Variations in the essential oil composition in buds of six blackcurrant (Ribes nigrum L.) cultivars at various development phases

Food Chemistry 114 (2009) 671–679

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Variations in the essential oil composition in buds of six blackcurrant (Ribes nigrum L.) cultivars at various development phases A. Dvaranauskaite˙ a, P.R. Venskutonis a,*, C. Raynaud b, T. Talou b, P. Viškelis c, A. Sasnauskas c a

Kaunas University of Technology, Department of Food Technology, Radvile˙nuz pl. 19, LT-50254, Kaunas, Lithuania National Polytechnic Institute of Toulouse, ENSIACET, 118 route de Narbonne, F-31077 cedex 4, Toulouse, France c Lithuanian Institute of Horticulture, Kauno g. 30, LT-54333, Babtai, Kaunas reg., Lithuania b

a r t i c l e

i n f o

Article history: Received 13 June 2008 Received in revised form 27 September 2008 Accepted 3 October 2008

Keywords: Blackcurrant buds Ribes nigrum Essential oil Harvesting period

a b s t r a c t The variations in the content and the composition of dormant bud essential oil in six blackcurrant (Ribes nigrum L.) cultivars collected at various vegetation phases (from December 15, 2004 until April 19, 2005) were studied. Essential oil yield varied from 0.6% to 1.8%, except for the buds harvested in April, when the yield was considerably lower, 0.19–0.27%. Fifty volatile compounds were identified in the bud oils, hydrocarbon (38–55%) and oxygenated (on average 30%) terpenes being the major chemical constituents. Sabinene, d-3-carene, terpinolene were dominant components, while cis- and trans-b-ocimene, a-thujene, a- and b-pinene, myrcene, a- and b-phellandrene, a- and c-terpinene, p-cymene, cis- and transsabinene hydrate, terpinen-4-ol, a-terpineol, trans-piperitol, bornyl acetate, terpinyl acetate, citronellyl acetate, germacrenes D, b-caryophyllene, a-humulene, a-selinene, d-cadinene and a-cadinol were found in reasonable amounts. Almiai may be considered as a superior cultivar, as possessing the most even content of oils ant the main constituents at all harvesting periods, except for April; however some other cultivars (Gagatai, Joniniai) accumulated higher amounts of oil at particular vegetation phases. January may be considered as a preferable harvesting time of buds; the amount of major terpenes at this phase was the highest in the all cultivars except for Joniniai. The concentration of the main oil compounds in buds harvested in April was 2–50 times lower than at other periods in the all six cultivars. Ó 2008 Elsevier Ltd. All rights reserved.

1. Introduction Different anatomical parts of blackcurrants (Ribes nigrum L.) are used as a raw material for aroma isolation due to the pleasant and unique flavour characteristics. More than 150 aroma compounds were reported in the volatile fraction of berries, including terpenes, esters and alcohols (Varming, Petersen, & Poll, 2004). The esters are considered to be responsible for the fruity notes of berries, which are absent in the buds and leaves. Various oxygenated compounds, particularly linalool, citronellol, isodiosphenol, diosphenol, p-mentha-1,8-dien-4-ol, m-cymen-8-ol, cis-carveol, isopulegol and perillyl alcohol were reported to contribute ‘‘floral”, ‘‘minty”, ‘‘coniferous” and ‘‘terpene” aroma notes to the fresh blackcurrant fruits (Boccorh, Paterson, & Piggott, 1999). However, the highest value essential oil is isolated from the dormant blackcurrant buds (De Toro, 1994; Orav, Kailas, & Müürisepp, 2002), which may be further used as a flavouring or aroma enhancer in cosmetic and food industry as well as a fragrance ingredient in perfume manuˇ urcˇanská, & facture (Del Castillo & Dobson, 2002; Píry, Príbela, D Farkaš, 1995). The buds accumulate remarkable amounts of essen* Corresponding author. Tel.: +370 37 300188; fax: +370 37 456647. E-mail address: [email protected] (P.R. Venskutonis). 0308-8146/$ - see front matter Ó 2008 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2008.10.005

tial oil exerting a strong terpenic aroma, which is overwhelmed by a ‘‘catty” note (Griffiths, Robertson, Birch, & Brennan, 1999; Le Quere & Latrasse, 1990; Píry et al., 1995). Recently, blackcurrant buds were also studied as a possible source of phenolics and antioxidants (Dvaranauskaite et al., 2008; Tabart, Kevers, Pincemail, Defraigne, & Dommes, 2006; Tabart et al., 2007). The composition of blackcurrant bud essential oil was comprehensively studied (Kerslake, Latrasse, & Le Quere, 1989; Kerslake & Menary, 1985; Le Quere & Latrasse, 1990; Orav et al., 2002; Píry et al., 1995). However, it is well-known that essential oil components are biosynthesized in the plants as secondary metabolites; therefore their composition is highly variable and depends on several factors, such as climatic conditions, harvesting time, plant cultivar and plant chemotype. For instance, it was reported that the yield and the composition of plant essential oils largely depend on harvesting time (Bylaite˙, Venskutonis, & Roozen, 1998; Bylaite˙, Venskutonis, Roozen, & Posthumus, 2000; Pitarevic´, Kuftinec, Blazˇevic´, & Kuštrak, 1984; Santos-Gomes & Fernandes-Ferreira, 2001). Essential oil composition of six blackcurrant cultivars (Joniniai, Almiai, Gagatai, Ben Alder, Ben Nevis and Ben Lomond) cultivated in Lithuania was recently reported; three chemotypes were defined according to the percentage of the main oil constituents (Dvaranauskaite et al., 2007; Dvaranauskaite et al., 2008).

