Original Article

Total and individual carotenoid profiles in Solanum phureja of cultivatedpotatoes: I. Concentrations and relationships as determined byspectrophotometry and HPLC

Gabriela Burgos a, Elisa Salas a, Walter Amoros a, Mariella Auqui a, Lupita Munoa a,Mieko Kimura b, Merideth Bonierbale a,*a International Potato Center, P.O. Box 1558, Lima 12, Perub UNESP – Sao Paulo State University, Food Engineering and Technology Department, Sao Jose do Rio Preto, SP, Brazil

Journal of Food Composition and Analysis 22 (2009) 503–508

A R T I C L E I N F O

Article history:

Received 30 March 2008

Received in revised form 28 July 2008

Accepted 4 August 2008

Keywords:

Potato

Solanum phureja

Carotenoids

Spectrophotometry

HPLC

Food composition

Biodiversity

A B S T R A C T

Total and individual carotenoid concentrations were determined by spectrophotometry and HPLC, in raw

tubers of a sample of 23 accessions of Solanum phureja potatoes taken at random from the world

germplasm collection following its stratification on tuber flesh color. Lutein, zeaxanthin, violaxanthin,

antheraxanthin and b-carotene were detected in all accessions and three distinct patterns of carotenoid

accumulation were evidenced by cluster analysis. Accessions in group 1 showed the highest

concentrations of total carotenoids (1258–1840 mg 100 g�1 FW) comprised largely of zeaxanthin

(658–1290 mg 100 g�1 FW) with very low or no presence of b-carotene (below 5.4 mg 100 g�1 FW).

Accessions in group 2 presented moderate total carotenoid concentrations with violaxanthin,

antheraxanthin, lutein and zeaxanthin as the major carotenoids. Accessions in group 3 showed low

concentrations of total carotenoids (97–262 mg 100 g�1 FW) and very low or no zeaxanthin, with lutein

and violaxanthin as the predominant carotenoids and relatively high concentrations of b-carotene (up to

27 mg 100 g�1 FW). Five accessions with significant concentrations of zeaxanthin were identified with

the accession 703566 showing the highest concentration (1290 mg 100 g�1 FW). This value is to our

knowledge higher than any value previously reported for potatoes, including those achieved through

genetic modification. For the 23 S. phureja accessions, total carotenoid concentration was positively and

significantly correlated with antheraxanthin and zeaxanthin concentrations, and negatively and

significantly correlated with b-carotene concentration.

� 2008 Elsevier Inc. All rights reserved.

Contents lists available at ScienceDirect

Journal of Food Composition and Analysis

journal homepage: www.e lsev ier .com/ locate / j fca

1. Introduction

There is a growing awareness of the health benefits ofcarotenoids in the human diet with individual carotenoidshaving different beneficial properties. Lutein and zeaxanthin(hydroxycarotenoids) are the major pigments of the yellow spotin the human retina (Landrum and Bone, 2001) and it is believedthat a high dietary intake of these carotenoids can protect fromage-related macular degeneration, a major cause of blindness inaging populations (Seddon et al., 1994). On the other hand, sincevitamin A (retinol) is essentially one half of the molecule of b-carotene with an added molecule of water at the end of thelateral polyene chain, b-carotene is a potent provitamin A

* Corresponding author. Tel.: +51 1 349 6017; fax: +51 1 317 5326.

E-mail address: m.bonierbale@cgiar.org (M. Bonierbale).

0889-1575/$ – see front matter � 2008 Elsevier Inc. All rights reserved.

doi:10.1016/j.jfca.2008.08.008

compound, to which 100% activity is assigned (Rodrıguez-Amaya, 2001). Epoxyxanthophylls like violaxanthin and anther-axanthin appear not to be absorbed by humans (Barua andOlson, 2001). However since violaxanthin and antheraxanthinare formed from zeaxanthin by an epoxidase, genetic manip-ulation to down-regulate this enzyme in crops high in theseepoxycarotenoids could result in zeaxanthin-rich crops (Romeret al., 2002).

