19-08-2014, 10:31 AM
Plant proteases, characterized by the reduced Sulphydryl group required for catalysis, can be produced from tropical plants. Crude or partially refined mixtures, including minor quantities of other enzymes, are used in a variety of food industries, detergent industries and leather industries. In comparison with bacterial proteases, the cost of plant proteases restricts their application to those situations where their high activity and high specificity make them particularly appropriate. Plant proteases rapidly split only certain peptide bonds in proteins, which makes this group of enzymes particularly suitable for applications where limited proteolysis is required.
Plant proteases, characterized by the reduced Sulphydryl group required for catalysis, can be produced from tropical plants. Crude or partially refined mixtures, including minor quantities of other enzymes, are used in a variety of food industries, detergent industries and leather industries. In comparison with bacterial proteases, the cost of plant proteases restricts their application to those situations where their high activity and high specificity make them particularly appropriate. Plant proteases rapidly split only certain peptide bonds in proteins, which makes this group of enzymes particularly suitable for applications where limited proteolysis is required.
Ficin, fruit bromelain, stem bromelain and papain are the best known examples of proteolytic enzymes from tropical fruits used in food processing, pharmaceutics and allied industries. Whenever bromelain use is described, only stem bromelain is considered because fruit bromelain is not currently commercially available. Unlike crude stem bromelain, which is used widely in industry (Caygill, 1979), fruit bromelain is not commercially available despite the large quantities of waste pineapple fruit portions at pineapple canneries the present work deals with the purification, crystallization and drying of bromelain, one of the best vegetal proteases. Bromelain is extracted from the fruit of Ananas comosus using precipitation technique. Attempts were made to obtain a crystalline enzyme preparation by fractionation of bromelain with acetone, ammonium sulfate and sodium chloride. Similarly, Bromelain extract was subjected to Freeze Drying, Spray Drying and Heat Pump Drying. Activity was calculated by a method suggested by Dapeau (Dapeau, 1976). Bicinchoninic Acid method was employed in order to estimate total protein content. Resulting residual activity and the specific activity were compared between dried powder and crystalline enzyme preparation. Lyophilized and Spray dried enzyme extract showed a higher specific activity than crystalline bromelain obtained by fractionation with ammonium sulfate and subsequently with sodium chloride. Freeze dried bromelain was found to posses the specific activity approximately twice as compared to the spray dried and Heat Pump dried powder. FTIR and DSC studies were also carried to study the unfolding and glass transition temperature of protein during drying.