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Industrial Crops and Products 33 (2011) 727–733

Contents lists available at ScienceDirect

Industrial Crops and Products

journa l homepage: www.e lsev ier .com/ locate / indcrop

romatic profile and odour-activity value of blood orange juices obtained fromoro and Sanguinello (Citrus sinensis L. Osbeck)

erkan Selli a,∗, Hasim Kelebekb

University of Cukurova, Faculty of Agriculture, Department of Food Engineering, Balcali, 01330 Adana, TurkeyUniversity of Adiyaman, Adiyaman Vocational School, Department of Food Technology, 02040 Adiyaman, Turkey

r t i c l e i n f o

rticle history:eceived 27 October 2010eceived in revised form 7 January 2011ccepted 13 January 2011vailable online 23 February 2011

a b s t r a c t

Aroma composition of blood orange juices obtained from Moro and Sanguinello (Citrus sinensis L. Osbeck)was analyzed by sensory and instrumental analyses. Liquid–liquid extraction with dichloromethane wasused for extraction of volatile components. According to sensory analysis, the aromatic extract obtainedby liquid–liquid extraction was representative of blood orange juice odour. A total of 83 and 78 aromacompounds, including alcohols, esters, terpenes, terpenols, aldehydes, acids, ketones, volatile phenols,

eywords:oro

anguinellolood orangeromaAV

and lactones were identified in the Moro and Sanguinello juices, respectively. Of these, 15 volatile compo-nents presented odour activity values (OAVs) greater than 1, with dl-limonene, nootkatone and linaloolbeing those with the highest OAVs in both cultivars.

© 2011 Elsevier B.V. All rights reserved.

epresentativeness

. Introduction

Orange is the third largest fruit crop in Turkey after grape andpple with an annual production of 1,426,965 tons in 2007 (FAO,009). It is produced in large amounts in the Cukurova regionf the southern part of Turkey. Among widely cultivated species,lood oranges Moro and Sanguinello (Citrus sinensis (L.) Osbeck)riginated from Malta and Sicilia islands. These oranges are char-cterized by their unique flesh and rind colour due to red pigmentselonging to anthocyanin class (Rapisarda et al., 2001; Kelebekt al., 2008). Another important characteristic of blood orangess the higher total odour intensity than in blond orange cultivarsArena et al., 2006).

The orange aroma is among the most popular fruit flavoursor beverages. Its fresh and uniquely delicate flavour is due toomplex combinations of several odour components that haventerdependent quantitative relationships (Shaw, 1991; Maccaronet al., 1998; Selli et al., 2004). Blond orange juice flavours haveeen extensively investigated. Moshonas and Shaw (1994) stud-

ed both hand extracted and mechanically extracted orange juiceolatiles. Shaw et al. (1999) investigated the commercial orangeuices based on relative amounts of volatile juice constituents.ordan et al. (2001) determined the effects of reducing insoluble

∗ Corresponding author. Fax: +90 322 338 61 73.E-mail address: sselli@cu.edu.tr (S. Selli).

926-6690/$ – see front matter © 2011 Elsevier B.V. All rights reserved.oi:10.1016/j.indcrop.2011.01.016

solids on aromatic composition of orange juice using HS-SPME.Plotto et al. (2004) evaluated the odour and flavour thresholdsfor key aroma components in an orange juice matrix. Fischeret al. (2008) characterized the most odour-active compounds byaroma extract dilution analysis in a peel oil extract from Pon-tianak oranges (Citrus nobilis var. Lour. microcarpa Hassk.). Theyused solvent extraction/vacuum distillation process for the isola-tion of volatile fraction from the peel of Pontianak orange. A totalof 32 odour-active compounds in the flavour dilution (FD)-factorrange of 4–2048 were detected in aromatic extract of orange peel,of which 26 were identified. However, there have been few stud-ies on the aroma components of blood orange varieties. Maccaroneet al. (1998) determined flavour components of Italian blond andblood orange juices. They identified nineteen aromatic compo-nents both blond and blood orange cultivars grown in Italy. Arenaet al. (2006) compared odour active volatile compounds by a fre-quency of detection method in hand-squeezed juices from Moro,Tarocco, Washington navel and Valencia late orange varieties.They found that the aroma profile of the orange juice samplesshowed the same distribution, of the descriptors grouped as fruity,citrus, herbaceous, spicy and floral, for the Moro and Taroccojuices.

No studies have been conducted on the volatile compo-nents of the blood oranges produced in Turkey, which is one ofthe great orange producer country. Therefore, our objective inthis study was to determine the volatile components of bloodorange juices obtained from Moro and Sanguinello (C. sinen-

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is (L.) Osbeck). In addition, odour activity values (OAVs) wereetermined for evaluating potent aroma components of orange

uice.

