Xe-gas pretreatment for frozen food
Publication Date: 2009-Dec-10
The IP.com Prior Art Database
One of the most widely used techniques to preserve food and extend its storage life is freezing. Primary objective of freezing is to maintain quality, functionality and organoleptic characteristic of food, while assuring absence of microbial growth. Despite various methods and technologies used for food freezing, it is still inevitable to avoid texture quality change of frozen food. Freezing affects physical and chemical processes within the food matrix, leaving the final product with lower texture quality than when it was in the fresh state.
Several pre-treatment technologies like blanching, adding additives and antifreeze agents are used to minimize damaging effect of freezing, however more improvement is needed in this field.
Antifreeze agent containing alkaline glycol, chlorine containing inorganic chloride, sweeteners like sorbitol, provides prominent antifreeze point depression effects by use of small volume.
Xe gas dissolved into water gives rise to a change in water structure to clathrate like structure, with increased population of hydrogen bonded water molecules.
Hydrogen-bonded water molecules will reduce water mobility and thus decrease metabolic process in food. Metabolic processes reducing before freezing will eliminate some distractive effect of freezing. Similar changes in the structure of water maybe anticipated for other noble gases and their mixtures (Ar, Ne, Kr), and the optimum mixture for pretreatment will depend upon the type of frozen food to be treated.
In the present disclosure we propose novel freezing technology aiming to protect food quality during freezing.
It is mainly based on the implementation of two steps:
1. Pre-treatment of food matter with Xe-gas (or any hydrophobic non-polar gases) and
2. Freezing Xe treated food stuff (using either cryogenic or mechanical freezing).
Coming back to the prior art of this field, there are many attempts to minimize damaging effect of freezing and provide frozen food which, after thawing, maintains same texture and mouth feeling as before freezing. One of the causes of food structure deterioration during freezing is cell dehydration and cell structure rupture, due to intra and extra cellular ice crystal formation. Several solutions were provided for enchasing frozen food quality.
An example is proposed in European patent EP1249171A2, whose inventors believe that extra cellular ice crystals are main cases of texture loss of frozen vegetables. To eliminate extra cellular ice they heat products, before freezing, destroy cell membrane and create uniform solute concentration across the tissue. After heat treatment, temperature of t...