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A. Dvaranauskaite˙ et al. / Food Chemistry 114 (2009) 671–679

However, to the best of our knowledge, possible variations in the yield and the composition of essential oil of blackcurrant buds at various vegetation phases have not been studied until now. Therefore, the main task of the present study was to assess essential oil content and its composition in six blackcurrant cultivars cultivated in Lithuania at different plant vegetation periods. This task is associated with the two important scientific and practical key points; first, determination of optimal harvesting time and the most productive cultivar, which may help increasing economical feasibility of the essential oil production; second, obtaining new scientific data on the changes of blackcurrant bud volatile secondary metabolites in the course of bud formation and vegetation. 2. Materials and methods

2.3. Gas chromatography and mass spectrometry Gas chromatography system with a flame ionisation detector (GC-FID) consisted of a Varian 3900 gas chromatograph (Palo Alto, California, USA) equipped with an automatic injector and non-polar fused silica capillary column DB-5 (50 m  0.32 mm i.d., 0.52 lm film thickness). Oven temperature was programmed from 100 °C to 250 °C (5.0 min hold) at 2 °C/min. Injection volume was 0.1 ll at 1:100 split; injector and detector temperature was 250 °C. Three replicate GC runs were performed for each sample. The amount of the individual compounds was expressed in two ways: in GC peak area percentage as it is calculated by the integrator, and in arbitrary units (a.u.), which were calculated by the formula

2.1. Plant material and chemicals Dormant buds of 6 blackcurrant (Ribes nigrum L.) cultivars (Joniniai, Almiai, Gagatai, Ben Alder, Ben Nevis and Ben Lomond) were harvested from the cuttings in the experimental field of Lithuanian Institute of Horticulture (LIH) at various vegetation phases, from December 2004 to April 2005 (Table 1). Joniniai is an early-bearing season cultivar; Almiai and Gagatai belong to the mid-season-bearing cultivars; while Ben Alder, Ben Nevis and Ben Lomond are the later-bearing cultivars. The breeds of Joniniai (Minaj Shmyriov  No. 67-59-3), Almiai (Minaj Shmyriov, self-fertilization) and Gagatai (Minaj Shmyriov  Objebyn) were developed in the Lithuanian Institute of Horticulture, Babtai, Lithuania; while Ben Lomond ((Brodtorp  Janslunda)  (Consort  Magnus)) and Ben Alder (Ben More  Ben Lomond) were developed in the Scottish Crop Research Institute, Dundee, Great Britain. The buds were stored in a freezer before hydrodistillation. The reference compounds for a-pinene (P99.0%), sabinene (P 98.5%), b-pinene (P98.5%), myrcene (P95.0%), a-phellandrene (P95.0%), d-2-carene (P96.0%), d-3-carene (P98.5%), p-cymene (P99.5%), limonene (P99.0%), ocimene (mixture of 70% cis-bocimene and 25% limonene), c-terpinene (P98.5%), sabinene hydrate (P98.0%), terpinolene (P97.0%), terpinen-4-ol (P99.0%), a-terpineol (P97.0%), b-caryophyllene (P98.5%), a-terpinene (P95.0%), bornyl acetate (P99.0%), terpinyl acetate (P90.0%), a-humulene (P98.0%) and caryophyllene oxide (P99.0%) were obtained from Fluka (Steinheim, Switzerland). 2.2. Isolation of essential oil Frozen dormant buds (20, 40, 60 or 100 g depending on the available amount and the concentration of oil in the sample) (Table 1) were mixed with 500 ml of distilled water and the essential oil was isolated by hydrodistillation in a slightly modified Clevengertype apparatus during 3 h (European Pharmacopoeia, 1997). The oil was collected and measured in a calibrated tube. Two replicate distillations were performed for each sample and the oils were stored in a freezer prior to further analysis.

C¼

Y  I  1000 100

where C is the amount of individual component, a.u.; Y is the total yield of essential oil,%; I is the content of individual component in the essential oil, %. Arbitrary unit represents an absolute concentration of the individual component which may be isolated from 1 kg of frozen buds and it is approximately equal to 1 lg; however, response factors were not measured for each compound in this study and therefore the a.u. can not be directly replaced by lg. We think that the unit is sufficiently informative, because it is closely associated with the absolute amount of the component which may be isolated from the raw material, whereas GC peak area percentage indicates the content of the component in the total oil. Gas chromatography-mass spectrometry (GC–MS) system consisted of a Clarus 500 gas chromatograph (Perkin Elmer, USA) equipped with mass selective detector Clarus 500 (Perkin Elmer, USA), automatic injector and non-polar fused silica capillary column Elite-5 (30 m  0.25 mm i.d., 0.25 lm film thickness). Mass spectra were obtained by EI at 70 eV. Oven temperature was programmed from 60 °C to 250 °C (5.0 min hold) at 3 °C/min. Injection volume was 0.5 ll at 1:200 split; injector and detector temperature was 250 °C. The compounds were identified by comparison their RIs relative to C5–C18 n-alkanes obtained on a non-polar DB-5 column with those provided in the database (Adams, 2001), by matching their mass spectra (NIST and WILEY 275 libraries) and by comparing the data with previously reported results (Kerslake & Menary, 1985; Kerslake et al., 1989; Le Quere & Latrasse, 1990; Orav et al., 2002; Píry et al., 1995) and by co-injection of available reference compounds. Two replicate runs were performed for each sample. 2.4. Statistical data handling Data are presented as mean values ± standard deviation calculated from triplicate (in some cases duplicate) determinations.

Table 1 Weight of buds (g) used hydrodistillation and yield (%) of essential oil of different blackcurrant cultivars at various vegetation phases. Cultivar

Joniniai Almiai Gagatai Ben Alder Ben Lomond Ben Nevis

Harvesting time I December 15, 2004

II January 14, 2005

III February 10, 2005

IV March 23, 2005

V April 19, 2005

Buds (g)

Yield (%)

Buds (g)

Yield (%)

Buds (g)

Yield (%)

Buds (g)

Yield (%)

Buds (g)

Yield (%)