. Materials and methods

.1. Samples and chemicals

The blood oranges of Moro and Sanguinello (C. sinensis L. Osbeck)ere harvested at optimum maturity from the Cukurova Univer-

ity experimental orchard and transported to the biotechnologyaboratory of the Department of Food Engineering, University ofukurova, Adana, Turkey in 2008. Harvest involved a random sam-ling from 12 trees for each variety. Research was carried outith 50 kg oranges of each variety. The oranges were extracted

y cutting the fruit in half and careful hand-squeezing in a house-old type electric hand reamer (Arcelik K-1775, Turkey). The juicesere passed through a strainer to remove pulp and seeds. Moro

range juice had a titratable acidity (TA; as citric acid) of 1.13%,H 3.4 and total soluble solids (TSS) 12.0. Sanguinello had a titrat-ble acidity of 1.34%, pH 3.1 and total soluble solids (TSS) 12.6.he TSS/TA ratios of Moro and Sanguinello juices were 10.62nd 9.40, respectively. The ratio of TSS/TA reported here was ingreement with previously reported ratios by Niu et al. (2008)nd Xu et al. (2008). A high TSS/TA value has generally beenegarded as a quality index for orange fruits, but its increase dur-ng storage period can also be accompanied by the development offf-odours due to formation of ethanol in the fruit (Rapisarda et al.,001).

The water used in the study was purified by a Millipore-Qystem (Millipore Corp., Saint-Quentin, France). The refer-nce aroma compounds were obtained from the followingources: ethyl butanoate, sabinene, ˇ-myrcene, �-terpinene,Z)-linalool oxide, �-terpinolene, 2-methyl-3-buten-2-ol, (Z)-3-exen-1-ol, acetic acid, dl-limonene, ethyl hexanoate, ethylctanoate, geranyl acetate, linalool, nerol, dihydrocarvone, methyl--hydroxyhexanoate, terpinen-4-ol, phenylethyl acetate, ethyl--hydroxyhexanoate, �-terpineol, valencene, ethyl linolenate,-cadinene, carvone, hexanoic acid, nerol, geraniol, (Z)-carveol, per-lla acetate, perilla alcohol, ˇ-sinensal, nootkatone (Aldrich, Stein-eim, Germany); 4-nonanol, decanal, hexanal, octanal, 1-propanol,-butanol, 3-penten-2-ol, octanoic acid, dodecanoic acid and hex-decanoic acid (Merck, Darmstad, Germany). Dichloromethane andodium sulphate were obtained from Merck (Darmstad, Germany).ichloromethane was freshly distilled prior to use.

.2. Extraction of aroma components

A 100 ml portion of orange juice was transferred into a 500 mlrlenmeyer flask and cooled to 0 ◦C in an ice bath. Before the extrac-ion of the flavour components, 5 �l of 4-nonanol (8 �g/�l) wasdded to the juice samples (100 ml) as an internal standard becausef its high recovery (Voirin et al., 1992). Dichloromethane (50 ml)as added and the mixture was stirred at 700 rpm for 15 min (Selli

t al., 2008). Then the mixture was centrifuged (Kubota, Japan) at◦C (9000 × g, 15 min). After the dehydration by anhydrous sodium

ulphate, the pooled organic extract was reduced to 5 ml in a Kud-rna Danish concentrator fitted with a Snyder column at 40 ◦CSupelco, St. Quentin, France) and then to 0.5 ml under a gentletream of nitrogen. The whole process was repeated three times.

he extracts were then stored at −20 ◦C in a glass vial equipped withTeflon-lined cap before the analysis. Each sample was extracted

n triplicate and the concentration of the volatiles was obtained as-nonanol equivalents and then the mean of the three repetitionsas calculated.

d Products 33 (2011) 727–733

2.3. Representativeness of the extract

2.3.1. Sample preparation and presentationThe panel was composed of seven judges from our laboratory

(two females and five males between 23 and 42 years old) trainedin sensorial characterization of food products. Different methodscan be used to evaluate the representativeness of the odour of aro-matic extracts depending on the type of extract (liquid or gaseous).We used a cardboard smelling strip (reference 7140 BPSI, Granger-Veyron, Lyas, France) to check the representativeness of the extractobtained by the liquid–liquid extraction with dichloromethanesince the smelling strip was reported to give good results for therepresentativeness test of grape musts from French and Romanianhybrids (Serot et al., 2001) and cv. Kozan orange wine extract (Selliet al., 2008). 2 ml of blood orange juice was placed into a 15 mlbrown-coded flask as a reference in these tests. An aliquot of orangejuice aromatic extract was adsorbed onto a cardboard smelling stripwith respect to the initial volatile compound concentrations (iso-intensity) of blood orange juice. After 1 min (the time necessary forsolvent evaporation) the extremities of the strips were cut off, thenplaced in dark coded flasks (15 ml) and presented to the panel after15 min. Since dichloromethane is a very volatile solvent and the testwas carried out after its evaporation, the panelists did not senseits odour. All of the samples were assessed at room temperature(20 ◦C).