Several studies have determined the carotenoid concentrationof raw potato tubers. In improved tetraploid Solanum tuberosum,yellow fleshed cultivars are reported to contain 58–175 mg 100 g�1

on a fresh weight basis (FW) and white fleshed cultivars, 38–62 mg 100 g�1 FW total carotenoids with violaxanthin and luteinas the predominant compounds (Breithaupt and Bamedi, 2002;Iwansik et al., 1983). In tubers of a hybrid population of the diploidcultivated potatoes (S.Phureja and S. stenotonum) the carotenoidcontent reached up to 1435 mg 100 g�1 FW with lutein 5–6

G. Burgos et al. / Journal of Food Composition and Analysis 22 (2009) 503–508504

epoxide and lutein as the major carotenoids and zeaxanthin at lowlevels (Lu et al., 2001).

However, there is a lack of information about total andindividual carotenoid concentration in native Andean potatoes.Of particular interest is the group of high carotenoid accumulatingS. phureja potatoes (Morris et al., 2004) that consists of Andeanlandraces, grown from western Venezuela to central Bolivia. Thesepotatoes form an important breeding stock due to their excellentculinary properties and crossability with other cultivated as well aswild potatoes. They are characterized by short-day adaptation,diploid constitution (2n = 2x = 24), and lack of tuber dormancy(Ochoa, 1990). A recent study determined the total carotenoidconcentration of 38 S. phureja accessions grown in the UnitedKingdom (85–1223 mg 100 g�1 FW) and the individual carotenoidconcentration of 5 of them (Griffiths et al., 2007).

The objectives of this study were to determine total andindividual carotenoid concentrations of 23 accessions comprising arepresentative sample of S. phureja potatoes and assess the relativeamounts of each that are likely to be found in tubers of a givengenotype.

2. Materials and methods

2.1. Plant material

Twenty-three accessions of 152 classified as Solanum phureja

(Hawkes, 1990) in the world potato collection conserved at CIP(http://research.cip.cgiar.org/genebank/) were used for this study.Selection of these accessions was at random but with attention torepresenting the range of tuber flesh colors (cream, light yellowand deep yellow) present in the collection. A randomized completeblock design with three replications of 10 hills per plot wasestablish in Comas, Junin, Peru (3335 m.a.s.l). A representativesample of accessions was selected for analysis immediately uponharvest to avoid inconsistencies due to changes in carotenoidconcentrations and profiles during the prolonged handling andpreparation period that would have been needed to assess theentire collection.

2.2. Sampling and sample preparation

Three representative samples of each accession (1 per plotreplication) comprised of five to ten unblemished medium sizedtubers were collected at random taking tubers from differentplants. The tubers of each sample were washed thoroughly withtap water (to remove soil residue), rinsed with deionized, distilledwater, patted dry with paper towels and peeled. Tubers werequartered longitudinally, from stem to bud end and two oppositequarters were cut into small pieces, homogenized in a foodprocessor and the homogenized samples were analyzed immedi-ately in fresh condition for total and individual carotenoidconcentrations.

2.3. Color characterization

A representative sample of 10 tubers per variety were collectedimmediately after harvest and put in opaque bags in order to avoidchange in the flesh color. Visual color characterization wasperformed during the first week after harvest using the colorchart developed for native potatoes (Gomez, 2006). Tubers of eachvariety were cut and given three numbers defined in the colorchart. The first number indicates the main color of the flesh, thesecond number refers to a secondary color and the third numberindicates the distribution of the secondary color (e.g. flecks orrings).

2.4. Total and individual carotenoid determinations

Carotenoid analysis was carried out according to Kimura et al.(2007) with the necessary precautions to avoid alterations orlosses during the analysis. These precautions include: completionof the analysis within the shortest possible time, exclusion ofoxygen, protection from light, avoiding high temperatures,avoiding contact with acid and use of high purity solvents, freefrom harmful impurities (Rodrıguez-Amaya, 2001).