20 20 20 40 40 40

1.30 ± 0.02 1.55 ± 0.00 0.60 ± 0.02 0.88 ± 0.01 1.20 ± 0.00 1.40 ± 0.03

60 40 60 40 40 60

0.83 ± 0.09 1.45 ± 0.00 1.76 ± 0.18 1.05 ± 0.18 1.60 ± 0.07 1.60 ± 0.07

20 20 20 40 20 40

1.75 ± 0.00 1.50 ± 0.10 1.15 ± 0.03 0.86 ± 0.02 1.10 ± 0.02 1.45 ± 0.07

40 20 40 40 40 40

0.78 ± 0.06 1.58 ± 0.03 1.25 ± 0.07 1.05 ± 0.00 1.23 ± 0.03 1.52 ± 0.03

100 100 100 100 100 100

0.22 ± 0.01 0.27 ± 0.02 0.28 ± 0.00 0.18 ± 0.01 0.19 ± 0.02 0.26 ± 0.02

A. Dvaranauskaite˙ et al. / Food Chemistry 114 (2009) 671–679

Standard deviations (SD) did not exceed 3% for the majority of the values obtained. Analyzes of variance were performed at a level of P < 0.05 to evaluate the significance of differences between mean values. 3. Results and discussion 3.1. Total essential oil In total, 30 essential oil samples (6 cultivars at 5 different vegetation phases) of blackcurrant (Ribes nigrum L.) dormant buds were analysed for chemical composition by using GC-FID and GC–MS. Typical GC–MS chromatogram of the essential oil is presented in Fig. 1. The yield of oil at various vegetation phases varied from 0.6% (Gagatai I) to 1.8% (Gagatai II and Joniniai III), except for the buds harvested in April, when the yield of oil was remarkably lower, from 0.2% to 0.3% (Table 1). It was reported previously that the yield of oil obtained by steam distillation from flower buds was approximately 0.75% (Burdock, 2002). Orav et al. (2002) reported that the yield of blackcurrant bud essential oil was only 0.21%, which is similar to the results obtained in our study for the buds harvested in April. According to the yield of the essential oil and excluding the results obtained for the buds, which were harvested in April, the studied blackcurrant cultivars may be classified into the two groups; first one with low variations in oil concentration (Almiai, Ben Alder and Ben Nevis), and the second one with remarkable variations in the essential oil content (Joniniai, Gagatai and Ben Lomond). For instance, the content of oil in Gagatai was almost three times higher in January than in December, while the differences between min and max values in Almiai was only 9% at the all vegetation phases (Table 1). These findings clearly indicate that harvesting time should be carefully selected for every individual plant breed.

Fig. 1. Typical GC–MS chromatogram of the blackcurrant bud essential oil of Gagatai cultivar: peak number as in Table 2.

673

3.2. General characterisation of oil composition Fifty compounds were detected in the bud oils; the identified compounds constituted from 92% (Ben Alder) to 98% (Almiai) of the total integrated GC peak area at the all vegetation phases. Hydrocarbon terpenes were the most abundant components in the buds consisting from 38% to 55% in the total oil; while the content of oxygenated terpenes, which was on average 30% was almost similar at the all vegetation phases, except for Joniniai V, containing 24% of the components belonging to this chemical group (Fig. 2). Hydrocarbon and oxygenated fractions of terpenes were also reported to be the major ones in the previously published articles, however, in different ratio. For instance, the percentage of hydrocarbon fraction was from 90% to 95%; while the content of oxygenated fraction varied from 5% to10%, which is considerably lower comparing to the buds analysed in our study (Le Quere & Latrasse, 1990). Monoterpenes and sesquiterpenes were identified among the hydrocarbon and oxygenated fractions, however monoterpenes were prevailing in both of these compound groups. Thus, monoterpenes in hydrocarbon fraction constituted from 52% to 74%; while monoterpenes in oxygenated fraction constituted from 60% to 83% (Fig. 3). It was reported previously that hydrocarbon monoterpenes constituted the major part (approx. 87%) in blackcurrant bud oils (Le Quere & Latrasse, 1990). Lower amounts of hydrocarbon monoterpenes were determined in the oils of Joniniai cultivar at all vegetation phases; this breed had the highest content of hydrocarbon sesquiterpenes as compared to other studied cultivars (Fig. 3a). The highest percentage of oxygenated sesquiterpenes was in the all cultivars harvested in April (V), except for Almiai V. The oil of Joniniai V was exceptional as containing higher content of sesquiterpenes than monoterpenes (Fig. 3b). It is known that the parent sesquiterpenes are biosynthesized from geranyl diphosphate by its condensation with isopentenyl diphosphate. It can be suggested that monoterpenes are consumed by the plants faster at late vegetation phases as compared to oxygenated sesquiterpenes. Sabinene, d-3-carene and terpinolene were dominant constituents in the analysed blackcurrant bud essential oils, however cis- and trans-b-ocimene, a-thujene, a- and b-pinene, myrcene, a- and b-phellandrene, a- and c-terpinene, p-cymene, cis- and trans-sabinene hydrate, terpinen-4-ol, a-terpineol, trans-piperitol, bornyl acetate, terpinyl acetate, citronellyl acetate, germacrene D, b-caryophyllene, a-humulene, a-selinene, d-cadinene and a-cadinol were also found in reasonable amounts (Table 2). Six analysed cultivars, according to the most abundant volatile compounds in bud essential oils, namely sabinene, d-3-carene and terpinolene were previously classified into the three different chemotypes (Dvaranauskaite et al., 2007; Dvaranauskaite et al., 2008). It should be noted that some minor and tentatively identified oxygenated compounds, such as trans-1-methyl-4-(1-methylethyl)-2-cyclohexen-1-ol, cis-1-methyl-4-(1-methylethyl)-2-cyclohexen-1-ol, p-mentha-1,5-dien-8-ol, thujol, p-cymen-8-ol, cyclohexylethylacetate may be generated during hydrodistillation procedure which is performed at 100 °C. Summarising the results on the main chemical components of bud oils, sabinene constituted on average 61% in Joniniai, Almiai and Gagatai breeds; d-3-carene and terpinolene constituted on average 47% and 20%, respectively in Ben Alder and Ben Nevis breeds; while sabinene, d-3-carene and terpinolene constituted on average 49%, 20% and 8%, respectively, in Ben Lomond breed (Fig. 4). b-Ocimenes constituting 4–9% were also quantitatively important compounds in blackcurrant bud essential oils. Higher amount of cis-b-ocimene was isolated from Almiai (1158– 1283 a.u./kg), Gagatai (597–1645 a.u./kg) and Joniniai III (613 a.u./ kg). The amount of trans-b-ocimene was higher in Gagatai (505– 1421 a.u./kg) and Joniniai III (690 a.u./kg) (Fig. 5).

A. Dvaranauskaite˙ et al. / Food Chemistry 114 (2009) 671–679

Amount of compounds, %

674

60 50 40 30 20 10 0 I

II

III IV V

I

Joniniai

II III IV V

I

Almiai

II

III IV V

Gagatai

I

II III IV V

I

Ben Alder

II

III IV V

Ben Nevis

I

II III IV V Ben Lomond

Samples Hydrocarbons

Oxygenated fraction

Other

80 70 60 50 40 30 20 10 0 I II IIIIV V I II IIIIV V I II IIIIV V I II IIIIV V I II IIIIV V I II III IV V Joniniai

Almiai

Gagatai

Ben Alder

Ben Nevis

Amount of compounds, %

Amount of compounds, %

Fig. 2. Hydrocarbon and oxygenated fractions in the bud essential oil of six blackcurrant cultivars at various vegetation phases.

90 80 70 60 50 40 30 20 10 0 I II IIIIV V I II IIIIV V I II III IV V I II IIIIV V I II III IV V I II III IV V Joniniai

Ben Lomond

Monoterpenes

Almiai

Gagatai

Ben Alder

Ben Nevis

Ben Lomond

Sesquiterpenes

Fig. 3. Hydrocarbon (a) and oxygenated (b) mono- and sesquiterpenes in blackcurrant bud essential oil.

