Compositional Diversity among Blackcurrant (Ribes nigrum) Cultivars Originating from European Countries (2024)

Berriesrepresenting 21 cultivars of blackcurrant were analyzedusing liquid chromatographic, gas chromatographic, and mass spectrometricmethods coupled with multivariate models. This study pinpointed compositionalvariation among cultivars of different origins cultivated in the samelocation during two seasons. The chemical profiles of blackcurrantsvaried significantly among cultivars and growing years. The key differencesamong cultivars of Scottish, Lithuanian, and Finnish origins werein the contents of phenolic acids (23 vs 16 vs 19 mg/100 g on average,respectively), mainly as 5-O-caffeoylquinic acid,4-O-coumaroylglucose, (E)-coumaroyloxymethylene-glucopyranosyloxy-(Z)-butenenitrile, and 1-O-feruloylglucose.The Scottish cultivars were grouped on the basis of the 3-O-glycosides of delphinidin and cyanidin, as were the Lithuaniancultivars. Among the Finnish samples, the content of myricetin 3-O-glycosides, 4-O-caffeoylglucose, 1-O-coumaroylglucose, and 4-O-coumaroylglucosewere significantly different between the two green-fruited cultivarsand the black-fruited cultivars. The samples from the studied yearsdiffered in the content of phenolic acid derivatives, quercetin glycosides,monosaccharides, and citric acid.

Materials

Blackcurrantcultivars originating from Scotland(9 cultivars), Lithuania (5 cultivars), Latvia (1 cultivar), Poland(1 cultivar), and Finland (5 cultivars) were cultivated in the testsite of Natural Resources Institute (Luke) in Piikkiö, Kaarina,southwest Finland (latitude 60°23′ N, longitude 22°33′E, altitude ca. 5 m). The propagation material of plants was providedby the breeding institute of each cultivar, to guarantee the true-to-typeof the cultivars. One-year old transplants were planted in 2009 inthree rows, with a distance of 4 m between rows and 1 m between plantswithin a row. Two plants of each cultivar were planted in a plot randomizedin each row. Berries for the analyses were sampled from the totalharvest of each plot in August 2014 and 2015, each representing onereplicate sample of each cultivar. The soil was silt moraine richin organic matter. Irrigation via a trickle tape, fertilization, andother cultivation methods were according to the Finnish standard guidelines.¹⁸ The harvesting time of each cultivar was definedby experienced horticulturist, the definition being based on the color,flavor, and structure of optimally ripe berries. The samples collectedin year 2014 were first stored in a freezer at −70 °Cfor 1 year and then transferred to −20 °C together withthe samples harvest in 2015 for 5 months. All frozen samples werethen delivered from Luke to University of Turku and stored at −20°C for a maximum period of 15 months until all analyses werecompleted. The information on the samples is shown in Supplemental Table 1, including cultivar names,origin countries, and harvesting dates.

Weather Conditions

Data on climatic conditions werecollected in the meteorological station in the Luke Kaarina test siteand provided by the Finnish Meteorological Institute (Helsinki, Finland),to give information on the climatic differences between the fruitripening periods of the two years. The main climatic factors withthe one-month time interval during July 20–August 20 are shownin Supplemental Table 4. The time intervalwas chosen to cover the harvesting period of all cultivars in 2014and all but two very late cultivars in 2015, and at least 12 dayspreceding the earliest harvest date.

Dry Matter Content

Approximately 5 g of currant sampleswere weighed accurately and cut with a blade in a watch glass. Theresidue on the blade was rinsed into the watch glass with Milli-Qwater. The samples were dried in the oven (Oy Santasalo-Sohlberg Ab,Helsinki, Finland) at 105 °C overnight until their weights reacheda constant value.

Phenolic Compounds

Phenolic compoundswere identifiedusing a Waters Acquity Ultra performance liquid chromatography (UPLC)system equipped with a 2996 DAD detector, an electrospray ionizationinterface (ESI), and a Waters Quattro Premier mass spectrometer (WatersCorp., Milford, MA, U.S.A.). All phenolics were characterized by comparingLC retention time and typical mass fragments with reference compoundsand literature.^6,19−29 Mass spectrometry was set in both negative- and positive-ion modes,the condition of which was reported in our previous study.²⁰

Two methods were applied for analysisbased on the types of phenolic compounds. For anthocyanins, 5 g offrozen berries were crushed into slurry and extracted with 15 mL ofacidic methanol (MeOH/HCl 99:1), followed by ultrasonication (10 min)and centrifugation (4420g for 10 min). The extractionwas carried out three times. The three supernatants were combined,and the total volume was set to 50 mL with acidic methanol. The sampleswere filtered through a 0.2 μm syringe filter before UPLC-DAD-ESI-MSanalysis. The analysis of anthocyanins was conducted according tothe method previously reported by Mäkilä and co-workers.¹⁹ The signal of anthocyanins in the LC analyseswas monitored at the wavelength of 520 nm.

Other phenolic compoundswere extracted from crushed materials(15 g) with 10 mL of ethyl acetate. Ultrasonication (15 min) and centrifugation(4420g for 15 min) were applied in the four-timeextraction. The combined supernatant was evaporated at 36 °C;the residue was dissolved with 3 mL of methanol and filtered througha 0.2 μm syringe filter. Liquid chromatographic separation wasperformed with a Phenomenex Aeris peptide XB-C18 column (150 ×4.60 mm, 3.6 μm, Torrance, CA, U.S.A.) at room temperature.The injection volume was 10 μL and the total flow was kept at1 mL/min. The mobile phase was a combination of Milli-Q water (A)and acetonitrile (B), both containing 0.1% (v/v) of formic acid. Thegradient applied was the following: 0–15 min with 8–10%solvent B, 15–20 min with 10–13% B, 20–25 minwith 13–16% B, 25–30 min with 16–18% B, 30–35min with 18–20% B, 35–40 min with 20–22% B, 40–45min with 22–25% B, 45–50 min with 25–60% B, 50–55min with 60–8% B, 55–57 min with 8% B. The chromatogramswere recorded at three different wavelengths (360 nm for flavonols,320 nm for phenolic acids, and 280 nm for flavan-3-ols and other phenoliccompounds).

