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Development of a high power ultrasound system for the low-cost, fast, effective and quality drying of fruit and vegetables

Final ReportSummary - ULTRAVEG (Development of a high power ultrasound system for the low-cost, fast, effective and quality drying of fruit and vegetables)

The research that has been carried out in the ULTRAVEG project indicates that a significant reduction of the drying time of 10 - 30 % for hot air drying as well as accelerated freeze-drying can be achieved. These results have been obtained using a novel approach to the application of HPU to drying processes, which has been developed in the project. Due to the novelty of the approach, it was necessary to extend the research work to ensure that these first results are reproducible on a larger scale and for a variety of foodstuffs.

ULTRAVEG may lead to a new patent protecting the novelty of the approach, which will provide the technological small and medium-sized enterprises (SMEs) from the ULTRAVEG consortium with a high strategic benefit. A decision on a patent application by the SME partners is currently pending a further extensive patent research.

Non-confidential information on the latest results and principles of the UTLRAVEG technology has been successfully disseminated during the project. The public website of the project (see http://www.ultraveg.eu online) informed the public and interested parties on the basics of the technology, latest press releases and the progress of the project insofar as it can be disseminated without threatening the proper protection of the developed intellectual property. A variety of press releases were successfully circulated in newspapers, magazines and professional food technology magazines and websites, raising the awareness of ULTRAVEG both in industry and in the public domain. In addition, ULTRAVEG was presented at several scientific conferences and on the public Turkish television. The interest and feedback generated by successful dissemination activities highlight the present demand in industry for innovative technology as well as industry's willingness to invest in such innovations.

Based on the promising results from the industry validation trials, the SME partners are now looking for further funding to bring this novel emerging technology to the market.

Project context and objectives:

The aim of the ULTRAVEG project was to develop a high power ultrasound (HPU) system for the low-cost, fast, effective and quality drying of fruits and vegetables.

Project results:

The results for direct sonication-assisted drying on sieves during year 1 were much more promising than the envisaged pre-treatments and showed a reduction in the characteristic drying time of up to 30 %. Due to these unexpectedly positive results, the direct sonication of product trays or sieves has been the focus during the second year of the project work. Improved drying characteristics were found both for hot air drying and freeze-drying both for apple and pepper samples. In the case of hot air drying, these results were also independent of the drying-air temperature. This shows the application potential of the ULTRAVEG system in a wide range of food drying processes.

Ultrasound-assisted hot-air drying with the ULTRAVEG prototype has been thoroughly tested and evaluated for low-temperature drying of apple rings at the pilot plant area of TTZ in Bremerhaven. The validation tests included an adaptation of sonication intervals, the respective impact on the prototype performance as well as an investigation on the drying curves of the test food under these processing conditions. Within the tests, product characteristics and food quality parameters were examined, such as appearance, lack of discoloration, texture, smell, taste and other sensory properties, content in polyphenols, ascorbic acid and sugar composition, by wet-chemical analysis, IC and HPLC analysis, as well as sensory tests performed with a consensus panel as well as untrained consumers.

Ultrasound-assisted freeze-drying with a second ULTRAVEG prototype has been validated with the test product red bell-pepper cubes at GREVEN. The trials comprised several abortion runs to monitor effects of the ultrasound application at various process stages, as well as repetitive trials to investigate effects on the fast-drying phase of the drying curve in more depth. The main validation parameter has thus been the residual moisture content of the test foods. In addition, fully freeze dried samples produced with and without ultrasound application have been analysed in terms of content in polyphenols, and have been evaluated by a sensory panel.

Overall, the ULTRAVEG trials have shown that there are no disadvantages in terms of nutritional and sensory quality of the test foods as a trade-off for the potential benefits of an accelerated drying curve.

The developed ULTRAVEG technology contains a number of innovations that could be considered as inventive steps serving as valid claims of a patent. The consortium identified these claims thus far as follows:

i. A food holding tray that is gently vibrated at frequencies between 20 - 40 kHz, whereby the vibrations
a. accelerate the dehydration in hot-air and freeze-drying processes; or
b. allow drying at lower temperatures in the same time for a better food preservation;
c. give the necessary thermal energy to the foodstuffs to initiate sublimation in freeze-drying, i.e. without the need for an additional heating device.

ii. A clamping system to couple an ultrasound probe as the source of the vibrations to the tray that relieves the need for a fixed screwed or welded connection for improved maintenance, loading and unloading, and cleaning.
iii. A system as in (i) that is applicable to various geometries (rectangular, squared, round, ellipsoid) and sizes (from 1 cm2 to 1 m2.
iv. A system as in (i) that can be used in conjunction with trays made of solid or perforated steel or aluminium, where the ultrasound coupling can occur at the centre or side of the tray with one probe or in multiple positions using several probes.
v. A system as I in (i) that can also be comprised by a mesh or sieve made of metal or plastic wires attached to a solid frame to which the ultrasound is coupled.
vi. An ultrasound system that applies gently frequency sweeping around the main frequency with a bandwith of +/- 1-5 kHz or more in order to ensure a homogeneous vibration across the tray area.

For ultrasound-assisted accelerated freeze-drying, lab results have shown that interval sonication is mandatory to avoid a counterproductive heating of the tray and foodstuffs on it above the melting of water (compare D3.1 and D3.2).

A complete overview of the results on the validation trials is given in deliverables D5.2 Report on the industrial results and recommendations for future commercialization.

