Toxicological Studies and Oxidative Stability of Choibá Oil (Dipteryx oleifera Benth.) with Addition of Rosemary Extract (Rosmarinus officinalis L.)

Choibá (Dipteryx oleifera Benth.) is a promising source of edible oil with high nutritional quality and a
significant content of oleic acid (52% - 54%). To promote Choibá as source of edible oil is necessary
to ensure its stability along the time of production, distribution and storage, as well as knowing its
toxicity. Loss of nutritional and organoleptic quality in lipids is mainly due to lipid peroxidation
reactions. The aim of this research was to evaluate the oxidative stability of Choibá oil supplemented
with rosemary extract (Rosmarinus officinalis L.), and to evaluate the degradation kinetics and shelflife
at 35˚C, 45˚C and 55˚C without addition of antioxidants (Control) and with addition of best
concentration of rosemary extract obtained from previous study. Progress in oil oxidation was
measured through the extent of oxidation products: peroxide value (PV) and thiobarbituric acid
reactive substances (TBARS); additionally, the cytotoxic and mutagenic effect using MTT and DNA
comet alkaline test over human lymphocytes were evaluated. Results revealed that the addition of
rosemary extract at 1500 mg/L significantly reduced de formation of hydroperoxides (PV), more than
BHT. Through correlations between concentrations of antioxidant (including control without
antioxidant) with peroxide values, the kinetics of degradation and shelf-life of Choibá oil with predictive
models are evaluated in real time and accelerated conditions (35˚C, 45˚C and 55˚C) using the
Arrhenius equation. In addition, the oxidation reactions of this oil follow a first order kinetic model for
PV and zero order kinetic model for TBARS. The rate of formation of PV was dependent on the
storage temperature, according to the Arrhenius equation with activation energy of 4611.51 J/mol for
Control and 7409.58 J/mol for RE1500 treatment. The result of TBARS did not adjust to Arrhenius
model, thus measurement of malondialdehyde (MDA) wasn’t a useful parameter for shelf-life
determination of Choibá oil. Toxicological tests showed the oil did not show cytotoxicity or genotoxicity
at concentrations up to 1200 μg/mL, presenting estimated IC50 values of 5830 μg/mL, which
represents a low risk of cell damage, however, more tests must be carried out to ensure complete
safety of this new food ingredient.