The amount of camphene, d-2-carene, trans- and cis-1-methyl4-(1-methylethyl)-2-cyclohexen-1-ol, p-mentha-1,5-dien-8-ol, thujol, p-cymen-8-ol, cis-piperitol, 1,9-decadiyne, cyclohexylethylacetate, b-elemene, germacrene B, germacrene D-4-ol, caryophyllene and aromadendrene oxide, s-cadinol, 6,10,14-trimethyl-2-pentadecanone and several unidentified compounds was remarkably lower (<200 a.u./kg) in the all samples, except for Joniniai I, which accumulated higher amounts of germacrene B (656 a.u./kg) and caryophyllene oxide (612 a.u./kg); for Joniniai II which gave higher amounts of aromadendrene oxide (322 a.u./kg); and for Gagatai IV which gave higher amounts of cis-piperitol (317 a.u./kg) (Tables 2 and 3). 3.3. Variations of the concentration of oil constituents The amount of all compounds of interest was very low in buds harvested in April; their concentrations at this phase of vegetation were 2–50 times lower than those at earlier periods of buds formation in the all six cultivars. The content of major compounds, namely sabinene, d-3-carene, terpinolene, cis- and trans-b-ocimene harvested in April was 3–9 times lower as compared to the content of the same hydrocarbon monoterpenes in buds harvested at other periods; while the concentration of terpinen-4-ol in Almiai, bpinene in Ben Nevis and sabinene in Ben Lomond harvested in April was lower 91, 130 and 255 times, respectively than at other harvesting periods. It seems that fast transformation and/or consump-

tion of terpenes take place in the buds in the end of March/ beginning of April. So far as the variations in the percentage content of the main oil components were not so remarkable, the concentration of these components in the buds harvested at various phases were mainly dependant on the content of total oil amount accumulated at that phase. For instance, the highest amount of sabinene was isolated from Joniniai III harvested in February (7599 a.u./kg) (Fig. 4), when the buds contained the highest amount of the total oil. The average amount of sabinene in Joniniai at all other vegetation phases (4770 a.u./kg) was the lowest among the oils of the first plant chemotype. Similar variations for sabinene were observed in Gagatai, which can be characterised by remarkable variations in oil content, while the content of sabinene in Almiai (on average 9670 a.u./ kg) with slight variations in the total oil content was quite stable during all vegetation phases. The variations in the concentration of the main components (d-3-carene and terpinolene) in the oils of the second chemotype (Ben Alder and Ben Nevis) were less pronounced (Fig. 4) because the differences in oil content in these cultivars at various harvesting phases were less considerable. The concentration of the main components (sabinene, d-3-carene and terpinolene) in Ben Lomond (third chemotype) was highest in January, when the buds accumulated the highest amount of oil. Sabinene is characterised in different literature sources by woody, citrus, spicy, pepper and turpentine aroma notes (Dvaranauskaite et al., 2008) and

Table 2 Variations in the concentration of bud essential oil components isolated from Joniniai, Almai and Gagatai cultivars at various vegetation phases (December 15-March 23), a.u./kg frozen buds. Peak no.

21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49. a b

a-Thujenea,b,c t a-Pinenea,b,c,d Camphenea,b,c t Sabinenea,b,c,d b-Pinenea,b,c,d Myrcenea,b,c,d d-2-Carenea,b,d a-Phellandrenea,b,c,d d-3-Carenea,c,d a-Terpinenea,b,c,d p-Cymenea,b,c,d Limonenea,b,c,d b-Phellandrenea,b,c t cis-b-Ocimenea,b,c,d trans-b-Ocimenea,b,c t c-Terpinenea,b,c,d cis-Sabinene hydratea,b,c,d Terpinolenea,b,c,d trans-Sabinene hydratea,b,c,d trans-1-Methyl-4-(1-methylethyl) -2-cyclohexen-1-ola t cis-1-Methyl-4-(1-methylethyl) -2-cyclohexen-1-ola t p-Mentha-1,5-dien-8-ola t Thujola t Terpinen-4-ola,b,c,d p-Cymen-8-ola,b,c t a-Terpineola,b,c,d cis-Piperitola,b,c t trans-Piperitola,b,c t 1,9-Decadiynea t Cyclohexylethylacetatea t Bornyl acetatea,b,c,d Terpinyl acetatea,b,c,d Citronellyl acetatea,b,c t b-Elemenea,b,c t b-Caryophyllenea,b,c,d c-Elemenea,b,c t a-Humulenea,b,c,d Germacrene Da,b,c t b-Selinenea,b t a-Selinenea,b t b-Guaienea,b,c t d-Cadinenea,b,c t Germacrene Ba,b,c, d t Germacrene D-4-ola,b t Caryophyllene oxidea,b,c Aromadendrene oxidea t s-Cadinola,c t a-Cadinola,b,c t 6,10,14-Trimethyl-2-pentadecanonea,c t Identification Identification Identification Identification

supported supported supported supported

by: by: by: by:

Almiai

Gagatai

I

II

III

IV

I

II

III

IV

I

II

III

IV

276 ± 16 386 ± 17 nd 4572 ± 66 256 ± 17 421 ± 14 nd 33 ± 2 107 ± 8 nd 268 ± 10 250 ± 11 202 ± 24 342 ± 10 89 ± 3 nd 81 ± 3 43 ± 1 74 ± 3 nd

179 ± 16 188 ± 17 nd 5165 ± 66 199 ± 17 156 ± 14 nd 17 ± 2 88 ± 3 46 ± 2 98 ± 1 nd 257 ± 24 237 ± 10 95 ± 3 87 ± 3 63 ± 2 122 ± 9 24 ± 3 14 ± 0

240 ± 3 450 ± 1 34 ± 1 7599 ± 243 489 ± 9 309 ± 6 nd 68 ± 1 45 ± 1 41 ± 1 118 ± 3 nd 154 ± 2 613 ± 9 690 ± 10 72 ± 1 94 ± 1 60 ± 1 47 ± 1 52 ± 1

140 ± 3 144 ± 2 nd 4579 ± 47 nd nd nd 13 ± 1 nd 66 ± 2 54 ± 1 nd 315 ± 8 118 ± 20 83 ± 3 118 ± 4 33 ± 1 34 ± 1 37 ± 1 19 ± 1

119 ± 2 588 ± 6 65 ± 1 9803 ± 59 462 ± 3 385 ± 35 116 ± 1 26 ± 3 64 ± 1 22 ± 1 265 ± 1 nd 594 ± 12 1283 ± 10 170 ± 1 112 ± 1 37 ± 1 44 ± 1 31 ± 1 16 ± 3