2.3.2. Similarity testA similarity test was performed to evaluate the closeness

between the odour of extract and the orange juice (reference sam-ple). The panelists were instructed to sniff and memorize the aromaof the reference sample and for extract, to sniff smelling stripodour and to determine the similarity of their odours. A 100 mmunstructured scale was used anchored with “very different fromthe reference” on the left and “identical to the reference” on theright. The position of the sample on the unstructured scale wasread as the distance in millimetres from the left anchor (Mehinagicet al., 2003).

2.3.3. Odour intensity evaluationThe panelists were asked to assess the odour intensity of the

extract. A 100 mm unstructured scale was used anchored with “noodour” on the left and “very strong odour” on the right. The positionof the sample on the unstructured scale was read as the distance inmillimetres from the left anchor.

2.4. GC-FID and GC–MS analysis of aroma compounds

The gas chromatography (GC) system consisted of an Agilent6890 chromatograph equipped with a flame ionization detector(FID) (Wilmington, DE, USA), and an Agilent 5973-Network-mass selective detector (MSD) (Wilmington, DE, USA). Volatilecompounds were separated on DB-Wax (30 m length × 0.25 mmi.d. × 0.5 �m thickness, J&W Scientific Folsom, CA, USA) column.1 �l of extract was injected in pulsed splitless (40 psi; 0.5 min)mode for minimizing artifact formation by thermal degradationof analytes in injection port. Injector and FIDs were set at 270 ◦Cand 280 ◦C, respectively. The flow rate of carrier gas (helium) was1.5 ml/min. The oven temperature of the DB-Wax column wasincreased from 50 to 250 ◦C at a rate of 4 ◦C/min with a final holdat 250 ◦C for 10 min.

The same oven temperature programs were used for the mass-selective detector. The MS (electronic impact ionization) conditionswere as follows: ionization energy of 70 eV, mass range m/z of30–300 a.m.u., scan rate of 2.0 scan/s, interface temperature of250 ◦C, and source temperature of 180 ◦C.

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The volatile compounds were identified by comparing theiretention index and their mass spectra on the DB-Wax column withhose of a commercial spectra database (Wiley 6, NBS 75k) and ofhe instrument’s internal library created from the previous labo-atory studies. Some of the identifications were confirmed by thenjection of the chemical standards into the GC–MS system. Linearetention indices of the compounds were calculated by using an-alkane series (Van den Dool and Kratz, 1963).

.5. Calculation of odour activity values

To assess the influence of the volatile compounds of overallrange juice aroma, the odour activity values (OAVs) were cal-ulated by dividing the concentrations of aroma compounds withheir sensory thresholds from literature (Averbeck and Schieberle,009). Only the compounds with an OAV greater than 1 contribute

ndividually to the orange juice aroma.

. Results and discussion

.1. Similarity and intensity evaluation of aromatic extract

The aim of the similarity and intensity evaluation tests waso check the representativeness of the odour of aromatic extractith that of the initial products. The similarity score of the aro-atic extract obtained by liquid–liquid extraction was found as

0.6 mm on a 100 mm unstructured scale. The similarity score ofhe extract was found to be in an acceptable level in compari-on to the literature. In our previous study, the similarity scoref orange wine extract obtained by liquid–liquid extraction was8.9 mm (Selli et al., 2008). When compared to other studies, sim-

larity score of the apple extract was between 49.1 and 53.4 mmMehinagic et al., 2003) and for orange juice extract between 51.0nd 63.0 mm (Rega et al., 2003). With regard to intensity evaluation,he intensity score of aromatic extract was 58.8 mm on a 100 mmnstructured scale. The intensity score of the extract was alsoigh. According to similarity and intensity results of the aromaticxtract, liquid–liquid extraction was found to be a reliable extrac-ion method in order to determine the orange juice volatile flavourompounds.

