flexible barrier packaging: Influence of botanic origin on starch nanocrystals properties

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Starch nano-particles for ecoefficient flexible barrier packaging: Influence of botanic origin on starch nanocrystals properties 2 nd year Déborah LE CORRE +33 476 826 974 deborah.lecorre@pagora.

eu/) Converting Biomaterials Packaging Nowadays, most efficient materials used for food Background packaging are practically undegradable [1] and fuel based, representing a serious environmental and

A solution consists in combining bio and nano-technologies. Nanofillers have strong Figure 1.

1 Starch nano-particles for ecoefficient flexible barrier packaging: Influence of botanic origin on starch nanocrystals properties 2 nd year Déborah LE CORRE deborah.lecorre@pagora.grenoble-inp.fr Supervisors : Pr. A.Dufresne, Dr. J.Bras Project : Flexpakrenew 7th Framework European Project ( Converting Biomaterials Packaging Nowadays, most efficient materials used for food Background packaging are practically undegradable [1] and fuel based, representing a serious environmental and sustainability problem. However, the uses of these materials have been limited by their poor performance such as brittleness, poor gas and moisture barrier. A solution consists in combining bio and nano-technologies. Nanofillers have strong Figure 1. Different ways of producing crystalline and amorphous starch nanoparticles, hydrolysis leads to nanocrystals, whereas regeneration and mechanical treatment lead to both amorphous and crystalline particles in final batch. 3 Up to now, a focus has been brought to starch nanocrystals. We have assessed the influence of botanic origin and chemical content (amylose/amylopectin ratio) of native starches on the features and properties of resulting nano-crystals. 461 rue de la Papeterie BP Saint Martin d'hères Cedex - France Tel 33 (0) Fax 33 (0)

2 Déborah Le Corre reinforcing effects and studies have also shown their positive impact in barrier packaging. The aim of our study is to consider the industrial use of starch nanoparticles in packaging. Starch structure has been under research for years and because of its complexity, an universally accepted model is still lacking.[2] However, the predominant model for starch is a concentric semi-crystalline multiscale structure which allows the production of new nano-elements: (i) starch nanocrystals resulting from the disruption of amorphous domains from semi-crystalline granules by acid hydrolysis and (ii) starch nanoparticles produced from gelatinized starch. Introduction on starch nanocrystals Starch nanocrystals result from the disruption of the semi-crystalline (presented Figure 1) structure of starch granules by the hydrolysis of amorphous parts. Figure 2. Starch multi-scale structure: (a) Starch granules from normal maize (30µm), (b) Amorphous and Semi-crystalline growth rings ( nm), (c) Amorphous and Crystalline lamellae (9nm): magnified details of the semi crystalline growth ring:, (d) Blocklets (20-50nm): constituting unit of the growth rings, (e) Amylopectin double helixes forming the crystalline lamellae of the blocklets:, (f) Nanocrystals: other representation of the crystalline lamellae called starch nanocrystals when separated by acid hydrolysis, (g) Amylopectin s molecular structure, (h) Amylose s molecular structure (0,1-1nm). Adapted from Gallant et al.,49 Donald et al.,132 and Tang et al Yearbook 2010 LGP2

Chemical processes Papermaking and environment engineeering Paperphysics Converting Biomaterials Packaging Printing processes The same hydrolysis process [4] for producing Material and Methods starch

Native starches showed different size, size distribution and shape as presented in Figure 3. Image analysis was used to determine the features of the resulting nanoparticles.

3 Chemical processes Papermaking and environment engineeering Paperphysics Converting Biomaterials Packaging Printing processes The same hydrolysis process [4] for producing Material and Methods starch nanocrystals was used for five different starches: Normal Maize, Amylomaize, Waxy Maize, Potato and Wheat; covering 3 botanic origin and 3 ranges of amylose content (0%, 25%, 70%) for Maize starch. Native starches showed different size, size distribution and shape as presented in Figure 3. Image analysis was used to determine the features of the resulting nanoparticles. Figure 3 Native starches Figure 4 Starch nano-particles SEM-FEG pictures analysis, as presented in Figure 4, were carried out to calculate an equivalent diameter of nano-particles. AFM measurements were used to assess the thickness of the plateletlike nano-particles. X-ray diffraction was performed on starches before and after hydrolysis to observe the expected gain in crystallinity, confirming the hydrolysis of amorphous parts. Nanocomposites materials based on Natural Rubber (NR) matrix and starch nanoparticles were film casted. Three fillers content were considered: 0%, 5% and 30%. The resulting nanocomposites mechanical performances were assessed by tensile tests on 3 different samples. 461 rue de la Papeterie BP Saint Martin d'hères Cedex - France Tel 33 (0) Fax 33 (0)

Déborah Le Corre Resulting nano-particles features are collected in Table 1. Results They exhibit very different shapes, sizes, crystallinity and yields.

