Stability and bioactivity of a Bowman-Birk inhibitor in orange juice during processing and storage.

The present research aimed to evaluate the feasibility of a soybean Bowman-Birk inhibitor (BBI) as a natural functional food ingredient. The influence of food processing, storage and digestion on the structure and bioactivity of BBI added to a food matrix was evaluated. The cytotoxic effect of the digested samples was also tested with the aim to provide information regarding the safe use of BBI as a functional food ingredient. Samples of freshly squeezed orange juice (OJ) and two orange juice model systems (OJ-ms) supplemented and non-supplemented with BBI were prepared and processed mimicking pasteurization and sterilization industrial conditions. Moreover, pasteurized samples were stored at 4 °C for two months. The samples were digested in vitro under oral-gastrointestinal physiological conditions. Results seem to indicate that the activity of BBI supplemented to the food matrix sufficiently survives thermal processing, storage and digestion processes. Changes in BBI bioactivity may be ascribed among others to the Maillard reaction. Formation of early Maillard reaction products also called Amadori products has been detected in the food sample. No cytotoxic effect was observed for the samples under study. In conclusion, our findings support that BBI has significant potential as a natural functional food ingredient in pasteurized orange juice stored at 4 °C.