There is a price premium for tomato sauce labelled as “natural” or “no artificial additives”. Citric acid (E330) is a common component of tomato sauces, and the cheapest form is biosynthetic (i.e. it is not “natural”). There is therefore an incentive for deliberate misrepresentation on the label, and a consequential need for test verification methods as to whether the citric acid is “natural”. Current reference specifications (e.g. AIJN) do not include tomato sauce.
In this conference presentation (open access) the authors report the successful use of Stable Isotope Ratio Analysis to discriminate the botanical source of the citric acid in tomato sauce Biosynthesised citric acid is from cane or corn feedstock (C4 plants) whereas inherent tomato citric acid is C3. The researchers established threshold values for citric acid carbon isotope ratios from authentic “natural” tomato sauces and used these to test a range of products on the market.
Photo by sentidos humanos on Unsplash
