Meaning
Light-activated chemical reactions that degrade the quality, color and flavor of a product occur when sensitive compounds are exposed to light. In consumer packaged goods, photo oxidation is a primary cause of rancidity in oils, fats and dairy products. This reaction is initiated by exposure to both natural and artificial light sources.
The degradation process ceases only when the light source is removed or the reactive substrates are exhausted.
Degradation Pathway
The process begins when light energy is absorbed by photosensitizers like riboflavin or chlorophyll in the product. These excited molecules transfer energy to oxygen, creating highly reactive singlet oxygen that attacks unsaturated lipids. In many food products, photo oxidation produces volatile compounds that create unpleasant odors.
This chemical change can occur within hours of exposure on a brightly lit supermarket shelf.
Packaging Barrier
Packaging serves to prevent this degradation by blocking the transmission of light. Manufacturers select materials such as aluminum foil or colored plastics that filter out harmful wavelengths. These packaging materials protect the product’s nutritional value and extend its shelf life.
This protection is especially important for products that must be displayed in clear containers.
Shelf Retention
Retailers must manage their store lighting to minimize the rate of chemical breakdown in displayed goods. Placing sensitive products further away from fluorescent bulbs or using LED lights can reduce the rate of degradation. These operational adjustments help maintain the product’s quality until the consumer purchases it.
