Sodium ascorbate and tuna meat colour change
What it found
In lab tests, adding sodium ascorbate to defrosted tuna and horse heart myoglobin produced a new red form of the meat pigment after about 24 hours.
This red colour could hide spoilage.
What they found
Animal and lab studies
New red form
After about 24 hours, adding the additives gave a final form with a Soret band shifted 4 nm to the red compared with the usual oxy species at 418 nm, but with similar Q bands.
Two oxygen species
Resonance Raman experiments in 16 O 2 and 18 O 2 showed the native oxy form alongside a second oxygen bound species. This second species had a stretching frequency upshifted 7 cm -1 and a greater isotopic shift of 33 cm -1 in 18 O 2.
Bent ligand shape
The data suggest a highly bent ligand conformation in the new species.
Masking aging
The new red colour can mask the aging of the product, which might then contain histamine.
How it was done
The authors wanted to see whether additives used to extend the shelf life of tuna meat bring a risk or a benefit to consumers.
They added sodium citrate, ascorbic acid and sodium ascorbate to defrosted yellowfin tuna loins from a local market and to horse heart myoglobin. They followed the changes using electronic absorption, second derivative spectra and resonance Raman spectroscopy, including experiments in 16 O 2 and 18 O 2.
What it can’t tell you
- We summarised it from the abstract only.
- These are lab tests on tuna meat and horse heart myoglobin, not studies in people.
- The tests do not show whether eating tuna treated with these additives would affect human health.
Who paid
- Authors work at
- Università di Firenze, Italy
The paper
- Title
- Addition of sodium ascorbate to extend the shelf-life of tuna meat fish: A risk or a benefit for consumers?
- Type
- Study
- Evidence
- Animals and lab studies
- Summarised from
- Abstract only
- Cite
- Howes BD, Milazzo L, Droghetti E, Nocentini M, Smulevich G (2019). Addition of sodium ascorbate to extend the shelf-life of tuna meat fish: A risk or a benefit for consumers?. Journal of inorganic biochemistry. doi:10.1016/j.jinorgbio.2019.110813PubMed 31491737DOI
Summary written 26 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error