2.4.1. Carotenoid extraction

2–8 g (depending on the color) of the homogenized tissue wasextracted with acetone (Merck KgaA, Darmstadt, Germany) in anUltra Turrax T25 homogenizer (IKA-Werke, Wilmington, NC, USA)for 1 min at 21,500 rpm. Extraction was repeated until the residuewas devoid of color. The extracts were transfer to petroleum etherand washed with water to remove any acetone residue.Saponification was done with an equivalent volume of 10%methanolic KOH, in the dark at room temperature overnight(16–20 h). Butylated hydroxytoluene (BHT, Sigma–Aldrich, St.Louis, USA) 0.1%, was added to the petroleum ether extract beforesaponification to prevent degradation of carotenoids. The recoveryand washing of the saponified carotenoids were carried out withthe help of diethyl ether (Merck KgaA, Darmstadt, Germany) andacetone following a previously reported method for vegetables (DeSa and Rodrıguez-Amaya, 2004). The resulting saponified extractswere brought to a volume of 25 ml with petroleum ether (Merck,Darmstadt, Germany).

2.4.2. Total carotenoid analysis

The total carotenoid content was calculated using theabsorbance value measured in a Shimadzu spectrophotometerUV-160A (Shimadzu Corp., Kyoto, Japan) at 450 nm and theextinction coefficient for mixtures of carotenoids (2500) (Davies,1976).

2.4.3. HPLC analysis

Fifteen ml of the extract were transferred to a tube and driedwith nitrogen gas (N2). Immediately before injection, the residuewas redissolved in 1 ml of HPLC grade acetone (Fisher Scientific,New Jersey, USA), filtered through a 0.22-mm PTFE syringe filter(Millipore, Carrigtwohill, Co., Cork, Ireland) directly into samplevials and 10 ml were injected into the HPLC. The analysis wasperformed in a Waters model 2995 separation system (WatersCorp., Milford, USA) equipped with quaternary pump, auto-sampler, in line degasser and photodiode array detector (model2696) controlled by Empower software. Separation was carried outon a YMC C30 polymeric column (3 mm, 4.6 mm � 250 mm) usingas mobile phase a linear gradient of methanol:methyl-tert-butylether starting in 100:0, going to 93:7 in 15 min, then to 90:10 in35 min, then to 60:40 in 45 min and maintaining this proportionfor 15 min. Flow rate was set as 0.8 ml/min with a re-equilibrationof 15 min. Detection of carotenoids was done at maximumabsorption wavelengths. Identification of the carotenoids wasbased on the combined analysis of the retention times, co-chromatography with pure standards from CaroteNature (Lupsin-gen, Switzerland) and the visible absorption spectra obtained bythe photodiodide array detector. Quantification was done byexternal calibration. Total and individual carotenoids wereexpressed as micrograms (mg) per 100 g fresh weight.

2.5. Statistical analysis

The total carotenoid, violaxanthin, antheraxanthin, lutein,zeaxanthin and b-carotene concentrations in raw potato tubers

Fig. 1. Mean of total and individual carotenoid concentrations of the 3 groups

obtained by cluster analysis of the 23 S. phureja accessions. Vio = all trans-

violaxanthin, Ant = all trans-antheraxanthin, Lut = all trans-lutein, Zea = all trans-

zeaxanthin and BC = all trans-b-carotene. Shaded bars indicate range of b-carotene

concentration in each group.

G. Burgos et al. / Journal of Food Composition and Analysis 22 (2009) 503–508 505

of the 23 accessions were subject to cluster analysis on the basis ofdistances computed from quantitative variables using fastclusprocedure or k-means model.

To assess the variability of total and individual carotenoidconcentrations between the accessions and within groups, analysisof variance (ANOVA) and random-effect nested analysis of variancewere performed considering a randomized complete design withthree replications. The means of groups were compared by Tukey’stest for parametric data (total carotenoid, violaxanthin, antherax-anthin and zeaxanthin) and by Kruskall–Wallis’s test for non-parametric data (lutein and b-carotene).

Correlations between the yellow flesh color and total andindividual carotenoid concentrations were assessed by the Pearsontest. A t-test was used to determine the difference of the respectivecorrelation coefficients from zero.

With exception of the Kruskall–Wallis’s test, all statistical testswere performed using SAS/STAT (version 9.1) software.17 (SAS,1999). Kruskall–Wallis’s test was performed using R packageversion 1.0–3.0 (De Mendiburu, 2007).

3. Results and discussion

3.1. Total and individual carotenoid determinations

Total and individual carotenoid concentrations determined inthe 23 S. phureja accessions are shown in Table 1. ANOVA indicatedsignificant (P < 0.001) genotypic variation in total and individualcarotenoid concentrations.