.2. Aroma compounds of the orange juices

The volatile compounds identified in Moro and Sanguinellorange juices and linear retention index values on the DB-Waxolumn for these compounds are presented in Table 1. A totalf 83 and 78 aroma compounds, including alcohols, esters, ter-enes, terpenols, aldehydes, acids, ketones, volatile phenols, and

actones were identified in the Moro and Sanguinello juices, respec-ively (Table 1). Nisperos-Carriedo and Shaw (1990) reportedsters, aldehydes, ketones, terpenes, and alcohols are among themportant contributors to orange juice flavour. It was observedhat the volatile profiles of both varieties were quite similar. Theotal concentration of aroma compounds in the Sanguinello juice24,520.3 �g/l) was greater than the Moro juice (22,232.2 �g/l).l-Limonene, followed by �-terpineol, linalool, isoamyl alcohol,exadecanoic acid, 3-hydroxy-2-butanone and phenylethyl alco-ol were found in large amounts in both juices. Table 2 shows theompounds with the OAV greater than 1, the sensory descriptors,nd the odour perception threshold values taken from the results

f other studies (Ahmed et al., 1978; Cullere et al., 2004; Fraatzt al., 2009; Palomo et al., 2007; Schieberle and Grosch, 1988).ifteen compounds may be present in orange juice, at concentra-ions higher than their corresponding odour threshold value, andossibly contribute to the overall blood orange juice aroma.

d Products 33 (2011) 727–733 729

3.2.1. TerpenesTerpene hydrocarbons in both blood orange juices quanti-

tatively represent the main group of volatile compounds. Thetotal content of terpenes in Sanguinello blood orange juice(14,903.3 �g/l) was higher than the Moro (10,992.3 �g/l). Ten ter-penes were identified in both orange juices. dl-Limonene was themost abundant component in both samples followed ˇ-myrcene.As indicated in Table 1, dl-limonene was 48.0% for Moro and 58.4%for Sanguinello juices of the total volatiles analyzed. Similar resultswere observed on Italian Moro, Sanguinello and Tarocco bloodorange juices as well (Maccarone et al., 1998). Perez-Cacho andRouseff (2008) reported that terpene compounds comprise over90% of the total citrus volatiles but are only responsible for lim-ited odour activity because of their high odour threshold values.On the basis of the OAVs results of this study, the main contribu-tors to orange juice aroma from the group most probably originatedfrom dl-limonene and ˇ-myrcene (Table 2). Both compounds werepresent at concentrations higher than their corresponding odourthreshold values (60 �g/l for dl-limonene; 36 �g/l for ˇ-myrceneaccording to Ahmed et al., 1978). dl-Limonene (orange-like, fruityodour) could be an important contributor in this fraction based onits strong OAV (177.8 for Moro and 238.5 for Sanguinello). This com-pound was detected with a lemon-mint odour in Moro, Tarocco,Washington navel and Valencia late orange juices by Arena et al.(2006). The next important terpene compound in terms of OAVswas ˇ-myrcene with a balsamic and geranium odour in both orangejuices. However, ˇ-myrcene’s odour is thought to make a negativecontribution to orange aroma in processed orange juice as previ-ously reported by Ahmed et al. (1978).

3.2.2. TerpenolsThirteen and eleven terpenols were quantified in Moro and

Sanguinello orange juices, respectively. Moro (4601.6 �g/l) bloodorange juices contained more terpenol components than the San-guinello (4233 �g/l). Linalool, �-terpineol and terpinen-4-ol werethe main terpenols in both cultivars. The linalool content of Moro(2009 �g/l) was higher than Sanguinello (1842 �g/l). As can be seenfrom Table 2, four compounds including linalool, terpinen-4-ol, �-terpineol and geraniol have higher OAVs than 1. The highest OAVvalue was recorded for linalool (80.4 for Moro; 73.7 for Sanguinello)which is responsible for floral and green odour. Linalool concentra-tion detected exceeds the odour threshold value (25 �g/l accordingto Cullere et al., 2004) in orange juice samples and can be regardedas having positive impact on Moro and Sanguinello orange juicesaroma. Similarly, linalool has been identified as a potent aromacompounds in Valencia (Hinterholzer and Schieberle, 1998), Nave-line (Rega et al., 2004), Washington navel orange (Arena et al.,2006), Pontianak orange peel oil (Dharmawan et al., 2009), andKozan orange wine (Selli et al., 2003). The next important terpenolcompound in terms of OAV was �-terpineol with a green and violetodour (Table 2). The OAV for �-terpineol of Moro (7.1) was higherthan Sanguinello (5.0). Other terpenols, including terpinen-4-ol andgeraniol, displaying characteristic floral-fresh and fruity-citrusy,may influence blood orange juice overall aroma. At the presentstudy, the lowest OAV value was recorded for geraniol in bothcultivars (Table 2).

3.2.3. EstersEsters are important volatile components on many fruits, and

most of them have a mature flavour and fruity aroma that con-tribute to the strong fruity and floral odour of fruits. The total

concentration of ester compounds in Moro orange juice was clearlygreater than Sanguinello. The seventeen esters were identified inthe Moro with a total concentration of 1002 �g/l, and twelve inthe Sanguinello with a total concentration of 448.7 �g/l (Table 1).Among the esters, ethyl butanoate and ethyl linolenate were found

730 S. Selli, H. Kelebek / Industrial Crops and Products 33 (2011) 727–733

Table 1Volatile flavour compounds of blood orange juices.

