Accelerated oven test
The samples submitted to aging in an oven were evaluated according to the tests: acid value, peroxide value, and
conjugated dienes. The acid values for the oil samples with and without additives varied from 0.06 to 0.4 mg KOH kg-1. No meaningful changes were noticed in this parameter during the period of evaluation for all the samples, which kept their acid values below the limit established by ANVISA of 0.6 mg KOH kg-1 [22]. Figure 3 shows the increase of the peroxide values of the samples during storage. Peroxides and hydroperoxides are products that represent the beginning of the lipoxidation [1], a step in which the chain-breaker antioxidants can interrupt the process and restore the fatty acid chain.
Conversely to the acid values, the peroxide values increased during the storage. For the vegetable oils without additives, the peroxide values (PV) were no bigger than the maximum limit established by ANVISA, of 10 meq kg-1.