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Enabling small-to-medium sized oven technology producers and bakeries to exploit innovative Low Energy Ovens

Final Report Summary - LEO (Enabling small-to-medium sized oven technology producers and bakeries to exploit innovative Low Energy Ovens)

Executive Summary:
The LEO project aimed to develop and test three oven prototypes based on an innovative Infrared baking technology. The consortium partners succeed in their respective tasks and by the end of the project we demonstrated the several advantages of the IR baking technologies which consist in energy savings, baking time reduction and last but not the least improvement of the organoleptic characteristics and shelf-life of bread products.

During the 2-year project the consortium partner Ramalhos manufactured two batch oven prototypes (one deck oven and one convection oven) based on the IR technology while Ircon manufactured a large-sized IR conveyor oven. The scientific partners ONIRIS and SP provided hands-on support to improve the efficiency of the prototypes and made several laboratory testing.

A detailed life-cycle assessment (LCA) of the IR oven prototypes has been led by the experts from Blonk. Many useful data on consumables, raw materials, energy consumption, etc. as been collected and the LCA will serve the interest of the consortium to promote low energy baking technologies. The partner LEMPA with the support of partnering bakeries in BPA and Die Havenbacker performed a sensory analysis and a consumer acceptance study that gave excellent results and it appeared that the bread baked with the IR prototypes received a better appreciation from consumers.

The bakery and bake-off markets have been analysed by the partner Intelligentsia. All the project results (e.g. energy consumption, time savings, consumer acceptance, LCA, etc.) have been used to produce a tailored business plan for the LEO IR technology and Intelligentsia received a first contact from a Turkish oven manufacturer interested by the IR technology.

Project Context and Objectives:
The LEO project enable small-to-medium sized oven producers and bakeries to exploit a key research result from the completed FP6 EU-FRESHBAKE project, “Freshly Baked Breads with Improvement of Nutritional Quality and Low Energy Demanding for the Benefit Of the Consumer and of the Environment”, (Project no. 036302, FP6 FOOD-2004-T0 ( The result to be exploited by the LEO project consists in an infrared technology for baking purposes.

A prototype batch oven was built by ONIRIS and the use of only infrared lamps for heating was successfully demonstrated for baking dough during the EU FRESHBAKE project. Compared to a standard baking oven, the pre-heating step with the prototype oven required between 20-40% less specific energy with a gain in time up to 70%. The invention has been patented by ONIRIS in 2009 (WO 2011/006955-A2).

The overall goal of the LEO (Low Energy Ovens) project is to develop three types of oven - i) batch deck oven, ii) batch convection oven and iii) conveyor oven - based on similar technology to reduce energy consumption and save time during the baking process for a wide target group (craft bakery and bake-off actors). The LEO infrared technology will provide an overall reduction in energy between 20-40% and can be used in a two step process (preheating and/or baking). The technology can be applied to partly-baked bread (Bake-off), fully-baked bread on-site (retail in-store and craft bakeries).

The LEO project addresses important strategic objectives:
• Allow the exploitation of the FP6 EU-FRESHBAKE project results based on further R&D activities
• Develop and demonstrate three (3) IR ovens ready for commercialisation on the market
• Conduct an environmental, social and economic life-cycle assessment in-line with ILCD to propose eco-constructed ovens
• Support the development of the bakery industry, composed of a large pool of SMEs
• Encourage the participation of SMEs in the project and offer them a competitive advantage: production of a new baking oven technology, using an innovative oven aiming to save cost and time, participating in the business development of a new, innovative and promising technology.

The LEO project will comprehensively address a broad range of scientific and technological issues faced by the consortium partners (research performers and SMEs) as well as the end-users (in-store bakeries, craft bakeries, semi-industrial bread producers) associated to the technological development.

Project Results:
S&T results obtained on the two IR batch oven prototypes:

1/ Selection of IR lamps
The partner Ramalhos was the main responsible to design and develop the two IR batch prototypes, namely, the deck oven and the convection oven. The partner Ircon provided a strong support to Ramalhos in this activity and especially concerning the selection of the best IR lamps to integrate into their specific ovens. Ircon built a test rig comprising an insulated stainless steel box with a mounted thermometer and a small stirrer. The IR lamp and the reflector were mounted on top of the steel box, over the opening.