No. LRIa Compounds Moro Sanguinello Identificationc

Concentrationb (mean ± SD)

1 1028 Ethyl butanoate 225.9 ± 5.52 75.6 ± 2.87 LRI, MS, Std2 1040 1-Propanol 125.7 ± 11.04 129.1 ± 12.26 LRI, MS, Std3 1060 2-Methyl-3-buten-2-ol 65.6 ± 2.92 41.1 ± 5.32 LRI, MS, Std4 1091 Hexanal 9.8 ± 1.91 30.9 ± 3.10 LRI, MS, Std5 1098 Isobutyl alcohol 274.4 ± 10.95 23.8 ± 1.60 LRI, MS, Std6 1132 3-Penten-2-one 20.7 ± 9.89 24.9 ± 1.76 LRI, MS, tent7 1142 Isoamyl acetate 13.5 ± 1.59 nd LRI, MS, Std8 1148 ı-3-Carene 9.4 ± 2.55 18.8 ± 1.34 LRI, MS, tent.9 1152 1-Butanol 112.7 ± 6.11 13.1 ± 2.86 LRI, MS, Std

10 1165 ˇ-Myrcene 177.9 ± 44.80 319.7 ± 11.88 LRI, MS, Std11 1170 3-Penten-2-ol 47.8 ± 4.36 44.7 ± 2.70 LRI, MS, Std12 1202 2-Heptanone nd 17.2 ± 4.49 LRI, MS, Std13 1224 dl-Limonene 10,670 ± 4678.71 14,310 ± 1004.33 LRI, MS, Std14 1231 Sabinene 13.8 ± 1.71 11.5 ± 1.41 LRI, MS, Std15 1232 1,8-Cineol 12.8 ± 0.97 nd LRI, MS, tent16 1236 Isoamyl alcohol 1628 ± 54.74 961.8 ± 33.17 LRI, MS, Std17 1238 n-Butyl-n-butanoate 8.8 ± 0.35 nd LRI, MS, Std18 1241 Ethyl hexanoate 14.6 ± 1.26 9.2 ± 1.53 LRI, MS, Std19 1255 �-Terpinene 6.9 ± 1.27 13.6 ± 3.06 LRI, MS, Std20 1260 1-Pentanol 9.7 ± 0.85 6.5 ± 0.58 LRI, MS, Std21 1291 3-Hydroxy-2-butanone 795.8 ± 9.71 333.5 ± 6.36 LRI, MS, Std22 1294 Octanal 62.5 ± 1.94 111.8 ± 3.56 LRI, MS, Std23 1249 2-Methyl-1-pentanol 14.5 ± 1.08 10.8 ± 0.39 LRI, MS, tent24 1313 2-Hexanol 26.6 ± 2.00 24.9 ± 0.93 LRI, MS, Std25 1318 3-Methyl-2-buten-1-ol 24.2 ± 1.56 16.4 ± 0.14 LRI, MS, Std26 1333 2-Heptanol 23.9 ± 1.00 21.0 ± 0.89 LRI, MS, Std27 1340 6-Methyl-5-hepten-2-one 4.9 ± 0.84 12.8 ± 0.72 LRI, MS, tent28 1370 1-Hexanol 104.6 ± 4.60 160.3 ± 2.82 LRI, MS, Std29 1384 (E)-3-Hexen-1-ol 22.5 ± 1.85 27.8 ± 1.52 LRI, MS, Std30 1390 3-Ethoxy-1-propanol 15.5 ± 3.69 4.1 ± 0.68 LRI, MS, Std31 1401 (Z)-3-Hexen-1-ol 54.2 ± 3.81 57.6 ± 6.88 LRI, MS, Std32 1420 2-Octanol 2.9 ± 0.10 1.9 ± 0.32 LRI, MS, tent.33 1446 Ethyl octanoate 4.4 ± 0.59 13.0 ± 1.17 LRI, MS, tent.34 1448 (Z)-Linalool oxide nd 8.7 ± 0.97 LRI, MS, Std35 1463 Acetic acid 280.3 ± 6.05 78.8 ± 5.30 LRI, MS, Std36 1481 Heptanol 4.5 ± 0.50 4.9 ± 0.47 LRI, MS, Std37 1484 (E)-Linalool oxide 16.1 ± 0.91 2.1 ± 0.14 LRI, MS, Std38 1488 ˛-Copaene 8.1 ± 0.94 12.7 ± 1.82 