Nitrate and Nitrite in Fresh Tomato and Tomato derived Products
Fatemehsadat Mir Mohammad-Makki1, Parisa Ziarati2*1Department of Food Sciences and Technology, Faculty of Advanced Sciences and Technology, Pharmaceutical Sciences Branch, Islamic Azad University, Tehran - Iran (IAUPS)
2Departments of Medicinal Chemistry, Faculty of Pharmacy, Pharmaceutical Sciences Branch, Islamic Azad University, Tehran - Iran (IAUPS)
Abstract: In recent years, an increasing interest concerning determination of nitrate levels in food products has been observed, essentially due to the potential reduction of nitrate to nitrite, which is known to cause adverse effects on human and animal health. The main goal of this study was measuring nitrite and nitrate contents of tomato derived products samples commercially available in Iran market in comparison on fresh tomato. Taking fresh and untreated samples was done by going to the chosen areas of recognized farms in Khuzestan, Kerman and South of Tehran provinces, and a total of 456 samples of 8 varieties of tomato products during 5 consecutive months of 2014 - 2015 were taken and analyzed. In order to conduct a comparison between the content of nitrate and nitrite in the samples studied, dry matter content was determined according to the association of office analytical chemists (AOAC, 2000). A fifty gram sample of the prepared tomato was blended with 50ml distilled water in a home blender. The mixture was filtered and was passed through a glass 39 column fitted with a tape and filled with activated alumina, in order to separate the color of Chlorophyll and get a transparent solution. The eluted solution by water filtered using 0.45um filter paper in order to eliminate the turbidity and get a clear solution. Nitrite concentration in tomato samples were determined by spectrophotometric methods at a wavelength of 538 nm, and nitrate concentration was determined after reducing nitrate to nitrite by using cadmium column. The different agricultural areas in the different provinces in this research show a significant effect on the nitrate and nitrite contents in tomato samples tested (p<0.003) as nitrate and nitrite content in Tehran farmlands were significantly higher. The highest level of nitrate was found in ketchup by range of: 15.01-167.54 and mean content of 65.73±0.007 (mg/kg FW ±SE). This concentration is significantly higher that other tomato products while in ketchup and pizza sauce the lowest nitrite content was found: 0.10±0.001 and 0.11±0.001 ( mg/kg FW ±SE) respectively and tomato juice packaged samples have the highest level of nitrite
Keywords: Nitrate; Nitrite; Fresh tomato; Tomato processed products Back to TOC