Minimal processing of fruit and vegetables: influence of concentration and activity of some naturally occurring antioxidants in orange derivatives

Nutritional factors are widely proved to be critical for human health. Overwhelming, evidence from epidemiological studies showed that diets rich in fruit and vegetables are associated with a reduced risk of degenerative diseases. This is attributed to the fact that these foods may provide an optimal mix of phytochemicals, such as antioxidants and their precursors. However, it is widely recognised that the health promoting capacity of fruit and vegetables strictly depends on their technological history. Processing is expected to affect content, activity and bio-availability of naturally occurring antioxidants. Although some experimental evidence has recently demonstrated that processing may have many effects, not always resulting in a loss of the health promoting capacity of fruit and vegetables, uncertainty still exists about the effective incidence of the various technological steps. This aspect, which is generally neglected or scarcely considered in present nutritional and epidemiological studies, is of great importance, considering that only a small amount of fruit and vegetables are consumed as fresh, whilst most of them need to be processed for safety, quality and economic reasons. Thus, investigation on the effects of processing on the activity of naturally occurring antioxidants is a key factor in order to find out the best technological conditions for preserving the above cited beneficial properties and to achieve a correct interpretation of data on dietary habits and human health. In the present investigation fresh and pasteurised orange juices, chosen by virtue of their high content in naturally occurring antioxidants and their widespread consumption, were considered. The changes in ascorbic acid concentration and in the overall antioxidant properties during juice preparation and storage, the latter carried out under different temperature conditions, were studied.