Application Of Polyphenol-lysozyme-SO₂ Complex System In Italian Riesling Ice White Wine

With the improvement of living conditions in these years, food safety is becoming a hot piont concerned by the whole society. Ice wine has already harvested much favor and respect from consumers dependent on its sweet taste and fragrance aroma. However, higher amounts of SO2 in ice wine is harmful to health, especially for the patients who suffering from some respiratory diseases such as asthma. Therefore, searching for effective alternatives to SO2 or reducing its usage become one of the basic sciences to be resolved in the field of wine. Polyphenols have antibacterial activity on microorganism and prominent antioxidant capacity, which have been widely used in the food industry. Lysozyme can not only inhibition on G+ bacteria, but also reduce the content of volatile acids and biogenic amines. Thus, In this paper, We have compared the antibacterial and antioxidant activity of polyphenols, then established an antibacterial complex system include polyphenol, SO2 and lysozyme for Italian Riesling ice white wine, to improve the stability in the aging process of ice white wine and reduce the SO2 usage in wine. The results show that:1. All the tested polyphenols had different effective radical scavenging capacity. ABTS+? clearance, DPPH? clearance and Fe2+chelating ability are high than O2-? clearance and OH? clearance by polyphenols. Polyphenols that had the highest clearance of O2-?, OH?, ABTS+?, DPPH?and Fe2+ chelating ability were myricetin, epigallocatechin-3-gallate, epigallocatechin-3-gallate, epigallocatechin-3-gallate and gallic acid, respectively.2. The IC50 value of polyphenol antioxidant capacity abtained by PCA shows that, epigallocatechin-3-gallate,(+)-catechin,(-)-epicatechin, myricetin and quercetin have high antioxidant capacity among the 8 tested polyphenols, while gallic acid, quercetin and kaempferol have low antioxidant capacity.3. The antimicrobial test show that, polyphenols have the highest antimicrobial activity by Oenococcus oeni VP41, Oenococcus oeni OMEGA, Acetobacter pasteurianus 1249, Acetobacter pasteurianus 1412 and Saccharomyces cerevisiae VL1 are myricetin, myricetin, epigallocatechin-3-gallate, epigallocatechin-3-gallate, and quercetin, respectively.4. The antimicrobial activity of polyphenols(10 g/L) abtained by PCA shows that, among the 8 tested polyphenols, myricetin has a better antimicrobial activity, while kaempferol and gallic acid have low antimicrobial activities.5.(+)-catechin,(-)-epicatechin and quercetin have a light affect of the stability of Italian Riesling ice white wine. Sensory evaluation showed that, quercetin, lysozyme and SO2 have a light affect of the sensory of Italian Riesling ice white wine.6. Quercetin(50 mg/L) complex with lysozyme(180 mg/L) and SO2(180 mg/L) could add in Italian Riesling ice white wine, roled as an alternative to reduce the amount of SO2 effectively, and played as a preservative(the inhibition zone diameter is 1.604 cm), at the same time improved the antioxidant capacity of wine(the IC50 values of O2-?、OH?、ABTS+?、DPPH? clearance and Fe2+chelating ability by quercetin are 0.972、1.067、0.291、0.066、0.037, respectively).