NATIVE STARCH DIGESTION

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Gervase Warren
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1 NATIVE STARCH DIGESTION PREVIOUSLY Individual techniques over limited size range Limited amylose content (< 50%; lamellar peak) Drying (freeze- or vacuum-) THIS STUDY Range of techniques over six orders of spatial range Broad range of samples ([amylose] <1 ~ 70%) No freeze-drying SAS First study digestion in-situ

$( 28%) TECHNIQUES X-Ray Diffraction (XRD) Scanning electron microscopy (SEM) Differential scanning calorimetry (DSC) SANS (Quokka) - in-situ 5-min intervals over lamellar q-range - complete q-range$

2 SAMPLES SAMPLES AND TECHNQUES A-type starches (cereal): B-type starches (tuber, HA) rice ( 10% amylose) waxy potato (<1%) tapioca ( 17%) high amylose maize Hylon VII ( 70%) wheat (26%) regular maize ( 28%) TECHNIQUES X-Ray Diffraction (XRD) Scanning electron microscopy (SEM) Differential scanning calorimetry (DSC) SANS (Quokka) - in-situ 5-min intervals over lamellar q-range - complete q-range on native and digested starch ( A -1 ) SAXS (Bruker Nanostar) ( A -1 ) SAXS

3 IN-SITU DIGESTION OF NATIVE STARCHES porcine pancreatic alpha-amylase, amyloglucosidase from Aspergillus niger kinetics determined gravimetrically 6 starches plus controls

4 SMALL ANGLE NEUTRON SCATTERING k f k i 2 40 m Detector 1x1m 2 ~5mm res Q 4 sin Velocity selector / ~10% d 1 100nm

5 IN-SITU DIGESTION OF NATIVE STARCHES

6 DIGESTION KINETICS extent = a(1 - e -kt ) + bt + c A-type > 35% B-type < 15%

7 native SEM (Tapioca A) after 24 hrs of digestion

8 native SEM (Regular Maize Starch A) after 24 hrs of digestion

9 native SEM (Eliane Waxy Potato B) after 24 hrs of digestion

10 CRYSTALLINITY (XRD) improved signal at 2 ~20 native digested difference characteristic peak for B-type starches

ring Cameron & Donald, 1992, Polymer, 33, 2628-2635 Agamalyan et al.

11 DONALD MODEL 3 regions c, a, u Repeat distance Gaussian width and crystallinity N number of lamellae Infinite - parallel to lamellae; infinite extent of growth ring Cameron & Donald, 1992, Polymer, 33, Agamalyan et al., Polymer 1992, 33, Blazek and Gilbert, Carbohydrate Polymers 85 (2011)

12 DONALD MODEL 10 parameters: scale factor, L, β (Gaussian width), Φ (crystallinity), N (pairs of lamellae) Δρ - cryst - amorphous phases; Δρ u - growth ring background and amorphous phases bkgd, power law prefactor, exponent P(qLΦ) lamellar form factor - monodisperse G(LΦ) thickness distribution function = f(β) S(qL) interlamellar structure factor F c, F a FT thickness distribution functions = f(β,l,φ) I( q) Aq B 1 G L L P ql S ql d L 2 ( ).[ ] ( ) ( ) ( ) bkgd 2 4 q Cameron & Donald, 1992, Polymer, 33, Agamalyan et al., Polymer 1992, 33, Blazek and Gilbert, Carbohydrate Polymers 85 (2011)

13 Intensity (a.u.) PROBLEMS Widely quoted, application limited Suitable only for low amylose UInsuitable for processed starches Limited q range (lamellar peak) BUT information in peak AND low q region! Too great simplification of reality? Alternative fit data that describe peak and account for underlying diffuse or interfacial scattering Return to Donald model later Hydrolysed Extruded GERS_i fit_gers_i q (A -1 )

