Imagine that perishable fruits, vegetables and flowers can last significantly longer in a good shape on groceries’ shelves. Imagine how much money could be saved and how much less food would be wasted globally. FreshInPac project and its participants strive to turn this idea into a reality. The results are very promising.
FreshInPac gathers research institutes, universities and companies that target at developing bio-based packaging for perishables (fruit and vegetables, but also flowers) with multiple functionalities (ethylene scavenging, release of plant-based antimicrobials, water vapor condensation control). To achieve these goals, the partners of the project from Poland, Germany and Belgium cooperate and put together their skills and expertise.
How to control ethylene?
Why does fresh food spoil or get ripe faster than needed? This is influenced by factors such as temperature, humidity, and also ethylene concentration in air. Controlling the latter factor is also particularly demanding, as ethylene is a plant ripening hormone that causes faster ripening in many fruit and vegetables. Ethylene gas is produced by fruit and vegetables in different quantities and is also released in air due to burning of hydrocarbons, for example, in exhaust of automobiles. High concentration of ethylene in air will cause faster spoilage in fresh fruit and vegetables.
– We try to develop new materials for ethylene scavenging that can be used for food packaging – explains Dr. Namrata Pathak, Postdoctoral Researcher at Leibniz Institute for Agricultural Engineering and Bioeconomy (ATB) in Potsdam. For FreshInPac project, the focus is on packaging of apples, bananas and tomatoes. – In general we want less ethylene in a packaging to slow down ripening and make the shelf life of the product longer.
ATB team experimented with various absorbents, activated carbon, silicate-based materials and zeolite (micro-porous, aluminosilicate minerals). Some of them have been developed by the research partners of the project. Some are the products of commercial partners and also external suppliers. During the first stage of the research, these substances were put inside an air tight chamber, into which ethylene was added later . Then the researchers examined how the substances scavenged the unwanted gas (by absorbing or oxidizing it). Many factors and variables needed to be taken under consideration in developing scavenging material suitable for fruit and vegetables. For example: there are climacteric and non-climacteric fruits. The first ones (e.g. mango, apples, ripe bananas) produce a lot of ethylene. The latter (e.g. strawberry)- produce less. Moreover different products react differently on exposure to ethylene. While green bananas are very sensitive to it, apples are moderately sensitive.
As a result of the first stage of FreshInPac project some very effective ethylene scavengers have been pointed out (for example zeolite). The next step is to find a way to apply the substances to packaging.
– Our research partners are currently trying to produce a film containing zeolite. The challenge we face is that in the form of film this substance does not work so effectively anymore. The film itself blocks access to the substance it contains. We should remember that the film used for packaging must not be too thick and must remain transparent – explains Dr. Pathak.
Nanomaterials, antimicrobials and co.
But scientists are not limited to film packaging. They analyze specially designed pads including absorbents and paper packaging containing ethylene scavengers as well. One of the FreshInPac participant, Belgian research center Celabor focuses on the development of active paper packaging
– We have prepared different coating formulations by dispersing the ethylene absorbents in different biopolymer coating solutions. These formulations were applied on paper sheets by bar-coating. We have developed some coating formulations using biopolymers such as cellulose, nano- and microcellulose fibers as well as proteins and incorporated zeolite and TiO2 nanoparticles as ethylene gas absorbents – says Dr. Sandro Gennen of Celabor scrl. Now the research center is about to start preparing coated paper sheets with antimicrobials supplied by ZUT (Zachodniopomorski Uniwersytet Technologiczny in Szczecin, Poland).
Another active Belgian partner in the FreshInPac project is Materia Nova research & innovation center. “We have developed different nanomaterials presenting catalytic activity against ethylene” explained Dr Axel Hemberg. In fact, Materia Nova established a method to coat particles and powders of nearly any size and shape by plasma. The coating thicknesses is in the range from 0.1 to 100 nm and can be achieved as uniform layer (coreshell) or not. Currently, up to 1/2 litre of powder can be coated in a single run, either with pure metal, organic or inorganic compound materials (e.g. oxides, nitrides etc.). With this approach, desireable coatings can be obtained (resistant, conductive, magnetic, optical or catalytic coatings), and divers surface modifications can be realized on the surface of the powder substrates. This technology has been used for covering (nano/micro) fillers by nm-scale layers of metallic coating that decompose ethylene by catalytic action. In addition, the limited metallic content reduces the production cost. Nano-porous fillers (ex: TiO2) have been coated. The “2 in 1” compound is able to adsorb (reduction of activation energy) and decompose ethylene.
“In the Polymeric and composite materials department of Materia Nova, we incorporated the coated nanoparticles in to polymer films, evaluated their properties and provided the active samples to the partners in order to evaluate their antimicrobial and ethylene destruction activities” said Dr Antoniya Toncheva.