Table 1Total and individual carotenoid concentrations by spectrophotometry and HPLC in 23

CIP number Flesh colora Concentrationb (mg 100 g�1 fresh weight)

Total carotenoid Violaxanthinc Anth

703566 Deep yellow 1840 � 102 a tr k 186 �705797 Deep yellow 1491 � 171 b 82 � 20 fg 270 �705799 Deep yellow 1490 � 65 b 77 � 20 fgh 325 �706753 Yellow 1400 � 80 bc 55 � 20 ghij 332 �704218 Yellow 1346 � 91 cd 67 � 5 fghi 275 �706751 Deep yellow 1258 � 86 d 94 � 24 f 268 �705807 Deep yellow 1229 � 165 d 274 � 60 d 357 �706781 Yellow 1070 � 85 e 410 � 28 a 275 �703654 Yellow 1270 � 110 cd 366 � 18 b 376 �703593 Yellow/redg 939 � 95 ef 344 � 55 bc 208 �703308 Light yellow 911 � 48 fg 364 � 31 b 147 �703291 Light yellow 800 � 203 gh 344 � 54 bc 135 �703812 Light yellow 740 � 76 h 319 � 33 c 106 �703507 Light yellow 682 � 112 h 172 � 32 e 160 �706813 Cream 256 � 40 i 50 � 16 ghij 11 �706828 Cream 212 � 46 ij 36 � 8 ijk 18 �706822 Cream 183 � 30 ij 34 � 11 ijk 9.3 �705821 Cream/redg 289 � 26 i 52 � 9 ghij 19 �705172 Light yellow/redg 262 � 29 i 50 � 2 ghij 14 �703506 Cream 253 � 68 i 39 � 8 hij 14 �703548 Cream/purpleg 221 � 9 ij 32 � 1 ijk 10 �705800 Cream 194 � 37 ij 32 � 11 ijk 13 �705806 Cream/redg 98 � 18 j 20 � 2 j 5.3 �

Group 1 1471 � 209 a 62 � 34 b 276 �Group 2 955 � 232 b 324 � 78 a 220 �Group 3 219 � 63 c 39 � 13 b 13 �

a Primary colorb Mean and standard deviation of three samples, each sample comprised of 5–10 tuc Trans configuration.d Transformed log10 data.e Non-parametric data.f Grouped according cluster analysis; tr = traces; nd = not detectable; for each paramg Secondary color.

Cluster analysis of the mean values grouped the accessions into3 groups. Accessions in group 1 (n = 6) showed the highest totalcarotenoid concentrations (from 1258 to 1840 mg 100 g�1 FW). Inthis group, zeaxanthin and antheraxanthin were the majorcarotenoids (Figs. 1 and 2A). Accessions in group 2 (n = 8) showedmoderate total carotenoid concentrations ranging from 682 to1270 mg 100 g�1 FW with violaxanthin, antheraxanthin, lutein andzeaxanthin as the principal carotenoids (Figs. 1 and 2B). Accessions

