Improving shelf life of viticulture-relevant biocontrol and biostimulant microbes using CITROFOL® AI as liquid carrier

In this video recording of the IVES science meeting 2021, Simone D. Castellarin (University of British Columbia, Wine Research Center, Wine Research Centre, Vancouver, Canada) speaks about the effects of water deficit on secondary metabolites in grapes and wines. This presentation is based on an original article accessible for free on OENO One.

Iron (Fe) deficiency is one of the important nutritional disorders for grapevine growing in alkaline and calcareous soils. Although Fe is an abundant element in soil, several factors limiting its availability, particularly the high levels of calcium carbonate or bicarbonate in soil, leading to a remarkable reduction in grapevine growth and productivity. The use of Fe chlorosis-tolerant rootstocks seems to be a cost-effective and efficient way to maintain Fe balance. Morphological and physiological changes occur in plants to cope with low Fe availability, including enhancement of ferric chelate reductase activity and altering root system by increasing lateral roots and root hairs.

Pressing has a relevant impact on the characteristics of the must and subsequently on white wines produced [1]. Therefore, the adequate management of pressing can lead to the desired extraction of phenols and other grape compounds (i.e. Organic acids), aromas and their precursors, allowing the production of balanced wines [2]. This aspect is especially important to sparkling wine where the acidity and pH, and the content of phenols affect its longevity and the expected sensory character.

Red wine ageing is an important step in the red wine evolution and impacts its chemical and sensory characteristics through many chemicals and physico-chemical reactions. The kinetics of these evolutions depend on the wine studied and influence the wine ageing potential. Generally, high quality red wines require a longer period of bottle ageing before consumption¹. The ageing potential is an impor-tant parameter for wine quality and is related to the capacity of a wine to undergo oxidation over time². Phenolic compounds which are ones of the main substrates for oxidation can then potentially modulate ageing potential³.

In sparkling winemaking several yeasts can be used to perform the primary alcoholic fermentation that leads to the elaboration of the base wine. However, only a few Saccharomyces cerevisiae yeast strains are regularly used for the secondary in-bottle alcoholic fermentation 1. Recently, advances in yeast development programs have resulted in new breeds of interspecific wine yeast hybrids that ferment efficiently while producing novel flavours and aromas 2. In this work, sparkling wines produced using interspecific yeast hybrids for the secondary in-bottle alcoholic fermentation have been chemically and sensorially characterized.METHODS: Three commercial English base wines have been prepared for secondary in-bottle alcoholic fermentation with different yeast strains, including two commercial and several novel interspecific hybrids derived from Saccharomyces species not traditionally used in sparkling winemaking. After 12 months of lees ageing, the 14 wines produced were analysed for their chemical and macromolecular composition 3,4, phenolic profile 5, foaming and viscosity properties [6]. The analytical data were supplemented with a sensory analysis.