The quantification of the phenolics was performedusing a ShimadzuLC-10AT liquid chromatograph system, coupled with a SPD-M20A VP photodiodearray (Shimadzu Corp., Kyoto, Japan). The chromatographic conditionswere the same as in the corresponding qualitative analyses. The concentrationof the compounds identified was determined using an external standardmethod as described previously.²⁰ The compoundslacking corresponding reference standards were quantified by the calibrationcurves of compounds with closest structures. For instance, cyanidin3-O-(6″-coumaroyl)-glucoside was quantifiedby the calibration curve of cyanidin 3-O-glucoside(y = 3 × 10^–8x + 0.0026, R² = 0.9990). The detailedinformation on external standards is given in Supplemental Table 6.

Sugars and Simple OrganicAcids

Fifteen grams of frozenberries was crushed with a T25 digital Ultra-Turrax (IKA Werke GmbH& Co. KG, Staufen im Breisgau, Germany) and extracted with 10mL of Milli-Q water at room temperature. The extraction was assistedwith ultrasonication (15 min) and centrifugation (4420g for 15 min). After the supernatant was collected, the residue wasextracted with the same procedure three times. The supernatants fromthe four times of extraction were combined and diluted with Milli-Qwater to a final volume of 50 mL. Sugars and simple organic acidsin the samples were analyzed as trimethylsilyl (TMS) derivatives byShimadzu GC-2010 equipped with a flame ionization detector (FID) (ShimadzuCorp., Kyoto, Japan). The compounds were identified on the basis ofthe retention time of reference standards. A mixed internal standard,consisting of sorbitol (for sugars) and tartaric acid (for acids),was used for quantification. The methods for preparation of samplesand standards, as well as gas chromatographic conditions, were thesame as described in the previous research.¹²

Statistical Analyses

The quantitative analyses of chemicalcompounds were performed in triplicates. The results were calculatedon the basis of dry weight (mg/g or 100 g of berries) and expressedas mean ± standard deviation (SD). Partial least-squares (PLS)regression with full cross validation was applied to determine thecorrelation between chemical profile and cultivar/country of origin/growingyear by using Unscrambler 10.4 (Camo Process AS, Oslo, Norway). PLSmodels were established with the concentrations of compounds as thepredictors (X-data) and the cultivars (and other factors listed above)as the responses (Y-data).

Table 1

Quantification of the Compounds

Total content of phenolicsranged from 598 to 2798 mg/100g in black cultivars and from 47 to104 mg/100 g in green ones (Supplemental Table 2). It has been discussed previously that the absence of anthocyaninsresulted in the lowest amount of total phenolics in green cultivars.³¹ Among all black cultivars, the total contentof anthocyanin was 1501 ± 587 mg/100 g, which was lower thanpreviously detected by Mattila et al. (2057 ± 442 mg/100 g dryweight, DW) in 32 Finnish blackcurrant cultivars in a germplasm collectionof mainly traditional cultivars.³² Nouret al. reported that glycosides of cyanidin and delphinidin (3-O-glucoside and 3-O-rutinoside) accountedfor 92–97% of total anthocyanins in blackcurrants.³³ Similar percentages were found in the currentstudy. Anthocyanins formed the dominating groups of the phenolicsin black-fruited samples, mainly as glycosylated delphinidin (34–66%of sum content of phenolics) and cyanidin (31–52%). The totalcontent of flavonols was 18–60 mg/100 mg dry weight, accountingfor 1–6% of sum content of phenolics in black cultivars and37–39% in green ones. The difference between black and greencultivars was also shown in the profile of flavonols. In accordancewith the results published by Mikkonen et al.,³⁴ myricetin glycosides was the dominant group of flavonolsin the black cultivars studied; however, total content of quercetinglycosides was 6–8 times higher than that of myricetin glycosidesin the green cultivars ‘Vilma’ and ‘Venny’.

For phenolic acids, the conjugates of coumaric acids (47–74%of total phenolic acid derivatives) were the major components in mostof the cultivars, followed by caffeic acid (17–40%) and ferulicacid (9–20%); however, the cultivars ‘Ben Tron’and ‘Joniniai’ contained more derivatives of caffeicacids and less of coumaric acids in both years. Moreover, the monomersof flavan-3-ols were found at a total content close to 10–20mg/100 g.