S. phureja accessions.

Groupf

eraxanthinc,d Luteinc Zeaxanthinc,e b-Carotenec,e

44 cd 148 � 12 cd 1290 � 70 a nd j 1

24 b 98 � 26 fg 854 � 168 b nd j 1

43 ab 115 � 20 ef 825 � 162 bc 5.4 � 0.5 i 1

32 ab 71 � 9 hi 653 � 272 cd nd j 1

15 b 69 � 12 hi 770 � 94 bcd nd j 1

55 b 73 � 19 ghi 658 � 47 d 4.8 � 2.9 hi 1

33 a 189 � 12 ab 171 � 20 e 7.1 � 0.7 g 2

26 b 168 � 20 bc 137 � 16 e nd j 2

36 a 166 � 6 bc 134 � 58 e 6.9 � 0.9 g 2

8 c 184 � 10 b 85 � 16 f 6.7 � 0.5 gh 2

16 e 211 � 23 a 27 � 6 g 11 � 2 f 2

41 ef 134 � 31 de 24 � 10 g 6.9 � 3 g 2

12 f 136 � 16 de tr h 11 � 2 ef 2

35 de 113 � 13 ef 80 � 11 f 6.9 � 0.3 g 2

1 ij 122 � 16 ef tr h 24 � 3 abc 3

1 g 80 � 18 gh tr h 23 � 7 abc 3

0.5 j 82 � 11 gh 1.9 � 0.8 h 15 � 4 def 3

2 g 136 � 23 de tr h 26 � 1 ab 3

1 h 127 � 10 de tr h 27 � 4 a 3

2 h 81 � 14 gh tr h 19 � 1 bcd 3

2 j 114 � 12 ef 12 � 1.3 g 18 � 5 cde 3

1 hi 63 � 12 hi tr h 21 � 5 abcd 3

1.8 k 55 � 10 i tr h 6.6 � 0.4 ghi 3

59 a 96 � 33 b 842 � 256 a 2.7 � 2.0 c

102 a 163 � 35 a 82 � 62 b 7.3 � 3.2 b

4 c 96 � 31 b 2.7 � 3.4 c 20 � 6.8 a

bers.

eter groups with different letters are significantly different (a = 0.05).

Fig. 2. Representative HPLC chromatograms (processed at 450 nm) of S. phureja accessions in group 1 (A), group 2 (B) and group 3 (C). Chromatographic conditions are

described in the text. Peak identification: Vio = all trans-violaxanthin, Ant = all trans-antheraxanthin, Lut = all trans-lutein, Zea = all trans-zeaxanthin and BC = all trans-b-

carotene.

G. Burgos et al. / Journal of Food Composition and Analysis 22 (2009) 503–508506

in group 3 (n = 9) showed the lowest total carotenoid concentra-tion (from 97 to 262 mg 100 g�1 FW). In this group lutein,violaxanthin and b-carotene were the predominant carotenoids(Figs. 1 and 2C). Aside from carotenoid amounts and profiles, thethree groups also differed for tuber flesh color. The accessions ingroup 1 had yellow to deep yellow flesh color, the accessions ingroup 2 showed light yellow to yellow flesh color, and theaccessions in group 3 presented cream to light yellow flesh color(Table 1).

The metabolic pathway of carotenoids supports the grouping ofgenotypes as found here. For example, since zeaxanthin is formedfrom the double hydroxylation of b-carotene; it could be expectedthat high b-carotene hydroxylase activity distinguishes genotypesrich in zeaxanthin relative to b-carotene, from those thataccumulate b-carotene and contain less zeaxanthin.

A previous study by Griffiths et al. (2007) demonstrated thateven when significant interactions between years and lines fortotal carotenoid concentration of S. phureja potatoes exist, theranking of lines and cultivars remained very similar from season toseason with highly significant correlations being found betweenthe years. Since no drastic changes in the carotenoid concentrationwould occur it is suggested that the groupings reported here arenot environment dependent.

Total carotenoid concentrations of the S. phureja accessionsevaluated in this study reached higher values (1840 mg 100 g�1

FW) than the highest previously reported for native andeanpotatoes (1643 mg 100 g�1 FW, considering 30% dry mattercontent; Andre et al., 2007), S. phureja germplasm bred forWestern European conditions (1226 mg 100 g�1 FW) (Griffithset al., 2007), yellow fleshed diploid clones from S. phureja and S.

stenotonum germplasm (1435 mg 100 g�1 FW) (Lu et al., 2001) andS. tuberosum cultivars. Yellow fleshed S. tuberosum cultivars havebeen reported to contain 58–175 mg 100 g�1 FW total carotenoidand white fleshed S. tuberosum cultivars contain 38–62 mg 100 g�1

FW total carotenoid (Breithaupt and Bamedi, 2002; Iwansik et al.,1983).

