Study On The Effect Of Phenolic Compounds On The Growth Of Oenococcus Oeni

The aim of this work was to investigate the effect of phenolic compounds （ferulic acid,caffeic acid and quercetin） on the growth of Oenococcus oeni （O. oeni SD-2a, O. oeni HB-2band O. oeni SD-2gf）, through investigating plasma membrane proteins and H⁺-ATPaseactivity. In order to provide a theoretical basis for the knowledge of choosing phenoliccompounds as SO₂substitutes in winemaking process. The results were as follows:1. Ferulic acid, caffeic acid and quercetin showed antimicrobial properties and theinhibition increased when the phenolic compounds concentration increased. It was observedthat bacterial specials exhibited different towards different phenolic compounds. Furthemore,ferulic acid and caffeic acid had little effect on the pH of the media, but the pH of differentsuspensions joined quercetin showed various trends. Inoculated O. oeni HB-2b, the pH of themedia decreased; when inoculated O. oeni SD-2a and O. oeni SD-2gf separately, the pH ofthe media increased firstly and then decreased, the maximum value was even above5.00, andeach bacterial suspension with quercetin was also higher than control.2. The results of investigating plasma membrane protein showed that: withoutpolyphenols, plasma membrane protein content of each strain gradually increased with thefermentation process. It was observed that the promotion of plasma membrane proteinexhibited different levels towards different phenolic compounds, and the content waspositively correlated. Compared with ferulic acid and caffeic acid, quercetin led to the highestplasma membrane protein content of each strain.3. The plasma membrane H⁺-ATPase activity of each strain at different growth stagesindicated that all phenolic compounds could reduce the enzyme activities of tested strains.Without polyphenols, enzyme activity of each strain showed the maximum in mid-logarithmicgrowth period. It was observed that bacterial specials exhibited different variation trendstowards the continuation of fermentation process. The enzyme activity of O. oeni SD-2adeclined firstly and then ascended, nevertheless enzyme activities of other strains decreasedgradually. The O. oeni HB-2b enzyme activities were higher than the other two strains at thesame time. Phenolic compounds could reduce the plasma membrane H⁺-ATPase acitivity. Thedegree of inhibition depended on different phenols and strains as well as the growth stages.Quercetin was the strongest inhibitor which was active against two of the three phenolsassayed. O. oeni HB-2b showed the highest enzyme activity. When it was in the late logarithmic period, the extent of inhibition was the minimum.4. For O. oeni SD-2a, it was the bactrium most sensitive to caffeic acid, followed byquercetin, and ferulic acid, respectively. With regard to O. oeni HB-2b, the resistance tocaffeic acid was strongest and quercetin was weakest. As to O. oeni SD-2gf, it was the mostresistant to ferulic acid. On the contrary it showed the strongest sensitivity to quercetin andexhibited the most notable inhibition. Combined with the strain growth and plasma membraneprotein as well as H⁺-ATPase activity, O. oeni HB-2b was more resistant than the otherbacteria.