Effects of processing and storage on antioxidant efficacy in foods - Oxidation in Foods and Beverages and Antioxidant Applications - page 372

Fig. 15.11 Synergism and antagonism of antioxidants.
antioxidants is higher than those of the same antioxidants present alone. In the
text, we shall use the broader term in order to avoid confusion.
Synergists increase the antioxidant activity to higher values than each
component (Fig. 15.11). On the contrary, in the presence of antagonists, the
resulting antioxidant activity of a mixture is lower than would be expected. A
few examples of synergism follow.
Among various tomato cultivars, the highest content of antioxidants, the
highest activity and high lycopene content were found in cherry tomatoes.
Lipophilic extracts were observed to contain the highest antioxidant activity and
high carotenoid content. Synergism was found in mixtures of lycopene and -
carotene or lutein, and lutein and -carotene (Zanfini et al., 2010). A positive
correlation existed between lycopene content and the antioxidant activity.
15.3 Changes of antioxidant functionality during isolation
from seeds
15.3.1 Preparation operations
Oil is located either in seeds of plants, or in some cases in the pericarp, too.
Seeds have only 6±10% water, thus are relatively stable on storage. After seed
cropping, they are usually stored in silos (elevators) at ambient temperature until
they are processed in an oil factory. They should remain dry, otherwise various
prooxidative enzymes could get activated. They contain natural antioxidants,
mainly tocopherols, carotenes, decomposition products of lignin, etc., which are
located in different parts of the cell than enzymes to minimize interaction.