Contributions concerning the study of the antiseptic effect of sulfur dioxide on the yeasts present in two wines provided by Cotnari vineyard

Sulfur dioxide is one of the most used antiseptics in vinification. Its action on the "infection" microorganisms found in wine cellars is demonstrated by numerous studies. The present study shows that the antiseptic potential of sulfur dioxide is highly dependent on the concentration of its free form. The high concentrations of free sulfur dioxide corroborated with the prolonged contact period lead to the killing of the yeast cells quickly and evenly, while at low concentrations its lethal effect is greatly diminished. At low concentrations the lethal effect of sulfur dioxide is highly dependent on the contact time of the yeast cells with the environment. In this case, their mortality rate is very uneven. This phenomenon is also explained by the losses that occur due to the volatilization of sulfur dioxide, of oxidation or on account of its binding to other compounds

Rapid assessment of mycotoxins in wine by on-line SPE-UHPLC-FLD

According to the latest statistics, grapes are one of the largest fruit crops worldwide. In this regard, it is important to consider all factors influencing quality of grapes and wine. In the last years, scientist focused on the study of mycotoxins that can influence the quality of wine. It is considered that toxins produced by moulds, causing significant economic losses, affect approximately one quarter of the world grape production. If the selective sorting of infected grapes is not done adequately, wine will present a major risk to consumers, mycotoxins being considered by the “International Agency for Cancer Research” a carcinogenic compound. The main mycotoxins monitored in this study come from Aspergillus sp., and are represented by aflatoxins B1, B2, G1, G2 and ochratoxin A. This study purpose is to develop a faster method for the analysis of mycotoxins, in order to increase rapidity and efficiency for the evaluation of the degree of infestation in wine. The purposed method is using an on-line large volume injection coupled to pre-concentration of sample (SPE) which is directly transfer to the ultra-high-pressure liquid chromatography (UHPLC) column for separation and the detection by means of the fluorescence detector (FLD). As the maximum tolerated level for mycotoxins in wines is 2 ppm, this method is able to detect under this limits of quantification with RSD below 2%

Rapid assessment of mycotoxins in wine by on-line SPE-UHPLC-FLD

According to the latest statistics, grapes are one of the largest fruit crops worldwide. In this regard, it is important to consider all factors influencing quality of grapes and wine. In the last years, scientist focused on the study of mycotoxins that can influence the quality of wine. It is considered that toxins produced by moulds, causing significant economic losses, affect approximately one quarter of the world grape production. If the selective sorting of infected grapes is not done adequately, wine will present a major risk to consumers, mycotoxins being considered by the “International Agency for Cancer Research” a carcinogenic compound. The main mycotoxins monitored in this study come from Aspergillus sp., and are represented by aflatoxins B1, B2, G1, G2 and ochratoxin A. This study purpose is to develop a faster method for the analysis of mycotoxins, in order to increase rapidity and efficiency for the evaluation of the degree of infestation in wine. The purposed method is using an on-line large volume injection coupled to pre-concentration of sample (SPE) which is directly transfer to the ultra-high-pressure liquid chromatography (UHPLC) column for separation and the detection by means of the fluorescence detector (FLD). As the maximum tolerated level for mycotoxins in wines is 2 ppm, this method is able to detect under this limits of quantification with RSD below 2%