Kirsi S. Mikkonen

Bio: Kirsi S. Mikkonen is an academic researcher from University of Helsinki. The author has contributed to research in topics: Cellulose & Lignin. The author has an hindex of 27, co-authored 82 publications receiving 2059 citations. Previous affiliations of Kirsi S. Mikkonen include University of Oulu & Oulu University Hospital.

Sustainable food-packaging materials based on future biorefinery products: Xylans and mannans

Abstract: Xylans and mannans are abundant plant cell wall polysaccharides that can potentially be recovered in large quantities from side-streams of the agriculture and forestry industry. The film-forming capacity and biodegradability of xylans and mannans make them an interesting alternative to the petroleum-based materials currently used as food packaging. The barrier properties, mechanical durability, and thermal behavior of polymers are essential characteristics in determining their applicability as food-packaging materials. Xylan- and mannan-based films and coatings show low oxygen and grease permeability and, in some cases, relatively high tensile strength. The chemical structure of xylans and mannans, use of blended polymers, and the addition of nanoparticles for reinforcement affect the material properties.

Prospects of polysaccharide aerogels as modern advanced food materials

Abstract: Aerogels are porous and lightweight materials capable of active sorption and releasing desired compounds and/or bearing mechanical load. Using polysaccharides as aerogel matrices instead of silicate or synthetic polymers has additional benefits. Polysaccharides can be developed as bio-based, biodegradable, and/or edible materials in food applications. Polysaccharides that could be used to prepare aerogels include cellulose, hemicelluloses, marine polysaccharides, and starch, all of which have in common the ability to form gels either by themselves in the presence of water or with dications, other cross-linking agents, and/or other, blended, or mixed polysaccharides. After the liquid phase is removed, the dry aerogels form solid particles of various shapes and sizes that have high porosity and surface area. These characteristics indicate vast possibilities for the use of polysaccharide aerogels as advanced food materials.

Films from oat spelt arabinoxylan plasticized with glycerol and sorbitol

Abstract: The development of packaging films based on renewable materials is an important and active area of research today. This is the first extensive study focusing on film-forming properties of an agrobiomass byproduct, namely, oat spelt arabinoxylan. A plasticizer was needed for cohesive film formation, and glycerol and sorbitol were compared. The tensile properties of the films varied with the type and amount of the polyol. With a 10% (w/w) plasticizer content, the films containing glycerol had higher tensile strength than the films containing sorbitol, but with a 40% plasticizer content, the result was the opposite. Sorbitol-plasticized films retained their tensile properties better than films with glycerol during 5 months of storage. The films were semicrystalline with similar crystallinity indices of 0.20–0.26. The largest crystallites (9.5 nm) were observed in the film with 40% glycerol. The softening of films with 40% (w/w) glycerol started at a significantly lower relative humidity (RH) than that of the corresponding sorbitol-containing films. The films with sorbitol also had lower water vapor permeability (WVP) than the films with glycerol. The films plasticized with 10% (w/w) sorbitol had a WVP value of 1.1 g mm/(m2·d·kPa) at the RH gradient of 0/54%. The oxygen permeability of films containing 10% (w/w) glycerol or sorbitol was similar: 3 cm3·μm/(m2·d·kPa) at 50–75% RH. A higher plasticizer content resulted in more permeable films. Permeation of sunflower oil through the films was not detected. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

A standardised static in vitro digestion method suitable for food – an international consensus

Abstract: Simulated gastro-intestinal digestion is widely employed in many fields of food and nutritional sciences, as conducting human trials are often costly, resource intensive, and ethically disputable. As a consequence, in vitro alternatives that determine endpoints such as the bioaccessibility of nutrients and non-nutrients or the digestibility of macronutrients (e.g. lipids, proteins and carbohydrates) are used for screening and building new hypotheses. Various digestion models have been proposed, often impeding the possibility to compare results across research teams. For example, a large variety of enzymes from different sources such as of porcine, rabbit or human origin have been used, differing in their activity and characterization. Differences in pH, mineral type, ionic strength and digestion time, which alter enzyme activity and other phenomena, may also considerably alter results. Other parameters such as the presence of phospholipids, individual enzymes such as gastric lipase and digestive emulsifiers vs. their mixtures (e.g. pancreatin and bile salts), and the ratio of food bolus to digestive fluids, have also been discussed at length. In the present consensus paper, within the COST Infogest network, we propose a general standardised and practical static digestion method based on physiologically relevant conditions that can be applied for various endpoints, which may be amended to accommodate further specific requirements. A frameset of parameters including the oral, gastric and small intestinal digestion are outlined and their relevance discussed in relation to available in vivo data and enzymes. This consensus paper will give a detailed protocol and a line-by-line, guidance, recommendations and justifications but also limitation of the proposed model. This harmonised static, in vitro digestion method for food should aid the production of more comparable data in the future.

Cellulose nanowhiskers: promising materials for advanced applications

Abstract: This review covers the production, structure, properties and applications of nanowhiskers of cellulose. It is shown that these nanowhiskers can be generated, from various plant sources, with transverse dimensions as small as 3–30 nm, giving a high surface to volume ratio. Since the nanowhiskers are rod-like, it is shown how they can be self-assembled into chiral nematic liquid crystalline structures, not only in solution, but also in the dry state. The production of thin films of cellulose nanowhiskers, by spin coating and in combination with polymer electrolytes, is also covered. A wide range of chemical modification of cellulose nanowhiskers are reviewed; including 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, polymerisation from the surface using Reversible Addition–Fragmentation chain Transfer (RAFT) and Atom Transfer Radical Polymerisation (ATRP), and the rendering of the surface with cationic and anionic charge. The mechanical properties of cellulose nanowhiskers will also be covered, including the measurement of their stiffness using both Raman spectroscopy and Atomic Force Microscopy (AFM) measurements. The final part of the review will cover the applications and potential industrial use of cellulose nanowhiskers; namely for nanocomposite materials, thin films and other applications. Finally, some conclusions, including perspectives and future developments will be presented.