New processing Technology

New processing technologies

n    The key to food preservation is:

n    Decrease MO activity

n    Decrease enzymatic activity

n    Decrease biochemical changes


New processing technologies

n     The most widely used and effective method used in killing bacteria is heat

n     It has detrimental effects on

n    Product quality

n    Flavor

n    Texture

n    Changes in protein

n    Changes in CHO

n    Changes in nutritional quality

Other methods

n    Irradiation

n    Microfiltration

n    Microwaves

Some new technologies

n    High pressure processing (Pascalization)

n    Pulsed electric field (ohmic heating)

n    UV light

n    Sonication

n    Ultrasound

High pressure processing

n    Application of extremely high pressures to food at ambient temperatures

n    Inactivates MO and enzymes

n    Retains flavor and nutrients

n    Pressure ranges

n    4000 9000 atm (400 900 MPa)

n    Can be applied to liquid or solid food

High pressure processing

n    Covalent bonds remain intact

n    Hydrophobic and ion-pair bonds are disrupted


n    Consists of

n    High pressure vessel

n    Pressure generation system

n    Temperature control device

n    Material handling system

High pressure

n    Food is packaged and loaded in to the vessel vessel

n    Filled with transmitting medium

n    Mostly water with a small amount of oil

n    After air is removed high pressure is generated by direct or indirect compression

n    Pressure is applied uniformly (isostatic)


Factors that influence processing and quality

n    Amount of pressure

n    Compression duration

n    Depressurization rate

n    Temperature

n    pH, aw, salt concentration of food


Food safety considerations

n    Low acid foods

n    Spore inactivation is an issues

n    Not much data on C.Botulinum spores

n    12D process needs to be identified

UV treatment

n    MO inactivation by UV is well known

n    Used for surface treatment and waste water

n    Mechanism

n    Cross linking of thymine (found in DNA and RNA nucleotides)

n    Prevents repair and reproduction

UV treatment

n    Wavelength for inactivation is 240 265 nm

n    Poor penetration

n    Regulated as a food additive

CCPs for UV process

n    Flow rate

n    Absorption

n    Particle size

n    Light intensity

Ohmic heating

n    Use of electrical energy

n    Electric current is passed through an electrically conducting product

n    Uses low frequency alternating current (50 60 Hz)

n    Microbial death is due to disruption of cell material and heat

Ohmic heating

n     Dependant on the electrical conductivity of food

n    Most foods contain a moderate percent of free water and dissolved ionic salts

n     Advantages

n    Fast

n    More uniform heating

n     Disadvantage

n    Nonuniformity in product will distort field