Improved stability, epithelial permeability and cellular antioxidant activity of β-carotene via encapsulation by self-assembled α-lactalbumin micelles

The low aqueous solubility, stability and bioavailability of hydrophobic bioactive compounds, such as beta-carotene (beta-c), greatly hinder their application in foods. Nanocarriers could overcome this problem by facilitating the delivery of the functional ingredients. We prepared lactalbumin (alpha-lac) micelles by partial enzymatic hydrolysis in aqueous solution. beta-c can be incorporated into the cores of these micelles via hydrophobic interactions. The aqueous solubility and stability under 60 degrees C heating or UV light irradiation of encapsulated beta-c improved significantly compared with free beta-c. Moreover, it had an increased cellular uptake (3 times) and transmembrane permeability (13 times) in a Caco-2 cell monolayer model. It suggested that alpha-lac micelle-encapsulated beta-c had an enhanced cellular absorption and transport efficiency. Encapsulated beta-c also exhibited an enhanced cellular anti-oxidant activity (CAA) compared with free beta-c. This work demonstrates that alpha-lac micelles showed a great potential for delivery of hydrophobic bioactive compounds in foods.