Effect of Emulsifying Agents on Inhibition of Enzymatic Browning in Apple Juice by Ascorbyl Palmitate, Laurate and Decanoate

The effects of emulsifying agents (EA) on the stability of aqueous dispersions of ascorbyl palmitate (AP), laurate (AL), and decanoate (AD), and on the effectiveness of these compounds as browning inhibitors in apple juice were investigated. The stability of 1.14 mM AP, AL or AD, dispersed in simulated juice, was greatly improved by the addition of hydrophilic EA's such as Tween 60. More lipophilic EA's also were effective in stabilizing AL and AD dispersions. However, the addition of EA's to these browning inhibitors failed to improve their effectiveness in juice and, in the case of Tweens, had a detrimental effect. These results are attributed to the solubilization or activation of bound polyphenol oxidase.