Action spectrum for photooxidation
Jens Petter Wold has authored a paper on photooxidation in full fat bovine milk together with Josefine Skaret, Trine Kastrup Dalsgaard. The paper is titled: “Assessment of the action spectrum for photooxidation in full fat bovine milk” and was recently published in the journal Food Chemistry.
- An action spectrum for photooxidation in full fat bovine milk has been obtained.
- The action spectrum deviates significantly from the absorption spectrum of milk.
- The action spectrum is based on sensory analysis and measured volatile compounds.
- Violet, yellow, orange and red light induces most oxidation in full fat milk.
- Protoporphyrin IX, a chlorophyll compound and riboflavin are responsible photosensitizers.
The action spectrum for photooxidation in full fat bovine milk was measured. Samples of milk with air or argon in headspace were exposed to narrow wavelength bands of light in the range 400–700 nm. Photooxidation in terms of off-flavors was measured by a sensory panel, volatile compounds by headspace solid phase micro extraction (SPME–GC–MS), and photobleaching of photosensitizers in milk (riboflavin, protoporphyrin IX and a chlorophyllic compound) by front face fluorescence spectroscopy. The action spectrum deviated significantly from the absorption spectrum of milk. Significant oxidation was induced by wavelengths around 400 nm and 500–650 nm in milk with air in headspace. Argon in headspace gave significant oxidation also at 700 nm. It is suggested that protoporphyrin IX and chlorophyll are responsible for oxidation induced by wavelengths >500 nm, and that also riboflavin is contributing from 400 to 500 nm.
- Action spectrum;
- Bovine milk;
- Sensory analysis;
Jens Petter Wold, Josefine Skaret, Trine Kastrup Dalsgaard, Assessment of the action spectrum for photooxidation in full fat bovine milk. Food Chemistry, Volume 179, 15 July 2015, Pages 68–75.