Author : Chitsuda Chaisakdanugull

Summary : Evaluation of the effectiveness of pineapple juice in enzymatic browning inhibition on the cut surface of banana slices after storage at 15 °C for 72 hrs indicated that unheated and heated pineapple juice were as effective as sulfite. Heating pineapple juice at 100°C for 5 min did not affect the effectiveness of pineapple juice in enzymatic browning inhibition. The visual color of banana slices treated with unheated pineapple juice and heated pineapple juice were acceptable within at least 6 hrs and 12 hrs storage at 15°C respectively. The results suggest that pineapple juice may be used as anti-browning solution of banana slices for at least 6 hrs. A kinetic study of the partially purified banana PPO indicated that pineapple juice was a noncompetitive inhibitor of the enzyme. Bromelain in pineapple juice did not inhibit PPO activity. Fractionation of unheated pineapple juice and heated pineapple juice by reversed-phased C18 cartridge revealed that directly eluted fraction (DE fraction) gave nearly 100% inhibition compared to the control. Preparation of pineapple juice beverage and banana beverage in 8mM ascorbic acid showed that unheated pineapple juice was as effective as 8 mM ascorbic acid in enzymatic browning inhibition of banana beverage. Pineapple juice may be used as an ingredient of banana beverage to inhibit enzymatic browning of banana.