Tartrate salt stabilization precipitation

Where membrane filtration is applied in the wine production process can also have long terms effects. Care should be taken to ensure that long term colloidal stability as a result of membrane filtration is not a problem. It may take several months for the colloids to reestablish new equilibrium. Proteins, anthocyanins, tannins and tartrate salts may precipitate. 

The stabilizing effect of buffers that have multiple charged species in solution should also be investigated to determine the potential reaction between excipients and API. For example, buffers that use carbonates, citrate, tartrate, and various phosphate salts may precipitate with calcium ions by forming sparingly soluble salts. However, this precipitation is dependent upon the solution pH. Because phosphate can exist in mono-, di-, and tribasic forms, each calcium salt has its own solubility product, and precipitation will only occur when one of the solubility product is exceeded. Calcium ions may also interact or chelate with various amino acids, and other excipients, which may also lower the effective concentration of calcium that is capable of interacting with phosphate ions. Finally, the activity of phosphate ions may be lowered due to interactions with other solution components. 

Use of Metatartaric Acid for Stabilization of Tartrate Salt Precipitation. 148... 

Work has been done to find whether the very expensive treatment of wines with artificial cold could be advantageously replaced by the addition of inhibitors of the crystallization process of tartrate salts such as metatartaric acid, yeast mannopro-teins or carboxymethylcellulose (CMC). Such inhibitors indeed increase the width of the supersaturation field of both KHT and TCa in the wine, thus delaying tartrate salt precipitation in the bottle. Metatartaric acid is currently the product most widely used for this purpose, though its efficacy is low as this compound does not remain stable over time. Yeast mannoproteins possess stabilizing properties, which result in the spontaneous improvement of protein and tartaric salt stability, as can be... 

It is well established that, during wine aging on lees, yeasts release mannoproteins that are able to prevent tartrate salt precipitation as was demonstrated first by Lubbers et al. (1993) in model wine solutions. Lubbers et al. (1993) used heat-extracted mannoproteins in alkaline buffers, that is, conditions very different from the spontaneous release of proteins during aging on lees. Nevertheless, Moine-Ledoux and Dubourdieu (1999) reported that heat-extracted mannoproteins added at a dose of 25 g/hL do not show any stabilizing effect as regard to tartrate salt precipitations in red, ros6 and white wines. 

Stabilizing wines to prevent precipitation of calcium tartrate is not easy, as the crystallization of potassium bitartrate does not indnce that of calcium tartrate, despite the fact that these two salts should logically syncrystallize as they have the same crystal systems. On the contrary, crystallization of TCa may induce that of KTH. The prevention of calcium tartrate precipitation is further complicated by the fact that the solubility of TCa (Postel, 1983) is not very temperature-sensitive. Thns, TCa is hardly three times more soluble at 20°C than at —4°C. 

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