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Radio Frequency Food Processing

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Tom Kuipers Stalam S.p.a.Nove (Vi) - Italy

FACTS & FIGURES

Year of establishment: 1978

Number of employees: 115 (worldwide)

Yearly turnover: EUR. 20+ million (year 2018)

Production capacity: over 120 industrial size machines per year

Sectors: textile and technical-textile (60%), food (35%), others (5%)

Sales organisation: worldwide network of agents (more than 70) and servicing centres (20)

Export share: more than 95%

Export markets: Europe (30%), Asia (50%), Americas & Africa (20%)

Market share: more than 50% worldwide (textile and food, RF technology)

Market position: no. 1 worldwide (textile and food, RF technology)

INDUSTRIAL APPLICATIONS

TextilesDryers for fibres, yarns, fabrics

Technical textilesDryers for glass fibres, latex foam,

polyurethane foam, felt, non-wovens, etc.

FoodPost baking drying, tempering & defrostingPasteurisation & sterilisation, disinfestation

Other applicationsLWIR technology for surface treatments(drying & curing), drying ceramics, etc.

ELECTROMAGNETIC SPECTRUM

RF are non-ionising electromagnetic waves !

THE ELECTROMAGNECTIC SPECTRUM RF heating mechanisms

DIPOLAR VIBRATION-ROTATION

_ _ _ _ _ _ _ _

H+

Electrode

Electrode

+ + + + + + +

o --

H+ H+

o --

H+

H+

o--

H+

Electrode

Electrode

27.12MHz

_ _ _ _ _ _ _ _

+ + + + + + +

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Endogenous (volumetric) heating

Controlled, uniform, fast heating

Selective heating

High energy efficiency

Outstanding quality results

High operational flexibility

RF MAIN CHARACTERISTICS

RF heating vs. Conventional heating

• heat transferred from the outside

by convection, conduction, irradiation

• part of the energy is wasted

• efficiency affected by surface conditions and thermal conduction

• non-uniform temperature distribution

• long heating / drying time

• user cannot control the powerabsorbed by the target

• selective heating is not possible

• heat generated inside the target

(volumetric heating)

• all the energy is dissipatedinside (no energy losses)

• uniform temperature distribution

• very short processing time

• user can set the power to beabsorbed by the target

• user can heat selectively part ofthe target

380÷415 V50Hz

57000 V811000 V

50 Hz

68000 V

DC 27.12 MHz

26000 V

27.12 MHz

ELECTRODE

ELECTRODE

HT TRANSFORMER RECTIFIER

OSCILLATING

CIRCUIT

COUPLING

CIRCUIT

RF EQUIPMENT

WORKING PRINCIPLE

MAIN SUPPLY

LEGEND

0 = Air dielectric constant Vm = Actual voltage on the productr = Product’s relative dielectric constant d0 = Distance between electrodes0r = ’- j” dm = Height of the product

V0 = Electrode voltage

d0 dm Vm

00 r

V0

UPPER ELECTRODE

LOWER ELECTRODE

THE PROCESS CONTROL

P ≈ f ∙ V2 ∙ Kε

d2

f = frequency (27.12 MHz)V = electrodes voltage Kε = product’s RF energy absorption rated = electrodes distance

Operational

parameters

controlled

by the user

Only few and simple adjustments

Outstanding process control and flexibility

• Suitable for products higher than 3-4 cm

RF power applicators: type 1

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• Designed to improve heating of products with varied height

• Uses fixed voltage and the energy applied is adjusted by

raising or lowering the upper electrode

RF power applicators: type 2

• Outstanding energy transfer efficiency to thin products

• Energy applied is adjusted through a variable capacitor

• Lower and controlled electrode voltage (no arching)

RF power applicators: type 3

-

-

+

+

Stalam RF machines in total:

>2400

Stalam RF machine in Food:

>180

In variety of applications: TEMPERING / DEFROSTING

FISH, MEAT, FRUITS,

VEGETABLES,BUTTER

IN BLOCKS OR IQF,

WITH OR WITHOUT PACKAGING

FAST, UNIFORM AND CONTROLLED HEATING PROCESS

IMPROVED PROCES STABILITY FURTHER PROCESSING.