130 ± 1 583 ± 8 63 ± 1 9294 ± 9 429 ± 5 413 ± 11 105 ± 0 110 ± 1 52 ± 0 58 ± 1 219 ± 1 nd 559 ± 18 1158 ± 21 131 ± 1 99 ± 0 43 ± 0 71 ± 3 37 ± 2 17 ± 1

152 ± 1 606 ± 8 67 ± 0 9483 ± 62 438 ± 3 274 ± 15 109 ± 1 48 ± 1 138 ± 15 65 ± 1 225 ± 1 nd 580 ± 20 1194 ± 8 136 ± 1 136 ± 1 48 ± 2 53 ± 3 45 ± 1 25 ± 0

148 ± 6 605 ± 21 69 ± 4 10116 ± 423 469 ± 13 455 ± 12 114 ± 3 20 ± 0 44 ± 1 130 ± 1 210 ± 3 nd 608 ± 26 1254 ± 31 126 ± 9 111 ± 4 57 ± 2 41 ± 2 33 ± 2 23 ± 4

45 ± 2 241 ± 10 28 ± 1 3557 ± 35 187 ± 1 152 ± 1 46 ± 2 5±1 19 ± 0 19 ± 0 21 ± 0 nd 111 ± 28 597 ± 28 505 ± 1 37 ± 1 14 ± 1 14 ± 0 12 ± 0 7±1

165 ± 2 747 ± 8 88 ± 1 10070 ± 150 533 ± 7 449 ± 6 134 ± 2 nd 72 ± 2 75 ± 2 59 ± 2 nd 253 ± 41 1645 ± 22 1421 ± 18 180 ± 5 144 ± 1 67 ± 3 93 ± 2 63 ± 3

87 ± 1 475 ± 3 55 ± 1 7119 ± 99 323 ± 2 278 ± 2 nd 6±0 72 ± 1 nd 92 ± 1 nd 93 ± 3 1096 ± 10 629 ± 6 32 ± 1 6±0 33 ± 1 17 ± 2 42 ± 3

108 ± 2 511 ± 12 61 ± 1 7161 ± 88 392 ± 36 317 ± 6 96 ± 2 nd 29 ± 2 56 ± 3 48 ± 2 nd 192 ± 30 1191 ± 12 1005 ± 16 127 ± 2 112 ± 4 42 ± 2 83 ± 3 20 ± 1

nd

nd

20 ± 0

13 ± 0

9±1

10 ± 0

15 ± 2

14 ± 1

4±0

30 ± 2

14 ± 2

14 ± 0

nd nd 318 ± 32 28 ± 1 25 ± 3 nd 24 ± 1 nd nd 31 ± 1 28 ± 2 17 ± 1 86 ± 2 911 ± 31 47 ± 2 496 ± 20 288 ± 1 27 ± 1 78 ± 1 nd 44 ± 1 656 ± 30 nd 612 ± 25 150 ± 10 81 ± 3 96 ± 1 45 ± 2

nd nd 346 ± 32 nd 31 ± 3 nd 8±1 8±1 nd 17 ± 1 20 ± 2 5±1 36 ± 3 691 ± 1 26 ± 1 169 ± 20 143 ± 1 9±0 9±1 20 ± 2 92 ± 3 70 ± 3 15 ± 1 80 ± 3 322 ± 33 25 ± 3 19 ± 1 6±0

nd nd 13 ± 1 nd 286 ± 6 nd 67 ± 3 33 ± 2 nd 44 ± 4 15 ± 1 11 ± 1 nd 541 ± 15 nd 184 ± 7 126 ± 7 nd 10 ± 2 126 ± 7 12 ± 2 nd 16 ± 2 34 ± 2 18 ± 1 95 ± 3 77 ± 3 51 ± 1

nd nd 3±1 nd 280 ± 15 nd 27 ± 2 13 ± 2 nd 11 ± 1 17 ± 1 8±1 18 ± 0 757 ± 31 25 ± 2 182 ± 15 137 ± 5 nd 13 ± 1 137 ± 5 48 ± 3 103 ± 14 50 ± 2 30 ± 2 188 ± 7 54 ± 3 13 ± 1 22 ± 2

nd nd 200 ± 6 nd 12 ± 2 nd nd 13 ± 1 nd 70 ± 3 15 ± 1 10 ± 0 nd 11 ± 1 nd 398 ± 6 149 ± 3 nd 115 ± 3 nd 9±1 nd 9±1 nd 20 ± 1 nd nd 35 ± 1

nd nd 241 ± 14 nd 17 ± 2 nd nd 13 ± 2 nd 67 ± 3 15 ± 1 9±1 nd 13 ± 1 nd 370 ± 16 182 ± 36 nd 92 ± 4 nd 10 ± 1 nd 36 ± 3 nd 20 ± 1 10 ± 1 11 ± 1 20 ± 1

nd nd 315 ± 16 nd nd nd 25 ± 0 nd 16 ± 3 74 ± 12 15 ± 1 11 ± 1 nd 15 ± 1 nd 394 ± 3 148 ± 3 nd 93 ± 4 nd nd nd nd nd 32 ± 10 nd 26 ± 1 16 ± 1

nd nd 339 ± 2 nd 17 ± 2 18 ± 0 14 ± 1 nd nd 89 ± 3 16 ± 1 9±1 nd nd nd 473 ± 16 183 ± 6 nd 88 ± 0 nd nd nd nd 69 ± 3 nd 27 ± 1 nd nd

nd nd 4±1 nd 91 ± 3 nd 5±0 4±0 nd 29 ± 0 nd 5±0 nd 4±0 nd 102 ± 3 3±0 29 ± 0 3±0 nd 10 ± 1 nd nd nd 14 ± 2 10 ± 2 4±0 nd

nd nd 18 ± 1 nd 421 ± 30 nd 36 ± 1 8±0 nd 95 ± 3 15 ± 1 10 ± 1 nd 10 ± 0 nd 330 ± 5 94 ± 3 nd nd nd 105 ± 6 nd 37 ± 2 9±1 33 ± 0 27 ± 2 10 ± 1 nd

10 ± 1 nd 5±1 5±0 165 ± 1 nd 72 ± 3 20 ± 1 11 ± 0 81 ± 3 29 ± 2 13 ± 2 13 ± 1 10 ± 1 nd 158 ± 5 49 ± 2 nd nd nd 22 ± 1 26 ± 1 nd nd 69 ± 1 nd 23 ± 1 14 ± 2

nd nd 14 ± 1 6±0 315 ± 21 37 ± 2 35 ± 1 6±0 nd 70 ± 3 11 ± 1 8±1 nd 8±1 nd 223 ± 11 62 ± 3 nd 7±1 nd 62 ± 3 nd 19 ± 0 7±1 34 ± 3 nd 47 ± 3 9±1

good match of MS. IR (Adams, 2001). agreement with published data (Kerslake and Menary, 1985; Kerslake et al., 1989; Le Quere and Latrasse, 1990; Píry et al., 1995). co-injection of reference compounds; t – tentative identification; nd – not detected.

