Details

Autor(en) / Beteiligte

• Reno, Marciu José
• Prado, Mônica Elisabeth Torres
• Resende, Jaime Vilela de

Titel

Microstructural changes of frozen strawberries submitted to pre-treatments with additives and vacuum impregnation

Ist Teil von

• Ciência e tecnologia de alimentos, 2011-03, Vol.31 (1), p.247-256

Ort / Verlag

Sociedade Brasileira de Ciência e Tecnologia de Alimentos

Erscheinungsjahr

2011

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Strawberries were submitted to freezing after pre-treatments with hydrocolloid and calcium salts (pectin and calcium chloride) at different concentrations, in the attempt to establish a correlation of the effects of these substances and their processing, on the physical and microstructural characteristics of fruits after thawing. Strawberry halves were submitted to impregnation with controlled vacuum pressure of 84.4, 50.5 and 16.6 kPa; comprising pectin at concentrations of 0, 1.5 and 3%; with the addition of calcium chloride at concentrations of 0, 3 and 6%; and glucose at 20%, for 4 hours. Measurements were made of the total soluble solid contents, cellular fluid loss, texture and viscosity of the solution, before and after the freezing/thawing. Images of the tissue cuts during the freezing, in function of time, were taken in an optic microscope coupled to a cold-stage and controlled temperature system, where the reduction of the cellular area was quantified using an image analyzing software. The pectin concentration had an influence on and demonstrated a potential for protection of the frozen tissue samples. The photomicrographs showed that the loss of cellular fluid occurs during the growth of ice formed in the intercellular spaces and it is retarded through treatments with high pectin concentrations.