Abstract
The aim of this study was to find out whether the ice
crystal size of a starch gel, a model food system, could
be reduced by high-pressure freezing compared with
freezing at atmospheric pressure. The size and number of
pores in thawed gels was determined by light microscopy
and image analysis, and was taken as an indirect measure
of ice crystals formed during the different freezing
processes studied. The pore size and the total area
occupied by the pores were clearly reduced by
high-pressure freezing at 150-240 MPa compared with
freezing at atmospheric pressure at the same cooling
rate. The pore size in the high-pressure (nor in the
atmospheric) frozen gels did not increase during a
storage time of 3 months at -24 °C (still air) at
atmospheric pressure. Industrial relevance High-pressure
processing at subzero temperatures is not yet
industrially applied. More evidence on the benefits of
high-pressure freezing or thawing on the quality of real
food materials as well as development of processing
equipment is needed for commercialization of the
processes. This study demonstrates that the pore size of
frozen and thawed starch gels can be reduced by
high-pressure freezing compared with freezing at
atmospheric pressure. The reduced pore size was assumed
to be a result of smaller ice crystals formed in the
high-pressure freezing process. Based on this study, no
conclusions can be drawn on the possibility of
high-pressure freezing to improve the quality of real
foods of a more complex composition and structure.
| Original language | English |
|---|---|
| Pages (from-to) | 117-126 |
| Journal | Innovative Food Science and Emerging Technologies |
| Volume | 8 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 2007 |
| MoE publication type | A1 Journal article-refereed |
Keywords
- High-pressure
- Freezing
- Starch gel
- Microscopy
- Texture