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Since carotenoids are synthesized inside the cell, it is desirable to find an efficient method to extract carotegenic pigments. This study aimed at comparing the effectiveness of different chemical and mechanical techniques to disrupt the cell wall of and yeasts isolated from environmental samples. Among the techniques under study, the ultrasonic bath and the abrasion with glass beads yielded the most promising results for (84.8 ± 2.3 and 76.9 ± 2.1 μg/g, respectively). The ultrasonic bath yielded the highest specific concentration of carotenoids for (193.5 ± 25.8 μg/g), while the biomass freezing process improved neither the extractability nor the specific concentration of carotenoids. Lyophilization increased the specific concentrations of carotenoids from and by 20 and 13.7%, respectively, while the freezing process did not significantly affect ( > 0.05) the recovery of carotenoids from both yeasts; thus, it may be eliminated from the process.

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BACKGROUND Aflatoxin B1 (AFB1) is the most commonly occurring and the most toxic of all aflatoxins (AFs). It is responsible for liver cancer in animals and it is listed as a Group I carcinogen by the International Agency for Research on Cancer. Thus, it is necessary to find decontamination methods that show efficiency, specificity, low cost, and that allow the disposal of contaminated raw materials into the environment. This study evaluated the effects of enzyme concentration, pH, temperature and reaction time on AFB1 biotransformation by commercial peroxidase (POD) in a model solution (100 mmol L−1 phosphate buffer). RESULTS When 0.015 U mL−1 was used to treat 0.5 µg L−1 of AFB1, at pH 7.0–8.0 and 30–40 °C, for 8.0 h, the AFB1 biotransformation reached its maximum (97%). KM value of POD for the biotransformation of AFB1 was 0.0160 µmol L−1 (5 µg L−1) with a VMAX of 6.4 µmol L−1 min−1, which were determined based on Lineweaver‐Burk's plot. POD (0.015 U mL−1) effectively reduces AFB1 (97%) and M1 (65%) in UHT milk and AFB1 (24%) in lager beer samples acquired in markets of Rio Grande‐RS (Brazil). CONCLUSION The use of POD may be a strategy to mitigate the impact of AFs found in food to reduce the risk of consumer exposure. © 2018 Society of Chemical Industry