Possible mutagenic constituents in nitrite-treated soy sauce

Area of Science:

• Food Chemistry
• Toxicology
• Analytical Chemistry

Background:

• Soy sauce is a common food condiment susceptible to chemical reactions during processing.
• Sodium nitrite is a food additive that can react to form potentially carcinogenic N-nitrosamines.
• Understanding nitrosamine formation in soy sauce is crucial for food safety assessments.

Purpose of the Study:

• To investigate the formation of N-nitrosamines in soy sauce treated with sodium nitrite.
• To assess the mutagenicity of reaction products using the Ames test.
• To evaluate the inhibitory effect of L-ascorbic acid on nitrosamine formation.

Main Methods:

• Soy sauce was heated with varying concentrations of sodium nitrite (100-2000 ppm) at 80°C and pH 3.
• Reaction products were extracted and analyzed using gas chromatography-thermal energy analysis and gas chromatography-mass spectrometry.
• Mutagenicity was evaluated using Salmonella typhimurium strain TA100 with S-9 mix.

Main Results:

• N-Nitrosodimethylamine, N-nitrosodiethylamine, and N-nitrosoproline were identified in soy sauce treated with 2000 ppm nitrite.
• Both dichloromethane and ethyl acetate extracts showed dose-related mutagenicity in Ames tests.
• L-ascorbic acid addition (10,000 ppm) completely inhibited the formation of mutagenic materials and detectable nitrosamines.

Conclusions:

• Sodium nitrite can induce the formation of mutagenic N-nitrosamines in soy sauce under specific conditions.
• The presence of L-ascorbic acid is effective in preventing the formation of these hazardous compounds.
• Findings highlight the importance of nitrite control and the protective role of ascorbic acid in food processing.