The following IR lamps were tested:
• Single short-wave IR lamp (SWIR), 2.0kW 220-250V
• Twin short-wave IR lamp (SWIR), gold-coated, 1.4kW 220-250V

The following IR lamps were tested:
• Single short-wave IR lamp (SWIR), 2.0kW 220-250V
• Twin short-wave IR lamp (SWIR), gold-coated, 1.4kW 220-250V

Two types of protection windows were tested:
• Quartz glass
• Ceramic glass.

Ircon designed a special test to use computer simulations in order to identify parameters and settings for even and quick heating of the oven stone and thereby gain knowledge for the development of the optimal IR emitters. A test oven sole has been equipped with eleven (11) thermocouples for the testing and a computer simulation model of the test oven was built in the Solidworks software.

The results obtained demonstrated that six (6) IR lamps of 2kW short-wave is the best configuration for the deck oven while four (4) IR lamps of 2kW short-wave located around the fan is the best configuration for the convection oven.

2/ Development of the steam boxes
The partner ONIRIS study the optimal steaming during the baking process and demonstrated that the optimal steaming consists in having 93 ml of water injected for about 130% of the oven volume occupied by steam. Based on this information, Ramalhos improved their steaming system for the deck and convection oven based on the research made by ONIRIS and the recommendations provided.

The conception of the steam box for the IR deck oven did not changed but the control system of the oven has been modified to improve the delivery of steam inside the oven.
For the convection oven, several solutions have been investigated and tested during the course of the project: projection of water on the hot fan and spread of water at the bottom of the cavity for a continuous evaporation.

3/ Manufacture of the IR batch oven prototypes
Ramalhos successfully manufactured two (2) batch ovens: one IR deck oven and one IR convection oven. Ramalhos used their existing models of oven to integrate the IR technology:
• The IR deck oven is based on the MODULORAM model
• The IR convection oven is based on the TURBORAM model

Ramalhos upgrade existing ovens during the project to save time and benefit from their experience in building these ovens but by doing so we demonstrated that the LEO IR technology could be easily integrated into existing ovens.

Also the partners Ramalhos, Ircon and ONIRIS gained valuable knowledge on the selection and integration of IR lamps, improvement of steam box as well as technical know-how to implement IR technology into ovens. Consequently this new knowledge generated by the LEO project is a significant added-value for the partners and it considerably improve the state of the art in IR baking technology.

The two batch IR oven prototypes received interesting results during the laboratory testing at ONIRIS, nevertheless more tests are foreseen to increase the performance of both ovens and take into consideration their actual use in the bakery environment.

The IR deck oven prototype results consist in:
• Extremely efficient for pre-heating (e.g. 7 minutes to reach 230°C) compared to the reference oven (e.g. 65 minutes to reach 230°C). The energy-saving during preheating is three times lower than conventional technology.
• When comparing the IR and reference deck ovens, the IR deck oven consumes 50% less energy for one (1) baking and one preheating, which is mostly due to its efficiency during pre-heating.
• The specific energy for one baking (without pre-heating) is similar for the IR deck oven and its reference oven. Nevertheless ONIRIS specified that the test was performed at 100% intensity of the IR lamps. The bread baked in the IR deck oven was most likely over baked compared to the reference oven, which is indicated by a darker colour as well as lower moisture content. Optimally, we could use shorter baking time and/or lower IR-intensity to obtain a product comparable to the reference oven and therefore reduce the energy consumption of the IR deck oven.

The IR convection oven prototype results consist in:
• No significant differences between the IR ventilated oven and its reference oven during the pre-heating phase mainly due to the convection/ventilated baking method.
• During baking, the IR ventilated and reference ovens have the same energy performances. But similarly than the IR deck oven, the IR ventilated oven was using IR lamps at their maximum intensity.
• The energy and time savings are not so important for the IR convection oven.

4/ In-situ testing and consumer acceptance study
The in-situ testing of the two IR batch ovens and their reference ovens at the German bakery Die Havenbacker, confirmed the results obtained before on the energy savings and time reduction. The French partner LEMPA, in charge of the sensory analysis and consumer acceptance study, also used the batch ovens and noticed the significant reduction in time.

Die Havenbacker performed several tests with different settings to reach the best quality of bread.
• The IR deck oven allows a reduction of the baking time from 18 min to 14 min representing 22% of time reduction.
• The IR convection oven allows a reduction of the baking time from 18 min to 16 min representing 11% of time reduction.

The setting for the intensity of IR lamps is currently analogical and it does not allow assessing precisely the reduction in intensity. In addition no energy counting was possible during the in-situ testing to define the energy reduction linked to the decrease of intensity of the IR lamps.

