Macrowine 2021
IVES 9 IVES Conference Series 9 Effect of nitrogen content on fermentation kinetics and aroma profile of assyrtiko wine

Effect of nitrogen content on fermentation kinetics and aroma profile of assyrtiko wine

Abstract

Today, there is need to design, produce and label terroir wines, with unique organoleptic properties and more “attractive to consumers”. For this purpose, two Saccharomyces cerevisiae yeast strains (Sa and Sb) isolated during spontaneous fermentations were used for white wine production from the Assyrtiko grape of Santorini. A third commercial strain was used as control. Two concentrations of Yeast Assimilable Nitrogen (YAN) and DAP (diammonium phosphate) were added to the must (150mg/L and 250mg/L) in order to evaluate the effcet of nitrogen content on the final wine quality. Both analytical chemical methods (HPLC, GC-MS, classical eonological methods) and sensory analysis were employed to assess the chemical composition of the wines and their organoleptic character. In addition fermentation kinetics were monitored throughout the experiment. By the second day of fermentation all three strains had consumed approximately 75% of amino acids. Differences among strains were observed concerning inorganic nitrogen requirements. Sa strain consumed it faster and was the first to compete fermentation independently from the level of added YAN. The commercial strain was characterized by the highest concentration of residual sugars, followed by Sb and Sa. Alcohol content ranged from 12.8-13.1% vol. Sb and the commercial one produced significant higher amounts of glycerol (about 0.7g/L), especially in the case of lower YAN. Sb also produced significant higher amounts of higher alcohols (1.9-fold) and ketones (5.6-fold) but significant lower amounts of esters (1.2-fold) in comparison with the commercial strain. Sa was characterized by significant higher concentrations of fatty acids (2.1-fold) and lower acetic acid (1.6-fold) production. No statistically important differences were observed in the oligomeric phenolic compound content of the samples. Both indigenous strains scored better results in overall aroma quality, and more specifically in “fruity”, “floral” descriptors compared with control. They were also preferred over the commercial strain as far as mouthfeel, body and acidity are concerned. The evaluation of both chemical and sensory data indicated the potential of the indeginous starins for commercial wine production with unique characteristics and high quality.

DOI:

Publication date: September 3, 2021

Issue: Macrowine 2021

Type: Article

Authors

Stefania Christofi, M.Dimopoulou1 Α, Papanikolaou1 G.J, M.Sadoveanu Alley

1 Department of Food Science & Human Nutrition, Laboratory of Oenology, Agricultural University of Athens, 75 Iera Odos, 11855 Athens, Greece, Terpou1 S, Nychas1  C.I., Bogdan2 Romania Academy – Iasi Branch, Research Centre for Oenology, Iasi 700490, Romania V., Cotea3 University of Agricultural Sciences and Veterinary Medicine Iaşi, 3 M. Sadoveanu Alley, Iaşi, 700490, Romania Kallithraka, S1.

Contact the author

Keywords

aminoacids, fermentation kinetics, saccharomyces cerevisiae, volatile compounds

Citation

Related articles…

Bioclimatic shifts and land use options for Viticulture in Portugal

Land use, plays a relevant role in the climatic system. It endows means for agriculture practices thus contributing to the food supply. Since climate and land are closely intertwined through multiple interface processes, climate change may lead to significant impacts in land use. In this study, 1-km observational gridded datasets are used to assess changes in the Köppen–Geiger and Worldwide Bioclimatic (WBCS)

Updating the Winkler index: An analysis of Cabernet sauvignon in Napa Valley’s varied and changing climate

This study aims to create an updated, agile viticultural climate index (similar to the Winkler Index) by performing in-depth analyses of current and historical data from industry partners in several major winegrowing regions. The Winkler Index was developed in the early twentieth century based on analysis of various grape-growing regions in California. The index uses heat accumulation (i.e. Growing Degree Days) throughout the growing season to determine which grape varieties are best suited to each region. As viticultural regions are increasingly subject to the complexity and uncertainty of a changing climate, a more rigorous, agile model is needed to aid grape growers in determining which cultivars to plant where. For the first phase of this study, 21 industry partners throughout Napa Valley shared historical phenology, harvest, viticultural practice, and weather data related to their Cabernet sauvignon vineyard blocks. To complement this data, berry samples were collected throughout the 2021 growing season from 50 vineyard blocks located throughout 16 American Viticultural Areas that were then analyzed for basic berry chemistry and phenolics. These blocks have been mapped using a Geographic Information System (GIS), enabling analysis of altitude, vineyard row orientation, slope, and remotely sensed climate data. Sampling sites were also chosen based on their proximity to a weather station. By analyzing historical data from industry partners and data specifically collected for this study, it is possible to identify key parameters for further analysis. Initial results indicate extreme variability at a high spatial resolution not currently accounted for in modern viticultural climate indices and suggest that viticultural practices play a major role. Using the structure of data collection and analyses developed for the first phase, this project will soon be expanded to other wine regions globally, while continuing data collection in Napa Valley.

