Antifreeze proteins in naturally cold acclimated leaves of Drimys angustifolia, Senecio icoglossus, and Eucalyptus ssp.

Avaliação de proteínas anticongelantes em folhas de Drimys angustifolia, Senecio icoglossus e Eucalyptus ssp. naturalmente aclimatadas ao frio

Summary

Antifreeze proteins (AFPs) present in plants may inhibit ice recrystallization even at low concentrations, and show potential application to many frozen foods. This study evaluated the presence of antifreeze proteins in naturally cold acclimated and non-acclimated leaves of Drimys angustifolia, Senecio icoglossus and Eucalyptus ssp. No proteins were detected in apoplastic extracts of Eucalyptus ssp. Extracts of cold acclimated and non-acclimated S. icoglossus showed protein concentrations of 42.89 and 17.76 µg mL^-1, both with bands between 25 and 37 kDa in the SDS-PAGE. However, they did not inhibit recrystallization. The extract of cold acclimated D. angustifolia contained a protein concentration of 95.17 µg mL^-1, almost five times higher than the extract of non-acclimated D. angustifolia. In the extract of cold acclimated D. angustifolia, there was presence of ice recrystallization inhibitors. This extract showed a protein band just below 37 kDa and another more intense band between 20 and 25 kDa. It is the first time that the presence of antifreeze proteins in this species is being described.

Keywords:
Antifreeze protein; Drimys angustifolia; Senecio icoglossus; Eucalyptus; Natural cold acclimation; Recrystallization inhibition