Once we have identified the optimal coatings, we will produce the final packaging by coating a paper tray with coating solutions containing ethylene gas absorbents and antimicrobials. In order to meet the concepts of the circular bioeconomy, our research focusses especially on the development of bio-based coatings which are recyclable and/or compostable. In the final step, we will perform migration tests on the most promising packaging to demonstrate the compliance of packaging with EU food contact regulations – adds Dr. Gennen.
ZUT and its Center for Bioimmobilisation and Innovative Packaging Materials (CBIMO) will also work on “food-contact” nanoTiO2 however as 2in1 active material, which possessing both ethylene degradation and antimicrobial properties., However the main task of researchers from ZUT is to select and use of antimicrobial substances which are safe and legally permitted for contact with food. They strive to utilize antimicrobiological properties that delay food spoilage.
– On the basis of the microbiological analyses we have selected four substances that seem to be most promising in extending the shelf life of apples, bananas, tomatoes and roses. We are now verifying the possibility of introducing these substances into packaging materials. There are two ways of application which are now evaluated including direct introduction into the polymer granulate from which the packaging film is produced or as coating on polymer film surface – says prof. Artur Bartkowiak, Director of the Center for Bioimmobilisation and Innovative Packaging Materials ZUT (CBIMO) and Member of The Board of Natureef Association (Poland).
Mathematical modeling
The FreshInPac project steps beyond material testing. Researchers of Fraunhofer-Institut für Verfahrenstechnik und Verpackung IVV developed a mathematical model based on ordinary differential equations to calculate the time evolution of the ethylene headspace concentration and the effect on the ripening process of fresh produce. The model includes the production rate of the fruit, the permeation of ethylene through the packaging material and perforations, the scavenger reaction, and the geometry of the packaging system. Therefore, the dynamics of the changing process rates are modeled explicitly.
– With the help of these simulations, we obtain quantitative guidelines how a scavenger material can be integrated into a packaging system in order to work. The results allow us to plan functional active packaging systems specifically and individually – explains Dr. Matthias Reinelt of Fraunhofer-Institut für Verfahrenstechnik und Verpackung IVV.
Scientists from the IT department of ZUT also contribute to the FreshInPac project by working on a mathematical model. Their solution is linked with CBIMO’s research and describes the way active substance migrates in packaging.
Benefits and challenges
What economic and environmental effects may developments of FreshInPac bring? According to Dr. Pathak it’s difficult to determine them precisely because the durability of products depend on many factors, such as the ambient temperature and humidity, but in the case of selected fruits, e.g. bananas, we can talk about a few days longer on the shop shelf. The annual losses in fruit and vegetables may reach 45% and in flowers 15-20 % annually (by weight). As the perishable products have high economic importance, the benefits to producers and retailers can be huge.
But also commercial partners of the project will benefit. SME partners’ materials will be used during FreshInPac research and further developed. Test procedures let involved companies use the project results directly for designing their packaging materials.
– I am glad that the commercial partners of the project, together with their clients, are determined enough to develop the solutions that are created within the project. Fast and effective implementation of the research results is one of the goals of our center, but also of Natureef association – underlines prof. Bartkowiak.
Dr. Namrata Pathak indicates that in the future possibility of using next (nano)materials will be tested. For example application of titanium dioxide combined with UV light (and finally maybe even with daylight) as well as titanium dioxide combined with palladium seems to be promising.
There are however some major challenges the FreshInPac participants need to face with. One of them is the complex nature of ethylene absorbance phenomenon. Its level depends on ethylene concentration, which makes it difficult to strictly control the process. Another problem is that not all ethylene scavengers can be used in real-life applications because the materials that may be used in food packaging is limited by the law. The researchers face the fact that the results of laboratory tests do not fully translate into the effectiveness of the developed solutions for real packaging.
– Nowadays there are many interesting solutions described in the scientific literature, but only few applications in practice. We are working on a material that works effectively not only from the point of view of lab tests, but more important as final packages of food products- says prof. Bartkowiak.
Get in touch, register to the webinar
To learn more about the possible industrial application of the research and to get familiar with the results and plans of the companies, universities and institutes involved in the FreshInPac project, register to the project’s webinar for business representatives. During the event that will take place in September, partner organizations will present to the interested and/or industry-related SMEs the outcome of the project.
About the project
On 1st of September 2019 a project Active packaging for Fresh Food Market (FreshInPac) under CORNET 26th call was launched. Scope of the project is: New multifunctional packaging materials with tailored active functionality (ethylene scavenging; release of plant based antimicrobials; water vapor condensation control) will be developed to extend the shelf‐life and to maintain safety of fruits, vegetables and flowers.
Numeric simulation models will be also developed to design these packaging materials. Furthermore, ethylene absorption kinetics and permeability will be determined and mathematically described which has been rarely done before. Additionally, new ethylene scavengers will be developed using nano‐structured powders of involved SMEs. All active materials will be embedded into biopolymers with high water vapor transmission rate. Project co-financed by NCBiR under the CORNET initiative. Project Partners are: IVV, ATB – Germany; Celabor, Materia Nova – Belgium; KCPK – The Netherlands; ZUT, Natureef – Poland.