LEMPA organised three hedonic panels with naïve and untrained consumers (62 + 60 + 61 people) where they have proposed two different recipes of bread, namely standard bread and tradition baguette. Then LEMPA performed a qualitative analysis by requesting tests from four (4) trained experts, in order to assess sensory attributes of bread baked with the IR technology.

The results of the sensory analysis and acceptance study surpassed our expectations:
• Both IR batch ovens have an overall acceptability above 6/10 for all types of bread
• The IR convection oven has undeniably produced bread of better quality than the reference oven.
• The IR deck and reference ovens are producing standard bread of equal quality but the IR deck oven produces tradition baguette of better quality.
• When comparing the two IR batch ovens together, the consumers preferred the bread baked with the IR convection oven.

S&T results obtained on the IR conveyor oven prototype:

1/ Selection of IR lamps
Based on experience gained during the development of IR emitters for batch ovens, the partner Ircon designed the optimal IR emitters for the conveyor oven. The system allows rapid and well controlled reheating of the stones returning at the entrance of the conveyor oven. The conveyor has IR reflecting walls and the length of the oven will be 3-4 m with a conveyor belt width of 600 mm. The speed of the conveyor belt is adjustable using frequency converters in the range 0.2 to 2 m/min. The power is preliminary set to 60-70 kW, requiring 2 x 63 A supplies.

In order to efficiently control the IR heating during the entire baking process, Ircon structured the conveyor oven in seven (7) IR sections with particular requirements and therefore specific settings:
• Section 1 'Heating of stones before loading dough': 5 lamps of 4kW
• Section 2 'Heating of stones underneath during baking': 5 lamps of 4kW
• Sections 3, 4, 5 and 6 'Baking process': 8 lamps of 2kW
• Section 7 Colouration': 2 lamps of 4kW

2/ Development of the steam boxes
Several steaming systems have been investigated and used in the conveyor oven prototype to reach the optimal amount of steam, defined by ONIRIS, and consisting in 130% of the oven internal volume. Ircon worked in close cooperation with Ramalhos, SP and ONIRIS.

The system implemented in the conveyor oven was a 15kg steam box (620 x 330 x 131 mm) with two continuous steam-exits (1,5”) that can support 8 litres of water in its interior. The power of the heating system is 0.8kW for 380V and 1kW for 220V. This system offers a maximum mass flow rate of steam which will be in the range of 0.354 g/s (0.8kW) and 0.442 g/s (1kW).

During the in-situ testing at BPA, the French bakery upgraded the steaming system which did not provided enough steam at the entry zone of the oven. BPA improved the steaming system by using an industrial humidifier called 'Defensor' and also modified the injection pipe with 11 holes of 6.5 mm diameter which had previously 9 holes of 1.5 mm. The combination of the industrial humidifier in the modification of the injection pipe significantly improved the steaming injection at the entry section. Some Silicon and Teflon™ curtains have been installed at the entry and exit of the oven to keep the steam inside. After these modifications, ONIRIS visited BPA to test the steaming system and they have recorded good results for the absolute humidity which is now 90g of water/Kg of dry air (e.g. previously 65g water/Kg dry air)

3/ Manufacture of the IR batch oven prototypes
Ircon successfully manufactured the IR conveyor prototype while the partner SP tested the different functionalities of the prototype in order to adjust and improve the IR conveyor oven before in-situ testing:
• Teflon inlet conveyor belt: The speed of the Teflon inlet conveyor belt was measured, in order to correlate transport speed with the motor setting for the inlet belt.
• Stone conveyor belt: The oven baking time was defined as the time from the vertically adjustable outer metal plate at the oven inlet to the vertically adjustable metal plate at the oven outlet. The distance between these two plates is 2500 mm.
• Stone heating: In order to reduce energy losses during the preheating step, the time for preheating should be minimized. Therefore, all IR lamps are used for heating the stone belt until the desired temperature is reached. In this case a desired temperature of 230°C was selected and all IR lamps were set on 90% of the maximal power.
• Heat flux: Heat flux measurement equipment provided by ONIRIS was used to evaluate the radiative and convective heat fluxes in the length and width direction of the conveyor oven prototype. The heat flux equipment comprises two sensors (one covered with a black square and the other covered with a golden square), air temperature sensors and a logger positioned in a thermal barrier box. The sections with IR lamps have a relatively high radiative heat flux (in average 6.8 kW/m2) compared to the convective heat flux (in average 2.1 kW/m2). In the first section of the oven with IR power off the radiative and convective heat fluxes are rather similar, in average 0.9 and 1.1kW/m2 respectively. The ratio is 39 % at the entry section with the IR lamps turned off, whereas it increases to 73 % in the middle and exit IR zones.
• Humidity measurements for installed steam box: The metal tube for steam spraying in the oven is positioned in the inlet zone of the oven. The humidity was measured by pumping air from the oven space through a sensor outside the oven and then back to the oven space. The steam generator delivers oven humidity on average of up to 40-45 g water/kg dry air (DA) in an empty oven. When the product is baking, the humidity increases in the entry zone, in average up to 55-60 g water/kg DA. Thanks to the improvement of BPA the absolute humidity increased to 90 g water/kg DA.
• Water inlet valve for steam box: The water valve for inlet water to the steam box is regulated by a sensor (high/low water level). When the sensor measures low water level, the water valve opens until water level is high enough or a pre-defined steaming time is reached.