LRI, MS, tent.39 1499 Decanal 13.1 ± 1.44 nd LRI, MS, Std40 1521 Benzaldehyde 27.0 ± 1.70 9.7 ± 1.22 LRI, MS, Std41 1540 Ethyl-3-hydroxy-butanoate 37.1 ± 2.26 10.7 ± 0.47 LRI, MS, Std42 1548 2,3-Butanediol 6.9 ± 0.25 4.3 ± 0.69 LRI, MS, Std43 1565 Linalool 2009 ± 79.45 1842 ± 44.40 LRI, MS, Std44 1586 Octanol 144.9 ± 4.94 350.5 ± 11.05 LRI, MS, Std45 1590 ˇ-Elemene 3.8 ± 0.95 nd LRI, MS, tent.46 1594 d-Fenchylalcohol 9. 8 ± 2.79 19.9 ± 4.00 LRI, MS, tent.47 1603 Terpinene-4-ol 608.4 ± 24.76 868.2 ± 22.33 LRI, MS, Std48 1611 �-Butyrolactone 111.3 ± 22.60 37.2 ± 3.39 LRI, MS, Std49 1640 (Z)-p-Mentha-2,8-dienol 26.8 ± 1.53 20.0 ± 0.85 LRI, MS, tent.50 1655 Terpinene-1-ol nd 56.1 ± 40.60 LRI, MS, Std51 1660 Methyl-3-hydroxy-hexanoate 20.5 ± 2.08 8.4 ± 1.84 LRI, MS, tent.52 1664 Furfurylalcohol 4.0 ± 0.43 3.5 ± 0.42 LRI, MS, Std53 1717 1,8-Mentha-dien-4-ol 27.2 ± 0.72 nd LRI, MS, tent.54 1719 �-Terpineol 1766 ± 23.21 1259 ± 38.48 LRI, MS, Std55 1726 Valencene 60.5 ± 2.68 166.6 ± 3.83 LRI, MS, Std56 1733 Carvone nd 4.8 ± 0.29 LRI, MS, Std57 1738 Geranial 22.2 ± 1.58 nd LRI, MS, Std58 1754 ı-Cadinene 25.8 ± 1.86 39.6 ± 23.73 LRI, MS, Std59 1758 Geranyl acetate 3.1 ± 0.56 5.0 ± 3.04 LRI, MS, Std60 1778 Perilla aldehyde 17.2 ± 0.91 16.0 ± 0.03 LRI, MS, Std61 1782 Citronellol 15.8 ± 0.67 28.2 ± 21.25 LRI, MS, Std62 1788 ı-Valerolactone 3.4 ± 0.44 nd LRI, MS, tent.63 1796 Nerol 23.9 ± 1.30 33.4 ± 0.64 LRI, MS, Std64 1809 Phenylethyl acetate 78.3 ± 2.25 nd LRI, MS, Std65 1836 (E)-Carveol 19.5 ± 0.90 24.8 ± 0.67 LRI, MS, tent.66 1838 Hexanoic acid 69.7 ± 17.70 142.0 ± 9.81 LRI, MS, Std67 1847 Geraniol 58.3 ± 6.39 63.6 ± 2.40 LRI, MS, Std68 1876 (Z)-Carveol 14.7 ± 0.35 17.8 ± 2.67 LRI, MS, tent.69 1883 Limonene-10-yl-acetate 75.3 ± 3.25 70.1 ± 1.98 LRI, MS, tent.70 1892 Perilla alcohol 40.2 ± 1.73 24.4 ± 1.87 LRI, MS, Std71 1908 Benzyl alcohol 162.4 ± 7.57 3.2 ± 0.21 LRI, MS, Std72 1914 Perilla acetate 3.1 ± 0.30 4.0 ± 1.73 LRI, MS, tent.73 1925 Phenylethyl alcohol 367.8 ± 15.03 243.8 ± 2.88 LRI, MS, Std74 2078 Methyl cinnamate 8.1 ± 0.59 nd LRI, MS, tent.

S. Selli, H. Kelebek / Industrial Crops and Products 33 (2011) 727–733 731

Table 1 (Continued)

No. LRIa Compounds Moro Sanguinello Identificationc

Concentrationb (mean ± SD)

