Mechanical and biochemical response of kiwifruit tissue to steam blanching.

LLANO C., HAEDO A., GERSCHENSON L.N. Y ROJAS A.M.

FOOD RESEARCH INTERNATIONAL

ELSEVIER LTD.

Lugar: The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, UK.; Año: 2003 vol. 36 p. 767 - 775

0963-9969

Abstract: Steam blanching effect on kiwifruit (Actinidia deliciosa, A. Chev.) halves was assessed, tending to optimize this process with respect to texture. Mechanical behaviour was evaluated as a function of heating time and tissue temperature through force-deformation and relaxation curves. Hystological changes were determined by transmission electron microscopy (TEM) and fluorescence microscopy (FM). Changes in colour, peroxidase and pectinmethylesterase activities were also determined. Breakdown of cell membrane occurred for blanching times of 5 min, being closely associated with green colour disappearance, deep drop in peroxidase activity and significant loss of initial and residual relaxation forces. Cell wall integrity seemed to remain at 5 min of heat treatment, as it could be seen by FM and TEM. Firmness decreased with increasing time and tissue temperature and was affected even after 1 min of heating, being a global measurement of the integrity of the cell and the tissue. The change suffered along heating could be described through multiple regresion allowing to model the process of change of kiwifruit as a consequence of blanching.