Changes of polyphenols, sugars, and organic acid in 5 Vitis genotypes during berry ripening

The concentrations of sugars, organic acids, and polyphenols during berry ripening in 5 grape genotypes were analyzed using HPLC and HPLC-MS to determine which were correlated. Veraison is critical stage during grape berry development, and marks the beginning of ripening. Glucose and fructose accumulated sharply in a 1 : 1 ratio, though the concentration of fructose was slightly higher than that of glucose at maturation. Malic acid and tartaric acid were the dominant organic acids, and they decreased rapidly during berry ripening. The 5 cultivars contained 28 anthocyanins and 8 other polyphenols. All anthocyanins accumulated and were positively correlated with the sugars and negatively correlated with the organic acids. Hydroxycinnamic acids declined and were positively correlated with anthocyanin contents. Changes in flavanols and flavonols different among the 5 genotypes, with flavonols positively correlated with anthocyanin content, but the flavanols procyanidin B1 and epicatechin negatively correlated with anthocyanins content. There were obvious differences in patterns of change of polyphenols among 5 grape genotypes. PRACTICAL APPLICATION: The results could be used for improving grape berry quality during ripening and developing a comprehensive database of primary and secondary metabolites in the Vitis for grape breeding.     

Dynamics of grape berry growth and physiology of ripening

Data from two experiments on development of grape berries is re-examined with emphasis on partitioning of berry weight into non-solutes per berry (largely water) and solutes per berry (largely sugar), using weight times juice °Brix. This approach is based on the thought that, since xylem flow is blocked after veraison, time curves of solutes per berry indicate the activity of phloem transport into the berry during ripening growth. Experiment 1: Measurements of Muscat Gordo Blanco berries from inflorescences with a spread of flowering times showed typical double-sigmoid volume/time curves but with divergent rates and amounts of volume increase. Despite this divergence, °Brix curves after veraison were almost coincident because, in each case, the rate of increase in solutes per berry was proportional to that of berry volume. These results indicate that sugar and water increments after veraison are linked and depend on the same source, namely, phloem sap. Experiment 2: An irrigation experiment on cv. Shiraz also showed divergent berry weight curves between treatments and years but with the difference that all berries shrank after a maximum berry weight was attained at 91 days after flowering (at about 20 °Brix). At this point, the curves of solutes per berry slowed then plateaued, indicating that inflow of phloem sap had become impeded. Prior to shrinkage these berries accumulated primary metabolites (mainly phloem sugar) but, during shrinkage, when berries were apparently isolated from vascular transport, non-anthocyanin glycosides accumulated. These results have implications for the study of berry flavour buildup and berry composition, and also for the understanding of sink competition within the vine, fresh and dried yield, and juice °Brix levels.     

六个早熟鲜食葡萄品种果实香气成分分析

以亲本‘葡萄园皇后’‘红香蕉’和子代‘丰宝’‘红双味’‘贵妃玫瑰’‘黑香蕉’6个早熟鲜食葡萄品种为试材,采用顶空固相微萃取结合气质联用技术对其果实的香气成分进行分析测定,调查各品种成熟果实的芳香物质差异。结果表明,成熟果实中C6化合物含量高,是贡献最大的挥发性化合物,其中相对含量最高的是具有青草、草本香气的2-己烯醛和己醛;烯烃类、酯类是构成不同品种葡萄特征香气的重要组成,其中反式-β-紫罗兰酮、里那醇、香茅醇等具有玫瑰花香的化合物的气味活性值高,对‘贵妃玫瑰’‘葡萄园皇后’贡献较大;具有果香、香蕉香气的己酸乙酯、辛酸乙酯、丁酸乙酯的气味活性值高对‘红香蕉’‘黑香蕉’的贡献突出。     

Characterisation and evolution of grape polyphenol profiles of Vitis vinifera L. cv. Tannat during ripening and vinification