Although the contents of simple organic acids significantlydifferedamong the cultivars, citric acid accounted for 75–97% of thetotal content of simple acids (Supplemental Table 3) in accordance with a previous report.³⁵ It was followed by malic acid representing 3–20%of total simple acids. The highest values of ascorbic acid were foundin ‘Tisel’ (2.0–2.5 mg/g), ‘Joniniai’(2.2–2.5 mg/g), and ‘Ben Tirran’ (1.7–2.3mg/g); however, in Finnish black cultivars, ascorbic acid was foundat considerably low contents ranging from 0.2 to 0.6 mg/g. A smallquantity of quinic acid was detected in all the samples. As the dominatingsugars in all blackcurrant cultivars studied, fructose and glucosecontributed 48–60% and 38–47% of total content of sugars,respectively. The concentration of fructose was higher than that ofglucose in all the cultivars. Compared with fructose and glucose,sucrose was present at a lower level in the black-fruited currantsas suggested by Woznicki.³⁶ In this study,‘Dainiai’ showed significantly higher sucrose content(12 mg/g on average) than other cultivars studied. The contents ofsimple organic acids and sugars found in the samples in the currentstudy deviated considerably from the levels reported in some blackcurrantcultivars studied in previous research studies.^13,35 This difference was likely due to the different genetic backgroundof the cultivars included in these studies. Also, the growth locationswere different in these studies; therefore, the environmental factorsmay have contributed to the difference observed.

Comparisonof Blackcurrant Cultivars Growing in Different Years

A largeand significant variation in chemical variables was observedwithin each cultivar between years 2014 and 2015. For phenolic compounds,two green cultivars presented significantly lower sum content of phenolicsthan the black cultivars. A newly bred Scottish sample, ‘S18/2/23’, was also low in phenolics (598–745 mg/100g of dry berries) in both years. Since annual deviation was seen likelydue to the response of plants to the environment, a PLS regressionmodel was used to find the distribution of individual compounds indifferent years. Regarding phenolic compounds, 78% of the chemicalvariables explained 89% of the variation among the cultivars in 7factors in Figure ​Figure11a. Samples from 2015 showed higher total amount of flavan-3-ols,quercetins (primarily as quercetin 3-O-rutinoside),kaempferols (kaempferol 3-O-rutinoside), isorhamnetins,and coumaric acid derivatives than berries of the year 2014. The PLSmodel did not show clear correlation between years and anthocyaninsor sum content of phenolics.

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Figure 1

PLS models of comparison of blackcurrant cultivarsin two differentgrowing years: (a) phenolic compounds (n = 8662),(b) sugars and simple organic acids (n = 1098). Legendof the scores plots: red open circle for the samples harvested inYear 2015, blue open square means the samples harvested in Year 2014.In the loading plots, the growing year is in red bold italic fontand the identified phenolic compounds are in blue font. The full namesof these compounds are referenced in Table 1.

For simple acids and sugars, ‘Ben Tirran’ hadthehighest content of simple acids (53 mg/g in 2014 and 52 mg/g in 2015)among all the cultivars studied. Sugars were abundant in ‘Tauriai’but poor in ‘Ben Finlay’. In the plot of Figure ​Figure11b, 64% of the chemical variablesof simple acids and sugars explained 65% of the variation among thecultivars in 2 factors. Citric acid, fructose, and glucose correlatedstrongly with the samples collected in year 2015, which explainedthe higher content of total simple acids and total sugars, respectively,in this year.

In our previous research, the weather conditionin the last monthsof growth before harvest showed special importance for blackcurrantfruit development,^10,11 since several main primary (sugars)and secondary (anthocyanins) metabolites start accumulating in thelast stage of ripening of blackcurrant.³⁷ In the present study, exceptionally high temperatures includingboth maximum day time and minimum night time temperatures were observedfrom mid-July to mid-August of year 2014, which was the last monthbefore harvesting (Supplemental Table 4). Zheng et al. reported that the average temperature of July correlatedpositively with the content of citric acid, fructose, and glucosein the Finnish cultivars ‘Mortti’ and ‘Ola’,based on analysis of berry samples collected in multiple years.³⁸ In our study, temperatures were higher thanthose in the study of Zheng et al.,³⁸ andour results showed the opposite: higher temperatures were relatedto the reduction of these sugars and citric acid. The phenomenon iscommonly seen in other species too. It was shown, for instance, instrawberry (Fragaria ananassa) fruit that sugar contentwas negatively correlated to the temperature during fruit development,³⁹ and high temperatures have been shown to reducethe organic acids in berries of grapevine (Vitis vinifera).⁴⁰ Yet, our study was not able to determinethat the climatic factors resulted in the yearly deviation of chemicalcomposition of blackcurrant berries because of the data limited totwo growing years only.

Comparison of Blackcurrant Cultivars Originatingfrom DifferentCountries

PLS models were applied to investigate the differenceamong the samples in order to establish correlation between individualcompounds and the cultivars. The PLS plots in Figure ​Figure22a show the interactions between chemicalcompounds, and notably, all cultivars of blackcurrants as 74% of thechemical variables explained 65% of the variation among the cultivarsin 7 factors. Sum of phenolics and total anthocyanins correlated negativelywith the green cultivars (‘Venny’ and ‘Vilma’)along the PC1. Along with the expected color-related compounds, myricetins,primarily 3-O-glucoside, 3-O-arabinoside,and the free aglycone of myricetin, also represented a negative correlationwith the green cultivars. Since there was only one Latvian and onePolish cultivar, comparison was conducted among black-fruited cultivarsof Scottish, Lithuanian, and Finnish origins.

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Figure 2

PLS models of comparisonof blackcurrant cultivars originatingfrom different countries: based on chemical variables (n = X) (a) all cultivars (n = 9760), (b) the blackcultivars (n = 6560) originating from Scotland andLithuanian, (c) the black cultivars originating (n = 5600) from Scotland and Finland, (d) the black cultivars (n = 3840) originating from Lithuanian and Finland. Legendof the scores plots: blue-filled square for Scottish samples, red-filledcircle for Lithuanian samples, green-filled triangle for Latvian samples,purple-filled diamond for Finnish black-fruited samples, brown-filledinverted triangle for Finnish green-fruited samples, and yellow-filledstar for Polish samples. In the loading plots, the origin of countryis in red bold italic font and the identified phenolic compounds arein blue font. The full names of the compounds are referenced in Table 1.

