INHIBITING THE ACTIVITY OF ACTINIDIN BY ORYZACYSTATIN FOR THE APPLICATION OF FRESH KIWIFRUIT TO GELATIN-BASED FOODS

Fresh kiwifruit has potent proteinase activity that can be ascribed to actinidin, a cysteine proteinase. Without regulating this activity, k iwifruit can not be used satisfactorily as a food ingredient for prote in-based foods. We found that oryzacystatin, a rice seed cysteine prot einase inhibitor, stoichiometrically inhibits the actinidin activity a nd can be used in making gelatin jellies with fresh kiwifruit slices. We also found that a gelatin solution mixed with an actinidin preparat ion did not form a gel because 118 kd and 130 kd components in the gel atin had undergone degradation. However, gelation occurred with no app reciable degradation in these two major gelatin components when oryzac ystatin was added to this actinidin preparation.