Separation Science and Metabolomics Laboratory, 90 South Street, Murdoch University, Murdoch, WA 6150, Australia.
CSIRO Agriculture and Food, PMB 2, Glen Osmond, SA 5064, Australia.
Molecules. 2018 Jan 12;23(1):152. doi: 10.3390/molecules23010152.
A full understanding of the origin, formation and degradation of volatile compounds that contribute to wine aroma is required before wine style can be effectively managed. Fractionation of grapes represents a convenient and robust method to simplify the grape matrix to enhance our understanding of the grape contribution to volatile compound production during yeast fermentation. In this study, acetone extracts of both Riesling and Cabernet Sauvignon grape berries were fractionated and model wines produced by spiking aliquots of these grape fractions into model grape juice must and fermented. Non-targeted SPME-GCMS analyses of the wines showed that several medium chain fatty acid ethyl esters were more abundant in wines made by fermenting model musts spiked with certain fractions. Further fractionation of the non-polar fractions and fermentation of model must after addition of these fractions led to the identification of a mixture of polyunsaturated triacylglycerides that, when added to fermenting model must, increase the concentration of medium chain fatty acid ethyl esters in wines. Dosage-response fermentation studies with commercially-available trilinolein revealed that the concentration of medium chain fatty acid ethyl esters can be increased by the addition of this triacylglyceride to model musts. This work suggests that grape triacylglycerides can enhance the production of fermentation-derived ethyl esters and show that this fractionation method is effective in segregating precursors or factors involved in altering the concentration of fermentation volatiles.
要有效管理葡萄酒风格，就必须充分了解导致葡萄酒香气的挥发性化合物的起源、形成和降解。葡萄的馏分代表了一种方便且强大的方法，可以简化葡萄基质，从而增强我们对酵母发酵过程中葡萄对挥发性化合物产生的贡献的理解。在这项研究中，对雷司令和赤霞珠葡萄浆果的丙酮提取物进行了馏分，并通过将这些葡萄馏分的等分物添加到模型葡萄汁醪液中发酵来生产模型葡萄酒。对葡萄酒进行非靶向 SPME-GCMS 分析表明，通过发酵用某些馏分刺激的模型葡萄汁醪液制成的葡萄酒中，几种中链脂肪酸乙酯更为丰富。进一步对非极性馏分进行分馏，并在添加这些馏分后发酵模型葡萄汁醪液，导致鉴定出了混合的多不饱和三酰基甘油，当添加到发酵模型葡萄汁醪液中时，增加了葡萄酒中中链脂肪酸乙酯的浓度。用市售的三油酸甘油酯进行剂量反应发酵研究表明，通过向模型葡萄汁醪液中添加这种三酰基甘油酯，可以增加中链脂肪酸乙酯的浓度。这项工作表明，葡萄三酰基甘油可以增强发酵衍生的乙酯的产生，并表明这种馏分方法可有效分离改变发酵挥发物浓度的前体或因素。