DRASTIC REDUCTION OF DRIP LOSS

NO PRODUCT DETERIORATION

NO BACTERIAL GROWTH

CONTINUOUS (IN-LINE) OPERATION

JUST IN TIME / ON DEMAND

WHITE CRUST BREAD

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– As bread rises in the baking oven, the energy asorbed by the product is constantly changing, the electrode configuration needs to change with it.

– The electrode configuration can be different along the process direction enabling a variable heating approach depending on physical shape.

RF bread baking ADVANTAGES

• reduced baking time, from three to five times less, depending on the chemical-

physical characteristics and the level of baking desired;

• a much shorter baking oven, for a certain production capacity, or a much higher

production capacity in the same space normally occupied;

• an energy efficient process, thanks to the endogenous (direct) heating system . But

electrical energy!

• a higher flexibility, to produce normal crusted bread or white-crust (crust less) bread,

without any product loss (due to crust removal from the normal crusted bread baked

traditionally).

- RAPID INACTIVATION OF ENZYMES AND MICROORGANISMSRESPONSIBLE FOR FOOD DETERIORATION

- END OF LINE CONTINUOUS TREATMENT AVOIDING ANY POST-CONTAMINATION

- EASILY INTEGRATED IN THE AUTOMATED PRODUCTION LINES

- VOLUMETRIC ENDOGENOUS HEATING TO REACH QUICKLY AND UNIFORMLY THE PASTEURIZATION TEMPERATURE

PASTEURISATION of PACKAGED FOOD PRODUCTS

PASTEURISATION OF FRESH PASTA PRODUCTS PASTEURISATION OF FRESH PASTA PRODUCTS

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SINGLE OR MULTI MODULE RF UNIT FOLLOWED BY HOT AIR CONVECTION SYSTEM (TUNNEL OR SPIRAL)

THE RF IS USED TO RAPIDLY INCREASE THE TEMPERATURE OF THE PACKAGED SLICED BREAD UP TO 70-80°C

A HOT AIR HOLDING SECTION KEEPS THIS TEMPERATURE FOR THE REQUIRED TIME

PASTEURIZATION TIME REDUCED 50%, DOUBLE PRODUCTION CAPACITY

PASTEURISATION OF PACKAGED BREAD

CYCLE DESCRIPTION:

10’ RF up to 70 - 80°C

20’ HOLD TIME AT 80°C

PASTEURISATION OF PACKAGED BREAD

PARAMETER U.M. BEFORE RF AFTER RF

COLONY COUNTS AT 30°C

CFU/G > 103 <10

MOLDS CFU/G 3.5 x 102 <10

YEASTS CFU/G >102 <10

INCREASED SHELF LIFE WITHOUT CHEMICAL PRESERVATIVES (ETHANOL, SORBATE, PRIOPIONATE…)

NO RISK OF POST-CONTAMINATION

EASY AUTOMATION (POSSIBILITY TO PASTEURIZE IN TRAYS OR BOXES)

REDUCED FLOOR SPACE AND PROCESS TIME COMPARED TO CONVENTIONAL HOT AIR CONVECTION SYSTEMS

INCREASED PRODUCTION CAPACITY

ENERGY SAVING

BENEFITS OF RF END OF LINE PASTEURISATION

- RAPID & UNIFORM TEMPERATURE RISEWITHIN THE PRODUCT, ALSO IN THE SUSPENDED SOLID PARTICLES OF ANY SIZE, WITH NO RISK OF OVER-PROCESSING THE LIQUID

- MICRO-BIOLOGICAL INACTIVATION (SAFETY) AT LOWER TEMPERATURES AND IN A SHORTER TIME

- BETTER QUALITY OF THE PRODUCT (SENSORIAL, CHEMICAL AND PHYSICAL CHARACTERISTICS, INCLUDING THE STRUCTURAL INTEGRITY OF SOLID PARTICLES)

PASTEURISATION & STERILISATION OF

LIQUID AND PUMPABLE PRODUCTS

- LESS ADDITIVES (COLOURS, FLAVOURS, THICKENERS, ETC.) REQUIRED

- SUITABLE FOR LOW- OR HIGH-VISCOSITY LIQUIDS, WITH OR WITHOUTSUSPENDED SOLID PARTICLES, SLURRY MIXTURES, JUICES WITH PULPS, ETC.

