The effects of calcium chloride and sucrose prefreezing treatments on the structure of strawberry tissues.
Suutarinen, J.; Heiska, K.; Moss, P.; Autio, K.;
Lebensmittel-Wissenschaft & Technologie Year: 2000 Vol: 33 Issue: 2 Pages: 89-102 Ref: 18 ref.
2000
บทคัดย่อ
Structural changes in strawberry tissues during prefreezing treatments, freezing and thawing were studied using textural and drip loss measurements, bright-field and confocal laser scanning microscopy, and Fourier transform infrared microscopy. Sucrose or calcium chloride (CaCl2) were used as dipping pretreatments prior to freezing. A full factorial screening design was used in the CaCl2 test, with the 3-level factors being CaCl2 concentration, dipping time, and solution temperature. In the 2 sucrose treatments, strawberries were either dipped in water-sucrose solutions or were sprinkled with crystallized sucrose. None of the pretreatments significantly affected the drip loss of thawed strawberries compared to water dips or untreated control samples. Pretreated fruits were firmer than untreated control samples, but some of the CaCl2 and sucrose treated fruits were less firm than strawberries dipped in water. The microscopical studies showed that both CaCl2 and crystallized sucrose pretreatments
affected the tissue microstructure. Pretreatments particularly affected pectin, protein, lignin and structural carbohydrates in the vascular tissue and cortex compared to the control. CaCl2 had an even stronger effect than sucrose on the above compounds, except for lignin. The epidermis, hypodermis and pith appeared unaffected by the pretreatments.