Three different patterns of individual carotenoid accumulationrelated to the amount of total carotenoid concentration have beenobserved for the S. phureja accessions evaluated here, withzeaxanthin as the major carotenoid in the high total carotenoidgroup and lutein and violaxanthin in the low total carotenoid group.Previous reports on S. phureja and S. stenotonum germplasm showedlutein-5,6 epoxide and lutein to be the major carotenoids with verylow levels of zeaxanthin (Lu et al., 2001), while lutein andviolaxanthin were found to be the major carotenoids in S. tuberosum

accessions (Breithaupt and Bamedi, 2002; Iwansik et al., 1983).The violaxanthin concentrations found here ranged from trace

to 410 mg 100 g�1 FW with the accessions of group 2 showing thehighest concentrations (above 170 mg 100 g�1 FW) which issimilar to that reported for yellow fleshed diploid clones from S.

phureja and S. stenotonum (from 145 to 438 mg 100 g�1 FW) (Luet al., 2001). Violaxanthin appears not to be absorbed by thehuman body (Barua and Olson, 2001); however accessions thataccumulate it may be valuable stocks for genetic manipulation. Astudy has demonstrated that it is possible to down-regulate theepoxidase that converts zeaxanthin to violaxanthin in order toobtain a zeaxanthin-rich potato (Romer et al., 2002). Hence, highviolaxanthin potato could produce a higher zeaxanthin potatothrough genetic manipulation.

The antheraxanthin concentration ranged from 5 to376 mg 100 g�1 FW with the accessions of groups 1 and 2 showingthe highest concentrations (above 100 mg 100 g�1 FW). Theseconcentrations exceed those previously reported for yellowfleshed German varieties (7.7–66 mg 100 g�1 FW) (Breithauptand Bamedi, 2002) and for yellow fleshed breeding lines of S.

tuberosum (7.1–11 mg 100 g�1 FW) (Iwansik et al., 1983).The lutein concentration ranged from 54 to 211 mg 100 g�1 FW.

The yellow fleshed accession 703308 showed the highest lutein

G. Burgos et al. / Journal of Food Composition and Analysis 22 (2009) 503–508 507

concentration. This value is lower than the highest luteinconcentration found for yellow fleshed diploid clones from S.

phureja and S. stenotonum (531 mg 100 g�1 FW) (Lu et al., 2001)but higher than that found for yellow fleshed German varieties(17–49 mg 100 g�1 FW) (Breithaupt and Bamedi, 2002) and foryellow fleshed breeding lines of S. tuberosum (31–119 mg 100 g�1

FW) (17).The zeaxanthin concentration ranged from trace to

1290 mg 100 g�1 FW. The accessions in group 3 which have creamand light yellow flesh showed no or very low zeaxanthinconcentrations. Similar results were found for white and yellowfleshed breeding lines of S. tuberosum (Iwansik et al., 1983). Theaccessions in group 1, which have from yellow to deep yellow fleshshowed zeaxanthin concentrations higher (above 600 mg 100 g�1

FW) than groups 2 and 3. These values are higher than thosepreviously reported for native andean potatoes (1643 mg 100 g�1

FW, considering 30% dry matter content; Andre et al., 2007),for yellow fleshed diploid clones from S. phureja and S. stenotonum

(5–44 mg 100 g�1 FW) (Lu et al., 2001), for yellow fleshed Germanvarieties (10–107 mg 100 g�1 FW) (Breithaupt and Bamedi, 2002),for S. tuberosum breeding lines (2–476.3 mg 100 g�1 FW) (Nester-enko and Sink, 2003) and for 5 S. phureja accessions (43–597 mg 100 g�1 FW) (Griffiths et al., 2007). The fact that some ofthe S. phureja accessions analyzed in this study showed highzeaxanthin concentration is interesting since zeaxanthin is foundin significant levels in relatively few dietary components includingsome maize cultivars and yellow orange pepper varieties (Kurilichand Juvick, 1999; Minguez-Mosquera and Hornero-Mendez, 1994).

The accession 703566 showed the highest zeaxanthinconcentration. This value is higher than that achieved throughgenetic manipulation of two different S. tuberosum potatovarieties (1000 mg 100 g�1 FW) (Romer et al., 2002) but lowerthan the highest zeaxanthin concentrations reported in maize(3800 mg 100 g�1) (Brenna and Berardo, 2004). Nevertheless,either potato or maize can provide a significant amount ofzeaxanthin to the human diet depending on consumption levels.