The two ULTRAVEG prototypes were designed in order to comply with most of the industrial requirements and the needs expressed by the SME partners. Based on the promising laboratory results, the different design components of the prototype - in particular the tray size and geometry, as well as the ultrasound system itself - were scaled-up step-by-step to a size close to the industrial scale. This scale-up was accompanied and aided by additional finite-element analysis studies. According to this design, the prototypes were assembled and tested by IRIS before shipment to partners TTZ and GREVEN for the use in industrial validation trials. The current design of the prototype is intended to meet the industry needs and requirements of a new drying technology. In particular, it lends itself to a straightforward increase in production capacity; it is affordable; easy to install and maintain; and it can be operated with minimal effort and without requiring special skills by the operator. The prototype will serve to validate whether the significant reduction in drying time can be successfully reproduced at a larger scale.

The full details of the pre-competitive prototype, including all mechanical, electrical and software components were made available to the SME partners in the deliverable D4.1 design of the ULTRAVEG pre-industrial prototype, and deliverable D4.2 construction of a pre-industrial prototype and evaluation of the prototype at laboratory scale. The following pictures show the final prototypes after assembly, a screenshot of the control software and the electronics box of the prototype.

Potential impact:

Given the status of the technology and the strongly fragmented market, it is hard, if not practically impossible, to quantify the expected socio-economic impact of the ULTRAVEG technology at this point. Much will depend on the post-project research and development (R&D) development, including the success of follow-up proposals for further funding through Eurostars.

Nevertheless, the SME partners were positive in the outlook that the knowledge acquired in the project on ultrasound-assisted drying and the food drying process and markets will have a long-lasting impact on their future business.

A technological breakthrough such as ULTRAVEG can make a significant contribution to improving the competitive position of European SMEs within the dried food sector. In particular, FM and Greven will be provided with access to an affordable, easy to use, ultrasound-based food treatment technology that significantly lowers the costs and time of their drying processes. By using ULTRAVEG, they will be able to save time, money and energy. This will enable them to maintain or even increase their market share in the face of low cost competition from third countries and to enter global markets which to date were unattainable for them. Such benefits, if communicated effectively to food drying processors, will stimulate market pull whereby it is expected that the uptake of the technology will materialise, especially if return-on-investment claims can be made and supported.

Such market pull, will be complemented with a very clear market push strategy that will be implemented by the supply SMEs from the ULTRAVEG consortium. An analysis of the market potential for the ULTRAVEG system, which is discussed below, reveals that ULTRAVEG represents a significant business opportunity for the SME that will make up the supply chain of this novel ULTRAVEG system. AKTIVE, on the one hand, intends to boost their competiveness by tapping into a new application for their ultrasound equipment and expertise. Gokser, on the other hand, will be able to increase their sales and turnover by distributing and installing the system in their home market of Turkey, as well as other key markets in the Middle East and Europe.

Due to the strong fragmentation of both the market for industrial drying technology and that of dried food producers, it is very hard to give tangible predictions in terms of the possible turnover of the technology. Moreover, no real standards appear to exist in the food drying industry in terms of tray sizes, production volumes of machines, treatment temperatures, etc. Nevertheless, based on the market research and the feedback obtained to date, it is possible to give some estimation of the potential market impact of ULTRAVEG.

First, it is necessary to split up the market impact into hot air and freeze-drying equipment. In a second step, it is also necessary to consider different sizes of equipment in terms of production volume. This also relates to the additional development work that is needed: the largest volume production sites predominantly use continuous belt systems (in hot air drying). Adapting the technology for belt systems will take more time and thus lead to a later market entry, but an attractive business opportunity nonetheless. This consequently leads to a market entry that will first focus on smaller production volumes before targeting larger production lines and, finally, also fully continuous, high capacity belt-driven systems.

Based on the market research in terms of food drying machines producers (section 2.3.4) and taking into account that production of new machines first needs to be ramped up to accommodate different machines sizes and techniques, the market potential in terms of turnover was estimated. This estimate is of course only a rough estimate. Due to the high fragmentation of the food drying market, it is practically impossible to determine solid market figures in terms of the numbers of players on the market, their customers etc. This holds true, unfortunately, both for food processors and machine producers. Instead, the table and its estimates are based on the client based of partners Gokser and Aktive, thus giving an estimate that is more closely related on the actual business plans of the partners rather than global market figures that are very tangible.

Initial market entry in Turkey with a first commercial hot air cabinet dryer is envisaged for the end of 2012 after additional R&D work will have been completed.

Starting from there, it is envisaged to extend the sales on small scale cabinet dryers continuously and enter the European and global markets not before 2015. At the same time, the technology will gradually be introduced also into larger scale dryers and it is envisaged to sell the first large scale continuous system by the end of 2015.

Owing to the fact that freeze-drying is a more complex as well as that overall, freeze-drying production is much smaller in volume, the market entry will follow roughly a year later than the for hot-air drying equipment.

It is important to bear in mind that these are estimates. Nevertheless, these figures can serve as an initial basis for further refinement. In addition, maintenance of the systems will also boost these figures. The market prices are estimates based on the numbers found during market research as well as the experience from the partners in the consortium. They reflect averages since, as mentioned above, no real standards in terms of production volume exist on the market place, i.e. the actual drying capacity of a particular machine sold may vary and, therefore, also will its price. In addition, these numbers have been estimated very conservatively. Especially, large scale drying equipment, such as tunnel dryers, can easily reach a market price above EUR 1 million per unit.

Project website: http://www.ultraveg.eu