G-FORSCHT 2015

WHICH PARAMETERS INFLUENCE THE TASTE OF VEGETABLES? Consumers demand tasty vegetables. Thus, the producers are interested in modulating the sensory properties of vege- tables by cultural practices. The taste of vegetable crops is mainly influenced by choice of variety. It was shown that purple carrots have less typical sensory flavor than orange varieties. Cultivation conditions – such as water supply – may impact the sensorial properties as well. This was true for tomato but not for cucumber. Fertilizer supply and graf- ting can modulate the taste of tomato fruits as well. Field vegetables such as asparagus are often covered by foil. In sensory evaluations no impact of the foil management was shown. However, the harvest date of asparagus was more responsible for tasty parameters, which has been proved for tomato as well. This project is co-ordinated by Prof. Dr. Jana Zinkernagel (Institute for Vegetables). Project partner is Prof. Dr. Mirjam Hey (Working Group of Beverage Technology, Chemistry and Sensory of Plant Food). AUTHOR: Dr. Lilian Schmidt Institut Gemüsebau lilian.schmidt@hs-gm.de GLYCOSYLATED TERPENOIDS IN WINE: LESS VARIETAL AROMA TYPICITY Terpenoids represent one of the biggest and most diverse classes of natural products and play a major role in the fruity, floral and citrus-like aroma of grape berries. Monoterpe- noids like geraniol and nerol are of exceptional importance for the varietal typicity of Gewurztraminer, White Riesling and Muscat à Petits Grains Blancs. However, the major part of terpenoids is bound to sugar (glycosylated), which in- creases water solubility and renders them odorless. For the first time, enzymes which glycosylate volatile terpenoids in planta (VvGT14 und VvGT15) were identified and characteri- zed within the collaboration project „Functional characteriz- ation of terpenoid glycosyltransferases of Vitis vinifera“ (funded by Deutsche Forschungsgemeinschaft). The co-operation partners TU Munich, University of Bonn and Geisenheim University followed an interdisciplinary appro- ach of analytical chemistry, molecular biology and bioche- mistry which led to success. AUTHOR: Dr. Johanna Frotscher Institut Rebenzüchtung johanna.frotscher@hs-gm.de

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