The Scottish cultivars generally had higher total contentof phenolicacid derivatives than the Lithuanian samples (Figure ​Figure22b; 69% of the chemical variables explained96% of the variation among the cultivars in 6 factors). Scottish cultivarscorrelated strongly to the derivatives of both coumaric acid (CoA)and ferulic acid (FeA), primarily as 4-O-coumaroylglucose(4-Co-Glu), (E and Z)-coumaroyloxymethylene-glucopyranosyloxy-(Z)-butenenitrile (Co-meGlu-B1 and 2), and 1-O-feruloylglucose (1-Fe-Glu). Positive correlations of Scottish cultivarswere also found with gallocatechin (GCat) and catechin (Cat). Theconjugates of both caffeic acid (CaA) and coumaric acid, as well aspeonidin glycosides, flavan-3-ols, and ascorbic acid (AsA) were themain variables to separate the Scottish from the Finnish cultivarson the first two PCs in Figure ​Figure22c (72% variation in X-data explained 96% of the variationY-data with 6 factors). Compared with the Finnish samples, the Lithuaniancultivars were richer in ascorbic acid and caffeic acid derivatives,mainly as 5-O-caffeoylquinic acid (5-CaQA) (Figure ​Figure22d; 66% of variationin X-data explained 97% of variation in Y-data with 5 factors). Also,higher amounts of 3-O-coumaroylquinic acid (3-CoQA)and peonidin 3-O-glucoside (Po-Glu) characterizedthe Lithuanian cultivars.

Comparison among Cultivars within ScottishOrigin

Thenine Scottish cultivars were classified into three groups as shownin the scores plot of Figure ​Figure33a based on the variation in the chemical variables (87% ofthe chemical variables explained 70% of the variation in Y-data with7 factors). Group A contained cultivars ‘Ben Dorain’,‘Ben Gairn’, ‘Ben Starav’, and ‘BenFinlay’. Two newly bred cultivars, ‘S 18/2/23’and ‘9154–3’, belonged to group B; group C consistedof ‘Ben Hope’, ‘Ben Tirran’, and ‘BenTron’. Since a single PLS model was not able to differentiateall Scottish blackcurrants, the comparison was performed by groups.

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Figure 3

PLS modelsof comparison of main groups of Scottish cultivars:(a) all Scottish cultivars (n = 4160), (b) the comparisonbetween groups A and B (n = 2720), (c) the comparisonbetween groups A and C (n = 3200), (d) the comparisonbetween groups B and C (n = 2400). In the loadingplots, the names of cultivars and groups are in red bold italic fontand the identified phenolic compounds are in blue font. The full namesof the compounds are referenced in Table 1.

In Figure ​Figure33b, 76%of the chemical variables explained 98% of the variation among thecultivars in 5 factors, and the cultivars in group A had higher amountsof sum-content of phenolic and total anthocyanins than group B. Positivecorrelations of group A were found with cyanidin 3-O-rutinoside (Cy-Rut), petunidin 3-O-glucoside (Pt-Glu),pelargonidin 3-O-glucoside (Pl-Glu), and all glycosidesof delphinidin (De) identified. Group B correlated mainly to 4-O-caffeoylglucose (4-Ca-Glu) and 4-Co-Glu. The blackcurrantsin group C contained more phenolic acid derivatives (CaA and FeA)and flavan-3-ols than those in Group A (Figure ​Figure33c; 54% of the chemical variables explained98% of the variation among the cultivars with 3 factors). Many ofthe minor flavonols, myricetin 3-O-galactoside (My-Gal),quercetin 3-O-galactoside (Qu-Gal), quercetin 3-O-arabinoside (Qu-Ara), and isorhamnetin 3-O-(6″-malonyl)-galactoside (Is-maGal) were not observed inthe group C, which also distinguished these cultivars from others(Figure ​Figure33c, Supplemental Table 5). Figure ​Figure33d (84% of the variation in X-data explained99% of the variation in Y-data with 5 factors) indicated that groupB was low in sum content of all studied phenolics compared to groupC, which was mostly due to the low content of anthocyanins (includingDe, Cy, Pt, Pl, and Po compounds) and flavonols (myricetin derivatives).

The variations within the groups A–C of Scottish cultivarsobserved in Figure ​Figure33 were further examined in PLS regression plots in Figure ​Figure44. ‘Ben Dorain’correlated strongly to citric acid (CiA), fructose (Fru), glucose(Glu), total simple organic acids, and total sugars (Figure ​Figure44a; 91% of the chemical variablesexplained 99% of the variation among the cultivars in 6 factors).‘Ben Starav’ correlated positively to both sucrose (Suc)and quinic acid (QuA) in the plot consisting of factor 2 and factor4 (not present in this paper). Cyanidin 3-O-arabinoside(Cy-Ara) was not found only in ‘Ben Gairn’; however,petunidin 3-O-rutinoside (Pt-Rut), epicatechin (ECat),and 4-Co-Glu were present at higher contents. ‘Ben Finlay’correlated only to (E)-feruloyloxymethylene-glucopyranosyloxy-(Z)-butenenitrile (Fe-meGlu-B). For minor components, myricetin3-O-rutinoside (My-Rut), and 3-O-coumaroylquinic acid (3-CoQA) showed negative correlations with‘Ben Gairn’, but 1-O-coumaroylglucose(1-Co-Glu) correlated positively to ‘Ben Gairn’.