14 STARCH STRUCTURE & OTHER FACTORS Botanic origin, selective breeding and amylose content: Carbohydrate Polymers 75 (2009) Carbohydrate Polymers 75 (2009) Biopolymers 89 (2008) Asia Pacific Journal of Clinical Nutrition 15 (2006) S44 Processing: J. Cereal Sci. 54 (2011) Carbohydrate Polymers 80 (2010) Carbohydrate Polymers 75 (2009) Biomacromolecules 9 (2008) J. Agriculture and Food Chemistry 55 (2007) Biomacromolecules, 8 (2007) Storage: J. Agriculture and Food Chemistry 55 (2007) Chemical Modification: Food Chemistry 120 (2010) Food Hydrocolloids 23 (2009)

15 TIME-RESOLVED SANS Peak intensity

16 A-TYPE STARCHES (TAPIOCA) SANS increase in low-q scattering SAXS decrease in lamellar peak intensity

17 B-TYPE STARCHES (HYLON high-am maize) SANS SAXS

18 OBSERVATIONS A-type B-type High Extent of Dig n Low Endo- Mode of access Exo- Increase Crystallinity (Small) increase Increase T gelatinisation (Small) increase --- Enthalpy --- Decrease Peak intensity (Small) decrease Increase Lamellar repeat --- Increase Low q Increase

19 CONTRAST VARIATION SANS Donald et al., 2001, Starch/Stärke, 53, A B A-type starches: amorphous lamellae have a more open structure than amorphous background 4 H 2 O/unit cell; semi-cryst growth/day B-type starches: the two amorphous regions have essentially the same composition 36 H 2 O/unit cell; constant darkness Different modes of biosynthesis

20 CAN DONALD MODEL HELP? Digestion of amorphous lamella increase of lamellar peak intensity increase in low-q scattering Digestion of amorphous growth ring Log I log q scale A-type starch Amorphous lamellae Growth Ring increase in low-q scattering no effect on the lamellar peak Decrease of β distribution parameter increase of lamellar peak intensity Increase of Ф crystallinity parameter decrease of lamellar peak intensity Contrast decrease c a Lamellar peak swelling of crystalline regions d-spacing increase

Blazek & Gilbert, Biomacromolecules 11 (2010) 3275-3289 A- & B-TYPE STRUCTURE & DIGESTION A-type Surface pores Endo-corrosion (SEM) Increase in crystallinity (XRD) low q increase (SAS) large peak

21 Blazek & Gilbert, Biomacromolecules 11 (2010) A- & B-TYPE STRUCTURE & DIGESTION A-type Surface pores Endo-corrosion (SEM) Increase in crystallinity (XRD) low q increase (SAS) large peak decrease (SAS) d-spacing increase Growth rings digested but Opportunity to disrupt, digest amorphous lamellae Relaxation of crystalline lamellae B-type Resistant granular surface Exo-corrosion No significant increase in crystallinity low q increase small peak decrease no change in spacing Although growth rings digested Less preference between amorphous growth-rings and amorphous lamellae

22 SUMMARY Why Food Materials Science? Applications of SAXS/SANS Proteins at low moisture Organogelators Neutron penetration Simultaneous RVA and SANS Enzymatic hydrolysis of granular starch Combination of SEM, XRD, DSC, SANS and SAXS Variations in low q scattering and lamellar peak intensity Functional fitting of data combined with Donald model First time - differences in hydrolysis location in A- versus B-type

23 ACKNOWLEDGMENTS Mike Gidley - University of Queensland Michael G. Huson, Ingrid A. M. Appelqvist CSIRO AND CFNS Wim Bouwman - U Delft, Netherlands Arjen Bot - Unilever, Netherlands

24 International Small-Angle Scattering Conference 2012 Sydney Australia November

Rapid Method for Quantifying the Molecular Order of Starches

Electronic Supplementary Material (ESI) for Chemical Communications. This journal is The Royal Society of Chemistry 2015 Electronic Supplementary Information (ESI) Rapid Method for Quantifying the Molecular