Environmental demands are pushing industry toward sustainable packaging solutions, particularly to replace plastics and PFAS-containing materials. Among the alternatives, modified starch proves effective in creating barriers against oils and fats, thanks to its film-forming ability and flexibility. Industrial tests confirm its strong performance, even in combination with mineral pigments
Environmental policies and industrial strategies are now inextricably linked. Growing environmental awareness and the need to make sustainability a priority—along with the drive to reduce waste production and promote a more circular economy—have led the European Commission to promote the search for and adoption of more sustainable alternatives to plastic in packaging wherever possible.
While paper and cardboard are among the most promising solutions in this respect, they do have some technical limitations that make them less suitable for preserving foods rich in water or fats. Not only do they tend to absorb moisture due to chemical affinity, but their structure can also be easily penetrated by fats and gases through migration or diffusion.
The barrier properties that are naturally lacking in paper and cardboard can, however, be achieved by applying protective coatings.
Roquette Frères one of the world’s leading producers of starches and starch derivatives, has developed an innovative starch-based solution, which was presented at the Aticelca Congress last May.
Starch and barrier properties
Currently, many effective solutions still rely on synthetic polymers derived from petrochemicals. Moreover, new environmental and health requirements exclude the use of certain key synthetic polymers, such as per- and polyfluoroalkyl substances (PFAS), which are known environmental pollutants and harmful to health.
In response to current market needs, Roquette has long been committed to researching and developing solutions that can support sustainability goals—particularly for the paper industry. The company’s new product is called Stabilys BA 25, an innovative starch-based barrier solution.
«Starch is a polymer of glucose» explains Enrico Bartoli, Technical Developer Coordinator, Paper and Board at Roquette. «It acts as a natural barrier against oils and fats because it is rich in OH groups and can form a film with low porosity. However, it also has a high affinity for water—again due to those OH groups—and is therefore hydrophilic.»
These characteristics make starch an excellent candidate to replace harmful products such as fluorinated compounds in food-grade paper, as well as an excellent primer for very porous or treated papers. Starch can thus create a physical barrier effect, but to be effective, it must have appropriate viscosity and film-forming ability.
«The viscosity of starch must suit papermaking process requirements, preventing it from dispersing too deeply into the substrate. If the starch is excessively absorbed, it can’t remain on the surface and therefore cannot form the barrier film.»
Film-forming ability refers to «the starch’s capacity to distribute evenly and homogeneously across a surface, forming—once dried—a uniform, thin, yet flexible layer that does not crack. To achieve this, starch must have low surface tension (or contact angle) and a high molecular weight to prevent absorption.»
The choice of modified starch
To reach the right balance between viscosity and surface tension, Roquette’s approach began with selecting an optimal botanical source for starch extraction. The choice fell on waxy maize (corn), which contains 99% amylopectin—one of the two main components of starch, along with amylose.
Roquette has long studied surface starches. Initially, the company developed the Stabilys A range, made of thermally modified dextrins—polysaccharides obtained by starch hydrolysis. This product, Bartoli explains, still represents an excellent compromise between efficiency and cost. But market and technological needs demanded something more high-performing and better suited to modern requirements.
Roquette’s technicians therefore developed a second family of dextrins, called Stabilys EVO, derived from the same waxy maize. Then, in 2021, the company’s R&D turned toward developing a solution capable of replacing all barrier materials that pose environmental or health risks.
«We began developing a new product, and from thermally modified dextrins we engineered a functionalized, waxy maize–based starch, which we named Stabilys BA 25—available in both powder and liquid form».
The decision to use modified starch, i.e., starch chemically functionalized with specific groups, was made to ensure several improvements, Bartoli explains.
«First, it reduces polarity, thus decreasing water affinity and enhancing the starch’s ability to remain on the surface. It also provides low surface tension, which allows for lower starch application levels while ensuring a homogeneous surface. Finally, it gives a plasticizing effect, improving the flexibility of the starch film and preventing cracking, which would otherwise compromise barrier properties.»
