Photodegradation Products And Their Analysis In Food

Food spoilage and corresponding waste of packaging material is a serious problem in modern society. Food products can be degraded due to different factors, of which one of them is light-induced degradation. This process can cause the colour of food products to fade or decrease the quality of the product. Moreover, nutrients can be lost or harmful degradation products can be formed. Due to the complex composition of food products, the process of photodegradation is not fully understood and appropriate analysis methods are not fully developed yet. Therefore, this work reviewed the photodegradation of different food components (i.e. carotenoids, chlorophylls, flavonoids and lipids) and the analysis of such photodegradation products. The photodegradation reactions involved were found to be photo-oxidation, -isomerisation, hydrogen transfer, hydrogen abstraction and photolysis, with a great variety of photodegradation products. Moreover, the analytical strategies to analyse these in the best possible way were critically reviewed. In general, no other approaches than standard methods have appeared to be used for the analysis of photodegradation studies. (Ultra) high performance liquid chromatography has been found to be the most commonly-used separation technique, with UV and MS as standard detection methods. For specific applications, GC can be used for the separation and unconventional detectors can be used for the detection of the photodegradation species. Examples listed in this review were the electron spray resonance detector for monitoring radical reactions, the vacuum ultraviolet detector for identifying volatiles and high-resolution MS for accurately characterizing the photodegradation species. Using the information and advices given in this review, a better understanding of the nature of the photodegradation species is gained together with strategies to properly analyse these. Nonetheless, due to the complex composition of food products and the influence of other factors than light, more extensive research on this topic still needs to be performed.