Actinidin (EC 3.4.22.14) is a sulfhydryl protease derived from the fruit and peel of
the kiwi fruit ( Actinidai chinesis ; Arcus, 1959) . Actinidin is extracted from kiwi fruit
and, because it is found in greater quantities with higher activity in ripe kiwi (Lewis
and Luh, 1988b) , it represents a potential use for over-ripe or discarded fruit.
Actinidin has been studied in meat systems and shown to be capable of milder tenderizing
reactions, although at higher enzyme concentrations (Lewis and Luh,
1988a) . It also has a lower temperature of inactivation than ficin, bromelain, or
papain which makes it easier to control the tenderizing reaction without
overcooking. Currently, actinidin is not approved in the United States for meat
tenderization.