Testing fat barriers
The new product was applied and tested in several case studies, leading to industrial-scale trials. Tests were carried out on special thin papers, characterized by very low porosity and good water resistance. About 1 g/m² of starch was applied as a reference level—comparing potato starch (one of the most widely used in papermaking), PVOH (polyvinyl alcohol), Stabilys EVO 280, and Stabilys BA 25, with an addition of 0.4 g PFAS. Two tests were used: a Roquette in-house test and the ASTM 119 test.
Bartoli explains that the standard Kit test had limitations, as it was developed for different systems and concepts. The ASTM 119 test, by contrast, involves placing a cotton pad impregnated with oil onto the paper sample, applying a weight, and heating it in an oven at 40 or 60 °C. The time from application to the oil appearing on the opposite side of the sheet is then measured.
Results showed that «compared to PVOH and oxidized starch, even Stabilys EVO 280 with PFAS addition performed better, forming a uniform film and acting as a carrier, thus enhancing the PFAS effect.» However, since the goal was to eliminate PFAS entirely, the fluoropolymer amount was halved—and yet «results still exceeded the reference standard. Meanwhile, Stabilys BA 25, without any additive, gave the best performance».
Flexibility and barrier properties
A second round of tests evaluated the flexibility of the different starch coatings. In their final applications, the paper supports are meant to be folded, posing a risk that folding could crack the film and compromise the barrier effect.
«We first tested our historical dextrin, Stabilys A025» says Bartoli. «Initially on its own, and then combined with our plasticizer, Plastilys. Results were virtually identical before and after folding. We then used Stabilys EVO 280, with and without Plastilys, and noticed some improvement after folding.»
The best results, however, were achieved with Stabilys BA 25, with or without plasticizer. «Although the difference between pre- and post-folding results was smaller than in other tests, with the addition of a plasticizer—further improving flexibility—the outcome remained identical before and after folding».
In combination with a mineral
Roquette experts took an additional step, aiming to meet the main goal of their study: replacing PFAS while obtaining a product that could also serve as a primer.
«The paper industry today demands barrier effects for various types of packaging papers» Bartoli notes. «To this end, we wanted to test our solutions in combination with a lamellar mineral pigment—in this case, talc.»
The synergy between starch and the mineral pigment reduces paper porosity, helping the starch stay on the surface. «The results confirmed our expectations. Based on all measured performance values, Stabilys BA 25 ranks first, Stabilys EVO 280 second, and Stabilys A020 third.»
Some less satisfactory data came from the Cobb test, which measures the amount of water absorbed by paper and cardboard surfaces over time. However, Bartoli explains that the discrepancy could be due to a portion of starch being solubilized.
Ultimately, all tests demonstrated the strong performance of the new Stabilys BA 25 solution—even when applied at 1 g/m² less, and in combination with talc. The new product thus stands as a viable solution to meet the design goals it was engineered for: eliminating hazardous chemicals like PFAS, replacing potentially polluting components such as plastics, and providing paper with barrier properties comparable to those of certain plastic packaging materials.
Innovation at the core
Roquette Frères is one of the world’s leading producers of starches and starch derivatives. Founded in France in 1933, the company boasts over 90 years of industrial activity across multiple application sectors, with an annual turnover of €4.5 billion. Today, with more than 40 production sites worldwide and 20 research, development and innovation centers, it employs around 10,000 people—approximately 300 of whom work exclusively in R&D.
The Paper & Board Business Unit in Europe employs about 50 people, including technicians, sales specialists, lab experts and engineers.
Recently, Roquette expanded further by completing the acquisition of IFF Pharma Solutions, a major player in the pharmaceutical industry. Announced last May, this acquisition allows Roquette to enter the excipient market, strengthening its position in the pharmaceutical sector. The new organization is structured around two Business Groups with dedicated teams and resources: Health & Pharma Solutions and Nutrition & Bioindustry.