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Figure 4

Comparisonof Scottish cultivars with PLS regression models basedon their chemical composition: (a) the comparison within group A (n = 2400), (b) the comparison within group B (n = 960), (c) the comparison within group C (n =1140). The groups are based on the model in Figure ​Figure33. The name of cultivars is in red bold italicfont and the identified phenolic compounds are in blue font. The fullnames of the compounds are referenced in Table 1.

The common difference between two cultivars in group B wasthat‘S18/2/23’ was more abundant in citric acid, ascorbicacid, and sucrose, whereas the cultivar of ‘9154-3’strongly correlated to the total content of flavonols, owing to thehigh concentration of glycosides of quercetin (Qu), and kaempferol(Ka) (Figure ​Figure44b; 67%of the variation in X-data explained 99% of the variation in Y-datawith 2 factors). Phenolic acids in ‘S18/2/23’ were mainlypresent as the derivatives of caffeic acid, but more ferulic acidconjugates were found in ‘9154–3’.

Figure ​Figure44c showed96% of the chemical variables explained 100% of the variation amongthe cultivars in group C with 5 factors. ‘Ben Tirran’contained the highest amount of citric acid and ascorbic acid. ‘BenTron’ exhibited positive correlations with most of the glycosidesof anthocyanidins, which explained the highest sum-content of phenolicsamong the samples in group C. Yet, delphinidin 3-O-(6″-coumaroyl)-glucoside (De-coGlu) and cyanidin 3-O-(6″-coumaroyl)-glucoside (Cy-coGlu) were abundantin ‘Ben Tirran’. ‘Ben Tirran’ was alsorich in gallocatechin (GCat),myricetin aglycone (My agly), and ferulic acid derivatives. High concentrationof total flavonols and caffeic acid derivatives correlated positivelyto ‘Ben Tron’, mainly due to the presence of Qu-Glu,5-CaQA, and Ka-Gal. Moreover, 3-O-coumaroylquinicacids (3-CoQA), quercetin 3-O-(6″-malonyl)-glucoside(Qu-maGlu), and a coumaroylquinic acid isomer (CoQA) were quantifiedmostly in ‘Ben Hope’.

Comparison of FinnishCultivars

Aside from anthocyanins, the Finnish green cultivars‘Venny’ and ‘Vilma’ contained high amountsof ascorbic acid, kaempferol glycosides (Ka-Gal and Ka-Rut), and thederivatives of phenolic acids (4-Co-Glu, 1-Co-Glu, Co-meGlu-B2, and1-Ca-Glu) compared with black ones. Additionally, myricetin was concentratedin black cultivars in forms of both glycosides (3-O-glucoside, 3-O-rutinoside, deoxylhexoside, and3-O-arabinoside) and aglycone (Figure ​Figure55a). The PLS model in Figure ​Figure55b presents the variation (90% in X-data)among Finnish black cultivars (99% in Y-data with 4 factors). Thesum of all phenolic compounds, including the main glycosides of delphinidinand myricetin, were most abundant in the cultivar ‘Marski’.Quercetins correlated strongly with ‘Mikael’ as 3-O-glucoside, 3-O-galactoside, and 3-O-arabinoside. ‘Mortti’ contained the highestlevels of sucrose and 3-O-coumaroylquinic acid butthe lowest concentrations of cyanidins, peonidins, malvidins, andtotal flavonols. ‘Venny’ and ‘Vilma’ sharedsimilar compositional characteristics, which was not surprising, bothbeing offsprings of the cultivar ‘Vertti’. ‘Vilma’highly correlated with the content of sucrose and (E)-feruloyloxymethylene-glucopyranosyloxy-(Z)-butenenitrile(Ca-meGlu-B), whereas ‘Venny’ correlated mainly withmalic acid (MaA), ascorbic acid, quinic acid, quercetin 3-O-rutinoside, and gallocatechin (Figure ​Figure55c; 92% of the variation explained 98% ofthe variation among the two green cultivars with 3 factors).

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Figure 5

Comparisonof Finnish cultivars with PLS regression models basedon their chemical composition: (a) all Finnish cultivars (n = 2400), (b) black cultivars (n = 1440),(c) green cultivars (n = 960). In the loading plots,the name of cultivars is in red bold italic font and the identifiedphenolic compounds are in blue font. The full names of compounds arereferenced in Table 1.

Comparison of LithuanianCultivars

Lithuanian sampleswere grouped as displayed in Supplemental Figure 2a,b. Group A consisted of ‘Almiai’, ‘Dainiai’,and ‘Gagatai’, presenting higher concentration of anthocyanins(mostly as De, Cy, and Po), myricetin glycosides, and phenolic acids(FeA derivatives) than both ‘Joniniai’ and ‘Tauriai’in group B. Among the samples in group A, ‘Almiai’ correlatedpositively to simple organic acids (mainly as CiA); whereas sucrose,malic acid, and quinic acid were abundant in ‘Dainiai’(Supplemental Figure 2c). The highest levelof total anthocyanins was present in ‘Gagatai’, mainlyowing to the high content of delphinidin 3-O-rutinoside,delphinidin 3-O-(6″-coumaroyl)-glucoside,and cyanidin 3-O-(6″-coumaroyl)-glucoside.This was in agreement with the results reported by Rubinskiene andco-workers showing higher content of anthocyanins in ‘Gagatai’than in ‘Joniniai’ and ‘Almiai’.⁴¹ In the present study, ‘Almiai’correlated negatively to the total content of both cyanidins and myricetins.‘Dainiai’ contained more (E)-coumaroyloxymethylene-glucopyranosyloxy-(Z)-butenenitrile, myricetin 3-O-galactoside,and myricetin 3-O-(6″-malonyl)-galactoside. Supplemental Figure 2d suggested that ‘Joniniai’was richer in malic acid, quinic acid, and sucrose than ‘Tauriai’.Positive correlations were found between ‘Joniniai’and both 3-O-glycoisdes and free aglycones of quercetinand myricetin, as well as some minor phenolics such as epicatechinand 4-O-caffeoylglucose. The total content of coumaricacid derivatives was higher in ‘Tauriai’ because ofthe presence of two isomers of coumaroyloxymethylene-glucopyranosyloxy-butenenitrile.