75 2084 Octanoic acid 81.3 ± 2.75 334.3 ± 6.68 LRI, MS, Std76 2139 Ethyl cinnamate 23.2 ± 0.49 nd LRI, MS, tent.77 2144 Nonanoic acid nd 25.0 ± 3.3 LRI, MS, Std78 2195 ˇ-Eudesmol 9.2 ± 0.94 nd LRI, MS, tent.79 2202 Methyl hexadecanoate 7.8 ± 0.73 12.1 ± 1.29 LRI, MS, tent.80 2206 4-Vinyl-2-methoxy phenol nd 60.7 ± 4.91 LRI, MS, Std81 2251 ˇ-Sinensal nd 12.9 ± 1.67 LRI, MS, Std82 2281 Ethyl hexadecanoate 91.5 ± 1.25 50.9 ± 0.94 LRI, MS, Std83 2296 Decanoic acid 10.7 ± 0.76 102.9 ± 5.58 LRI, MS, Std84 2415 4-Vinyl phenol 140.5 ± 21.09 22.9 ± 0.92 LRI, MS, Std85 2477 Ethyl-9-octadecenoate 94.1 ± 6.81 43.2 ± 2.64 LRI, MS, Std86 2517 Dodecanoic acid 48.2 ± 11.92 28.1 ± 1.45 LRI, MS, tent.87 2532 Nootkatone 177.1 ± 6.11 167.3 ± 1.44 LRI, MS, Std88 2542 Ethyl linolenate 293.3 ± 11.64 146.5 ± 2.58 LRI, MS, Std89 2567 Vanillin 19.4 ± 1.86 37.1 ± 0.43 LRI, MS, Std90 2861 Hexadecanoic acid 437.3 ± 9.41 1145 ± 25.80 LRI, MS, tent.

Total 22,232.2 24,520.3

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a Linear retention index calculated on DB-Wax capillary column.b Results are the means of three repetitions as �g/l.c Methods of identification; LRI (linear retention index), MS tent. (tentatively ident

f a compounds, it must be considered as an attempt of identification.

t high concentrations in both cultivars. Ethyl butanoate is gen-rally the major volatile ester in orange juice. It contributes asuch or more than all the other ester combined (Perez-Cacho

nd Rouseff, 2008). Shaw (1991) reported that amounts of ethylutanoate varied from 80 to 140 �g/l in orange juice. The amountf esters was 225 �g/l and 75.6 �g/l in Moro and Sanguinello,espectively. According to OAV, the main contributors to bloodrange juice aroma from this group would be ethyl butanoate, ethylexanoate and ethyl octanoate. Among these, ethyl butanoate, aompound associated with fruity and apple notes, could be anmportant aroma contributor based on its OAV (Table 2). The OAVsor ethyl butanoate were 11.3 and 3.8 for the Moro and Sanguinellouices, respectively. Ethyl hexanoate (green and floral) had OAVsf 1.0 and <1 for the Moro and Sanguinello juices, while ethylctanoate (fruity and banana) had OAVs of 2.6 and <1 for theanguinello and Moro, respectively. Both esters have low OAVs

nd their contribution to orange juice aroma is poor. Similarly,hese esters have been identified as potent aroma-active com-ounds in Italian Moro and Tarocco blood orange juices by Arenat al. (2006).

able 2dour thresholds and odour activity values (OAVs) of potent volatile compounds in blood

No. Compound Odour thresholda

1 Ethyl butanoate 201

2 ˇ-Myrcene 362

3 dl-Limonene 602

4 Ethyl hexanoate 141

5 Octanal 151

6 Ethyl octanoate 51

7 Decanal 101

8 Linalool 251

9 Terpinen-4-ol 1303

10 �-Terpineol 2501

11 Carvone 2.72

12 Geranial 124

13 Geraniol 303

14 ˇ-Sinensal 3.82

15 Nootkatone 15

a Odour threshold values (�g/l) were taken from the literatures [1Cullere et al., 2004, tSchieberle and Grosch, 1988; 5Fraatz et al., 2009].

b OAVs were calculated by dividing the concentration by the odour thresholds. Thresht al. (2004) in water/ethanol solution.

y MS), Std (chemical standard); when only MS or LRI is available for the identification

3.2.4. AldehydesSix (hexanal, octanal, decanal, benzaldehyde, geranial, and

perilla aldehyde) and five aldehydes (hexanal, octanal, benzalde-hyde, perilla aldehyde and ˇ-sinensal) were identified Moroand Sanguinello orange juices, respectively. These aldehydes arewidespread and present in many other orange juices and products,such as cv. Naveline (Brat et al., 2003), Pera Rio oranges (Averbeckand Schieberle, 2009), and Pontianak orange peel oil (Dharmawanet al., 2009). Table 1 shows that, octanal was the most abundantaldehydes in both Moro (62.5 �g/l) and Sanguinello (111.8 �g/l)juices. Aldehydes are secondary metabolites formed during ripen-ing and maturation period of orange fruit and their concentrationincreases with fruit maturity (Perez-Cacho and Rouseff, 2008).These compounds have long been considered effective on orangeflavour (Nisperos-Carriedo and Shaw, 1990). Based on OAVs, themain contributors to orange juices aroma of aldehydes would be

octanal, decanal and geranial for Moro, and octanal and ˇ-sinensalfor Sanguinello (Table 2). Octanal (green and fruity odour) could bean important contributor based on its strong OAV in both juices.OAVs for octanal were 4.2 and 7.5 for the Moro and Sanguinello

orange juice.