675

c d

Joniniai

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1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.

Compounds

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11000 10000 9000

a.u./kg buds

8000 7000 6000 5000 4000 3000 2000 1000 0 sabinene a)

sabinene b)

sabinene c)

-3-carene terpinolene d) d)

1st chemotype

-3-carene terpinolene e) e)

sabinene f)

-3-carene terpinolene f) f)

2 nd chemotype

December

January

3 rd chemotype

February

March

Fig. 4. Variation of major compounds in bud essential oil of six blackcurrant cultivars ((a) – Joniniai, (b) – Almiai, (c) – Gagatai, (d) – Ben Alder, (e) – Ben Nevis and (f) – Ben Lomond) at different vegetation phases.

1800 1600

a.u./kg buds

1400 1200 1000 800 600 400 200

Joniniai

Almiai

December

Gagatai

January

Ben Alder

February

Ben Nevis

trans- -ocimene

cis- -ocimene

trans- -ocimene

cis- -ocimene

trans- -ocimene

cis- -ocimene

trans- -ocimene

cis- -ocimene

trans- -ocimene

cis- -ocimene

trans- -ocimene

cis- -ocimene

0

Ben Lomond

March

Fig. 5. Variation of b-ocimene in bud essential oil of six blackcurrant cultivars.

remarkable variations in the content of this compound may have an influence on the overall aroma of blackcurrant oil. As an example, the variations in the concentration of ocimene isomers are presented in Fig. 5. The pattern of the changes of the amount of ocimenes in Joniniai cultivar is in correlation with the changes in the total content of oil, however intensive biosynthesis of trans and cis isomers may be observed in February, reaching the

peaks of 613 and 690 a.u./kg, respectively. The concentration of both ocimene isomers was similar in Almiai at all vegetation phases, while the variations of these monoterpene isomers in Gagatai were most remarkable; the most intensive formation of ocimenes was observed in January, i.e., one month earlier as compared to Joniniai. Constant increase in the content of ocimenes was observed in Ben Alder from December until March, while the effect

Table 3 Variations in the concentration of bud essential oil components in Ben Alder, Ben Nevis and Ben Lomond cultivars at various vegetation phases (December 15-March 23), a.u./kg frozen buds. Peak no.

21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. 36. 37. 38. 39. 40. 41. 42. 43. 44. 45. 46. 47. 48. 49.

a-Thujene a-Pinene Camphene Sabinene b-Pinene Myrcene d-2-Carene a-Phellandrene d-3-Carene a-Terpinene p-Cymene Limonene b-Phellandrene cis-b-Ocimene trans-b-Ocimene c-Terpinene cis-Sabinene hydrate Terpinolene trans-Sabinene hydrate trans-1-Methyl-4-(1-methylethyl) -2-cyclohexen-1-ol cis-1-Methyl-4-(1-methylethyl) -2-cyclohexen-1-ol p-Mentha-1,5-dien-8-ol Thujol Terpinen-4-ol p-Cymen-8-ol a-Terpineol cis-Piperitol trans-Piperitol 1,9-Decadiyne Cyclohexylethylacetate Bornyl acetate Terpinyl acetate Citronellyl acetate b-Elemene b-Caryophyllene c-Elemene a-Humulene Germacrene D b-Selinene a-Selinene b-Guaiene d-Cadinene Germacrene B Germacrene D-4-ol Caryophyllene oxide Aromadendrene oxide s-Cadinol a-Cadinol 6,10,14-Trimethyl-2-pentadecanone

Ben Alder

Ben Nevis

Ben Lomond

I

II

III

IV

I

II

III

IV

I

II

III

IV

nd nd 22 ± 1 105 ± 1 nd 21 ± 1 nd 83 ± 1 4348 ± 63 10 ± 0 35 ± 0 35 ± 0 247 ± 1 45 ± 1 16 ± 0 275 ± 2 224 ± 2 1761 ± 44 15 ± 0 nd

nd nd nd 25 ± 1 nd 25 ± 0 nd 120 ± 2 4979 ± 41 78 ± 1 44 ± 1 96 ± 2 307 ± 2 59 ± 13 13 ± 0 323 ± 2 270 ± 3 2047 ± 10 85 ± 3 nd

21 ± 0 103 ± 0 22 ± 1 79 ± 0 246 ± 8 9±0 nd 80 ± 2 4242 ± 14 63 ± 1 11 ± 0 nd 452 ± 32 114 ± 0 176 ± 30 233 ± 1 69 ± 0 1724 ± 27 7±0 5±0

30 ± 1 139 ± 5 26 ± 0 233 ± 1 294 ± 6 21 ± 1 nd 92 ± 4 5107 ± 102 67 ± 1 21 ± 0 nd 531 ± 28 166 ± 3 200 ± 2 257 ± 3 77 ± 4 1913 ± 72 13 ± 2 11 ± 1

60 ± 1 257 ± 7 34 ± 2 788 ± 15 381 ± 5 151 ± 17 nd 108 ± 7 6340 ± 80 90 ± 18 50 ± 5 nd 530 ± 64 178 ± 8 253 ± 12 112 ± 4 14 ± 1 2715 ± 28 23 ± 1 nd

78 ± 2 294 ± 7 nd 39 ± 3 863 ± 14 601 ± 13 nd 149 ± 13 7052 ± 80 119 ± 12 17 ± 1 nd 650 ± 9 283 ± 11 361 ± 21 63 ± 3 86 ± 3 3170 ± 19 20 ± 1 nd

118 ± 3 295 ± 1 70 ± 1 34 ± 2 914 ± 7 607 ± 3 nd 134 ± 3 6802 ± 24 108 ± 1 21 ± 0 nd 648 ± 3 198 ± 1 273 ± 1 51 ± 3 66 ± 3 2669 ± 18 12 ± 0 10 ± 0

67 ± 0 285 ± 6 37 ± 3 845 ± 18 413 ± 8 177 ± 2 nd 135 ± 2 7065 ± 112 86 ± 1 25 ± 1 nd 642 ± 5 204 ± 5 266 ± 6 47 ± 2 62 ± 2 2733 ± 84 17 ± 1 15 ± 0

