Innovations in Non-Thermal Food Processing Techniques
The
main
problem
with
the
thermal
processing
of food
is
loss
of
volatile
compounds, nutrients,
and
flavour.
To
overcome
these
problems
non
thermal methods
came
into
food
industries
to
increase
the
production rate
and
profit.
The non
thermal
processing
is used for
all foods
for
its
better
quality,
acceptance,
and for
its
shelf
life.
The
new
processing
techniques
are
mostly
employed
to
the
liquid
packed
foods
when
compared
to
solid
foods.
Why
Non
thermal?
Since
the
non
thermal methods
are used for
bulk
quantities
of
foods,
these
methods
of food
preservation
are
mainly
used in
the
large
scale
production.
The
cost
of
equipments
used in
the
non
thermal
processing
is
high
when
compared
to
equipments
used in
thermal
processing.
After
minimising
the
investment
costs
of non
thermal
processing
methods,
it
can
also
be
employed
in
small scale
industries.
N
O
N
-
T
H
E
R
M
A
L
P
R
O
C
E
S
S
A
R
E
:-
Ohmic Heating
Microwave
heating
Radiofrequency
heating
Infrared
heating
High Pressure Processing
Pulsed
Electric
Field
Ultrasonics
Pulsed
Light
Technology
Pulsed
X-rays
Irradiation
Oscillating
Magnetic
Field
Microwave
Heating:
•
Refers
to
the
use
of
electromagnetic
waves
of
certain
frequencies
(
2450MHz
and
915MHz
.
)to
generate
heat
in
material.
•
Container
with
food is
placed
in a
microwave
oven
•
And
then
a oven is
activated,
the
food
at
the
edge
of
the
container
heats
faster
and
a
temperature
gradient
develops
between
the centre
and
the
edges
M
e
c
h
a
n
i
s
m
D
i
p
o
l
a
r
i
n
t
e
r
a
c
t
i
o
n
:
polar
molecules such
as
water
molecules(
dipole
)
inside
the
food
will
rotate
according
to
the
alternating
electromagnetic
field.
The
rotation
of
water
molecules
would
generate
heat
for
cooking
I
o
n
i
c
i
n
t
e
r
a
c
t
i
o
n
:
Ionic
compounds
(i.e.
dissolved salts
)
in food
can
also
be
accelerated
by
the electromagnetic
field
and
collided
with
other
molecules
to
produce
heat
PULSED
ELECTRIC FIELD (PEF)
TECHNOLOGY
•
PEF
is
a non-thermal
food
preservation
technology
that
involves
the
discharge
of
high
voltage
electric
pulses
(
up
to
70
kV/cm
)
into
the
food
product,
which
is
placed
between
two
electrodes
for a
few
microsec
H
I
G
H
P
R
E
S
S
U
R
E
P
R
O
C
E
S
S
I
N
G
:
(
H
P
P
)
High
Pressure
Processing is also
known
as
“High
Hydrostatic
Pressure”
or
“Ultra
High
Pressure
”
processing.
HPP
uses
up
to
900MPa
to
kill many
of
the
micro
organisms
found
in
foods,
even
at
room temperature
without
degrading
vitamins,
flavor
and
colour
molecules
in
the
process
.
Food
packages
are
loaded
onto
the
vessel and
the top
is
closed.
The
pressure
medium
usually
water
is
pumped
into
the
vessel
from
the
bottom.
Once
the
desired
pressure is
reached,
the
pumping
is
stopped,
valves are
closed,
pressure
can
be
maintained
without
further
need
for
energy
input.
P
r
i
n
c
i
p
l
e
:
A
principle
underlying
HPP
is
that
the
high
pressure is
applied in an
“isostatic
”
manner
such
that
all regions
of
food
experience
a
uniform
pressure
,
unlike
heat
processing
where
temperature
gradients
are
established.
P
U
L
S
E
D
L
I
G
H
T
(
O
R
)
H
I
G
H
I
N
T
E
N
S
I
T
Y
L
I
G
H
T
T
E
C
H
N
O
L
O
G
Y
:
•
High
Intensity Light
Technology
can
be
used for
the
rapid
inactivation
of
micro
organisms
on food
surfaces,
equipments
and
food
packaging
materials.
•
High
intensity
white
light
and UV
light
food
preservation
methods
employ
light
wave
lengths
ranging
from
ultra
violet
to
near
infra-red
i
n
short
intense
pulse.
•
Pulses
of
light
used for food
processing
applications
typically
emit
one
to
twenty
flashes
per
second
of
electromagnetic
energy
•
It
is
generally
accepted
that
UV
plays
a
critical
role in
microbial
inactivation.
