novel techniques in food processing

1. SUBMITTED BY:
AAKRITI
GFT/115201

2.  Electro-heating, High voltage electrical discharge
 HPP, High intensity light, Ultrasound
 MAP, Active packaging
 Jet impactation
 Gamma radiation, X-rays
 LASERS and MASERS
 Microfiltration
 Cryogenic thermal shock
 Immobilized enzymes
 Ozone
 Nitrous oxide

3. THERMAL
 Ohmic heating
 Microwave heating
 Radiofrequency
heating
 Infrared heating
 Inductive heating
NON-THERMAL
 High pressure
processing
 Pulsed electrified field
 Ultrasound
 High intensity light
 Pulsed X-rays
 Gamma radiation
 MAP
 Membrane technology

4.  Short electric pulses (20-80kV, microseconds)
 Alternative of thermal pasteurization
 Used for liquid and semi-liquid food products
 Microbial inactivation:- Electroporation
 Factors affecting:- electric field strength,
treatment time, cell size, growth phase
 Products with no air bubbles, low electrical
conductivity and easily pumpable
 Stored: refrigeration
 Components:- Pulse generator, treatment
chamber, control & data acquisition

6.  Sound waves, frequency >16 kHz
 Principle:- Intracellular cavitations
 Types:- high frequency low energy, low frequency
high energy, power ultrasound
 Requirements:- a liquid medium, source of high
energy vibration
 Applications:- a) Physical-freezing, degassing,
crystallization, extraction, filtration, drying,
homogenization/emulsification, extrusion, cleaning
b) Chemical- oxidative ageing, enzymatic activity,
bacteriocidal, effluent treatment, living cell
 Microbial destruction
 Designs- Ultrasonic bath, probe system, reaction
vessel, liquid whistle, resonating type

9.  Isostatic principle
 Food subjected to high hydrostatic pressure
(100-800MPa for 1 sec to 30 min)
 Instantaneous and uniform
 Independent of food size, shape, composition
 3ºC rise in temp per 100MPa
 Inactivation depends on temp
 C. botulinum spores (500-700MPa, 90-
100ºC)
 Order of resistance:-
Spores>gram +ve >gram -ve

10.  Effects of high hydrostatic pressure:-
a) Cell enveloped related effect
b) Pressure induced cellular changes
c) Biochemical aspect
d) Genetic mechanism
 △V=2.3 R T [Log Kp1-Log Kp0]/[P1-P0]
 Applications:- enzyme inactivation, gel
formation, protein denaturation, tenderization
of meat, tempering of chocolate
 Components:- pressure vessel, pressure
generating system, temp controller

12.  ITU (915±13MHz and 2450±50MHz)
 Similar to visible light
 Non ionizing radiation
 Depends on:-size, shape, dielectric constant
 Penetration depth is inversely proportional to
frequency
 Penetration depth- dielectric constant & the loss
factor of food.
 Lower the loss factor, greater the penetration
 Mechanism:- ionic polarization, dipole rotation
 Mechanism of microbial destruction
 Components:- power supply, magnetron, wave
guide, stirrer, oven capacity

14.  Electrical energy is dissipated into heat
 Also called electrical resistance heating, Joule
heating, or electro-heating.
 Volumetric heating
△P=△U2/△Ω=σE2△A△Z=σE2△V
 Liquid foods, soups, fruit slices in syrups,
sauces, heat sensitive liquids, proteinaceous
foods
 Every 120ºC rise in temp causes 2-3 times fall
in resistance
 Rapid heating 1ºC/sec
)U(=Q 2


16.  An evolving field
 Better potential
 Equipment cost (though coming down) still is
a major limiting step
 Process documentation, verification
procedures need to be worked out for
government approval to assure safety
(adequate processing)

17. ANY QUERIES????