THE “RF/L” TECHNOLOGY DEVELOPED BY STALAM MAKES IT POSSIBLETO CARRY OUT PASTEURISATION AND STERILISATION PROCESSES ATHEATING RATES FROM 1°C/SEC UP TO 100°C/SEC.

PRODUCTION LINES WITH TYPICALTHROUGHPUT OF 2,000 L/H,INCORPORATING THE “RF/L”EQUIPMENT, HAVE BEEN WORKINGFOR SOME YEARS AT LEADINGEUROPEAN DAIRY AND FRUITPREPARATION PRODUCERS.

PASTEURISATION & STERILISATION OF

LIQUID AND PUMPABLE PRODUCTS

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PASTEURISATION OF A STRAWBERRY FRUIT PREPARATION

MESOPHYLIC AEROBIC LOAD:

BEFORE >5000 C.F.U./G

AFTER RF TREATMENT <5 C.F.U./G

SPOROGENIC MESOPHYLIC BACTERIA:

BEFORE >200 C.F.U./G

AFTER RF TREATMENT <5 C.F.U./G

HYPHOMYCETES:

BEFORE >1000 C.F.U./G

AFTER RF TREATMENT <5 C.F.U./G

YEASTS:

BEFORE >1000 C.F.U./G

AFTER RF TREATMENT <5 C.F.U./G

STERILISATION OF APPLE DICE WITH SYRUP

STERILISATION CYCLE (1200 l/h)Pre-heating to 50°C with heat exchanger in 63”RF heating to 105°C in 36”Holding time at 105°C in 18”

PRODUCT DESCRIPTION50% liquid syrup pH 3.4, 1.5 mS/cm, 18° Brix50% solid dice 1.2 x 1.2 x 1.2 cm, pH 3.8

15.3 Log reduction for target microorganism L. plantarum

PASTEURISATION & STERILISATION OF

LIQUID AND PUMPABLE PRODUCTS

The fluid substrate to be treated is continuouslypumped through one or more Teflon tubeshaving a suitable diameter (from DN16 to DN80)depending on product’s characteristics

The tubes are placed between especially designed electrodes (according to the tubediameter and the product’s characteristics)

The temperature achieved is a function of the RF power and of the product flow rate: generally 80-110°C for pasteurisation and

over 120°C for complete sterilisation

“RF/L” technology

no use of steam

energy efficiency >70%

compact lay-out

lower product losses

higher added value

REDUCED PROCESS TIME

REDUCED USE OF THICKENERS, ADDED COLOURS AND FLAVOURS

EASY CLEANING (NO CRUSTING EFFECT) AND LOW MAINTENANCE

COSTS

DOUBLE STERILISATION EFFECT (THERMAL + ELECTROCHEMICAL)

REDUCED FACTORY FLOOR SPACE REQUIREMENTS

HIGH ENERGY EFFICIENCY

BETTER WORKING ENVIRONMENT

CIP SYSTEM CAN BE USED FOR WASHING

PIG SYSTEM CAN BE USED FOR IN-LINE CHANGE AND RECOVERY OF

THE PRODUCT

THE PLANT STERILITY IS MAINTAINED ALSO IN STAND-BY

CONDITIONS

PASTEURISATION & STERILISATION OF

LIQUID AND PUMPABLE PRODUCTS

Advantages over conventional thermal processing

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RADIO FREQUENCY DISINFESTATION OF

DRY AGRICULTURAL COMMODITIES

- Fast and continuous process

- Environmentally safe

- Max product preservation

- Selective and homogeneous

- Suitable for “organic” and “bio” production chain commodities

- High energy & cost efficiency

Pasteurising Dried Mushrooms

Pasteurising Almonds / WalnutsRADIO FREQUENCY CONTINUOUS DRYING OF

AGRICULTURAL COMMODITIES

- Conveyor-type drying tunnel

- In-line continuous processing

- Easy automatization for constant product flow

- Modular construction to achieve high production capacity

- Low temperature drying for thermo-sensitive products

- Accurate control and uniformity of the moisture content

- Suitable for nuts, grains, seeds, beans, cereals and pulses

RF Drying vs. conventional drying

Technical advantages

• high drying speed / High evaporation efficiency(irrespective of product shape, size, density, moisture content)

