Influence of glycosides on behavior of Oenococcus oeni in wine conditions: growth, substrates and aroma compounds

Abstract

Autochthonous Oenococcus oeni strains (MS9, MS20 and MS46) with good malolactic performance and yielding adequate diacetyl levels, were selected to investigate the effect of synthetic and grape glycosides on bacterial growth, substrate utilization and β-glucosidase (βGlu), α-arabinofuranosidase (αAra) and α-rhamnopyranosidase (αRha) activities in a wine-like medium containing 6% ethanol, pH 4.0 (WBM). Then, changes in the volatile compounds profile were evaluated at the end of malolactic fermentation (MLF) carried out by the MS46 strain in WBM containing 1 mg L of natural glycoside. All strains grew and efficiently degraded L-malic acid in WBM where βGlu and αAra activities were found but not αRha. In presence of a synthetic glycoside (eriodictyol 7-O-β-rutinoside) βGlu activity was significantly enhanced for two of the cultures tested (MS20 and MS460) while a low αRha activity was induced, presenting MS46 the better performance. Glycosides extracted from fermented grape musts under different conditions allowed maximum growths, L-malic acid utilization rates and glycosidase activities in the MS46 strain. Thus, βGlu, αAra and αRha activities increased between 30-50 and 3-11% respectively. This indirectly correlated to significant changes in total esters and higher alcohols at the end of MLF, which increased by up to 140 and 30% respectively. Moreover, ethyl and acetate esters formed up to 100-fold than alcohols or esters degraded highlighted the main role of this microorganism in the esters synthesis. Results obtained encourage the potential use of selected indigenous O. oeni strains as a tool to enhance wine complexity through MLF, mainly on highly fruity aroma.

Advantages of Using Blend Cultures of Native L. plantarum and O. oeni Strains to Induce Malolactic Fermentation of Patagonian Malbec Wine

“…Strains UNQLp11 and UNQOe73.2 were also able to produce β- citronellol, which is an odorant terpene released by β- glucosidase activity, previously described in some LAB ( Maturano and Saguir, 2017 ). Although this compound was below the sensory threshold, both strains seemed to have β-glucosidase activity that allowed aroma precursors hydrolysis and release of odorant aglycones, such as terpenes alcohols with pleasant floral odor properties.…”

Assessment of β-D-glucosidase activity and bgl gene expression of Oenococcus oeni SD-2a

“…Research in progress shows that LAB, possessing glycosidase activities, can modify sensory properties and aroma profile of wine. Glycosidase activities are of interest as they are responsible for the release of volatile aromas in winemaking [2,37]. Mostly, attentions are focused on βG activity of O. oeni strains during MLF [2,16,38].…”

“…Glycosidase activities are of interest as they are responsible for the release of volatile aromas in winemaking [2,37]. Mostly, attentions are focused on βG activity of O. oeni strains during MLF [2,16,38]. O. oeni SD-2a, one patent strain screened in China, possesses important oenological characteristics, particularly being able to perform MLF effectively under winery conditions.…”

“…Most white wines and almost all red wines undergo a secondary fermentation, or malolactic fermentation (MLF), a process in which dicarboxylic L-malic acid is decarboxylated into monocarboxylic L-lactic acid [1,2]. This bioconversion is carried out by lactic acid bacteria (LAB), especially by Oenococcus oeni the predominant LAB to conduct MLF [3].…”

“…These odorless precursors are largely present in grape and wine as glycosides, often structured as mono-glucoside in which the volatile aglycone is bound to a glucose moiety, or as disaccharide in which the glucose moiety is further substituted with a second sugar such as α-L-arabinopyranose, α-L-rhamnopyranose, β-D-apiofuranose and β-D-xylopyranose [10]. Volatile aglycones in these glycosides constituting a reserve of powerful odor active-compounds are often dominated by monoterpenes, C 13 -norisoprenoids and benzene derivatives and can greatly enhance wine aroma after release from glycosides [2,8,10].…”