Malolactic fermentation (MLF) is a process in winemaking responsible for the conversion of l-malic acid to l-lactic acid and CO2, which reduces the total acidity, improves the biological stability, ...and modifies the aroma profile of wine. MLF takes place during or after alcoholic fermentation and is carried out by one or more species of lactic acid bacteria (LAB), which are either present in grapes and cellars or inoculated with malolactic starters during the winemaking process. Although the main bacterium among LAB used in commercial starter cultures for MLF has traditionally been Oenococcus oeni, in the last decade, Lactobacillus plantarum has also been reported as a malolactic starter, and many works have shown that this species can survive and even grow under harsh conditions of wine (i.e., high ethanol content and low pH values). Furthermore, it has been proved that some strains of L. plantarum are able to conduct MLF just as efficiently as O. oeni. In addition, L. plantarum exhibits a more diverse enzymatic profile than O. oeni, which could play an important role in the modification of the wine aroma profile. This enzymatic diversity allows obtaining several starter cultures composed of different L. plantarum biotypes, which could result in distinctive wines. In this context, this review focuses on showing the relevance of L. plantarum as a MLF starter culture in winemaking.
How to cite: Brizuela NS, Tymczyszyn E, Semorile LC, et al. Lactobacillus plantarum as a malolactic starter culture in winemaking: a new (old) player? Electron J Biotechnol 2019;38. https://doi.org/10.1016/j.ejbt.2018.12.002.
Argentina is the fifth world-wide wine producer, with an area of emerging importance in the Southwest of Buenos Aires Province, where climatic conditions are rather challenging. We studied the ...variations in soil and wine bacterial diversity through three consecutive vintages, and how climatic conditions affected said diversity. During the years of our study there were two harsh climatic events, a prolonged drought that extended over two vegetative periods, and an unseasonable spring frost in 2017. We found that the bacterial diversity reacted to these climatic events, given that there was a shift in the taxa exclusive to soil and wine, and shared by both, through time. Our results show a core of microorganisms in soil as well as in wine, belonging to different phyla that are conserved across the vintage years. A trend to an enrichment in
Actinobacteria
was detected in soil samples, whereas a high relative abundance of the
Acetobacteraceae
family and a scarcity of Lactic Acid Bacteria (LAB) were detected in the wine samples. We believe our results contribute to a better understanding of the impact of climatic conditions on the soil and wine microbiota, and can provide vintners with valuable knowledge for improving their wine production.
Winemaking is a complex process involving two successive fermentations: alcoholic fermentation, by yeasts, and malolactic fermentation (MLF), by lactic acid bacteria (LAB). During MLF, LAB can ...contribute positively to wine flavor through decarboxylation of malic acid with acidity reduction and other numerous enzymatic reactions. However, some microorganisms can have a negative impact on the quality of the wine through processes such as biogenic amine production. For these reasons, monitoring the bacterial community profiles during MLF can predict and control the quality of the final product. In addition, the selection of LAB from a wine-producing area is necessary for the formulation of native malolactic starter cultures well adapted to local winemaking practices and able to enhance the regional wine typicality. In this sense, molecular biology techniques are fundamental tools to decipher the native microbiome involved in MLF and to select bacterial strains with potential to function as starter cultures, given their enological and technological characteristics. In this context, this work reviews the different molecular tools (both culture-dependent and -independent) that can be applied to the study of MLF, either in bacterial isolates or in the microbial community of wine, and of its dynamics during the process.
The malolactic fermentation (MLF) of Patagonian Malbec wine inoculated with blend cultures of selected native strains of
and
was monitored during 14 days, analyzing the strains ability to modify the ...content of some organic acids and to change the volatile compounds profile. The performance of the LAB strains was tested as single and blends cultures of both species. An implantation control by RAPD PCR was also carried out to differentiate among indigenous and inoculated strains. The
strains UNQLp11 and UNQLp155 and the
strain UNQOe73.2 were able to remain viable during the monitoring time of MLF, whereas the
strain UNQOe31b showed a decrease of five log CFU at day 14. The four strains assayed showed a similar behavior in wine whether they were inoculated individually or as blend cultures. All strains were able to consume L-malic acid, particularly the
strains, which showed the highest consumption values at day 14, both as single or blend cultures. The changes in the volatile compounds profile of Malbec wine samples, before and after MLF, were determined by HS-SPME and GC-MS technique. Wines inoculated with blend cultures containing strain UNQLp155 showed a decrease in the total alcohols content and an increase in the total esters content. On the other hand, wines inoculated with single cultures of strains UNQLp155, UNQOe31b or UNQOe73.2 showed no significant decrease in the total alcohols concentration but a significant increase in the total esters content. When strain UNQLp11 was inoculated as single or as blend culture with strain UNQOe31b, wines exhibited an increase in the total alcohols content, and a decrease in the total esters content. The content of diethyl succinate showed the greatest increase at final of MLF, and a particular synergistic effect in its synthesis was observed with a blend culture of strains UNQLp155 and UNQOe73.2. These results suggest that the use of blend cultures formulated with strains belonging to
and
species could offer an interesting advantage to induce MLF in Malbec wines, contributing to diversify their aromatic profiles.
