title: Influence of Distillation Temperature in the Determination of Added Sulfites in Dehydrated Garlic Powders Using the Modified Optimized Monier-Williams Method.
abstract: Influence of distillation temperature on the determination of added sulfites in dehydrated garlic originating from China and California using the modified optimized Monier-Williams method was evaluated. In the study, the temperature of the distillation was monitored and maintained from 90° to 95°C instead of boiling temperature (>95°C). Samples from 38 unsulfited dehydrated garlic powders were analyzed at the 90° to 95°C temperature and at boiling temperature (>95°C) at 94 m above sea level. At the boiling distillation temperature, 25 of the 38 unsulfited garlic samples had a positive result for sulfite content ranging from 10.2 to 14.1 ppm using the modified optimized Monier-Williams procedure. Maintaining distillation temperature between 90° and 95°C eliminated false-positive results for added sulfite and had an average spiked sulfite recovery of 95.6% with a coefficient of variation of 3.79%. Lowering of the distillation temperature decreases the possible acid hydrolysis of organosulfur compounds that can lead to positive added sulfite results in unsulfited dehydrated garlic samples.