Formation of dextran deposits in Brazilian sugar cane spirits.

The formation of dextran deposits in sugared Brazilian cachaça was studied as a function of the time considering the effects of temperature, molecular weight (M(w)), visible light, pH, and the presence of Ca, Mg, Cu, and Fe ions in the concentrations at which they are usually present in this beverage. At 25 °C and pH 4.4, the experimental half-lives (t(1/2)) for precipitation are 73 and 124 days for dextrans with M(w) 5.9 × 10(6) and 2.1 × 10(6) Da, respectively. For dextrans with M(w) 5.0 × 10(5) and 4.0 × 10(4) Da, the experimental t(1/2) values are >180 days. For a dextran with M(w) 2.1 × 10(6) Da a change in pH from 4.4 to 5.5 at 25 °C resulted in a t(1/2) decrease from 124 to 25 days. At pH 4.4 the visible light and the presence of metal ions in average concentrations usually found in cachaças do not exhibit noticeable influence on the rate of dextran precipitation.