Evaluation of Cytotoxicity, Antioxidant Activity, and Allergenic Potential of Brazil Nut Protein Isolates Obtained by Conventional and Ultrasonic Methods

Brazil nut (Bertholletia excelsa) is recognized for its high nutritional value and the presence of proteins with functional and bioactive properties. However, the presence of allergens limits its use in food formulations. This study aimed to evaluate the cytotoxicity, antioxidant activity, and allergenic potential of Brazil nut protein isolates obtained by conventional and ultrasonic methods. The protein isolates were prepared from defatted Brazil nut flour, subjected to alkaline extraction and isoelectric precipitation. The ultrasonic method was applied at a frequency of 20 kHz and a power of 200 W, aiming to promote the structural modification of the proteins. The isolates were characterized for their proximate composition, antioxidant activity (DPPH and ABTS), and cytotoxic potential by cell viability assay (MTT) in VERO cells. Allergenicity assessment was performed by an in vitro IgE binding assay in samples of sensitized human serum. The results indicated that ultrasonic treatment significantly reduced IgE reactivity and promoted a slight increase in antioxidant activity (p < 0.05), without inducing cytotoxic effects. These findings demonstrate the potential of using ultrasound as a safe and efficient physical technique to reduce the allergenicity of vegetable proteins, expanding the possibilities for applying Brazil nut in functional and hypoallergenic foods.