4/ In-situ testing and consumer acceptance study
The in-situ testing of the IR conveyor oven was carried out at the French bakery BPA. The bakery tested different configurations to optimise the quality of the baking and defined the optimal parameters (e.g. pre-heating and baking time, intensity of lamps in different sections and the optimal stone temperature). The energy measurements performed during the testing showed a ratio of energy consumption above 2kWh/kg for crispy rolls (50g) and 1.5kWh/kg for standard bread (200g).

Together with LEMPA, the partner BPA prepared samples of bread baked with the IR conveyor oven and with the reference oven selected for these tests (e.g. rotative rack oven using gas). BPA run two main trials for the sensory analysis, the first one with employees and relatives for a total of 180 panellists. A large majority of panellists preferred the bread baked by the IR conveyor prototype, whereas 138 preferred the LEO bread, 42 liked both equally, and none preferred the reference bread. The reasons stated by the consumers are:
• Thinner crust, and despite being contradictory, having a longer crispiness over time no matter the weather conditions (even with high humidity),
• Softer crumb,
• Increased shelf-life: after 24 hours, the bread appeared fresher than the reference.

For the second trial, BPA managed to work with 19 clients: 8 companies, 9 high schools and universities, 1 hospital and 1 nursing house. Overall BPA obtained a significant population representation consisting of 271 people. BPA collect 93 feedbacks to analyse the consumer acceptance. The results of the second trial are not as satisfactory as during the first trial: 26 preferred the LEO bread, 46 liked both equally, and 21 preferred the reference bread.

The conveyor oven is extremely sensitive and minor variations affect the level of baking. Nevertheless, the final point of this study is that the bread baked with the IR conveyor oven is of better quality than the one baked with the reference oven and the capacity of the IR technology to produce a thin and crispy crust at the same time is very interesting for industrial bakers.

Life Cycle Assessment of IR technology
The partner Blonk is expert in LCA study and thanks to the contribution of all consortium partners, they have managed to collect a large number of data and developed a tailored methodology to study the impact of the IR technology on the environment.

IR deck oven prototype:
Overall the LEO technology has significantly reduced the marked effect of almost all the environmental impact categories, especially those in which the pre-heating of the oven had a great contribution to the total impact, including ozone depletion and ionizing radiation. These declines are related to the reduction of 60% energy (direct savings and reduction of time) use during the pre-heating.

However, these environmental improvements decreased when the number of baking increases after the pre-heating phase. For example, the total impacts of ozone depletion and ionizing radiation decrease already 40% of their impact from one to two baking cycles; 65% for five baking cycles and about 80% for 40 baking cycles.

In the case of climate change, its impact is reduced as much as 30% after 5 baking cycles. This lower reduction percentage is due to the low contribution of the pre-heating to the total impact of climate change: about 35% for one baking session, and under 10% for 5 baking cycles. Moreover, the IR technology did not show any improvement regarding the energy use of the deck oven during the baking process.

IR convection oven prototype:
For the convection ovens, no environmental improvements of the IR technology were found since no significant changes in energy use were measured. Nevertheless, if the convection ovens are compared to deck ovens, it appears that the environmental burdens present are much lower in the case of convection ovens.

IR conveyor oven prototype:
With regards to the conveyor oven, it cannot be directly compared a reference conveyor oven of the same size, same loading capacity and baking method (e.g. in the case of the IR conveyor oven, it is comparable to a deck oven). However, a preliminary conclusion is that the IR conveyor oven may have a lower impact than the reference deck oven.