•
The
treatment
is
most
effective
on
smooth,
nonreflecting
surfaces
or
in
liquids
that
are free of
suspended
particulates.
•
•
In
surface
treatments,
rough
surfaces
hinder
inactivation
due
to
cell
hiding.
O
h
m
i
c
h
e
a
t
i
n
g
Ohmic heating
is
an advanced terminal
processing method
where
in the
food
material
which
serves as an electrical resistor, is
heated
by passing electricity through
Which
result
in
rapid
&
uniform
heating
Electrical resistance heating or
joule heating
or
electro-heating
1
3
I
m
p
o
r
t
a
n
t
b
e
n
e
f
i
t
s
1.
Fast
Processing
2.
Homogeneous
Treatment
3.
More
effective
method
1
4
1
5
Non-thermal processing methods have emerged as a solution to the limitations of thermal food processing, offering benefits such as better retention of volatile compounds, nutrients, and flavors. This article explores various non-thermal techniques like Ohmic Heating, Microwave Heating, Pulsed Electric Field Technology, and more, highlighting their mechanisms and advantages in food preservation. These methods are particularly important for large-scale food production due to their efficiency and quality preservation capabilities.
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Presentation Transcript
Why Nonthermal? The main problem with the thermal processing of food is loss of volatile compounds, nutrients,and flavour. To overcome these problems non thermal methods came into food industries to increase the production rate and profit. The non thermal processing is used for all foods for its better quality , acceptance, and for its shelflife. The new processing techniques are mostly employed to the liquid packed foods when compared to solidfoods.
Since the non thermal methods are used for bulk quantities of foods, these methods of food preservation are mainly used in the large scaleproduction. The cost of equipments used in the non thermal processing is high when compared to equipments used in thermalprocessing. After minimising the investment costs of non thermal processing methods, it can also be employed in small scale industries.
NON-THERMAL PROCESS ARE:- Ohmic Heating Microwave heating Radiofrequency heating Infrared heating High Pressure Processing Pulsed Electric Field Ultrasonics Pulsed Light Technology Pulsed X-rays Irradiation Oscillating Magnetic Field
Microwave Heating: Refers to the use of electromagnetic waves of certainfrequencies(2450MHzand915MHz.)to generateheatinmaterial. Container with food is placed in a microwave oven And then a oven is activated, the food at the edge of the container heats faster and a temperature gradient develops between the centre and the edges
Mechanism Dipolar interaction: polar molecules such as water molecules(dipole) inside the food will rotate according to the alternating electromagneticfield. The rotation of water molecules would generate heat forcooking Ionic interaction: Ionic compounds (i.e. dissolved salts) in food can also be accelerated by the electromagnetic field and collided with other molecules to produce heat
PULSED ELECTRIC FIELD (PEF) TECHNOLOGY PEF is a non-thermal food preservation technology that involves the discharge of high voltage electric pulses (up to 70 kV/cm) into the food product, which is placed between two electrodes for a fewmicrosec
HIGH PRESSURE PROCESSING: (HPP) High Pressure Processing is also known as High Hydrostatic Pressure or Ultra High Pressure processing. HPP uses up to 900MPa to kill many of the micro organisms found in foods, even at room temperature without degrading vitamins, flavor and colour molecules in the process. Food packages are loaded onto the vessel and the top is closed. The pressure medium usually water is pumped into the vessel from thebottom.
Oncethedesiredpressureisreached,thepumpingis stopped,valvesareclosed, pressurecanbemaintained withoutfurtherneedforenergyinput. Principle: A principle underlying HPP is that the high pressure is applied in an isostatic manner such that all regions of food experience a uniform pressure, unlike heat processing where temperature gradients areestablished.
PULSED LIGHT (OR) HIGH INTENSITY LIGHT TECHNOLOGY : High Intensity Light Technology can be used for the rapid inactivation of micro organisms on food surfaces, equipments and food packagingmaterials. High intensity white light and UV light food preservation methods employ light wave lengths ranging from ultra violet to near infra-red in short intensepulse. Pulses of light used for food processing applications typically emit one to twenty flashes per second of electromagneticenergy
It is generally accepted that UV plays a critical role in microbialinactivation. The treatment is most effective on smooth, nonreflecting surfaces or in liquids that are free of suspended particulates. In surface treatments, rough surfaces hinder inactivation due to cellhiding.
Ohmic heating Ohmic heating is an advanced terminal processing method where in the food material which serves as an electrical resistor, is heated by passing electricity through Which result in rapid & uniform heating Electrical resistance heating or joule heating or electro-heating 13
Important benefits Fast Processing 1. Homogeneous Treatment 2. More effective method 3. 14
