Multi-Scale Structures of Starch as Revealed by 

Scattering Techniques: From Unit Cell to 

Nanostructure

Amy Musser, University of Maryland

NCNR SURF 2022

Mentors: Yimin Mao and Susana Teixeira

1
Overview

Background Method Results Future Work

Starch Sample preparation, 

SAXS, WAXS Graphical analysis SANS for future 

work

2
What is starch?

Scanning electron microscopy 

of corn starch granules. Scale 

bar 20 μm

DOI 10.1002/star.201000013 3

Starch granule growth rings (left) semi-crystalline and 

amorphous layers (center), branching of amylopectin (right)

Amylose

(straight chain)

Amylopectin

(branched chain) 3
Experimental Objective

Question: How does addition of water within 

hydrated starches affect the structure of type A 

and type B starches?

Objective: Use small angle scattering (SAS) and 

contrast variation techniques to determine the 

effect of water on structure in hydrated starch 

samples in both type A and type B crystals

DOI 10.1071/CH07168 4

Starch granule growth rings (left), 

semi-crystalline and amorphous layers 

(right). Scale bar 1 μm
Type A and B Crystals

Amylose Percent Crystalline Type 0

26

70

30-40

A

2 Normal Maize 

A

(NM)

4 Pea 3 High Amylose 

Maize (HAM)

1 Waxy Maize 

(WM)

BAAC

0

26

70

30-40

Type A Type B

Y. Mao, Surf Project Introduction: Starch and Pickering Emulsions, UMD/NIST (2022)

5
Small and Wide Angle Scattering

(a) Simplified scattering experiment and (b) scattering geometry which defines scattering vector q 

6 Y. Mao, Scattering 101: A Heuristic Treatment for the Impatient, UMD/NIST (2022)
Wide Angle Scattering

● Bruker D8 Diffractometer

○ UMD X-ray Crystallography Center

● X-rays from copper

○ Wavelength: 1.54 Å

● Software for data processing: Topaz

X-ray source

Sample holder

Detector

Bruker D8 WAXS Diffractometer, 

zoomed view (top), full view (right)

Sample Exposure Time

Dry 20 minutes per sample

Wet 

5 minute increments for 20 

minutes, 2x, no significant 

difference between rounds

7
Small Angle Scattering

X-ray source

Vacuum Tube

Detector

Sample chamber

● Xeuss SAXS/WAXS System

○ UMD X-ray Crystallography Center

● X-rays from copper

○ Wavelength: 1.54 Å

● Software for data processing: Igor Pro 8

Xeuss system (top), sample chamber (left)

Sample holder

8
SAXS Data Processing Parameters

● Detector: Pilatus 300k

● Sample holder thickness (mm): 0.8

● CCD pixel size (mm): 0.172

● Beam size (mm): 0.8

● Calibration standard: AgBe

● Background: Kapton

● Plotting: Q-dot, 300 points and circular average

● Data from two sample to detector distances (SDD) stitched together

SDD (mm) Exposure Time

2500 20 minutes, 2x for starches; 10 minutes, 1x for kapton

590 15 minutes, 2x for starches; 15 minutes 1x for kapton

9
Sample Preparation

Crystalline Type Dry Moisture (%)

0

26

70

30-40

A

2 Normal Maize A

(NM)

4 Pea

3 High Amylose 

Maize (HAM)

1 Waxy Maize 

(WM)

12

13

13

13.58

A

A

B

C

WAXS Wet Moisture (%)

49.7

49.9

50.0

50.0

SAXS Wet Moisture (%)

50.0

50.0

50.0

50.0

10
SAXS of wet starches (50% hydration). Data at 

SDD 2500 and 590 mm stitched. Log scale.

SAXS of dry starches. Data at SDD 2500 and 

590 mm stitched. Log scale

Dry Starches Wet Starches

11

(0.0630, 2.136x10-8)

(0.0650, 3.379x10-8)

(0.0656, 6.852x10-8)

(0.0676, 1.691x10-8)

SAXS Results Type A Type B

Crystalline

Amorphous

Crystalline

Amorphous

Crystalline

(0.0680, 2.131x10-8)

(0.0727, 3.007x10-8)

(0.0911, 3.301x10-8)

Miller Index 

(hkl): (010)

Miller Index 

(hkl): (010)
d = 

SAXS Results

SAXS of dry starches (top) and wet starches (bottom). 

Data at SDD 2500 and 590 mm stitched. Log scale.

Wet Starches

12

Type A Type B

Crystalline and Amorphous 

Interlamellar Distance (d)

2 x π

q

Crystalline

Amorphous

Crystalline

Amorphous

Crystalline

Peak Width

Starch Crystal 

Type Amylose (%) d (dry)(nm)

d (wet)

(nm)

Waxy Maize A 0 6.90 9.58

Normal Maize A 26 8.64 9.67

High Amylose Maize B 70 -- 9.27

Pea C 30-40 9.24 9.98

Water increases degree of organization

● Waxy Maize (most sharp)

○ Most ordered

● High Amylose Maize (least sharp)

○ Least ordered

Dry Starches
WAXS Results

--- Waxy Maize (A)

--- Normal Maize (A)

--- High Amylose Maize (B)

--- Pea Starch (C)

13

Type A Type B

--- Waxy Maize (A)

--- High Amylose Maize (B)

Crystal Type A Type B

Symmetry Space Group B112 P61

Cell Length A (Å) 20.83 18.52

Cell Length B (Å) 11.45 18.52

Cell Length C (Å) 10.58 10.57

Gamma (degrees) 122.0 120.0

Dry Starches

Wet Starches

Future Work: Analysis of wet 

normal maize and pea starch

Hydrated samples show narrow, 

exaggerated peaks

Parameters

WAXS of dry starches (top) and wet (50% hydration) starches (bottom). Data fitted 

using TOPAZ and crystal unit cell parameters.
Conclusions

Hydrated Starch

● Swells crystalline and amorphous 

inter-lamellar distance (nm scale)

● Increases organization of crystalline and 

amorphous lamella (nm scale)

○ Type A starch more so than Type B starch

● Increases crystallinity of unit cells (μm scale)

○ Type B starch more so than Type A starch

14

Type A Type B

Y. Mao, Surf Project Introduction: Starch 

and Pickering Emulsions, UMD/NIST (2022)
Future Work

Question: How does addition of water within hydrated 

starches affect the structure of type A and type B 

starches?

Objective: Use SAS and contrast variation techniques 

to determine the primary location water in hydrated 

starch samples in both type A and type B crystals

Purpose: Knowledge of starch structure can inform 

measurement techniques and choices in composition 

and corresponding applications in the food and 

nonfood industry (e.g. paper making, clothing, etc)

DOI 10.1071/CH07168 15
Acknowledgements

● Yimin Mao

● Susana Teixeira

● Robert Briber

● Joe Dura

● Paul Butler

● Susan Krueger

● Brandi Tolivar

● Mary Ann Fitzgerald

● Natalie Schwab

16