Analysis of Cabernet Sauvignon and Aglianico winegrape (V. vinifera L.) responses to different pedo-climatic environments in southern Italy

Water deficit is one of the most important effects of climate change able to affect agricultural sectors. In general, it determines a reduction in biomass production, and for some plants, as in the case of grapevine, it can endorse fruit quality. The monitoring and management of plant water stress in the vineyard

Organic recycled mulches in sustainable viticulture: assessment of spontaneous plants communities and weed coverage

In recent years, developing more efficient and sustainable viticulture management has been essential due to the impact of climate change in semiarid regions. For this reason, the use of recycled organic mulching (ROM) in the vineyard has become an interesting strategy to cope with water stress, isolated soil from extreme temperatures and improving soil humidity, control the presence of weeds and therefore reduce the inputs of herbicides and improve soil fertility. This work aimed to analyse the effect of three different organic mulches [straw (S), grape pruning debris (GPD) and spent mushroom compost (SMC)] and two traditional soil management techniques [herbicide (H) and interrow (IN)] on weed coverage and the spontaneous plant communities’ presence. Data sampling was collected throughout the vine vegetative cycle of 2021 in La Rioja, Spain. The different soil management techniques had a clear effect on weed coverage and his development during the vine vegetative cycle. SMC and H were the treatments with the highest and the lowest coverage percentage, respectively. IN had a delayed weed emergence at the beginning of the vine vegetative cycle, but finally it reached maximum values nearby SMC. GPD and S had similar effects on weed emergence, reaching 25-30% of the maximum coverage values. A total of 29 herbaceous species were identified during the vegetative cycle, some of them very isolated and occasional. Principal component analysis (PCAs) showed a good association between spontaneous species and treatments, furthermore, specific species-treatment associations were found. Moreover, three clear groups of herbaceous communities were identified by cluster analysis. This study provides interesting information about the effect of different alternative soil management on herbaceous plant coverage and weed species communities which could contribute to making more sustainable viticulture.

Diagnosis of soil quality and evaluation of the impact of viticultural practices on soil biodiversity in a vineyard in southwestern France

Viticulture is facing two major changes – climate change and agroecological transition. In both cases, soil quality is seen as a lever to move towards a more sustainable viticulture. However, soil biological quality is little considered in the implementation of viticultural practices. Gascogn’Innov (2017-2022) is an Operational Group funded by the European Innovation Partnership for Agriculture. As such, it brings together winegrowers from the south-west of France, scientists, advisors and technicians, around a project focused on viticultural soil biological functioning and the design of technical routes more respectful toward soil heritage. To achieve this, the project aims to acquire references on the impact of viticultural practices on soil biology from a dynamic way, and to test a methodology to integrate information provided by the soil bioindicators to manage farming systems. A set of indicators of soil biological quality are evaluated in the project: microorganisms (bacteria and fungi abundance and diversity), fauna (abundance and diversity of nematodes and earthworms), physico-chemical characteristics, soil structure assessment and degradation rate of organic matter. Based on a network of 13 plots that have been subject to an initial diagnosis in 2017, several agronomical practices to restore soil fertility are experimented to redesign the cropping system (for instance plant cover, organic matter inputs, reduction of herbicides, mineral fertilizers). System redesign was made in collaboration by winegrowers and an interdisciplinary group of experts (agronomists, biologists). Several indicators are measured on vine and soil at each vintage to assess vine health and productivity. At the end of the project (2021), a final diagnosis was carried out. Gascogn’Innov allowed to create a regional database on the quality of wine-growing soils, which permitted to evaluate the effect of practices according to soil types. Especially, decreasing the intensity of tillage and increasing the duration and diversity of grass coverage tends to increase the abundance of all the organisms studied. This project confirmed the value of soil biological quality indicators to drive the sustainability of practices, but also highlighted the key-role of expertise, in both agronomy and soil biology, to help winegrowers understand and appropriate their soil quality diagnoses.