Page 32 - FoodFocusThailand No.165 December 2019

SMART PRODUCTIONON
SMART PRODUCTI

Advanced Food Processing Technology

Thermal Food Processing Technology

For advanced food processing technology part II, thermal processing technologies including Pressure Assisted
Temperature Sterilization (PATS), Ohmic Heating (OH) and microwave heating are discussed. These technologies
have been introduced to produce safer, higher quality and healthier food products which can be shelf stable.

Thermal Food Processing Technology electric field strength and electric conductivity. The electrical
• High Pressure Sterilization (HPS) or Pressure Assisted conductivity increases with temperature resulting in the increase in
Temperature Sterilization (PATS) As already mentioned in the 1 part, heating rate. For solid-liquid mixture foods, heating uniformity can be
st
HPP is cold pasteurization and insufficient to inactivate microbial spores; achieved when the electrical conductivity of solid and liquid is in the
therefore, the combination of HPP and heat called Pressure Assisted same range. Ohmic heating inactivates vegetative cells and spores
Thermal Processing (PATP) or Pressure Assisted Temperature due to the nature thermal effect. However, many researches indicate
Sterilization (PATS) or High Pressure Sterilization (HPS) is developed that the microbial death is caused by electrical effect.
to produce shelf-stable foods. Food products are preheated to 75-90 C Ohmic heating has been used in food industries throughout the
o
prior to transferring the products to HPP at 500-700 MPa with the target world such as USA, Italy, England, Japan, Mexico and France
temperature of 90-120 C for 3-10 min (Balasubramaniam et al., 2015). (Kamonpatana et al., 2013; Yildiz-Turp et al., 2013) the form of
o
With a lower temperature and shorter processing time, PATP shows the continuous flow ohmic heating system. Therefore, OH is appropriate
potential to preserve foods with better quality and value compared to the to preserve liquid foods and solid-liquid foods including soup, fruit
conventional heating. In 2009 mashed potatoes processed by PATP was juice, milk, yoghurt, sauce, egg, vegetable side dishes and ready-to-
approved by the FDA. Although the food products processed by PATP eat packaged foods.
have been not commercially available, PATP shows great potential for Since liquid foods containing large chunks or unflowable foods
the production of shelf stable low-acid foods with high quality and might such as sausage or rice cannot be processed through the continuous
be worldwide used in the future. flow ohmic heating system, ohmic assisted-thermal sterilization system
• Ohmic Heating (OH) Ohmic heating is a thermal processing in has been recently introduced and developed by a researcher from
which alternating electrical current passes through food products. Heat Faculty of Agro-Industry, Kasetsart University. This system can
is uniformly and rapidly generated within the products as a function of produce safe foods for pasteurization and sterilization with a shorter
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