Claus-Dieter Patz

Dr. Claus-Di­eter Patz

Postal Ad­dress:Von-Lade-Straße 1
D-65366 Geisen­heim
Publications
Research Projects

Project start: 01.12.2020
Project end: 31.05.2024
Sponsor: Federal Ministry for Economic Affairs and Energy

Stirred fruit yogurt is the most widely consumed dairy mix product in Germany and contains up to 17% sugar, of which 4-6% is the sugar lactose from milk. Previous research approaches pursued the possibility of reducing sugar by increasing the sweetness of naturally present sugars by using bi-enzymatic processes. As a result, for instance, the sweeter monosaccharides glucose and galactose were formed from the comparably poorly sweet disaccharide lactose and, thus, less sugar had to be added by recipe to achieve the same sweetness. Our new research approach now involves reducing the added sugar (fruit preparation, priority 1) as well as the naturally present lactose (yogurt, priority 2) and fructose (fruit puree, priority 3). The aim of the project is to develop practical, food-technological principles for the production of sufficiently sweet fruit yogurts with high sensory quality and acceptance and a reduced total sugar content from an average of 15 g/100 g to 6-9 g/100 g (corresponding to a reduction of 40-60 %).

Project start: 01.07.2016
Project end: 31.08.2018
Sponsor: Hessen State Ministry of Higher Education, Research and the Arts

Climate change cannot currently be ignored and impacts all fields of agriculture. IPCC reports forecast an increase of up to 700 ppm of atmospheric carbon dioxide concentration at the end of the 21st century. Parameters such as elevated global temperature, reduced precipitations in certain areas of the world and increase of atmospheric carbon dioxide concentration are modifying plants’ environment. Grapevine, which is a crop of economic and cultural importance, is very sensitive to climate modifications. The effects of temperature or water stress on grapevine has been widely investigated, and elevated carbon dioxide has been mainly studied in enclosed systems such as greenhouses. However, the impact of increased concentration of carbon dioxide on plants in open-field experiments remains scarcely studied because of the technical challenge that it represents. In this context, the aim of this PhD work was to investigate the impact of elevated carbon dioxide concentration using the set-up VineyardFACE located at Geisenheim University. This open field set-up enables to apply a moderate and gradual increase (+20%) of ambient carbon dioxide concentration on two grapevine cultivars, Riesling, and Cabernet Sauvignon. While knowing the impact of elevated carbon dioxide treatment on leaf physiology and vegetative growth from previous studies (Wohlfahrt et al., 2018), as well as on berry composition during the early years of fumigation, the goal of this study was to determine the effects of elevated carbon dioxide treatment on agronomical traits, primary metabolites (sugars, organic acids, amino acids) and secondary metabolites (anthocyanins, terpenes) on vines undergoing six years of fumigation, as well as monitoring berry development and following berry ripening for successive seasons. Intermediates from central metabolism were also studied for two years (2020 and 2021), and terpene analysis was realized on Riesling must 2021. Our results showed that although photosynthesis was still enhanced, little effects were found of

Project start: 01.11.2014
Project end: 31.05.2018
Sponsor: Forschungsring des Deutschen Weinbaus, Deutsche Landwirtschaftsgesellschaft

Hochschule Geisenheim
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