75 ± 2 189 ± 3 13 ± 1 6029 ± 79 367 ± 5 85 ± 1 26 ± 0 38 ± 1 2438 ± 23 63 ± 1 51 ± 3 nd 214 ± 3 163 ± 2 216 ± 3 84 ± 0 31 ± 1 961 ± 12 26 ± 0 9±1

129 ± 1 247 ± 2 15 ± 2 7409 ± 84 465 ± 5 111 ± 2 33 ± 1 51 ± 3 3141 ± 39 109 ± 1 91 ± 2 nd 249 ± 2 214 ± 2 313 ± 3 170 ± 1 151 ± 1 1316 ± 4 57 ± 1 27 ± 0

72 ± 2 189 ± 5 13 ± 1 5988 ± 200 312 ± 12 82 ± 2 27 ± 0 18 ± 0 2081 ± 42 nd 148 ± 4 83 ± 3 160 ± 5 145 ± 5 28 ± 1 nd 33 ± 2 534 ± 1 23 ± 2 30 ± 3

101 ± 1 186 ± 1 13 ± 0 5629 ± 78 366 ± 6 82 ± 1 27 ± 1 39 ± 2 2497 ± 18 97 ± 1 211 ± 4 nd 172 ± 3 221 ± 4 115 ± 2 134 ± 4 52 ± 1 1042 ± 14 52 ± 1 24 ± 1

56 ± 0

30 ± 2

12 ± 2

12 ± 1

19 ± 2

99 ± 4

74 ± 1

102 ± 1

21 ± 3

17 ± 0

9±1

16 ± 2

17 ± 0 45 ± 0 39 ± 0 68 ± 2 nd 18 ± 0 12 ± 0 38 ± 2 11 ± 0 26 ± 1 5±0 52 ± 1 nd 18 ± 1 nd 254 ± 9 nd nd 79 ± 3 nd 5±0 nd 105 ± 3 8±1 11 ± 1 34 ± 3 13 ± 1 35 ± 2

nd 13 ± 0 50 ± 0 7±0 144 ± 10 28 ± 0 23 ± 0 50 ± 2 8±1 9±1 6±1 47 ± 2 5±2 22 ± 1 nd 415 ± 5 134 ± 2 nd 194 ± 4 nd 9±1 nd 7±0 183 ± 10 6±1 18 ± 0 79 ± 3 nd

30 ± 0 28 ± 2 12 ± 0 90 ± 2 nd 14 ± 0 18 ± 3 26 ± 3 23 ± 2 22 ± 2 25 ± 2 4±1 nd 11 ± 1 nd 275 ± 5 87 ± 1 nd 151 ± 17 nd 5±0 8±1 4±1 37 ± 4 4±0 52 ± 4 39 ± 2 12 ± 1

65 ± 3 15 ± 1 23 ± 1 159 ± 8 16 ± 3 14 ± 3 31 ± 1 22 ± 3 34 ± 1 30 ± 1 9±1 30 ± 3 nd 10 ± 0 nd 295 ± 11 88 ± 3 nd 120 ± 2 nd 10 ± 1 nd nd 10 ± 0 97 ± 4 32 ± 2 31 ± 2 nd

nd 60 ± 3 12 ± 0 25 ± 2 138 ± 2 nd 32 ± 2 47 ± 8 28 ± 1 32 ± 8 16 ± 2 12 ± 3 nd 21 ± 12 nd 451 ± 2 138 ± 11 nd 134 ± 24 nd 20 ± 9 29 ± 9 nd 125 ± 51 21 ± 3 30 ± 2 43 ± 2 nd

nd 21 ± 1 30 ± 1 14 ± 2 222 ± 7 23 ± 2 14 ± 0 25 ± 4 27 ± 1 37 ± 2 12 ± 1 18 ± 1 9±1 21 ± 1 27 ± 1 622 ± 11 182 ± 13 nd 189 ± 25 nd nd nd 87 ± 3 62 ± 3 43 ± 2 103 ± 12 50 ± 2 nd

14 ± 1 28 ± 0 12 ± 0 71 ± 0 63 ± 1 17 ± 1 17 ± 0 35 ± 2 30 ± 1 49 ± 0 nd 14 ± 0 nd 17 ± 0 nd 381 ± 11 111 ± 9 nd 94 ± 4 nd 10 ± 0 nd nd 21 ± 2 85 ± 2 141 ± 10 25 ± 1 16 ± 0

26 ± 1 35 ± 1 28 ± 1 93 ± 3 126 ± 2 26 ± 1 68 ± 1 14 ± 0 60 ± 1 42 ± 1 14 ± 1 nd nd 21 ± 0 nd 452 ± 15 135 ± 15 nd 101 ± 20 nd nd 14 ± 0 14 ± 1 nd 22 ± 3 124 ± 6 55 ± 2 15 ± 3

nd nd 157 ± 18 6±1 17 ± 1 nd 6±1 10 ± 1 11 ± 1 6±1 10 ± 1 6±0 nd 11 ± 1 nd 258 ± 7 91 ± 3 6±1 86 ± 3 nd 27 ± 3 nd 12 ± 1 8±1 25 ± 2 29 ± 3 6±1 12 ± 2

nd 22 ± 0 492 ± 27 9±1 24 ± 0 nd 9±0 30 ± 1 15 ± 1 32 ± 1 8±1 9±1 9±1 13 ± 1 nd 352 ± 17 129 ± 7 8±0 105 ± 5 nd 34 ± 2 nd 11 ± 1 49 ± 4 49 ± 3 nd 22 ± 1 10 ± 1

47 ± 1 nd 130 ± 4 8±1 111 ± 1 68 ± 4 nd nd nd 52 ± 2 28 ± 2 71 ± 2 44 ± 3 18 ± 2 nd 156 ± 7 75 ± 1 nd nd nd nd nd nd 30 ± 2 65 ± 4 nd nd nd

23 ± 2 nd 411 ± 32 12 ± 0 20 ± 1 nd 13 ± 0 11 ± 0 9±0 nd nd 10 ± 1 nd 11 ± 1 nd 275 ± 5 100 ± 4 nd 73 ± 4 nd 19 ± 0 nd nd 46 ± 1 44 ± 3 nd 17 ± 1 nd

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1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.