The aim of this study was to characterize the microbial communities of Malbec vineyards recently established in a re-emerging wine region of Argentina. We studied the wine microbiota at different ...fermentation stages and the soil and rhizosphere microbial communities of two vineyards. A next-generation sequencing (NGS) approach was used to identify bacterial and fungal communities. The soil and rhizosphere samples showed a predominance of the phyla Proteobacteria and Actinobacteria. The order Rhizobiales stood out in the soil and rhizosphere of the two vineyards analyzed. Members of this order are recognized for their plant-growth promotion properties. Regarding fungal communities, Ascomycota and Basidiomycota were the most abundant phyla. The high abundance of the genus Ilyonectria in one of the vineyards may have impact on the health of vines. In wine samples, we detected low levels of lactic acid bacteria and the persistence of acetic acid bacteria (AAB) throughout the fermentation process, although there were no discernible effects on the acidity of wine. The results achieved could allow winemakers to improve the vineyard management practices and the fermentation process to favor the growth of microorganisms potentially beneficial for the health of the vines and the wine quality, while maintaining the regional microbial biodiversity.
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•Alpha & Beta Diversity suggested differences in the bacterial and fungal community composition.•Bacterial communities were largely dominated by Proteobacteria spp.•Acetic Acid bacteria were detected in all the wine fermentation stages of Malbec wine.•Control of excess volatile acidity and use of autochthonous LAB should be considered.•The high abundance of Ilyonectria could have an impact on the health of the vines.
In vitro selection tests such as exposure to low pH and bile salts, competitive exclusion of pathogens, adherence to cell lines and prokaryotic-eukaryotic co-cultures have been commonly used to ...predict the functional properties of lactobacilli and bifidobacteria for their use as probiotics. However, the correlation of in vitro results with in vivo performance remains obscure.
To review the current state of evidence linking in vitro predictions to in vivo outcomes in selecting probiotic candidates and to discuss the advantages and limitations of the various assays presently available.
The successful use of lactobacilli and bifidobacteria as traditional probiotics is based on their occurrence in human milk, naturally fermented foods, in the gastrointestinal tract and feces of infants and adults as well as on their culturability, technological robustness and long history of safe use. The lack of standardized protocols for in vitro and in vivo studies hampers comparison of the potential of new species and strains. There is thus a need to conduct selection of potential probiotics in a more robust manner and to focus well-defined in vitro and in vivo studies to document health benefits.
•Lactobacilli and bifidobacteria are traditional probiotics based on their documented benefits and long history of safe use.•The value of in vitro tests as predictors of probiotic capacity is still uncertain.•There is a lack of standardized in vitro protocols for strain selection.•Nevertheless, present criteria allow narrowing down potential candidates when selecting new strains.
Sensory analysis for stuffed cheese with Penicillium nalgiovense superficial growth using a descriptive analysis was performed. Cheeses were manufactured in a pilot plant. Penicillium nalgiovense was ...superficially inoculated and the cheeses were ripened at 12 °C and 90% relative humidity until packaged using a microperforated polyethylene film on day 14. The ripening process continued at either 5 °C or 12 °C for 21 days. Results showed that P. nalgiovense not only confers the external desirable appearance but also has a protective effect against dehydration process. Inoculated cheeses showed descriptors of odour and flavour associated with moulds. Ammonia notes were perceived only for inoculated cheeses on day 35 being more pronounced at 12 °C than 5 °C. The high fat content of the cheeses and the transparent and microperforated packaging might affect the oxidative stability of cheeses at the end of the ripening.
Penicillium nalgiovense is not used intentionally by the dairy industry although it is a well-known species for meat products. The aim of this study was to select P. nalgiovense strains characterized ...in their genetic diversity, based on their ability to grow on the surface of a stuffed cheese and produce the lowest amounts of penicillin in that product. The most suitable strain was used to develop an innovative cheese, which was characterized (physicochemical properties and penicillin content) and subjected to sensory evaluation. ISSR cluster analysis showed low genetic diversity and all strains were able to express penicillin on synthetic media at 25 °C. Three out 20 P. nalgiovense strains were selected to inoculate stuffed cheeses elaborated with commercial melted cheese. The products were ripened at 12 °C and 90% r.h. for 14 days and then preserved at 5 °C. The three strains gave a homogeneous covering surface. Strain C5 showed the lowest penicillin production; thus, it was selected to inoculate stuffed cheese elaborated with semi-hard cheese mass. This novel stuffed cheese is feasible and the amount of penicillin produced does not represent a toxicological risk. This product presented high acceptance scores for the attributes flavor, texture, and overall acceptability.
•Penicillium nalgiovense successfully grew on stuffed cheeses.•The stuffed cheeses developed proved to be safe.•The physicochemical properties changed slightly during ripening.•The product obtained 6.9 on a 9-point scale of overall sensory evaluation.•The dehydration over time is a limiting factor for the shelf life of the product.
The impact of microperforated polyethylene film packaging on the ripening process of a stuffed cheese with superficial fungal growth was evaluated. Cheeses were manufactured in a pilot plant using ...synthetic casings. Penicillium nalgiovense was superficially inoculated and the cheeses were ripened at 12 °C and 90% relative humidity until packaged using a microperforated polyethylene film on day 14. The ripening process continued at either 5 °C or 12 °C for 29 days. Results showed that the packaging used was useful in decreasing dehydration while maintaining fungal viability. After packing, the external appearance of cheeses was not modified. SEM micrographs did not show high disintegration of the fungal hyphae throughout the ripening time. Fungal peptidases passed through the casing contributing to proteolysis.
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