For all the baking ovens, when considering a full (from cradle-to-grave) LCA and thus introducing the distribution and consumption phases, all marked effects rise to around 20-30%. This is due to the increase of ingredients required for bread production (since losses are enhanced along the whole production chain and consumption phase) and the energy and diesel consumption of these two phases. However, these two phases together only contribute 5 to 10% of the total footprint for all the impact categories.

Potential Impact:
The LEO project will have a significant socio-economical impact in the democratisation of low energy baking technologies. During the project the partner Intelligentsia prepared a study of the bakery and bake-off markets which has been downloaded 53 times on the project website, read 80 times online and distributed to the main national and European bakery associations. The market analysis showed a raising concern of the buyers (e.g. the bakeries) to use energy efficient technologies to reduce their production cost as well as from the end-users (e.g. the consumers) willing to buy product with a reduced impact on environment.

The LEO technology is not the only low energy baking technology but so far it is one of the few providing real energy savings without decreasing the quality of the bread. By the way the LEO technology offers much more than energy savings, our IR technology is actually reducing the baking time and therefore would allow the bakers to increase their production volume. In addition the bread baked with our LEO technology has been fully accepted by the consumers and it appeared that the bread baked with LEO prototypes had a better quality than the one baked with the reference ovens. The sensory analysis and in-situ testing on the bread made with the IR conveyor oven showed an increased in the shelf-life of product.

All these good results are encouraging for the development of the LEO technology by several oven manufacturers in Europe and worldwide. The Turkish oven manufacturer Mimta ltd. enters in contact with the LEO coordinator Intelligentsia and the scientific manager ONIRIS to discuss the possibility of licensing the IR technology. In the coming years we are expecting an increasing number of licensees for the LEO technology as described within our Business Plan. In general the consortium partners believe that the success of the LEO project will pave the way for an increase number of R&D activities to develop low energy baking technologies including infrared heating but not only.

During the 2-year project, the consortium partners designed a project website and frequently updated it with news articles and downloadable materials. The partners prepared the following promotional materials:
• One (1) Project leaflet and one (1) poster
• One (1) PowerPoint presentation
• Four (4) project newsletters
• One (1) Bakery and bake-off market study

All the promotional materials have been distributed to a scientific and industrial audience interested by innovative low energy baking technologies. All the partners contributed to disseminate the project results by participating to relevant national/European and international events such as:
• European Federation for Food Science and Technology 2014 and 2015
• EUROPAIN 2014 (France)
• FIPAN 2014 (Brazil)
• SIAL Fair 2014 (France)
• Congress Cereal & Europe 2015
• Etc.

The partners made several scientific presentations during international events to disseminate the project results:
• "Environment and energy in the baking sector"; A. Le Bail (ONIRIS); European Federation for Food Science and Technology; 2014
• "Energy consumption during bread baking: focus on the IR technology and key results from LEO Project"; T Gally, V Jury, A. Le Bail (ONIRIS); Congress Cereal & Europe; 2015
• "Increasing the sustainability of bread baking: new strategy to keep crust quality while reducing energy"; N Hesso, T Gally, V. Jury, A. Le Bail (ONIRIS); Congress Cereal & Europe; 2015
• "Infrared Baking Technology: LEO project"; A Le Bail et al. (ONIRIS); Congress BIET; 2015
• Poster presentation "Improvement of the energy efficiency of bread baking: optimization of the steaming and of the sole material"; V. Jury et al. (ONIRIS); ICEF-12 International Congress on Engineering and Food; 2015
• Poster presentation "Improvement of the energy efficiency of bread baking: optimization of the steaming and of the sole material"; V. Jury et al. (ONIRIS); ICC Congress Milano; 2015
• "Reduction of energy in baking ovens; an overview of LEO (“Low Energy Oven”) European project based on infrared technology and on water spraying to replace steam injection during baking"; A. Le Bail et al. (ONIRIS); EFFOST Congress; 2015
• Poster presentation "Life-cycle assessment of low energy baking ovens using an innovative infrared heating system"; Blonk Consultants; LCA for feeding the planet and energy for life at EXPO Milano; 2015
• "Deux stratégies d'optimisation énergétique des fours de cuisson"; ONIRIS; Professional Journal Process Alimentaire France; 2016
• "Ecoconception des procédés alimentaires: cas de la cuisson du pain"; ONIRIS; Revue des Industries Alimentaires et Agricoles France; 2016
• "Pilot scale stone belt infrared conveyor oven for baking applications"; Ircon; Foodtech Innovation Portal by Hightech Europe; 2015

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