hpp in food

1. High Pressure Processing (HPP)

2. High Pressure Processing (HPP)
What?
–Subjecting foods to 300-
800MPa for 1-30 min at or
around room temp.
Why?
– Cold pasteurization
–- Inactivation of micro-
organisms and enzymes,
-No adverse sensory
changes,
-2-3 times extension in
shelf life,
->6 log reduction in Listeria,
Salmonella, E-coli
(Source: www.relayresearch.ie).

4. High Pressure Processing (HPP)
History
• HPP has been recognized by scientist to kill bacteria as
early as the 1890’s.
Effects of HHP on organisms
• Viable bacteria on water samples collected from 5100 m
depth ( 50 MPa) . Certes, 1883
• Reduction of spoilage organism by HHP (Hite 1899)-1st
time in food
• From Milk and meat products to fruits and vegetables ( Hite
et.al,1914)
• Peaches and pears treated at 400 MPa for 30 min at room
temperature – good after 5 years of storage
• European, Japanese and US food Industries are investing
on HPP research

5. High Pressure Processing (HPP)
• Non thermal in nature
• Inactivates the vegetative microorganisms, spores
and enzymes
• Increase in shelf life of foods
• Denatures proteins and polysaccharides
• Interesting application in the area of food
texturization
• Development of novel foods of superior nutritional
and sensory quality
• Higher safety
• Increased ambient shelf life

6. Will HPP damage the food product?
• During HPP, pressure is uniformly
applied around and throughout the
food product
• Grape is squeezed from all sides
simultaneously, it will not be
crushed.
• By squeezing the bottle, you
pressurize the water inside as well
as the grape. Yet the grape is not
damaged,
• Foods processed by high pressure
will not be damaged by the applied
pressure.
Isostatic ,uniform pressure ,no shear stress

7. High Pressure Processing (HPP)
Principle
Iso-static Principle
• Application of pressure is
instantaneous and uniform
through out the sample
Le Chateliers’s Principle
• Any chemical reaction
associated with a decrease
in total molar volume will be
accelerated by pressure
• In combination with mild
heat, reaction rates also may
increase according to
Arrhenius law.

8. • Electrostriction
• Pressure leads to ionisation-water molecules
arrange compactly around the electric charge
leading to destruction of m.o
• Compression energy
• The compression energy contained in the
pressure vessel is approximated as 2/5CPV0
• Adiabatic heating
• There is no net heat heat transfer between the
system and sorrounding

9. High Pressure Processing (HPP)
• What functional properties does HPP impart to food
products?
• High pressure treatment is expected to be less
detrimental than conventional processes to low
molecular weight food compounds such as flavouring
agents, pigments, vitamins, etc., as covalent bondings
are not affected by pressure
• Heat-sensitive, antimutagenic and therefore health-
promoting substances in fruit and vegetables are also
largely retained.

10. High Pressure Processing (HPP)
• What functional
properties does HPP
impart to food
products?

12. High Pressure Processing (HPP)
Pressure effects on microorganisms
Mechanism of action
• Number of changes to the morphology, biochemical
reactions, genetic mechanisms, cell membrane and
wall of microorganisms.
Cellular morphology
• Intracellular gas vacuoles can collapse at 0.6 MPa
• Cell wall damage and sub cellular structure altered in
yeasts above 200 Mpa
• Lethal effects of HHP – mechanism involved –ionization
and precipitation of protein complexes
Spores has proven pressure resistance
• Spore proteins are protected against the ionization
precipitation by dipicolinic acid (Timson and Short 1965)
• Highly viscous glassy state within the core of a spore
contribute to resistance and dormancy (Gould 1986)

14. HPP batch equipment
Model CIP 42260,ABB Autoclave Systems, Columbus,OH,USA).

15. HPP - Sugarcane and pine apple juice
Research at McGill, Canada
• Research at
McGill,canada
• Pressure – 100-
400 MPa
• Holding time
15-45 min
• Storage studies

16. HPP – Sugarcane and Pine apple juice
• Pressure – 100- 400 MPa
• Holding time 15-45 min
• Storage studies
• Microbial reduction of 4 log cycle at 400
MPa and 45 min time
• Pressure reduced the Polyphenoloxidase
activity
• Bromelin activity increased up to 100 MPa
stabilized from 100-300 and increased
after 300MPA