PREPARATION OF PROTEOLYTIC-ENZYME EXTRACTS FROM ANANAS-COMOSUS L MERR FRUIT JUICE USING SEMIPERMEABLE-MEMBRANE, AMMONIUM-SULFATE EXTRACTION, CENTRIFUGATION AND FREEZE-DRYING PROCESSES

Crude purified bromelain extracts were obtained from 0.26% protein pineapple juice using sequential batch membrane processing systems which included microfiltration (MF) and ultrafiltration (UF) followed by ammonium sulfate extraction, ultracentrifugation and freeze drying. The membrane treatments (with an 8-mu-m mineral MF and a 10 000 molecular weight cut-off (MWCO) organic UF membranes), combined with 60% ammonium sulfate extraction resulted in 0.75-0.8% protein concentration, with 99% protein rejection. A 70% ammonium saturation and ultracentrifugation process (27 000 x g at 2-3-degrees-C), prior to freeze drying, were used in the last step to remove the residual non-protein constituents. These processes achieved low-moisture freeze-dried, and light-colored extracts, free of non-protein constituents and which accounted for about 50% yielded extracts containing 98% protein. The extracts assayed for bromelain and proteolytic activity resulted in almost 100% potential recovered, at completion. However, bromelain and proteolytic activity decay during the processes described above is essentially caused by losses through adsorption on the UF membrane relative to the level of concentration reached.