#M.E.A.T. STEAM SERIES#

Authors have modified this method of vacuum-steam defrosting by introducing an additional stage of preliminary dehydration of the material. However, this technology was withdrawn due to the negative phenomenon of significant drip loss. In the 1970s industrial solutions for vacuum-steam thawing were executed. In this manner, overheating of the surface of defrosted food products is avoided, which takes place in the case of defrosting in normal pressure with steam with the temperature of 100 ☌ 19, 23, 24, 25, 26, 27. A favorable outcome of this method is the fact that thawing with vacuum steam takes place at the temperature of 20 ☌. 120 g of condensing water defrosts 2 kg of frozen product) 22, 23.

The condensation heat is used by the frozen product, resulting in its quick defrosting (approx.

This is normally done by heating with steam, sometimes through a water heat exchanger or electric heaters. In order to maintain the water in the boiling state it must be heated. 2400 Pa), water starts boiling at room temperature (approx. As a result of this underpressure (approx. An open vessel with water is located on the bottom of the chamber, or the chamber is linked to an external tank. The product defrosted using this method is place in a vacuum chamber, from which air is pumped away. The steam thawing variant consists in the application of underpressure for the process, known as vacuum-steam thawing (VST). This heat, required for the phase change of ice into water in a frozen raw material is obtained from the phase change from steam to water. The latter method is covered by the present study.įollowing the methodology of steam thawing, the thermal energy is provided by means of water vapour condensation on the surface of the defrosted food products. vacuum-steam, sublimation contact or sublimation-vacuum-steam thawing 10, 11, 17, 21, 22.

#M.E.A.T. STEAM SERIES#

A series of studies concerns modifications of known methods, i.e. Research on dielectric, radio wave and high-voltage electrostatic field thawing has been conducted 5, 9, 18, 19, 20. In the recent years, a continuous interest has been expressed in the study on finding new defrosting technologies, such as the use of high pressure microwave, ultrasonic and infrared 8, 12, 14, 16, 17. The defrost chambers for contact or steam–air defrosting are an alternative to this method. This thawing method is rather prolonged (it may last for up to 3 days), requires ensuring large storage surface area and it forms a significant microbial hazard due to the possibility of cross contamination 13, 14, 15. The most well known methods of meat raw materials thawing are traditional methods-air thawing and water or brine immersion thawing. Numerous thawing methods are available 7, 8, 9, 10, 11, 12. To this end, overheating of the product surface during its thawing and defrosting drip loss should be limited, which are causes of significant quality losses and physical, biochemical and microbiological changes of the product 1, 2, 3, 4, 5, 6. It should be conducted conditions ensuring the most complete restoration of the original characters of the product. Along with freezing and storage, this process has a significant impact on the quality of food products. Based on the results it was demonstrated that the use of 12% sublimation dehydration of a meat sample enables its complete defrosting (reaching the temperature not exceeding the cryoscopic temperature).Ĭonsidering that frozen foods, in particular meat and fish, are used in food processing, the thawing operation is necessary. Thawing kinetics was determined with the SRVST method, degree of sample defrosting and level of their rehydration. longissimus lumborum) assessing the final effect of the process of vacuum-steam thawing. The study was carried out for different variants of initial sublimation degree (in the range from 0 to 15%) of a slice of pork loin (m. The study presents a modification of this method, introducing an additional stage of sublimation-dehydration vacuum steam thawing (SRVST). The condensated steam has the role of thermal energy carried enabling product thawing.

The water vapour formed in vacuum with the temperature of 20 ☌ fills the defrosting chamber and condenses on the surface of the defrosted product. Vacuum-steam thawing is one of the methods used for defrosting food, realized in the atmosphere of water vapour under the conditions of reduced pressure.

M.e.a.t. steam