However, for the same botanic origin (Maize) with varying amylose content, differences in yield were even more important. Differences in shape and crystallinity were comparable.

4 Déborah Le Corre Resulting nano-particles features are collected in Table 1. Results They exhibit very different shapes, sizes, crystallinity and yields. For the same amylose content, Maize, Potato and Wheat resulted in slightly different yield, size and crystallinity proving the weak influence of botanic origin. However, for the same botanic origin (Maize) with varying amylose content, differences in yield were even more important. Differences in shape and crystallinity were comparable. AFM measurements confirmed the platelet-like morphology of nano-particles and thicknesses of 5 to 10 nm in accordance with the theory of crystalline lamellae. Table 1 Starch nano-particles analysis The mechanical behaviour (tensile test) of starch nano-particles filled NR composites is reported in Table 2. Table 2 Mechanical properties of NR nano-composites 92 Yearbook 2010 LGP2

Chemical processes Papermaking and environment engineeering Paperphysics Converting Biomaterials Packaging Printing processes Figure 5.

5 Chemical processes Papermaking and environment engineeering Paperphysics Converting Biomaterials Packaging Printing processes Figure 5. Tensile properties of Natural Rubber (NR) based composites filled with starch nanocrystals produced from starches with different amylose content. It shows a strong reinforcing effect of starch nano-particles by keeping elongation properties. As for features, botanic origin does not seem to influence mechanical properties whereas amylose content do as shown, in Figure 5. To our knowledge, it is the first time starch nano-particles Conclusion from different sources are being compared this way. This study proves the influence of botanic origin and amylose content on resulting features and properties and it enables also to confirm the thickness of these entities. The reinforcing effect of starch nanocrystals in nanocomposites has been presented. With the objective of making starch nanocrystals at industrial scale, further optimization of the production process is being undertaken and new properties investigated for the most promising sources. Other production processes for starch nanoparticles are also being investigated. References 1. Azeredo, H. M. C. d., Food Res. Int. 2009, 42, (9), Oksman, K., Bondeson, D., Mathew A.P, Cellulose 2006, Le Corre, D.; Bras, J.; Dufresne, A. Submitted to Biomacromolecules in rue de la Papeterie BP Saint Martin d'hères Cedex - France Tel 33 (0) Fax 33 (0)

6 Déborah Le Corre 4. Gallant, D. J.; Bouchet, B.; Baldwin, P. M., Carbohydr. Polym. 1997, 32, (3-4), AM Donald, P. J., TA Waigh Cooking corn on LOQ; The Rutherford Appleton Laboratory (University of Cambridge) Tang, H.; Mitsunaga, T.; Kawamura, Y., Carbohydrate Polymers 2006, 63, (4), Publications Le Corre, D.; Bras; J., Dufresne, A. Starch Nanocrystals for eco-efficient barrier packaging 8th Pagora Days Internationnal workshop on biopackaging Grenoble, France Le Corre, D.; Bras, J.; Dufresne, A., Starch Nanoparticles for ecoefficient packaging: influence of botanic origin. In 2nd International Conference on Biodegradable Polymers and Sustainable Composites (BIOPOL 2009), Jimenez, A., Ed. Alicante, Spain, Le Corre, D.; Bras, J.; Dufresne, A. Starch Nanoparticules: A Review, Submitted to Biomacromolecules (December 2009) 94 Yearbook 2010 LGP2

Nantes. Morphologies de grains d amidon

Nantes. Morphologies de grains d amidon Morphologies de grains d amidon Spherulitic organization of the starch granule Positive birefringence, average radial orientation Amylose C 2 C 2 C 2 α(1-4)linkages Mw ~10 6-10 7 Amylopectin Ø cluster