Introduction
Humans use microbial metabolism in various ways; one example is wine production. Virdis et al. (2021) claim that currently, the primary function of Lactic Acid Bacteria (LAB) in wine is to perform malolactic fermentation (MLF). This method improves microbiological stability, enhances wine flavor and smoothness, and decreases acidity. LAB may also release hydroxycinnamic acids from tartaric esters and can degrade anthocyanin glucosides, influencing wine color (Virdis et al., 2021). Moreover, the bacteria can create enzymes that have the potential to aid in the production process and contribute to the end product’s longevity. For instance, LAB has peptidolytic and proteolytic activity, which might help break down the proteins that cause wine haze, lowering the requirement for bentonite. The bacteria may demonstrate both wine’s beneficial and harmful effects on human health (Virdis et al., 2021). Organic acids, such as lactic and acetic, phenyl lactic acid, diacetyl, cyclic dipeptides, and bacteriocins, which can prevent the growth of spoilage or pathogenic bacteria, are among the metabolites produced by LAB.
Discussion
Although wines from a single grape variety have distinct characteristics that set them apart from other types, these active-flavor components are not always discernible during the pre-fermentative phases. Virdis et al. (2021) argue that they are frequently the result of yeast and microbial metabolism and are changed and generated in wine throughout the fermentation. LAB enzymes that may be found in wine contain glycosidases, esterases, and proteases. These enzymes’ activity may considerably improve wine’s appearance, taste, mouthfeel, and fragrance, eventually contributing to establishing its structure. Lactic Acid Bacteria are Gram-positive bacteria that belong to the Firmicutes phylum, class Bacilli, and order Lactobacillales (Virdis et al., 2021). Several Lactobacillaceae genera are employed in the food business and manufacturing process of several fermented products such as yogurt, cheese, and kimchi (Virdis et al., 2021). Consequently, the only genera connected with wine are Oenococcus, Leuconostoc, and Pediococcus from the formerly identified Leuconostocaceae family and Lactobacillus from the once-recognized Lactobacillaceae family.
Lactic acid bacteria may be both damaging and beneficial to wine quality. Their effectiveness in wine is influenced by unique species, strain genes, and several other variables like atmospheric temperatures and microbial interactions (Virdis et al., 2021). Oenococcus oeni is one of three and the most well-known species in the Oenococcus genus. O. oeni is the primary LAB of preference in winemaking due to its high tolerance for low pH, high ethanol concentrations, and nutrient lack of supply (Virdis et al., 2021). Nevertheless, with rising temperatures during expansion and harvest, and a resultant increasing pH trend for many wines, other LABs have the prospects to evolve into a reasonable alternative to Oenococcus, playing a crucial role in the adjustments of wine aroma.
Conclusion
The wine color is a significant sensory property of red wines that are determined mainly by grape variety and vintage, and to a lesser extent, by winemaking processes. The activities of yeast and LAB can also influence wine color. Wines post-MLF have lower concentrations of polymeric pigments and Visitin A and B content and a higher content of monomeric anthocyanins than their equilibrium values that did not undergo MLF(Virdis et al., 2021). Acetaldehyde is valuable for preserving wine color because it moderates the formation of permanent ethylene-linked pigments, which are more stable than their equilibrium values that were not subjected to MLF (Virdis et al., 2021). Additionally, pyruvic acid and acetaldehyde combine with pigments like malvidin-3-glucoside to form the comparatively stable pyranoanthocyanins Visitin A and Visitin B. Overall, utilizing the enzyme reactions of LAB will expand the possibilities available to winemakers in shaping the wine of their preference.
Reference
Virdis, C., Sumby, K., Bartowsky, E., & Jiranek, V. (2021). Lactic acid bacteria in wine: Technological advances and evaluation of their functional role. Frontiers in Microbiology.