Background and Aims: Changes in different polyphenol families during grape ripening and vinification were determined in Tannat grapes. This was done to establish a polyphenol profile for Tannat grapes during ripening and for young wines. Methods and Results: We demonstrated, by high‐performance liquid chromatography with diode array detection and mass spectrometry (HPLC‐DAD‐MS) analysis, that the content of flavan‐3‐ols in Tannat seeds was higher than that reported for a large number of other grape varieties analysed. Forty per cent of the total flavan‐3‐ols in seeds were galloylated compounds, whereas the flavan‐3‐ol profile in skins was characterised by the absence of galloylated forms. Prodelphinidins in skins ranged between 30 and 35% with very low values for epigallocatechin. Epicatechin gallate was not detected in Tannat wine and galloylated forms represented a low percentage of total flavan‐3‐ols. Tannat grapes had very high concentrations of anthocyanins in skins with levels increasing during ripening. Eleven phenolic acids were identified in Tannat grape skins and wines, but only gallic and protocatechuic acids were found in the seeds. Conclusions: Tannat wines were shown to have one of the highest levels of phenolic compounds reported for vinifera grape varieties. The profiles for different polyphenol families present in Tannat grapes (skins and seeds) and wines were determined. Significance of the Study: The results presented will help to better understand the phenolic winemaking potential of this variety and its functional properties within food chemistry.     

不同类型果袋对葡萄果实有关性状的影响

以晚熟葡萄品种红地球为试材,探讨了几种不同透光率的果袋对葡萄果实有关性状的影响,结果表明:不透光的复合袋极为显著地降低果实单粒重、总糖含量和糖酸此;透光率为16％的红色袋显著降低果实糖酸比,但对总糖含量、单粒重无显著影响;透光率为60％的无纺布袋对果实品质有一定提高作用;套袋处理的果实钙含量显著低于对照,且随着果袋透光率的降低而降低;透光率高的果袋袋内果实单宁含量偏高;各处理果实Vc含量均无显著差异.葡萄果实对光照强度的需求存在临界值,当袋内光照强度低于外界自然光照的1.4％左右时,果实生长发育开始受到影响.     

Influence of berry ripeness on concentration,qualitative composition and extractability of grape seed tannins

Background and Aims: The evolution of seed tannins in three grape varieties grown in the same vineyard was followed from preveraison to harvest, to determine their pattern of accumulation. Also, to elucidate whether the use of 70% acetone as extracting solvent overestimate what will occur during fermentation, seed tannins were extracted throughout the ripening period with a method that involved a 3 days extraction with aqueous 12.5% ethanol and the results compared with the acetone extraction method. Methods and Results: For both methods, the extracted tannins were analysed following acid‐catalysis in the presence of excess of phloroglucinol. Seed tannins reached a maximum around veraison and decreased towards maturity, the mean degree of polymerization (mDP) varying only slightly during the studied period. When tannins were extracted with 12.5% ethanol, their concentration was much higher during the first part of the maturation than using acetone but was significantly lower at harvest. Conclusions: The decrease in extractable seed tannins during ripening was observed with both solvents. The differences observed in the concentration of tannins with both solvents could be due to the histochemical changes occurring in seeds during maturation. Significance of the Study: The differences observed in tannin concentration with the two different methods may indicate that when pulp maturity is reached before seeds are ripe, the fermenting solution will extract more tannins than the acetone method. These results point to the importance of extraction methodology when monitoring seed maturity for the prediction of seed tannins in wine.     

Comparative analysis of flavonoids in white and red table grape cultivars during ripening by widely targeted metabolome and transcript levels

The flavonoid metabolites were compared between red ‘Summer Black’ (SB) and white ‘Shine Muscat’ (SM) table grapes during fruit development based on widely targeted metabolome. A total of 134 flavonoids were identified in two cultivars, including 37 flavones, 33 flavonols, and 11 anthocyanidins, and so on. From young to veraison, the composition and the content of most flavonoids were decreasing in both cultivars but increased at maturation in SB. In general, SB has higher flavonoid compositions and content than SM during the whole fruit development, especially the content of anthocyanin after veraison. While the SM had higher content of flavonols such as quercetin, kaempferol and their derivatives. The expression of anthocyanin-related genes such as UFGT, OMT, GST, MATE, MYBA1, and MYBA2 was remarkably higher in SB than those in SM, which may attribute to higher anthocyanin content, while the higher expression of F3H and FLS resulted higher level of flavonols in SM. These results improve our understanding of flavonoid profiles and molecular mechanism in table grape cultivars.     

