Food processing and its impact on phenolic constituents in food

Most food processing techniques involve a sequence of operations bringing about the desired changes in the raw material, with each operation having its impact on the food constituents. For bioactive compounds (phenolics) to exert their positive health effect, they first have to withstand food processing conditions, be released from the food matrix and be bioaccessible in the gastrointestinal tract, undergo metabolism and reach the target tissue of interest. Because of their possible biological effects in humans, it is necessary that changes in phenolic compounds during processing should be evaluated to assess the dietary value of the processed products. Data on the effect of processing on phenolic compounds show that food processing plays a significant role in the bioaccessibility and bioavailability of polyphenols. Consequently, food processing research should be tailored towards optimisation of processing methods that have the potential of retaining, releasing or at best transforming these compounds into more bioavailable forms.