Bäckerei- und Getreidetechnologie NanoBAK The NanoBAK technology Prof. Klaus Lösche, ttz BILB/EIBT...
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Transcript of Bäckerei- und Getreidetechnologie NanoBAK The NanoBAK technology Prof. Klaus Lösche, ttz BILB/EIBT...
Bäckerei- und Getreidetechnologie
NanoBAK
The NanoBAK technology
Prof. Klaus Lösche, ttz BILB/EIBT
Project 1st year meeting12th April – Holstebro/Denmark
Bäckerei- und Getreidetechnologie
Table of contents
1. Introduction
2. The NanoBAK System
3. The NanoBAK System - Ripening control with an optimal humidity in the atmosphere
4. The NanoBAK System – Humidity assisted cooling and freezing processes
5. Conclusions– Low energy and Premium quality
Bäckerei- und Getreidetechnologie
Table of contents
1. Introduction
2. The NanoBAK System
3. The NanoBAK System - Ripening control with an optimal humidity in the atmosphere
4. The NanoBAK System – Humidity assisted cooling and freezing processes
5. Conclusions– Low energy and Premium quality
Bäckerei- und Getreidetechnologie
Fuente: Chen. C.S., Lebensm.-Wiss.U. Technol., 18, 192-196, 1985
High energy demand
1. Introduction
Bäckerei- und Getreidetechnologie
• The ripening control:
retarded dough, interrupted dough, frozen dough.
• Bake-off processes:
par-baked and fully baked frozen products, pre-fermented dough, fully fermented and frozen dough, etc.
• Cooling after baking:
For packaging, for slicing, for post processing.
Current trends in bakery – fermentation control and frozen products
1. Introduction
Bäckerei- und Getreidetechnologie
Slow fermentation
Delayed fermentation
Interrupted fermentation
Deep-freezing
Control of the fermentation through less amount of yeast. It takes place at room temperature. Craft bakeries.
The fermentation speed is delayed through a quick decrease of the dough temperature.T range: +5°C to -6°C .
Interruption of the fermentation through a quick decrease of the dough temperature. T range: -7° to -18°C.
Long storage at lower temperatures than-18°C.
Maximum storage time: 8h.
Storage up to 72 h at aprox. 0°C, 80-85% RH.
Storage up to 72 h (90h) at aprox. -10°C, 80-85% RH.
Storage for several months Lower than -25°C, 75% RH
The fermentation process takes place during storage.
Final fermentation in a climatic chamber with optimal conditions depending on product.
Final fermentation in a climatic chamber: gradual change of temperature (1-2h, 3-10°C) followed by fermentation in optimal conditions depending on product characteristics.
Variations:DoughPar baked productsBaked products
Climatic chambers
1. Introduction
Bäckerei- und Getreidetechnologie
Cooling and freezing are high energy demanding processes and critical stages for the product quality
Conventional processingRel. Ambience H.= ~ 80-90 %
Desorption
Dough: Bread:Drying surfaces Freeze bruningIrregular products Weight losesWeight loses Undiserable colourUndesirable productCrust splitting
aW = 0,80-0,96(depending of it is dough or
bread)
Low cooling and freezing velocity
Skin formingHeterogeneous distribution of temperatureHumidity and temperature gradients
Low qualityHeterogeneous final products
Low conductivity
1. Introduction
Bäckerei- und Getreidetechnologie
Table of contents
1. Introduction
2. The NanoBAK Technology
3. The NanoBAK System - Ripening control with an optimal humidity in the atmosphere
4. The NanoBAK System – Humidity assisted cooling and freezing processes
5. Conclusions– Low energy and Premium quality
Bäckerei- und Getreidetechnologie
Ultrasound based humidification system which generates a cold fog (mist) with water drops of around 1 micron
Cooling and freezing with assisted humidity
For assuring:
- High relative humidity in the chamber- Better humidity distribution (without sedimentation, without condensation)- Better conductivity- Saving yeast- and enzyme- activities in the surface- Less turbulences
Energy saving
2. The NanoBAK technology
Bäckerei- und Getreidetechnologie
Mollier h,x-Diagram
With a relative humidity of 70 % with +30°C 1kg air contains approx. 19g water
With a relative humidity of 75 % at +5°C , 1kg air contains approx. 5g water (retarder)
2. The NanoBAK technology
Bäckerei- und Getreidetechnologie
• Mechanical oscillations of the water surface that liberate the aerosol droplets
• Size of the water droplets depending upon the ultrasonic frequency (minimum 1MHZ), being down to 1 micron and generating a cold fog
• Mass-output, energetically efficient
The aerosol (~ 0.001 -0,005mm) is delivered by the air flow in the chamber and is distributed very fast and homogenously within the ambient air.
