Effect of Stern Bromelain on the Browning of Apple Juice

The effectiveness of pineapple stem protease (bromelain) in enzymatic browning inhibition was evaluated on apple juice and compared with that of L-cysteine and ascorbic acidat 25±1°C. The relative effectiveness of these anti-browning agents was determined in terms of color (L*) and enzymatic activity measurements with respect to time. L-cysteine at 0.7 and 1.0 mM concentrations gave the best results though the latter is associated with undesirable odor and bleaching effect. Ascorbic acid seemed to be only effective within the first 5 h after which its effectiveness dropped sharply. Stem bromelain, as compared to both L-cysteine and ascorbic acid, was found weakest in enzymatic browning inhibition hence considered ineffective.