Reduction of Orange Allergen Cit s 2 Levels in Fresh Orange Juice with Pineapple Bromelain Enzymatic Treatment

Oranges are consumed worldwide; however, they contain Cit s 2, a major profilin allergen. We aimed to reduce Cit s 2 levels by preparing mixed orange fresh juice with pineapple, as a convenient method for any kitchen. Cit s 2 levels in orange extracts digested with pineapple extract and its protease bromelain were evaluated with quantitative enzyme-linked immunosorbent assay. Cit s 2 levels decreased according to reaction temperature and time, which was inhibited by iodoacetic acid. Treatment with pineapple extract diluted 40-fold and 0.1 mg/mL of bromelain at 37 degrees C for 30 min contributed to reducing residual Cit s 2 levels below the cut-off of 15%, respectively. Since this condition can increase the proportion of orange juice and reduce the risk of ingesting the pineapple allergen bromelain, it is considered to be more practical. Broad utilization of proteases in hypoallergenic food products is expected following clinical studies for verification.