一年两收栽培‘赤霞珠’葡萄冬果与夏果花色苷组分差异解析

Difference in anthocyanin composition between winter and summer grape berries of‘Cabernet Sauvignon'under two-crop-a-year cultivation

【目的】探究一年两收栽培模式下酿酒葡萄品种‘赤霞珠’两季葡萄花色苷的组分差异。【方法】以成熟期‘赤霞珠’冬果和夏果为试验材料,利用高效液相色谱质谱(HPLC-MS)联用技术检测其果皮中花色苷的组成和含量,并监控不同发育期浆果的理化指标变化。【结果】‘赤霞珠’冬果果粒质量小于夏果,但果皮鲜质量和可溶性固形物含量高于夏果;成熟期‘赤霞珠’冬果果皮中共检测到17种花色苷,而夏果中检测到16种;成熟期‘赤霞珠’冬果果皮中的花色苷总量及大多数花色苷含量显著高于夏果;‘赤霞珠’冬果葡萄果皮中3’,5’-羟基取代花色苷、酰化修饰及甲基化花色苷的含量显著高于夏果。【结论】通过对气候条件的分析,与夏季相比,一年两收栽培区南宁下半年较长的光照时间、较少的极端高温(≥35℃)及更为干燥的气候是酿酒葡萄冬果成熟度高、花色苷总量及稳定花色苷含量都显著高于夏果的主要原因。因此,南宁地区下半年的气候条件更有利于酿酒葡萄生产。

[Objective] The grape skin colour varies mainly due to the difference in the composition and the content of anthocyanins. Climatic conditions have significant influence on grape ripening and quality. In Nanning, a two-crop-a-year grape culture system is adopted for different wine grape cultivars. However, the differences in composition and content of anthocyanins between winter and summer grape berries are still unclear. The present study analyzed the differences in anthocyanins in the winter and summer grape berries of ‘ Cabernet Sauvignon＇ （Vitis vinifera L.） under two-crop-a-year cultivation system. [ Methods]The composition and contents of anthocyanins in berry skin were analyzed using HPLC-MS and the physical and chemical indexes were analyzed during developmental stages. Anthocyanin analysis was done on frozen grapes after removing the pedicels. Skins were taken from the frozen berries, grinded into powder and freeze-dried at -40 ℃. Grape skin powder （0.50 g） was immersed in methanol （10 mL） containing 2% formic acid. This extraction was performed with the aid of ultrasound for 10 min, and the mixture was then shaken in the dark at 25 ℃for 30 min at a rate of 150 r. min-1. The homogenate was centri-fuged at 8 000× g for 10 min and the supernatant was collected. The residues were re-extracted four times. All the supernatants were pooled, reduced to dryness using a rotary evaporator and then re-dis- solved in 10 mL of solvent mixed with 90% mobile phase A and 10% mobile phase B. Solvent A was 2% （V：V） formic and 6% acetonitrile in water, and solvent B was acetonitrile containing 2% formic acid and 44% water. The resulting suspensions were filtered through 0.22 Ixm filters prior to HPLC-MS analysis. An Agilent 1100 series LC-MSD trap VL was used for anthocyanin detection. A flow rate of 1 mL. min-1 at ambient temperature was used. Proportions of solvent B in the mobile phase varied as follows： 1-18 min, 10% to 25%; 18-20 min, 25%; 20-30 min, 25% to 40%; 30-35 min, 40% to 70% and 35-40 min, 70% to 100%. Injection volume was 30 μL, and the detection wavelength was 525 nm. The column temperature was 50 ℃. MS conditions were： electrospray ionisation （ESI） interface, positive ion model, 30 psi nebulizer pressure, 12 mL. min-1 dry gas flow rate, 300 ℃ dry gas temperature, and scans at m. z-1 100-1 500. Anthocyanins were quantified at 525 nm as malvidin-3-O-glucoside using calibration curves obtained within a concentration range between 0.5 and 500 mg. L -1, with linear correlation coefficients greater than 0.999. [Results]The results indicated that the fresh weight of the winter grape was smaller than that of the summer grape, but the winter grape had a higher berry skin weight and soluble solid concentration. 17 anthocyanins were detected in winter grape skins at mature stage, and 16 anthocyanins were detected in summer grape skins. The content of total anthocyanins and most of the anthocyanins in the winter grape skins were significantly higher than those in the summer grape skins. However, the summer grape skins contained higher content of malvidin-3-O-（trans-6-O-coumaroyl）-glucoside. The winter grape had higher contents of 3＇ 5＇ -substituted and 3＇ -substituted anthoeyanins than the summer grape, and the proportion of 3＇ 5＇ -substituted anthocyanins in the winter grape was higher than that in the summer grape. The con- tents and proportions of non-aeylated and coumaroylated anthocyanins in the winter grape were higher than those in the summer grape, but the proportion of acetylated anthocyanins in the summer grape skins were higher. The content of non-methylated and methylated anthocyanins were higher in the winter grape, but the proportion of methylated anthocyanins were higher in the summer grape. In Nanning, effective accumulative temperature and sunlight hours during the growing season of the winter grape were higher than those during summer grape growing season, but the average temperature of the 3 months before harvesting, rainfall during berry maturation, and hydrothermic coefficient of the 2 months before harvesting in the winter grapes were all lower than those in the summer grapes. From green fruit stage to full mature stage, the daily maximum temperature and minimum temperature displayed decreasing trends for the winter grape, but they showed increasing trends for the summer grape. Daily maximum temperature during the growing season of the winter grape was always lower than 35 ℃ , but there were 29 days with daily maxi- mum temperature ≥35 ℃ during summer grape growing season. [ Conclusion ] The second half of the year has much a longer sunlight time, less extreme high temperatures （≥35 ℃） and drier climatic conditions than the first half of the year in Nanning, where two-crop- in-a-year grape cultivation system is adopted. Thus, the winter grape berries have a higher level of maturity, with higher contents of total anthocyanins and stable anthocyanins than the summer grape. Generally, the climate condition of Nanning in the second half of the year was more favorable for wine grape production.