Effect of co‐inoculation with yeast and bacteria on chemical and sensory characteristics of commercial Cabernet Franc red wine from Switzerland

Abstract

BACKGROUND: Malolactic fermentation (MLF) is a critical step in modern winemaking and the co-inoculation of lactic acid bacteria with yeasts represents an emerging approach to improve the quality of wine. This study aims to evaluate the effect of inoculation timing on the chemical and sensory characteristics of two commercial Cabernet Franc wines: (i) a control wine in which MLF was inoculated after the completion of alcoholic fermentation (AF); and (ii) a co-inoculated wine where simultaneous alcoholic and malolactic fermentations occurred.RESULTS: Besides the expected full conversion of malic acid into lactic acid, the MLF with co-inoculum of yeast/bacteria at initial AF allowed for reduced fermentation times, i.e. faster winemaking process. Although important changes in the chemical parameters of wines were found, especially color intensity and volatile compounds, there was a trend on the sensory evaluation of wines with a greater perception of red and ripe fruits in the case of co-inoculation wine, while the control wine was dominated by notes of spice and herbs. The results of GC/MS analysis showed the largest differences for the 3-hydroxy-2-butanone (acetoin, the reduced form of diacetyl) and isoamyl alcohol concentrations, the former was 3.2 times higher under co-inoculum conditions, whereas the latter showed the opposite behavior. CONCLUSION: The co-inoculation protocol proposed is a valuable choice for innovative winemaking of Cabernet Franc wines, and results from a large-scale winemaking process are provided for the first time.

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

“…The co‐inoculated wines (CSAO and CSCO) had a lower amount of LPP compared to the corresponding AF wines (CSA and CSO), thus indicating that the co‐inoculation influences polymeric pigment formation. Similar findings were found in Pinot noir, Merlot and cabernet Franc wines, where MLF resulted in loss of colour and anthocyanin, regardless of whether this occurred consecutively or concurrently. The reduction was attributed to the biodegradation of acetaldehyde and pyruvic acid during the MLF, which further affected the formation of polymeric pigments.…”

“…Co‐inoculated cabernet wines had an additional hazelnut note compared to the corresponding AF wines, suggesting the influence of co‐inoculation on wine aroma. However, the aroma was also affected by yeast bacterial combination, as well as grape variety . The co‐inoculated wines scored low for color compared to the corresponding wines; however, this did not affect the overall acceptability of the wines.…”

“…Co‐inoculated wines indicated a loss of CI compared to the corresponding AF wines. Earlier studies had suggested that the wine color intensity is affected by anthocyanins and polymeric pigments, as well as co‐pigmentation This implied that the bacterial metabolism had significantly affected polyphenol transformation or metabolism during the co‐inoculation and thus influenced wine color, as well as astringency …”

“…Therefore, slowly, the global wine industry is considering the co‐inoculation of yeast and bacteria to must . This provides lactic acid bacteria with the time to adapt to the medium and also reduces the overall fermentation time . Such a reduction enhances microbiological stability and winemaking efficiency.…”

Impact of inhibitory peptides released by Saccharomyces cerevisiae BDX on the malolactic fermentation performed by Oenococcus oeni Vitilactic F

“…Although the 5-10 kDa peptides gradually appeared during the AF as demonstrated by the present study, the MLF was improved. More recently, co-inoculation was suggested as a worthwhile alternative for winemaking both for better malate consumption and sensorial characteristics when compared with the traditional sequential inoculation (Cañas et al 2015;Versari et al, 2015;Tristezza et al, 2016).…”