Analysis of anthocyanin compositions and contents in eight grape cultivars

Abstract: 【Objective】The content and composition of anthocyanins is an important determinant of the color and functional value of grape berries and wine, and thus is crucial for their market value. In order to de⁃termine the anthocyanin content and composition in different grape varieties for breeding table grape orwine grape varieties with rich anthocyanins, we introduced some varieties with deep-color skin and goodresistance in recent years.【Methods】The test was carried out in a demonstration vineyard in Shandong Agricultural University, where a warm temperate semi-humid continental monsoon climate dominates. Thevineyard was established in 2011, the vines were planted with vertical trellis systems, in a north-south ori⁃entation, with 1.2 m between plants, 2.2 m between rows and 2 m in height. The training system was spurprunedvertical shoot-positioned (VSP), and all the grapes were under the same cultivation management.The tested materials included Vitis vinifera‘Cabernet Sauvignon’,‘Manna’ (a hybrid of ‘Cabernet Sauvignon’),‘Cabernet Mitos’,‘Acolon’, V. vinifera-V. labrusca‘Kyoho Early’,‘Moldova’‘( Guzal kara’בSV.12-375’),‘Frontenac’‘( Riparia 89’בLandot4511’),‘Becker’(an interspecific species with par⁃ents unknown, bred by Becker and presented by Hance). For each variety, plants with uniform vigor andsize were selected, and 3 plants per plot with replicates (totally 9 plants) were used for the study. Four ma⁃ture berry clusters born in the middle shoots were taken from every plot (12 clusters in total) and all theberries from the same plot were peeled, pooled and rapidly frozen in liquid nitrogen for measuring anthocyanins. Extraction of anthocyanins was conducted using the method of Zhaoquan. The HPLC-MS analyseswere carried out using a WATERS ACQUITY UPLC-PDA detector. Chromatographic separation was carried out using a 100 mm ×2.1 mm i.d. thermostated at 45 ℃. The mobile phase was a linear gradient of water/formic acid (98∶2) (solvent B) in acetonitrile (solvent A), at a flow rate of 0.3 mL·min^-1. The followinggradient was used: 0-20 min, 6%-16% A; 20-28 min, 16%-23% A; 28-35 min, 23%-50% A; 35-37min, 50% A; 37-40 min, 50%-60% A; and MS analyses. MS operating parameters were: capillary volt⁃age, 3 000 V; cone voltage, 30.0 V; cone gas flow, 10 L·h^-1; desolvation gas flow, 700 L·h^-1; ion sourcetemperature, 100 ℃; desolvation temperature, 400 ℃. The instrument was operated in a positive ion modescanning from m·z^-1 50 to 2 000.【Results】The total anthocyanin content in‘Moldova’skin was the high⁃est (8 131.08 mg·kg^-1), followed by‘Cabernet Mitos’,‘Acolon’and‘Frontenac’in a range of 7 016.25-7 546.66 mg·kg-1. It was the lowest in‘Manna’and‘Cabernet Sauvignon’, being 2 608.59 and 2 442.87mg·kg^-1, respectively. Malvidin, petunidin, delphindin, cyanidin, peonidin, and their derivatives could bedetected in all varieties tested, although their proportions were different among varieties. Malvidin and itsderivative malvidins were the main components in all varieties, accounting for 80.76%. Anthocyanin com⁃position was similar between‘Cabernet Sauvignon’and‘Manna’,‘Cabernet Mitos’and‘Acolon’,‘Kyoho Early’and‘Moldova’, while‘Becker’and‘Frontenac’had an anthocyanin composition whichwas different with the others.‘Becker’had the highest modification degree of the anthocyanins, whichreached 99.41%, followed by‘Moldova’and‘Manna’with a modification degree of 96.51% and 94.60%respectively.‘Frontenac’had the lowest modification degree of 81.20% only. The result also showed thatV. vinifera varieties‘Cabernet Sauvignon’,‘Manna’,‘Cabernet Mitos’and‘Acolon’did not contain diglucosides, while‘Kyoho Early’,‘Moldova’,‘Frontenac’and‘Becker’contained much diglucosides,indicating that they did not belong to V. vinifera. The principal component and cluster analyses indicatedthat‘Cabernet Mitos’,‘Acolon’,‘Cabernet Sauvignon’and‘Manna’were closer in relationship, but‘Kyoho Early’,‘Moldova’,‘Frontenac’and‘Becker’had a distant relationship based on the composi⁃tion of anthocyanins.【Conclusion】Different varieties differ significantly in anthocyanin content and composition in their skin. Methylation is the main modification form of anthocyanins.‘Moldova’,‘CabernetMitos’,‘Acolon’and‘Frontenac’have a high content of total anthocyanins, but a high degree of modification of anthocyanins occurs in‘Becker’,‘Moldova’and‘Manna’. Malvidins are the main componentsin all grape varieties, and peonidin and its derivatives (peonidins) are the second most abundant anthocyanin components in most V. vinifera，while V. vinifera×V. labrusca’s is dominant by petunidin and its derivatives (petunidins).‘Moldova’,‘Cabernet Mitos’and‘Acolon’can be used as a source of dyes, asthey have a higher anthocyanin content with a higher modification degree. Therefore they can be cultivated in large scale as important pigmented varieties. Anthocyanin composition analysis can be an effectivemethod to classify grape cultivars.