To our best knowledge, the present study is the first one revealingsystematic information on compositional variation among blackcurrantcultivars originating from different countries. The overall differentiationamong cultivars of different origins was highlighted by the concentrationsof different phenolic acid derivatives, even after more than a five-yearcultivation in the same geographical location with the same climaticcondition. The study also found that the contents of organic acids,sugars, and phenolic acid derivatives in blackcurrants correlatedstrongly with growing year. This may have been caused by differentweather conditions during fruit development. The results provide importantguidelines for the selection of raw materials in food and beverageprocessing industry. For example, cultivar ‘Dainiai’is rich in sucrose, and high levels of ascorbic acid were found in‘Tisel’, ‘Joniniai’, and ‘Ben Tirran’.‘S 18/2/23’, and ‘9154-3’ are poor sourcesof anthocyanins compared with other black-fruited cultivars. The manufacturerscan select cultivars accordingly based on the requirements of theirproducts.

In addition, the knowledge of variation in metabolitesis essentialfor breeding new cultivars of blackcurrants. Besides agronomic traitssuch as yield, fruit size, and environmental resistance, the chemicalcomposition in fruits of new cultivars will be probably more emphasized,when more specific information on human health-related effects ofdifferent compounds will be available in the future. Our results suggestthat the breeding programs have resulted in variation in chemicalquality of currants developed in different countries. The cultivarsfrom the same country may share more similarities than those createdin different countries. Therefore, it would be possible for plantbreeding to improve fruit quality by introducing new quality characteristicsfrom blackcurrant cultivars originating from different countries.

