Non-anthocyanin polyphenolic transformation by native yeast and bacteria co-inoculation strategy during vinification

Malolactic Fermentation: New Approaches to Old Problems

Malolactic fermentation (MLF) is the decarboxylation of L-malic acid to L-lactic acid by lactic acid bacteria (LAB). For the majority of wine production, secondary fermentation is crucial. MLF significantly impacts the quality of most red and some white wine. The outcomes of the spontaneously initiated and finished MLF are frequently unpredictable and can even cause the wine to deteriorate. As a result, individuals typically favour inoculating superior starter cultures when performing MLF. The MLF method for wine has, however, faced new difficulties because of the altered wine fermentation substrate environment brought on by global climate change, the growing demands of winemakers for production efficiency, and the rising demand for high-quality wine. To serve as a reference for the study of wine production and MLF in the current situation, this review primarily updates and summarises the research findings on increasing the effectiveness and dependability of MLF in recent years.

Evolution of polyphenolic, anthocyanin, and organic acid components during coinoculation fermentation (simultaneous inoculation of LAB and yeast) and sequential fermentation of blueberry wine

This research aims to investigate the effects of both sequential fermentation and coinoculation fermentation with yeast and lactic acid bacterial (LAB) on the dynamics of changes in basic quality parameters and organic acid, anthocyanin, and phenolic components as well as antioxidant activity during the fermentation of blueberry. The coculture-fermented blueberry wine showed significant decreases in total phenolics, flavonoids, and anthocyanins,by 23.9%, 15.9%, and 13.7%, respectively, as compared with those before fermentation Fermentation changed the contents of organic acids in each group, with a more than 7-fold increase in lactic acid contents as well as a more than 4-fold reduction in quinic acid and malic acid contents. The content of all investigated anthocyanins first increased and then decreased. Moreover, different fermentation strategies exerted a profound influence on the dynamic change in phenolic components during fermentation; specifically, most of the phenolic acids showed a trend of increasing first, then decreasing, and finally increasing. Gallic acid, p-coumaric acid, quercetin, and myricetin were increased by 116.9%, 130.1%, 127.2% and 177.6%, respectively, while syringic acid, ferulic acid, cinnamic acid, and vanillic acid were decreased by 49.5%, 68.5%, and 37.1% in sequentially fermented blueberry wine. Coinoculation fermentation with yeast and LAB produces faster dynamic variations and higher organic acid, anthocyanin, and phenolic profiles than sequential inoculation fermentation. PRACTICAL APPLICATION: In this work, brewing technology of sequential fermentation and coinoculation fermentation with yeast and LAB (Lactobacillus plantarum SGJ-24 and Oenococcus oeni SD-2a) was adopted to ferment blueberry wine. This is an innovative technology of fruit wine brewing technology to produce wine products. Compared with traditional sequential brewing, simultaneous inoculation brewing can significantly accelerate the brewing process of fruit wine and slightly improve the quality of fruit wine in terms of active ingredients.

Technological Improvements on FML in the Chianti Classico Wine Production: Co-Inoculation or Sequential Inoculation?

Winemaking variables and techniques are known to affect the composition of wines. To obtain a rapid and safe fermentation course, with a reduced risk of proliferation of unwanted microbial species, frequent recourse is made to the use of selected microorganisms, which can greatly simplify the complex management of the fermentation process. In particular, selected strains of lactic acid bacteria are used, which are much more sensitive than yeasts to the operating conditions of the medium. In this regard, the overall aim of this research was to verify whether the early inoculation of homolactic acid bacteria for hexoses (Lactobacillus plantarum) carried out after 24 h, compared with that of saccharomycetes operating alcoholic fermentation, could be advantageous compared with a traditional innoculation with a different heterolactic bacterial strain for hexoses (Oenococcus oeni) operated at the end of alcoholic fermentation. The grape variety chosen was Sangiovese, the protagonist of Tuscan oenology. The evaluation focused on different aspects such as the management of winery operations, and the quality and longevity of the product; was carried out in all phases of winemaking; and analysed both from a chemical and sensory point of view.

The microbial challenge of winemaking: yeast-bacteria compatibility

The diversity and complexity of wine environments present challenges for predicting success of fermentation. In particular, compatibility between yeast and lactic acid bacteria is affected by chemical and physical parameters that are strain and cultivar specific. This review focuses on the impact of compound production by microbes and physical interactions between microbes that ultimately influence how yeast and bacteria may work together during fermentation. This review also highlights the importance of understanding microbial interactions for yeast-bacteria compatibility in the wine context.

Adsorption and biotransformation of anthocyanin glucosides and quercetin glycosides by Oenococcus oeni and Lactobacillus plantarum in model wine solution

BACKGROUND

Anthocyanins and flavonols play a significant role in contributing to wine color and mouthfeel, and the interaction of malolactic fermentation with these compounds is not well known. Here we investigated the adsorption of these compounds by Oenococcus oeni and Lactobacillus plantarum.

RESULTS

Delphinidin-3-glucoside (D3G) was adsorbed the most, followed by malvidin-3-glucoside (M3G) and peonidin-3-glucoside (P3G) for both the bacterial species, while flavonols were not adsorbed. An increase in β-glycosidase activity suggested that this enzyme breaks down the anthocyanin glucosides, providing sugars for growth. An average decline of approximately 65% in enzyme activity in the presence of substantial residual sugar was observed. The specific metabolic rates were found to be dependent on the class of anthocyanin and species / strain of the bacteria. Selective adsorption of anthocyanins and not the flavonol glycosides suggest that electrostatic interactions mediate the adsorption. Further, a breakdown of anthocyanins resulted in phloroglucinol aldehyde from the flavonoid A-ring and corresponding phenolic acids from the B-ring, i.e., gallic acid for D3G, syringic acid for M3G, and vanillic acid for P3G.

CONCLUSIONS

The breakdown and adsorption of the anthocyanin glucosides can help explain the color loss and aroma changes, such as the appearance of syringic and vanillic acid, associated with malolactic fermentation. © 2019 Society of Chemical Industry.

Feasibility of using integrated fingerprinting, profiling and chemometrics approach to understand (bio) chemical changes throughout commercial red winemaking: A case study on Merlot

This study assessed the feasibility of using a multiplatform approach; integrating untargeted fingerprinting of volatiles and targeted profiling of phenolic and oenological attributes (soluble solids, pH, titratable acidity and colour properties) coupled with chemometrics to understand complex (bio) chemical reactions occurring during Merlot red winemaking. The changes were investigated at three winemaking stages, starting from pre-maceration (PM), maceration-alcoholic fermentation (MAF) up to completion of malolactic fermentation (MLF). Merlot musts at PM were characterised by lighter colour and higher amount of green aroma-related volatiles. Completion of MAF led to increased extraction of anthocyanins, flavonols, and stilbenes, resulting in a more intense and darker fermenting juice. Furthermore, development of yeast-fermentation associated volatiles such as esters and alcohols was observed at this stage. The final wine, when MLF was completed, was rich in phenolic acids, esters, alcohols, and terpenes. The multiplatform analytical approach was effective to unravel the complex reactions throughout Merlot winemaking process and find relevant markers, which could help to predict expected quality attributes in the finished wine.