Varietal difference in actinidin concentration and protease activity in fruit juice of Actinidia species

Abstract

Actinidin, a cysteine protease in the fruit of Actinidia species, affects taste, allergenic properties and characteristics for processing the fruit. The actinidin concentration and the protease activity in the fruit juice of 12 Actinidia cultivars/selections were determined by quantitative sodium dodecyl sulfate-polyacrylamide gel electrophoresis and a spectrophotometric assay using L-pyroglutamyl-L-phenylalanyl-L-leucine-p-nitroanilide as a substrate. In 'Sanuki gold' and 'Ananasnaya', both actinidin concentration and protease activity in the juice were much higher than those of 'Hayward', the most common cultivar of kiwi fruit. In contrast to these cultivars, both actinidin concentration and protease activity in 'First emperor', Tear drop' and 'Kosen' fruit juice were significantly lower than those of 'Hayward'. Specific activity of actinidin in A. arguta fruit was much higher than that in A. deliciosa or A. chinensis fruit.