• Vijayan K.; Chakraborti S. P.; Ercisli S.; Ghosh P. D.NaCI induced morpho-biochemicaland anatomical changes in mulberry (Morus spp.). Plant Growth Regul.2008, 56 (1), 61–69. 10.1007/s10725-008-9284-5. [CrossRef] [Google Scholar]
• Serce S.; Ercisli S.; Sengul M.; Gunduz K.; Orhan E.Antioxidantactivities and fatty acid composition of wild grown myrtle (Myrtus communis L.) fruits. Pharmacogn.Mag.2010, 6, 9–12. 10.4103/0973-1296.59960. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
• Tian J.; Chen J.; Ye X.; Chen S.Health benefits ofthe potato affected by domestic cooking: A review. Food Chem.2016, 202, 165–175. 10.1016/j.foodchem.2016.01.120. [PubMed] [CrossRef] [Google Scholar]
• Sandell M.; Laaksonen O.; Järvinen R.; Rostiala N.; Pohjanheimo T.; Tiitinen K.; Kallio H.Orosensory profiles and chemicalcomposition of black currant (Ribes nigrum) juiceand fractions of press residue. J. Agric. FoodChem.2009, 57, 3718–3728. 10.1021/jf803884y. [PubMed] [CrossRef] [Google Scholar]
• Gopalan A.; Reuben S. C.; Ahmed S.; Darvesh A. S.; Hohmann J.; Bishayee A.The health benefitsof blackcurrants. Food Funct.2012, 3 (8), 795–809. 10.1039/c2fo30058c. [PubMed] [CrossRef] [Google Scholar]
• Laaksonen O.; Mäkilä L.; Tahvonen R.; Kallio H.; Yang B.Sensory qualityand compositional characteristics of blackcurrant juices producedby different processes. Food Chem.2013, 138, 2421–2429. 10.1016/j.foodchem.2012.12.035. [PubMed] [CrossRef] [Google Scholar]
• Laaksonen O.; Mäkilä L.; Sandell M.; Salminen J.; Liu P.; Kallio H.; Yang B.Chemical-sensory characteristicsand consumer responses of blackcurrant juices produced by differentindustrial processes. Food Bioprocess Technol.2014, 7, 2877–2888. 10.1007/s11947-014-1316-8. [CrossRef] [Google Scholar]
• Battino M.; Beekwilder J.; Denoyes-Rothan B.; Laimer M.; McDougall G. J.; Mezzetti B.Bioactive compounds in berries relevant to human health. Nutr. Rev.2009, 67, S145–150. 10.1111/j.1753-4887.2009.00178.x. [PubMed] [CrossRef] [Google Scholar]
• Puupponen-Pimiä R.; Nohynek L.; Alakomi H.-L.; Oksman-Caldentey K.-M.Bioactiveberry compounds – novel tools against human pathogens. Appl. Microbiol. Biotechnol.2005, 67, 8–18. 10.1007/s00253-004-1817-x. [PubMed] [CrossRef] [Google Scholar]
• Yang B.; Zheng J.; Laaksonen O.; Tahvonen R.; Kallio H.Effects oflatitude and weather conditions on phenolic compounds in currant (Ribes spp.) cultivars. J. Agric. FoodChem.2013, 61 (14), 3517–3532. 10.1021/jf4000456. [PubMed] [CrossRef] [Google Scholar]
• Zheng J.; Yang B.; Ruusunen V.; Laaksonen O.; Tahvonen R.; Hellsten J.; Kallio H.Compositional differencesof phenolic compounds between black currant (Ribes nigrum L.) cultivars and their response to latitude and weather conditions. J. Agric. Food Chem.2012, 60 (26), 6581–6593. 10.1021/jf3012739. [PubMed] [CrossRef] [Google Scholar]
• Zheng J.; Kallio H.; Yang B.Effects oflatitude and weather conditionson sugars, fruit acids and ascorbic acid in currant (Ribes sp.) cultivars. J. Sci. Food Agric.2009, 89, 2011–2023. 10.1002/jsfa.3682. [PubMed] [CrossRef] [Google Scholar]
• Vagiri M.; Ekholm A.; Öberg E.; Johansson E.; Andersson S. C.; Rumpunen K.Phenols and ascorbicacid in blackcurrants (Ribes nigrum L.): variation due to genotype,location, and year. J. Agric. Food Chem.2013, 61 (39), 9298–9306. 10.1021/jf402891s. [PubMed] [CrossRef] [Google Scholar]
• Mikulic-Petkovsek M.; Rescic J.; Schmitzer V.; Stampar F.; Slatnar A.; Koron D.; Veberic R.Changes in fruit quality parametersof four Ribes species during ripening. Food Chem.2015, 173, 363–374. 10.1016/j.foodchem.2014.10.011. [PubMed] [CrossRef] [Google Scholar]
• Milivojevic J.; Slatnar A.; Mikulic-Petkovsek M.; Stampar F.; Nikolic M.; Veberic R.The influence of earlyyield on the accumulation ofmajor taste and health-related compounds in black and red currantcultivars (Ribes spp.). J.Agric. Food Chem.2012, 60 (10), 2682–2691. 10.1021/jf204627m. [PubMed] [CrossRef] [Google Scholar]
• Pluta S.; Ma̧dry W.; Sieczko L.Phenotypic diversity for agronomictraits in a collection of blackcurrant (Ribes nigrum L.) cultivars evaluated in Poland. Sci. Hortic.2012, 145, 136–144. 10.1016/j.scienta.2012.07.036. [CrossRef] [Google Scholar]
• Brennan R. M.Currants andgooseberries. Temperate Fruit Crop Breeding:Germplasm to Genomics; Hanco*ck J. F., Ed.; Springer: The Netherlands, 2008; pp 177–196. [Google Scholar]
• Matala V.Cultivation of the currants (Finnish name: Herukan viljely, only in Finnish language); Puutarhaliitto ry: Helsinki, Finland, 1999. [Google Scholar]
• Mäkilä L.; Laaksonen O.; Alanne A. L.; Kortesniemi M.; Kallio H.; Yang B.Stability of hydroxycinnamic acidderivatives, flavonol glycosides, and anthocyanins in black currantjuice. J. Agric. Food Chem.2016, 64 (22), 4584–4598. 10.1021/acs.jafc.6b01005. [PubMed] [CrossRef] [Google Scholar]
• Tian Y.; Liimatainen J.; Alanne A. L.; Lindstedt A.; Liu P.; Sinkkonen J.; Kallio H.; Yang B.Phenolic compoundsextracted by acidic aqueous ethanol from berries and leaves of differentberry plants. Food Chem.2017, 220, 266–281. 10.1016/j.foodchem.2016.09.145. [PubMed] [CrossRef] [Google Scholar]
• Gavrilova V.; Kajdzanoska M.; Gjamovski V.; Stefova M.Separation, characterizationand quantification of phenolic compounds in blueberries and red andblack currants by HPLC-DAD-ESI-MSⁿ. J. Agric. Food Chem.2011, 59, 4009–4018. 10.1021/jf104565y. [PubMed] [CrossRef] [Google Scholar]
• Wu X.; Gu L.; Prior R. L.; McKay S.Characterization of anthocyaninsand proanthocyanidins in some cultivars of Ribes, Aronia, and Sambucus and their antioxidantcapacity. J. Agric. Food Chem.2004, 52 (26), 7846–7856. 10.1021/jf0486850. [PubMed] [CrossRef] [Google Scholar]