• No influence of atmospheric conditions on drying(outside air temperature, humidity, dustiness)

• Full operational flexibility (one dryer for all products)

• Instantaneous start / stop (no need for pre-heating / cooling)

• Continuous and “just in time” operation

• Reduced floor space requirement and modular construction

• Improved working conditions(little noise, no heat dispersions, no fumes released)

• Parameters easily controlled

• Full automation easily fitted

Product Quality advantages

• Accurate and consistent residual moisture control

• Outstanding drying uniformity

• Extended shelf-life

• No colour change

• Reduced product loss due to overprocessing

• No surface deterioration (skin loss, cracks, burns)

• Preservation of nutritional and sensorial properties

RF Drying vs. conventional drying

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RF Food commodity Drying: example

RF drying tunnel of post-harvest corn/rice/sorghum processing:

Installation: MULINO MARELLO – Alessandria (Italy) gluten-free dry mill for the food industry

Equipment size: single module 85 kW RF output powerInitial moisture: 20 ÷ 25% w/wFinal moisture: 12 ÷ 14% w/wProcessing time: 40 minutesProduction capacity: 700 ÷ 800 kg/h

POST-BAKING DRYING

- AFTER THE BAKING OVEN

- RAPID AND EFFICIENT DRYING

- UNIFORM AND ACCURATERESIDUAL MOISTURE CONTROL

- NO OVER-BAKING (EXCESSIVE

BROWNING) OF THE SURFACE

- THE PRODUCTION LINE SPEEDCAN BE INCREASED UP TO 25%

- SUITABLE FOR BISCUITS, COOKIES, MERINGUES, SPONGE CAKES,PUFF PASTRY, CRACKERS, BREAD STICKS, APPETISER SNACKS, ...

POST BAKING DRYING

ADVANTAGES OF RF DRYING AFTER THE BAKING OVEN

• INCREASED THROUGHPUT BY EXISTING OVEN WITH HIGHER M.C.

• MOISTURE PROFILE OUT OF THE RF DRYER IS MORE UNIFORM

• REDUCED “CHECKING” OF DELICATE PRODUCTS

• REDUCTION OF ACRYLAMIDE FORMATION

• EXTENDED SHELF-LIFE

• IMPROVED SENSORIAL PROPERTIES

18% 12%Conventional last

oven section.16% 6%

18% 12%

RF Dryer

12% 18% 10%

10%

Non-uniform moisture distribution

Maximum uniformity and consistency

>> moisture levelling effect

REDUCED CHECKING Due to:

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THE PATENTED DOUBLE POLARITY ELECTRODE DESIGN PRODUCES AN EFFICIENT HORIZONTAL FIELD FOR THIN PRODUCTS

MAXIMUM UNIFORMITY AT LOWER VOLTAGES

NO ELECTRICAL ARCING

POST BAKING DRYING RF POST BAKING DRYING

IMPROVING THE PRODUCTION LINE CAPACITY

+10% Floor space = +20% Production capacity

No additional browning during RF Drying > No additional AA.

Increased production capacity from the baking oven enabling a

higher output moisture content - RF performs the final drying

No changes in the recipe

POST BAKING DRYING

TRADITIONAL APPROACH TO REDUCE AA LEVELS:

USE SODIUM OR POTASSIUM CARBONATE

INSTEAD OF AMMONIUM CARBONATE AS

RAISING AGENT

REDUCTION OF BAKING TEMPERATURES

ADDITION OF AMINO ACIDS OR PROTEIN

BASED INGREDIENTS

THESE MODIFICATIONS AFFECT THE TASTE

OF THE PRODUCT

POST BAKING DRYING

35% LOWER AA

FORMATION BASED ON:

CONVENTIONAL BAKING

TO 10% R.M.C. AND USE

OF RF TO GO DOWN TO

4% R.M.C.

REDUCING ACRYLAMIDE - EXAMPLE

POST BAKING DRYING

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Questions....!