葡萄花色苷合成的影响因素研究进展

花色苷是存在于葡萄果皮中的水溶性天然色素,属于类黄酮化合物。花色苷主要是由葡萄品种所决定的,但其生物合成还受到其他各种因素的调控,如气候(光照、温度和湿度)、土壤、植物激素、果实负载量等。本文对近年来影响葡萄花色苷合成的因素的研究进行综述,为改善葡萄果皮中花色苷的相关研究提供参考。      

提高酿酒葡萄糖份含量的分子生物学机制

果实品质在很大程度上取决于果实内所含糖的种类和数量,要提高果实的品质需深入了解果实内糖积累的机制,抓住关键的环节人为加以调控或在遗传特性上加以改良.本文综述了酿酒葡萄的糖代谢生理生化及分子生物学机制,并提出了国内外最新研究动态.     

Physiological and modelling approaches to understand water and carbon fluxes during grape berry growth and quality development: a review

Recent advances in the understanding of the physiology of berry growth and in modelling allow simulation of fruit growth and sugar accumulation from the perspective of water and carbon balance. This review summarises present knowledge on the modelling and molecular physiology of carbon and water fluxes related to grape berry growth and quality. It focuses principally on the effects of environmental factors and cultural practices on fruit quality through their consequences on water and carbon fluxes during fruit growth. Together with ecophysiological and molecular approaches, process-based models show promising ability to aid in integrating physiological results, generating novel hypotheses and consequently providing a full picture of the control of berry growth and quality development. In the future, nitrogen and sulfur fluxes, necessary for the synthesis of secondary metabolites important for quality, should also be integrated. Modelling at the organ level should extend to metabolic content and metabolite fluxes (metabolomic and fluxomic studies). Genotypes naturally or artificially affected on a key gene or function will also be helpful to validate modelling hypotheses.     

浸钙处理对黄桃后熟软化的影响

研究了在不同贮藏温度下,浸钙处理对黄桃后熟软化的影响,实验结果表明:浸钙处理可以明显地延缓黄桃果实后熟,保持较高硬度,防止软化。     

葡萄果实发育过程中花色素还原酶的免疫组织化学定位

以赤霞珠葡萄果实为试材,采用免疫组织化学方法,对果实发育过程中花色素还原酶(ANR)的分布及其动态变化进行原位分析.结果表明,在果皮、果肉和种子中均可观察到ANR的存在;种子中的ANR主要定位于内珠被(in),果皮和果肉中的ANR则主要分布在维管束(VB)、果皮(BS)细胞壁和果肉(BP)细胞壁中,而且这种特异性分布并不随果实发育进程而发生改变.     

适合酿酒葡萄果实、果皮及种子的蛋白质提取方法

制备高质量的蛋白质样品是进行蛋白免疫印迹(Western blot)分析的前提.酿酒葡萄果实中含有大量的多酚和多糖等物质,给蛋白质的提取带来了因难.本研究比较了不同聚乙烯聚吡咯烷酮(PVPP)浓度和料液比对赤霞珠葡萄果实、果皮和种子中粗蛋白提取的影响.结果表明,采用10%PVPP及1:2料液比对果实、5%PVPP及1:3料液比对果皮或10%PVPP及1:3料液比对种子的蛋白进行提取,可获得较好的SDS-PAGE图谱;对花色素还原酶(ANR)的蛋白免疫印迹分析显示,ANR在果实、果皮和种子中均有表达,分子量约为43kDa.     

萘乙酸对草莓采后成熟与软化的影响

为了延长草莓保鲜期,探索外源NAA对草莓采后成熟与软化的影响。采摘不同发育期(白色期、初红期、半红期、红熟期)的"丰香"草莓,以不同浓度萘乙酸(NAA浓度分别为0.1、0.2、0.3 g/L)溶液浸泡处理15 min,测定草莓的硬度、色泽a值、电导率、可滴定酸(TA)和总可溶性固形物(TSS)在室温条件下的变化趋势。0.1～0.3 g/L NAA都能起到抑制软化的作用。0.3 g/LNAA溶液处理,对初红期草莓进一步着色,对初红期和半红期果实TSS增加和成熟期果实酸度下降有一定抑制作用;对各期果实成熟过程细胞膜通透性增加均有显著的抑制作用。外源NAA对草莓成熟有抑制作用。以外源NAA处理推迟草莓成熟和软化,延长货架期,值得进一步深入研究。