• Ancillotti C.; Ciofi L.; Rossini D.; Chiuminatto U.; Stahl-Zeng J.; Orlandini S.; Furlanetto S.; Del Bubba M.Liquid chromatographic/electrosprayionization quadrupole/timeof flight tandem mass spectrometric study of polyphenolic compositionof different Vaccinium berry species and their comparativeevaluation. Anal. Bioanal. Chem.2017, 409, 1347–1368. 10.1007/s00216-016-0067-y. [PubMed] [CrossRef] [Google Scholar]
• Koponen J. M.; Happonen A. M.; Auriola S.; Kontkanen H.; Buchert J.; Poutanen K. S.; Törrönen A. R.Characterizationand fate of black currant and bilberry flavonols in enzyme-aided processing. J. Agric. Food Chem.2008, 56, 3136–3144. 10.1021/jf703676m. [PubMed] [CrossRef] [Google Scholar]
• Borges G.; Degeneve A.; Mullen W.; Crozier A.Identification of flavonoidand phenolic antioxidants in black currants, blueberries, raspberries,redcurrants, and cranberries. J. Agric. FoodChem.2010, 58, 3901–3909. 10.1021/jf902263n. [PubMed] [CrossRef] [Google Scholar]
• Määttä K. R.; Kamal-Eldin A.; Törrönen A. R.High-performanceliquid chromatography (HPLC) analysis of phenolic compounds in berrieswith diode array and electrospray ionization mass spectrometric (MS)detection: Ribes species. J.Agric. Food Chem.2003, 51, 6736–6744. 10.1021/jf0347517. [PubMed] [CrossRef] [Google Scholar]
• Anttonen M. J.; Karjalainen R. O.High-performance liquid chromatography analysis ofblack currant (Ribes nigrum L.) fruit phenolics growneither conventionally or organically. J. Agric.Food Chem.2006, 54, 7530–7538. 10.1021/jf0615350. [PubMed] [CrossRef] [Google Scholar]
• Lu Y.; Foo L. Y.; Wong H.Nigrumin-5-p-coumarateand nigrumin-5-ferulate, two unusual nitrile-containing metabolitesfrom black currant (Ribes nigrum) seed. Phytochemistry2002, 59, 465–468. 10.1016/S0031-9422(01)00441-1. [PubMed] [CrossRef] [Google Scholar]
• Cyboran S.; Bonarska-Kujawa D.; Pruchnik H.; Żyłka R.; Oszmiański J.; Kleszczyńska H.Phenolic content and biological activityof extracts of blackcurrant fruit and leaves. Food Res. Int.2014, 65, 47–58. 10.1016/j.foodres.2014.05.037. [CrossRef] [Google Scholar]
• Mikulic-Petkovsek M.; Slatnar A.; Schmitzer V.; Stampar F.; Veberic R.; Koron D.Chemical profile ofblack currant fruit modified by different degreeof infection with black currant leaf spot. Sci.Hortic.2013, 150, 399–409. 10.1016/j.scienta.2012.11.038. [CrossRef] [Google Scholar]
• Määttä-Riihinen K. R.; Kamal-Eldin A.; Mattila P. H.; González-Paramás A. M.; Törrönen A. R.Distribution and contents of phenoliccompounds in eighteen Scandinavian berry species. J. Agric. Food Chem.2004, 52 (14), 4477–4486. 10.1021/jf049595y. [PubMed] [CrossRef] [Google Scholar]
• Mattila P. H.; Hellström J.; Karhu S.; Pihlava J.-M.; Veteläinen M.High variabilityin flavonoid contents and composition between different North-Europeancurrant (Ribes spp.) varieties. Food Chem.2016, 204, 14–20. 10.1016/j.foodchem.2016.02.056. [PubMed] [CrossRef] [Google Scholar]
• Nour V.; Stampar F.; Veberic R.; Jakopic J.Anthocyanins profile,total phenolics and antioxidant activity of black currant ethanolicextracts as influenced by genotype and ethanol concentration. Food Chem.2013, 141, 961–966. 10.1016/j.foodchem.2013.03.105. [PubMed] [CrossRef] [Google Scholar]
• Mikkonen T.; Määttä K.; Hukkanen A.; Kokko H.; Törrönen A.; Kärenlampi S.; Karjalainen R.Flavonol content varies among blackcurrant cultivars. J. Agric. Food Chem.2001, 49, 3274–3277. 10.1021/jf0010228. [PubMed] [CrossRef] [Google Scholar]
• Bordonaba J. G.; Terry L. A.Biochemical profilingand chemometric analysis of seventeenUK-grown black currant cultivars. J. Agric.Food Chem.2008, 56 (16), 7422–7430. 10.1021/jf8009377. [PubMed] [CrossRef] [Google Scholar]
• Woznicki T. L.; Sønsteby A.; Aaby K.; Martinsen B. K.; Heide O. M.; Wold A. B.; Remberg S. F.Ascorbate pool,sugars and organic acids in black currant (Ribes nigrum L.) berries are strongly influenced by genotype and post-floweringtemperature. J. Sci. Food Agric.2017, 97 (4), 1302–1309. 10.1002/jsfa.7864. [PubMed] [CrossRef] [Google Scholar]
• Jarret D.A.; Morris J.; Cullen D. W.; Gordon S. L.; Verrall S. R.; Milne L.; Hedley P. E.; Allwood J. W.; Brennan R. M.; Hanco*ck R. D.A transcriptand metabolite atlas of blackcurrant fruitdevelopment highlights hormonal regulation and reveals the role ofkey transcription factors. Front. Plant Sci.2018, 9, 1235. 10.3389/fpls.2018.01235. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
• Zheng J.; Yang B.; Tuomasjukka S.; Ou S.; Kallio H.Effects oflatitude and weather conditions on contents of sugars, fruit acids,and ascorbic acid in black currant (Ribes nigrum L.)juice. J. Agric. Food Chem.2009, 57, 2977–2987. 10.1021/jf8034513. [PubMed] [CrossRef] [Google Scholar]
• MacKenzie S. J.; Chandler C. K.; Hasing T.; Whitaker V. M.The role of temperaturein the late-season decline in soluble solids content of strawberryfruit in a subtropical production system. HortScience2011, 46, 1562–1566. 10.21273/HORTSCI.46.11.1562. [CrossRef] [Google Scholar]
• Sweetman C.; Sadras V. O.; Hanco*ck R. D.; Soole K. L.; Ford C. M.Metaboliceffects of elevated temperature on organic acid degradation in ripening Vitis vinifera fruit. J. Exp. Bot.2014, 65, 5975–5988. 10.1093/jxb/eru343. [PMC free article] [PubMed] [CrossRef] [Google Scholar]
• Rubinskiene M.; Viskelis P.; Jasutiene I.; Viskeliene R.; Bobinas C.Impact of various factors on thecomposition and stabilityof black currant anthocyanins. Food Res. Int.2005, 38, 867–871. 10.1016/j.foodres.2005.02.027. [CrossRef] [Google Scholar]