Odour activity value (OAV)b Odour descriptors

Moro Sanguinello

11.3 3.8 Fruity, apple4.9 8.9 Balsamic, geranium

177.8 238.5 Orange-like, fruity1.0 <1 Green, floral4.2 7.5 Green, fruity

<1 2.6 Fruity, banana1.3 <1 Citrus-like

80.4 73.7 Floral, green3.7 6.7 Floral, fresh7.1 5.0 Green, violet

<1 1.8 Minty1.9 <1 Flowery, citrus-like1.9 2.1 Fruity, citrusy

<1 3.4 Fruity, orange177.1 167.3 Citrusy, grapefruit

he matrix was a water/ethanol solution; 2Ahmed et al., 1978; 3Palomo et al., 2007;

old values from the literature were calculated in water matrix except for Cullere

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range juices, respectively. Octanal was previously identified inv. Valencia late (Hinterholzer and Schieberle, 1998) and cv. Peraio (Averbeck and Schieberle, 2009) orange juices as aroma-activeompounds.

.2.5. AlcoholsA total of 23 higher alcohols were identified and quantified in

oth orange juices. The total concentration of alcohols was highern Moro (3283.5 �g/l) than the Sanguinello (2197.5 �g/l) orangeuice. Differences between two cultivars were found for isobutyllcohol, 1-butanol, 3-ethoxy-1-propanol and benzyl alcohol, whichere higher in Moro than Sanguinello, whereas octanol predom-

nant in the latter with 350.5 �g/l compared to 144.9 �g/l in theormer orange juice. Similar alcohol compounds have also beendentified in Italian Moro, Sanguinello and Tarocco blood orangeuices (Maccarone et al., 1998).

The major alcohol of Moro and Sanguinello juices was isoamyllcohol which represented about 49.6% and 44.1% of the sum of alllcohol compounds, respectively. Another alcohol present at highoncentration is phenylethyl alcohol in both juices. They could havensignificant contribution to orange juice due to their high odourhreshold values.

.2.6. Ketones3-Penten-2-one, acetoin, 6-methyl-5-hepten-2-one, and

ootkatone were found in both cultivars as ketone compounds.s can be seen in Table 1, 2-heptanone and carvone were foundnly in Sanguinello cultivar. The total ketone content of Mororange juice (998.5 �g/l) was higher than Sanguinello (560.5 �g/l).mong the ketones, acetoin show the highest concentration inoth samples. Another ketone present at quite high concentration

n nootkatone. In the present study, nootkatone, with its character-stic citrusy-grapefruit odour, was found at exceeding amount thandour threshold value (1 �g/l) in both samples and can be regardeds having a important impact on blood orange juice aroma. OAVsor nootkatone were 177.1 and 167.3 for the Moro and Sanguinellorange juices, respectively. Nootkatone is a sesquiterpene ketonehat has also been characterized as important aroma compounds ofresh and hand extracted Valencia late orange juice (Hinterholzernd Schieberle, 1998) and freshly reconstituted orange juice fromoncentrate (Averbeck and Schieberle, 2009). In addition, carvone,ith minty odour, was present at a concentration above the odour

hreshold value for Sanguinello cultivar (OAV = 1.8).

.2.7. AcidsFive and six acid compounds were determined in Moro and

anguinello juices, respectively. Significant difference for nonanoiccid was present only in Sanguinello, but not in Moro (Table 1). Theotal amount of acids in Sanguinello juice (1856.1 �g/l) was higherhan the Moro (927.5 �g/l). Hexadecanoic acid was the most domi-ant acid in both cultivars, as it accounted for the largest proportionf the total acid components. Generally, acid compounds do noteem to contribute to the overall aroma of orange juice because ofheir high odour threshold values (Etiévant, 1991).

The other group of volatile compounds identified in Morond Sanguinello blood orange juices were volatile phenols (4-inyl-2-methoxy phenol, 4-vinyl phenol, and vanillin) and lactones�-butyrolactone and ı-valerolactone).

. Conclusions

In the present study, volatile profile of Moro and Sanguinellolood orange juices was determined. A total of 83 and 78 aromaompounds were identified and quantified in the aromatic extractf Moro and Sanguinello cultivars, respectively. Terpenes, terpenolsnd alcohols were found as the main types of volatile components.

d Products 33 (2011) 727–733

It was observed that the volatile profiles of both varieties werequite similar. In terms of aroma contribution to blood orange juices,15 compounds were prominent based on the OAVs. Within these,dl-limonene, nootkatone and linalool were the most powerful con-tributors to the aroma of both cultivars.

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