2.2. Clarification of fruit crude juice
The stalk (central core) of ripe pineapple fruit was separated from fleshy fruit. The fruit portion was then cut into small pieces and crushed in a laboratory juicer to get approximately 500 ml juice. The juice was filtered through a muslin cloth to remove the fibrous material. The filtrate was then subjected to vacuum filtration to remove ruptured plant cells.The filtered crude juice was kept for centrifugation (Remi R-24) at 10,000×g for 20min at 4◦C to remove any insoluble materials. The clear supernatant obtained as a clarified extract was stored in aliquots at 4◦C and used when ever required. The protein content in the supernatant was determined before further purification using precipitation and ion exchange chromatography.