Piezokeramic transducer (Transducer, Schwinger)
2. The NanoBAK technology
Bäckerei- und Getreidetechnologie
0,1
1,0
10,0
100,0
1000,0
0 200 400 600 800 1000 1200 1400 1600
Droplet size [µm]
Fal
ling
sp
eed
[cm
/s]
10 30 60 100 250 500 750 1000 15000,303 2,68 10,2 27 94 210 313 400 545
Droplet size [µm]
sedimentation rate [cm/s]
Small drops have nearly no falling, float, can drift
Ultrasonic equipment: < 1,0µm electro-humidifier: > 50 – 150 µm
electro-humidifier
ultrasonic technology
2. The NanoBAK technology
Bäckerei- und Getreidetechnologie
An optimized humidity distribution in the chamber is achieved through the cold fog
Simulation of the humidity distribution in a climatic chamber with the MICROTEC system
Optimal humidity distribution
2. The NanoBAK technology
Bäckerei- und Getreidetechnologie
2. The NanoBAK technology
Without condentation problems
Bäckerei- und Getreidetechnologie
- Dried surface - Water loses and mass transfers (crust splitting)- Condensation on the surface- Sticky dough- Quality loses
-No drying effects, no condensation problems- homogenous Temperature and Humidity distribution- Water loses and mass transfer are minimized, so that the crust stress and consequently splitting is avoided- High quality products and low energy demand
aW = 0,89-0,96 aW = 0,89-0,96
2. The NanoBAK technology
Conventional processingRel. Ambience H.= ~ 80-90 %
NanoBAK technologyRel. Ambience H.= ~ 99 %
The improvement
Bäckerei- und Getreidetechnologie
Table of contents
1. Introduction
2. The NanoBAK System
3. The NanoBAK System - Ripening control with an optimal humidity in the atmosphere
4. The NanoBAK System – Humidity assisted cooling and freezing processes
5. Conclusions– Low energy and Premium quality
Bäckerei- und Getreidetechnologie
3. Case study: retarded fermentation
Remark: the temperatures depend on the chamber capacity and the size of the product, as well as on the design and production criteria.
Bäckerei- und Getreidetechnologie
expansion expansion
Conventional chamber Humidity assisted chamber
Retarded fermentation, T =+3°C, 16 hours
3. Case study: retarded fermentation
Bäckerei- und Getreidetechnologie
3. Case study: retarded fermentation
Conventional chamber Humidity assisted chamber
Retarded fermentation, T =+3°C, 16 hours
Bäckerei- und Getreidetechnologie
Conventional chamber
Hours
Crispiness retention
+Color
+ Crispiness
Conventional process
Humidity assisted
Humidity assisted chamber
Retarded fermentation: T = +3°C, 16 hours
3. Case study: retarded fermentation
Bäckerei- und Getreidetechnologie
3. Case study: interrupted fermentation
Remark: the temperatures depend on the chamber capacity and the size of the product, as well as on the design and production criteria.
Bäckerei- und Getreidetechnologie
Conventional chamberdough properties:sticky, wet and rough surface.
Humidity assisted chamberproperties:easily handling dough, humid inside but dry and smooth surface.
expansion expansion
Interrupted fermentation, T = -10°C, 20 hours
3. Case study: interrupted fermentation
Bäckerei- und Getreidetechnologie
Conventional chamber
Humidity assisted chamber
Interrupted fermentation, T =-10°C, 20 hours
3. Case study: interrupted fermentation
Bäckerei- und Getreidetechnologie
Conventional chamber with an electric humidifier (only able to work until +5°C) Energy consumption of the interrupted process, 20 hours= 44,40 KWh
Chamber with the humidity assisted system though cold fog (during the whole process)Energy consumption of the interrupted process, 20 hours = 27,80 KWh
3. Case study: interrupted fermentation
Bäckerei- und Getreidetechnologie
High conductivity, better mass and heat transfer, faster browning:
Energy saving
Low conductivity, limited mass and heat transfer
Humidity assisted
Conventional process
Interrupted fermentation, T -10°C, 20 hours
3. Case study: interrupted fermentation
Bäckerei- und Getreidetechnologie
Influence of the additional humidity on the enzymatic activity and/or the browning reaction (same baking conditions)
Decrease of the baking time
3. Case study: interrupted fermentation
Conventional chamber Humidity assisted chamber
Interrupted fermentation, T =-10°C, 20 hours
Bäckerei- und Getreidetechnologie
Table of contents
1. Introduction
2. The NanoBAK System
3. The NanoBAK System - Ripening control with an optimal humidity in the atmosphere
4. The NanoBAK System – Humidity assisted cooling and freezing processes
5. Conclusions– Low energy and Premium quality
Bäckerei- und Getreidetechnologie
Conventional process: shock freezer
The freshly baked bread (previously cooled down) is frozen in a chamber at – 40°C (until -7°C on the core) and afterwards stored at -18 °C (or even -25°C)
Advantages:- Fast freezing
Disadvantages:- High energy consumption- Water loses up to 4%- Quality loses due to crust splitting- Freezer burn
4. Case study fully baked frozen bread
Bäckerei- und Getreidetechnologie
Crust splitting
- The crust splitting is evidenced after the freezing stage
- Part of the product surface is broken
- The storage of the product worst the problematic
4. Case study fully baked frozen bread
Bäckerei- und Getreidetechnologie
a) Thermodynamic problem due to the temperature gradient
b) Gas pressure drop/ the gas bubbles contract
Hypothesis for the crust splitting problematic:
- Humidity diffusion to the cold crust- Condensation below the crust-Possibility of crystal formation below the crust-Expansion of ice will cause crust splitting
Congel.