Compounds

nd – not detected. 677

678

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of vegetation phase on the concentration of ocimenes in Ben Nevis and Ben Lomond was less evident. Taking into account that cultivation conditions and harvesting periods were similar for the all studied cultivars it can be suggested that genetic peculiarities are the main factors regulating the biosynthesis of individual terpenes in blackcurrant buds in the course of their development. Remarkable variations were also observed for many other identified components, constituting lower content in the total oil of buds. These variations in most cases were also correlating with the content of the total essential oil, however some peculiarities were observed for different compounds and cultivars and some of them will be briefly discussed. For instance, the amount of hydrocarbon monoterpenes, a-thujene and myrcene isolated from Joniniai was highest in December, although the content of the total essential oil was highest in February; the concentration of p-cymene, a-humulene and germacrene D was similar at all vegetation phases, except December; the content of b-pinene, b-phellandrene and terpinen-4-ol were similar in December and January; while the amount of a-terpineol was similar in February and March. The highest amount of hydrocarbon sesquiterpene b-caryophyllene was isolated from Joniniai cultivars as compared to other studied breeds. Such sesquiterpene compounds as c-elemene, b-selinene and b-guaiene were detected solely in Joniniai cultivar at the all vegetation phases. The content of all compounds isolated from Almiai was similar at all vegetation phases, except for a-terpinene and terpinen-4-ol, which increased during vegetation. The changes in the concentrations of the all compounds isolated from Gagatai are in correlation with the changes in the total content of oil in this cultivar; the highest amount of numerous constituents was in January and the lowest one was in December (Table 2). The amount of hydrocarbon monoterpenes a-thujene, a- and b-pinene in Ben Alder essential oil was highest in February and March; the content of oxygenated monoterpene cis-sabinene hydrate was highest in December and January. The concentration of a-phellandrene, cterpinene, a-humulene and a-selinene was similar at all vegetation phases in this cultivar, except January; while the amount of hydrocarbon monoterpene b-phellandrene increased during the whole period of vegetation. The concentration of all compounds in Ben Nevis was similar at all vegetation phases, except b-pinene, myrcene, a-terpineol and a-humulene. The amount of hydrocarbon monoterpenes b-pinene and myrcene was highest in January and February in this breed; while the content of oxygenated monoterpene a-terpineol and hydrocarbon sesquiterpene a-humulene was highest in January. The highest concentration of all compounds in Ben Lomond breed was in January, except aromatic hydrocarbon p-cymene and oxygenated monoterpenes a-terpineol and citronellyl acetate. Such compounds as a- and c-terpinene, aselinene, d-cadinene and a-cadinol were not the detected in the buds collected in February; while the content of p-cymene and bornyl acetate in this cultivar increased during the whole period of vegetation (Table 3). As it was already mentioned the content of oil and the concentration of oil components in the buds was considerably lower in blackcurrants harvested in April. However, some exceptions are worth mentioning. Thus, the content of monoterpenes trans-bocimene (215 a.u/kg) and a-terpineol (66 a.u/kg) isolated from Almiai was higher 1.5 and 4.3 times, respectively as compared to the average content of these compounds at other periods. The concentration of other monoterpene, a-phellandrene isolated from Gagatai buds harvested in April was 3.1 times higher than at other periods; while the amount of d-cadinene (58 a.u/kg) isolated from Ben Nevis and b-phellandrene (330 a.u/kg) in Ben Lomond was 3.8 times higher in April than at other vegetation phases. Increased concentration of trans-piperitol (35 a.u/kg) was also observed in Ben Lomond buds collected in April.

Sensory assessment of blackcurrant bud essential oils obtained at different vegetation phases was beyond the scope of the present study due to a very high number of the analysed samples. However, it is well-known that sensory quality depends on the concentration of individual constituents, their sensory characteristics and odour threshold values. Odour notes were assigned to the majority of the identified components in blackcurrant buds in numerous publications and were summarised in our recent study (Dvaranauskaite et al., 2008); therefore, the results obtained in the present study may be useful for the preliminary prediction of possible variations in sensory quality of bud essential oils isolated at various development phases from different cultivars. It is obvious, that harvesting time should be carefully selected for each plant cultivar, first of all taking into account total essential oil content and its compositional variations.

4. Conclusions Remarkable variations in the content of the total essential oil as well as in the concentrations of individual components were observed for the studied blackcurrant bud cultivars at different development phases. Most likely, these variations strongly depend on the genetic peculiarities of the individual cultivar; some of them contained quite stable amount of oil (e.g. Almiai, Ben Nevis) and less remarkable fluctuations in the concentration of the main constituents during the whole harvesting season, while the content of oil and the concentrations of individual compounds in some other cultivars (e.g. Joniniai, Gagatai) were highly variable. Consequently, individual approach should be applied to every individual plant cultivar in order to select an optimal time of harvesting for the highest product quality and economical value. In general, the end of March is a critical time for harvesting blackcurrant buds, as the content of the essential oil severely decrease at the later phases, while January can be considered as a preferable harvesting time for all studied cultivars except for Joniniai. Acknowledgment This study was supported by the Agency for International Science and Technology Development Programmes in Lithuania, (E3490). References Adams, R. P. (2001). Identification of essential oil components by gas chromatography/ quadrupole mass spectroscopy. Carol Stream, sIlinois, USA: Allured Publishing Corporation. Boccorh, R. K., Paterson, A., & Piggott, J. R. (1999). Sources of variations in aromaactive volatiles, or flavour components, of blackcurrant concentrates. Zeitschrift für Lebensmitteluntersuchung und-Forschung A, 208, 362–368. Burdock, G. A. (2002). Handbook of flavor ingredients. USA: CRC Press. Bylaite˙, E., Venskutonis, R. P., & Roozen, J. P. (1998). Influence of harvesting time on the composition of volatile components in different anatomical parts of lovage (Levisticum officinale Koch). Journal of Agricultural and Food Chemistry, 46, 3735–3740. Bylaite˙, E., Venskutonis, R., Roozen, J. P., & Posthumus, M. A. (2000). Composition of essential oil of costmary [Balsamita major (L.) Desf.] at different growth phases. Journal of Agricultural and Food Chemistry, 48, 2409–2414. De Toro, A. A. (1994). Blackcurrants as an energy crop and for production of essential oils. A review of the literature. Biomass and Bioenergy, 6, 261–268. Del Castillo, M. L. R., & Dobson, G. (2002). Varietal differences in terpene composition of blackcurrant (Ribes nigrum L.) berries by solid phase microextraction/gas chromatography. Journal of the Science of Food and Agriculture, 82, 1510–1515. Dvaranauskaite, A., Venskutonis, P. R., Raynaud, C., Talou, T., Viškelis, P., & Dambrauskiene, E. (2007). Chemical and sensory characterization of essential oils from six blackcurrant bud cultivars. Chemine˙ Technologija, 4, 6–10. Dvaranauskaite, A., Venskutonis, P. R., Raynaud, C., Talou, T., Viškelis, P., & Dambrauskiene, E. (2008). Characterization of volatiles in the essential oil of

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