Enoforum 2021
IVES 9 IVES Conference Series 9 Enoforum Web 9 Enoforum Web Conference 2021 9 Cellar session 9 Adaptation of Lactobacilli towards low ph and SO2 to develop MLF in base musts for sparkling wines

Adaptation of Lactobacilli towards low ph and SO2 to develop MLF in base musts for sparkling wines

Abstract

In some white wines, malolactic fermentation (MLF) is very interesting, and for low pH wines this process is particularly difficult. Although MLF is generally not recommended for sparkling white wine, some winemakers prefer to promote MLF to contribute to organoleptic complexity. Oenococcus oeni is generally the bacterium of choice for MLF. However, people’s interest in other species (such as Lactobacillus) is increasing. However, one disadvantage of lactobacilli is that they are more sensitive to low pH and SO2, and some producers of starters inoculate high doses of non-growing bacteria in grape musts. This work aims to grow some selected strains of Lactobacillus in grape juice and perform early MLF. With this strategy, beyond performing the MLF homolactic bacteria can contribute clearly to maintain or even decrease the final pH in wines by producing lactic acid from sugars; they also produce more complex wines, and prevent the spoilage of an undesired late MLF in bottles. 

To perform this selection, twelve Lactobacillus strains were successively inoculated after adapting to the lowering of pH and the increasing concentration of SO2. The cell concentration of the inoculum was in the order of x 106 CFU/mL to allow growth and synthesis of lactic acid. All Lactobacillus strains gradually adapted to low pH and SO2 and could grow at pH 3.2 and the highest SO2 concentration, thereby maintaining or even increasing their final biomass. After 7 days, all strains always underwent MLF. Malic acid consumption rate and lactic acid production depend on the strain. The final pH of wines was maintained or even decreased, even when complete MLF was achieved. This strategy helps in biological acidification of wines against the loss of acidity derived from climate change.

DOI:

Publication date: April 23, 2021

Issue: Enoforum 2021

Type: Article

Authors

FERRER Sergi, POLO Lucía, ANDRÉS Lorena, PARDO Isabel

Institut de Biotecnologia i Biomedicina (BioTecMed), Universitat de València, Spain

Contact the author

Tags

Enoforum 2021 | IVES Conference Series

Citation

Related articles…

Soil fertility and confered vigour by rootstocks

The adaptation of rootstock to scion variety and soil determines largely the control of the vegetative growth for grapevine. Many experiments were performed in the vineyard to classify the rootstocks according to their soil adaptation and to their effect on vine vigour. So far there are no data describing the course of appearance of rootstock effects after plantation. Moreover the underlying mechanisms of conferred vigour remain largely unknown.

How a microscopic yeast makes a big difference – how geographic limitations of yeast populations can determine the regional aroma of wine

Aim: Microbial biogeography contributes to regional distinctiveness of agricultural products and is important to determine for quality and marketing of wine products. We evaluated the microbial influence on wine characteristics by considering the microbial diversity of soil, plant, grapes, must and wine in grapegrowing regions across Victoria, Australia. 

Traditional agroforestry vineyards, sources of inspiration for the agroecological transition of viticulture

A unique “terroir” can be found in southern Bolivia, which combines the specific features of climate, topography and altitude of high valleys, with the management of grapevines staked on trees. It is one of the rare remnants of agroforestry viticulture. A survey was carried out among 29 grapegrowers in three valleys, to characterize the structure and management of these vineyards, and identify the services they expect from trees. Farms were small (2.2 ha on average) and 85% of vineyards were less than 1 ha. Viticulture was associated with vegetable, fruit and fodder production, sometimes in the same fields. Molle trees were found in all plots, together with one or two other native tree species. Traditional grapevine varieties such as Negra Criolla, Moscatel de Alejandría and Vicchoqueña were grown with a large range of densities from 1550 to 9500 vines ha-1. From 18 to 30% of them were staked on trees, with 1.2 to 4.9 vines per tree. The management of these vineyards (irrigation, fertilization and grapevine protection) was described, the most particular technical operation being the coordinated pruning of trees and grapevines. Three types of management could be identified in the three valleys. Grapegrowers had a clear idea of the ecosystem services they expected from trees in their vineyards. The main one was protection against climate hazards (hail, frost, flood). Then they expected benefits in terms of pest and disease control, improvement of soil fertility and resulting yield. At last, some producers claimed that tree-staking was quicker and cheaper than conventional trellising. It can be hypothesized then that agroforestry is a promising technique for the agroecological transition of viticulture. Its contribution to the “terroir” of the high valleys of southern Bolivia and its link with the specificities of the wines and spirits produced there remain to be explored.

Cross analytical and sensory differentiation of monovarietal white wines from four autochthonous grape varieties: focus on macromolecules

White wines contain macromolecules such as proteins, phenolic compounds and polysaccharides. On a sensory
level, these compounds contribute to the ‘mouthfeel’ that differentiates the white wines worldwide [1].

Identifying New Zealand Sauvignon blanc terroirs

The concept of terroir is well established in the ‘old world’ wine industry but its use is still relatively new in New Zealand. Marlborough Sauvignon blanc has become a benchmark