15 | 558.52±9.42 |
40.64±0.86 | 56.59±1.94 | 4.94±0.63 | 103.70±2.13 |
G | 2.64±0.29 | 49.25±1.16 | 2.56±0.21 | 2.06±0.45 | 410.75±5.34 | 13.30±0.62 | 31.22±1.12 | 1.97±0.45 | 30.00±2.74 |
Mean standard deviation (n=3).
Tocopherol contents (mg·Kg−1 of oil) of lipid fractions extracted from apple seed oil samples
Cultivar | αTF | βTΦ | γTΦ | δTF |
---|---|---|---|---|
A | 54.83±6.23 | 99.15±11.64 | ND | 0.12±0.02 |
B | 57.52±6.87 | 125.29±12.62 | 0.28±0.03 | 0.69±0.09 |
C | 55.27±4.88 | 85.22±6.12 | 0.41±0.06 | 1.78±0.15 |
D | 52.43±3.06 | 84.57±5.93 | 0.31±0.05 |
0.10±0.02 |
E | 79.65±4.15 | 79.31±3.66 | 0.46±0.05 | 1.33±0.08 |
F | 84.76±5.02 | 89.27±4.89 | 0.77±0.12 | 2.13±0.17 |
G | 84.68±5.61 | 79.21±4.25 |
4.33±0.21 | 7.55±0.58 |
Mean standard deviation (n=3).
ND: Not Detected.
Triglyceride composition (%) of lipid fractions extracted from apple seed oils
Cultivar | LLL | LLO | LLP | OOL | SOL | SOL | OOO | OOP | PPO |
---|---|---|---|---|---|---|---|---|---|
A | 22.57±1.18 | 6.10±0.58 | 41.17±1.98 | 5.60±0.35 | 20.42±1.38 | 0.57±0.07 | 1.77±0.23 | 1.38±0.26 | 0.23±0.08 |
B | 27.12±1.32 | 7.90±0.72 |
39.79±1.35 | 5.75±0.21 |
16.85±1.29 | 0.50±0.08 | 1.44±0.13 |
0.51±0.18 | 0.17±0.04 |
C | 17.80±1.96 | 4.49±0.18 |
40.69±2.04 | 5.67±0.06 | 24.71±1.86 | 0.96±0.08 | 3.96±0.15 | 1.76±0.04 | 0.28±0.03 |
D | 23.15±1.96 | 7.61±0.61 | 39.32±1.66 | 6.67±0.51 | 19.09±1.38 | 0.81±0.13 |
2.04±0.16 | 1.18±0.14 | 0.22±0.05 |
E | 22.11±1.64 | 7.20±0.49 | 39.88±1.47 | 7.29±0.38 |
19.35±1.24 | 0.76±0.16 |
1.98±0.19 | 1.09±0.11 | 0.31±0.06 |
Mean standard deviation (n=3).
A PCA was applied to the data set to obtain linear combinations of the variables called principal components (PCs). The first principal component (PC1) expresses the largest variability and each successive PC represents as much of the residual variability as possible. The results of this analysis are included in
Eigenvalues of correlation matrix, and related statistics. Active variables only
Compound classes | PC | Eigenvalue | % Total-variance |
---|---|---|---|
Fatty acids | 1 | 5.665 | 62.95 |
2 | 1.464 | 16.27 | |
Triacylglycerols | 1 | 5.120 | 56.89 |
2 | 2.058 | 22.88 | |
Phospholipids | 1 | 3.347 | 66.95 |
2 | 1.296 | 25.91 | |
Sterols | 1 | 7.686 | 69.88 |
2 | 1.442 | 13.11 | |
Tocopherols | 1 | 2.171 | 54.27 |
2 | 0.847 | 21.17 |
The two-dimensional plots of the PCs can be used to reveal the internal structure of the data and visualize data trends Jolliffe (
Score plot in the plane of the two first PCs. Letters A, B, C, D, E, F, G, I corresponding to the different compound groups that are gathered in
The following step in our analysis was to apply the procedures of supervised pattern recognition in order to achieve a better separation. Accordingly, LDA (Coomans,
Scatterplot of the canonical scores corresponding to different species samples. Letters A, B, C, D, E, F, G, I corresponding to the different compound groups that are gathered in
On the basis of the present study, it may be concluded that the nutritional properties of the studied apple seed oils possess a high added value. The composition in lipids of these seeds presents high contents in polyunsaturated fatty acids C18:2, sterols (β-sitosterol), phospholipids (phosphatidilcoline), and tocopherols (alfa-tocopherol). The extraction of these apple seed oils is an option to obtain high added value oils and an additional channel for their use as rich in bioactive nutraceutical compounds to assess the potential use of the oils in foodstuffs. From the point of view of authenticity, it could be a useful tool to know the trazability of apple seed oil with DO compared to others in order to avoide adulteration through the study of the minor oil components.
This research was conducted with support from the regional Government of the Principado of Asturias (Spain). The authors would like to acknowledge Isabel Cuesta, Ana Hernández and Jorge Alvarez for their technical assistance and the Serida and San Martín de Llanes for the selection of DO apples. The authors also wish to thank Dra. M. Prieto from the University of Oviedo, a group associated with the Spanish Scientific Research Council (CSIC).