Determination of Nitrite and Nitrate in Brazilian Meats Using High Shear Homogenization

Abstract

Nitrate and nitrite are usually added to processed meat products to protect against the growth of microorganisms. Two sample preparation methodologies using either manual grinding (with a mortar and pestle) or mechanical high shear homogenization were investigated and compared. The results showed that high shear homogenization was the most suitable for the extraction of nitrite and nitrate from ham, salami, and bacon samples, achieving high extraction recoveries (> 98%) together with low relative standard deviations (RSDs) for the samples analyzed. Analyses were performed using capillary electrophoresis. A running buffer consisting of 60 mmol L-1 tetraborate and 0.2 mmol L-1 cetyltrimethylammonium bromide enabled separation of the analytes in < 5 min. In validation experiments, good repeatability was obtained for both migration times (< 0.8% RSD) and peak areas (< 1.1% RSD). Analytical curves for nitrite and nitrate were linear (r > 0.998) in the 0.2- to 2.5-mg L-1 and 0.5- to 5-mg L-1 concentration ranges, respectively. The limits of detection were 0.15 mg L-1 for nitrite and 0.17 mg L-1 for nitrate. The method developed was applied to the analysis of different kinds of meats (sausage, ham, salami, bacon, and others) produced in Brazil. The ranges of concentration found were 17.3-46.4 mg kg(-1) (nitrite) and 69.9-198.1 mg kg(-1) (nitrate). The contents of nitrate and nitrite in the samples were below the Brazilian legislation limit values (150 and 300 mg kg(-1) for nitrite and nitrate, respectively).