The b-carotene concentrations were very low in all accessionsevaluated (not detected in five) in this study. They ranged from 5 to27 mg 100 g�1 FW. The values found in this study are lower thanpreviously reported b-carotene concentrations for S. andigenum

potatoes which rich up to 66 mg 100 g�1 FW, considering 30% drymatter content (Andre et al., 2007) but higher than previousreported b-carotene concentrations for white and yellow fleshedpotatoes in German varieties (Breithaupt and Bamedi, 2002), foryellow fleshed diploid clones from S. phureja and S. stenotonum (Luet al., 2001) and for breeding lines of S. tuberosum (Iwansik et al.,1983). Higher levels of b-carotene concentration have beenachieved by reducing b-carotene hydroxylase activity in highzeaxanthin potato lines (330 mg 100 g�1 FW) (Van Eck, 2006) andby transforming potato with a mini-pathway of bacterial origin,driving the synthesis of b-carotene from geranylgeranyl diphos-phate (3643 mg 100 g�1 FW) (Diretto et al., 2007, pp. 350–357).

The total and individual carotenoid concentrations in S. phureja

accessions reported in this study can be considered for inclusion inthe Peruvian Food Composition Table that at the present time doesnot include this type of information (MINSA-INS-CENAN, 1996).However, since potatoes are eaten cooked it is necessary tocomplement these results with the evaluation of cooked potatoes,a study that is currently in progress.

3.2. Relation of total and individual carotenoid concentrations

Total carotenoid concentration was positively and significantlycorrelated with the antheraxanthin and zeaxanthin concentrations(r = 0.91 and 0.88, respectively, P < 0.001) and negatively and

significantly correlated with the b-carotene concentration(r = �0.77, P < 0.001). According to these results it is possible topredict that S. phureja accessions with the lowest total carotenoidconcentration are those higher in b-carotene.

3.3. Relation of yellow flesh color with total and individual carotenoid

concentrations

Yellow flesh color was highly significantly and positivelycorrelated with the total carotenoid, antheraxanthin and zeax-anthin concentrations (r = 0.93, 0.81 and 0.82, respectively,P < 0.001) and highly significantly and negatively correlated withthe b-carotene concentration (r = �0.77, P < 0.001).

4. Conclusion

This research demonstrates that significant genetic diversityexists for total and individual carotenoids in S. phureja potatoeswith zeaxanthin levels higher than any previously reported forpotato. Three different carotenoid profiles and a high positivecorrelation between total carotenoid and zeaxanthin and anther-axanthin, together with the high negative correlation betweentotal carotenoid and b-carotene were found for a representativesample of 23 S. phureja accessions. This new understanding ofpatterns of diverse carotenoids accumulated in potato germplasmwill be useful in setting objectives and selecting parents forbreeding programs aimed at enhancing nutritional traits.

Acknowledgments

This research was largely supported by the HarvestPlusChallenge Program. We thank Eduardo Porras for his technicalassistance.

References

Andre, C.M., Oufir, M., Guignard, C., Hoffmann, L., Hausman, J., Evers, Larondelle, Y.,2007. Antioxidant profiling of native andean potato tubers (Solanum tuberosumL.) reveals cultivars with high levels of b-carotene, a-tocopherol, chlorogenicacid and petanin. J. Agri. Food Chem. 55, 10839–10849.

Barua, A., Olson, J., 2001. Xanthophyll epoxides, unlike b-carotene monoepoxides,are not detectibly absorbed by humans. J. Nutr. 131, 3212–3215.

Breithaupt, D., Bamedi, A., 2002. Carotenoids and carotenoid esters in potatoes(Solanum tuberosum L.): New insight into an ancient vegetable. J. Agri. FoodChem. 50, 7175–7181.

Brenna, O.V., Berardo, N., 2004. Applications of near-infrared reflectance spectro-scopy (NIRS) to the evaluation of carotenoids in maize. J. Agri. Food Chem. 52,5577–5582.

Davies, B., 1976. Carotenoids. In: Goodwin, T.W. (Ed.), Chemistry and biochemistryof plant pigments, 2nd ed., vol. 2. Academic Press, London, pp. 38–165.

De Mendiburu, F., 2007. Agricolae: statistical procedures for agricultural research. Rpackage version 1.0–4. .

