[Book Chapter] 5-Light-Induced Quality Changes In Food And Beverages

For marketing reasons, foods and beverages are often sold in transparent packaging material, but many products are sensitive to light exposure leading to off-flavours, discoloration and loss of nutritive value. The light-induced reactions most harmful to meat and meat products, frozen fish, dairy products, vegetable oils, beer and other alcoholic beverages are indentified as photooxidation and photoisomerization. With use of photophysical and photochemical principles, light-induced oxygen activation and free radical formation is described for various products. Kinetic methods based on quantitative descriptions, including reaction quantum yields, bimolecular quenching rate constants and inner filter effects, are suggested for optimizing protection of vulnerable products against light-induced quality deterioration using manipulation with packaging atmosphere and properties of packaging material together with adjustment of wavelength distribution of light used for illumination.