Bio-protection by one strain of M. Pulcherrima: microbiological and chemical impacts in red wines

Metschnikowia pulcherrima is a well-studied non-conventional oenological yeast due to its positive contributions to winemaking as a bioprotective agent and as an aroma-enhancing starter in sequential fermentations with Saccharomyces cerevisiae (Binati et al., 2023; Canonico et al., 2023).

The use of pectinolytic enzymes in winemaking is state of the art. These enzymes catalyse the degradation of pectic substances through depolymerization (hydrolases and lyases) and de-esterification. As a result, it supports the extraction of juice and facilitates filtration. It has also been shown in winemaking that the presence of pectinolytic enzymes improves the stability, taste, texture, colour and aroma of products. With regard to enzymes currently applied in winemaking, enzymes derived from filamentous fungi dominate the enzyme industry. Fungal-based pectinolytic enzymes specifically require purification from the culture medium to eliminate unwanted side reactions, which is poorly sustainable. Some non-traditional yeast strains have been reported to exhibit pectinolytic activities. Therefore, the direct use of pectinolytic yeast during wine fermentation process can be an attractive and alternative source for the use of enzymes as input.

Aim: In this work, we have optimized a robust methodology for investigating possible correlations between the phytochemical profile of wine and the terroir (including the climate), considering the specific wine-growing area. In particular, the untargeted metabolomic and sensorial profiles of Gutturnio DOC commercial wines (both still and “frizzante” types) from different production areas in the Piacenza province were determined. The geographical areas taken into consideration for this study consisted in Val Tidone, Val Nure and Val d’Arda.

Wines made with grapes submitted to postharvest dehydration are often referred to as “passito” or “straw wines.” This distinct style of winemaking consists of a process of water loss that allows the berries to undergo a mild water stress and senescence process [1].

Erysiphe necator Schwein is a fungus that causes grapevine powdery mildew. It is one of the most problematic pathogens attacking Vitis vinifera L. The pathogen infects all green parts of the plant and reduces grape yield and quality. The suppression on mildew-susceptible cultivars requires intensive use of fungicides against pathogen, which has negative impact on the environment and human health.