Dry air
Source: Prof. Le Bail (ENITIAA, Francia)
4. Case study fully baked frozen bread
Bäckerei- und Getreidetechnologie
Freezing process with additional humidity (at controlled intervals)
From 95°C until -10°C in the core (-20°C in the chamber), followed by storage at -18°C
Advantages:
- Better quality- Avoidance of water loses- Minimum crust splitting- Better conductivity = energy saving
4. Case study fully baked frozen bread
Bäckerei- und Getreidetechnologie
Fully baked Baguette
Shock freezer immediately after baking (-40°C) until -10°C in the core followed by storage at -18°C (with packaging)
Fully baked Baguette
Humidity assisted freezing (-20°C) until -10°C in the core followed by storage at -18°C (with packaging)
Chamber at - 40°C Chamber at - 20°C, less energy consumption!
4. Case study fully baked frozen bread
Bäckerei- und Getreidetechnologie
4. Case study: bread cooling
Adiabatic cooling
Bäckerei- und Getreidetechnologie
Step 1Adiabatic cooling with humidity contribution (discountinously) Freshly baked bread, from 95°C to +30 °C (core) (chamber at 20°C)Advantages:- Better final quality- No refrigeration system necessary, energy saving
Step 2Humidity asssisted freezing (interval)From 30°C up to -10°C in the core (chamber at -20°C)Advantages:- Better conductivity = energy saving- Better quality- Avoidance of the weight loses- Avoidance of the crust splitting and the freezer burn
Currently under study!
4. Case study fully baked frozen bread
Bäckerei- und Getreidetechnologie
Figure 2: bread after 30 minutesIn a humidity assisted chamber at +1°C
Figure 1: bread after 30 minutesin a conventional chamber at +1°C
Case study: 1000g bread. Pictures taken using a thermograph after 30 minutes of cooling in a chamber at +1°C
27,3 °C 21,5 °C
Cooling process after baking
4. Case study: bread cooling
Bäckerei- und Getreidetechnologie
The product water loss during the cooling process can be avoided
4. Case study: bread cooling
Bäckerei- und Getreidetechnologie
Table of contents
1. Introduction
2. The NanoBAK System
3. The NanoBAK System - Ripening control with an optimal humidity in the atmosphere
4. The NanoBAK System – Humidity assisted cooling and freezing processes
5. Conclusions– Low energy and Premium quality
Bäckerei- und Getreidetechnologie
• Refrigeration technologies have enormously contributed to the growth, among others, of the bakery industry (starting by 1980/1985)
• Refrigeration technologies provide the bakery sector, both craft and industrial bakeries, with a great potential for innovation and development
• The way to optimal climatic techniques is driven by the final product quality and the energy demand
• The humidity assistance during the cooling and freezing stages improves enormously the current trendy processes and contributes to the energy reduction
• Optimal humidity conditions in the chamber and in the dough/bread are achieved
• Improvement of the bread and baked products quality: premium quality thanks to the humidity in the atmosphere
• At the same time, a significant energy saving can be achieved leading to an important reduction of costs
5. Conclusions – Low energy and Premium quality
Bäckerei- und Getreidetechnologie
Prof. Klaus Löschettz BILB/EIBT Am Lunedeich 1227572 BremerhavenTel. : +49 471 97297-13 Fax.: +49 471 97297-22
Vielen Dank für Ihre Aufmerksamkeit
Thank you for your attention
Bäckerei- und Getreidetechnologie