*3.2. Antioxidant Activity of the Biosurfactant*

Oxidation can occur during the processing and/or storage of food, resulting in the deterioration of their nutritional value, color, flavor, texture and safety. The most effective, convenient and economical method employed to control oxidation is the use of antioxidants [34]. The food industry uses antioxidants to stabilize lipids in food, which are the most sensitive compounds to the oxidation process [35]. In addition to the preservation of food, antioxidants are also used in fields related to health and wellbeing due to their capacity to protect the body from oxidative damage.

The results of the total antioxidant capacity (TAC) as well as those of scavenging the DPPH• radical and the ABTS cation radical (ABTS•<sup>+</sup> ) by the biosurfactant are presented in Table 3.


**Table 3.** Total antioxidant capacity (TAC) and oxidative inhibition based on the DPPH• and ABTS•<sup>+</sup> scavenging capacity of the biosurfactant produced by *Bacillus cereus* UCP 1615 at different concentrations.

The biosurfactant showed promising results in terms of reducing the phosphomolybdenum complex when comparing its percentage of the total antioxidant capacity (TAC) with that of ascorbic acid at a concentration of 1 mg/mL. The addition of the biosurfactant at the lowest concentration (0.32 mg/mL) led to a TAC of 15.34%; it exceeded 100% with concentrations above 2.5 mg/mL and reached 476.43% at the highest concentration (40 mg/mL). A linear increase in the TAC with the increase in biosurfactant concentration was observed.

One percent (equivalent to 10 mg/mL) was the maximum concentration of the biosurfactant tested in the present study for application in the cookie formulation. The TAC at this concentration was 218.25%, demonstrating that the biosurfactant had potential regarding protection from oxidation in food. The total antioxidant activity in this study was consistent with the indices reported for biosurfactants from *Candida bombicola* [31] and *Saccharomyces cerevisiae* [22], which were also evaluated for use in food.

In the assessment of the oxidative inhibition in terms of the DPPH• scavenging capacity of the biosurfactant, the results were low even at the highest concentration tested (40 mg/mL), preventing only 28.45% of oxidation (Table 3). In the assessment of the antioxidant activity based on ABTS•<sup>+</sup> scavenging, the index achieved at the highest biosurfactant concentration was 36.67%. These results show that the biosurfactant under investigation did not have sufficient antioxidant potential to serve as the only antioxidant agent in a formulation.