De Sa, M., Rodrıguez-Amaya, D.B., 2004. Optimization of HPLC quantification ofcarotenoids in cooked green vegetables—Comparison of analytical and calcu-lated data. J. Food Comp. Anal. 17, 37–51.

Diretto, G., Al-Babili, S., Tabaza, R., Papacchioli, V., Beyer, P., Giulano, G., 2007.Metabolic engineering of potato carotenoid content through tuber-specificoverexpression of a bacterial mini-pathway, vol. 4. , doi:10.1371/journal.-pone.0000350 (Plos one).

Gomez, R., 2006. Guıa para las caracterizaciones morfologicas basicas en colec-ciones de papas nativas. In: Estrada, R., Medina, T., Roldan, A. (Eds.), Manualpara caracterizacion In situ de cultivos nativos. INIEA, Lima (Peru), pp. 26–50.

Griffiths, W., Dale, F., Morris, W., Ramsay, G., 2007. Effects of season and postharveststorage on the carotenoid content of Solanum phureja potato tubers. J. Agri. FoodChem. 55, 379–385.

Hawkes, J., 1990. The Potato: evolution biodiversity and genetic resources. Smith-sonian Institution Press, Washington, p. 259.

Iwansik, W., Tevini, M., Stute, R., Hilbert, R., 1983. Carotinoidgehalt und—Zusam-mensetzung verschiedener deuutscher Kartoffelsorten und deren Bedeutungfur die Fleischfarbe del Knolle. Potato Res. 26, 149–162.

Kimura, M., Kobori, C.K., Rodriguez-Amaya, D.B., Nestel, P., 2007. Screening andHPLC methods for carotenoids in sweetpotato, cassava and maize for plantbreeding trials. Food Chem. 100, 1734–1746.

G. Burgos et al. / Journal of Food Composition and Analysis 22 (2009) 503–508508

Kurilich, A.C., Juvick, J.A., 1999. Quantification of carotenoid and tocopherol anti-oxidants in Zea mays. J. Agri. Food Chem. 47, 1948–1955.

Landrum, J., Bone, R., 2001. Lutein, zeaxanthin and macular pigment. Arch. Biochem.Biophys. 385, 28–40.

Lu, W., Haynes, K., Wiley, E., Clevidence, B., 2001. Carotenoid content and color indiploid potatoes. J. Am. Soc. Horti. Sci. 126, 722–726.

Minguez-Mosquera, M., Hornero-Mendez, D., 1994. Comparative study of the effectof paprika processing on the carotenoids in peppers (Capsicum annuum) of Bolaand Agridulce varieties. J. Agri. Food Chem. 42, 1555–1560.

MINSA-INS-CENAN, 1996. Tablas Peruanas de Composicion de Alimentos. Minis-terio de Salud, 7th ed. Instituto Nacional de Salud (INS), Lima (Peru), p. 86.

Morris, W., Ducreux, D., Griffiths, D., Stewart, D., Davies, H., Taylor, A., 2004.Carotenogenesis during tuber development and storage in potato. J. Exper.Bot. 55, 975–982.

Nesterenko, S., Sink, K., 2003. Carotenoid profiles of potato breeding lines andselected cultivars. Horti. Sci. 38, 1173–1177.

Ochoa, C., 1990. The potatoes of South America. Translated by D. Ugent. CambridgeUniversity Press, Cambridge, pp. 314–337.

Rodrıguez-Amaya, D., 2001. A guide to carotenoid analysis in foods. ILSI Press,Washington, DC.

Romer, S., Lubeck, J., Kauder, F., Steiger, S., Adomat, C., Sandmann, G., 2002. Geneticengineering of a zeaxanthin-rich potato by antisense inactivation and co-supression of carotenoid epoxidation. Metab. Eng. 4, 263–272.

SAS Institute Inc, 1999. SAS OnlineDoc1, version 8.2. SAS Institute Inc, Cary, NC.Seddon, J., Ajan, U., Sperduto, R., 1994. Dietary carotenoids. Vitamin A, C and E and

age-related macular degeneration. J. Am. Diet. Assoc. 273, 1413–1420.Van Eck, J. (2006). Enhancement of beta-carotene content in plants. WO 068946.

Patent cooperation treaty 045640.