Starch

1. LEARNING OUTCOMES Usage of starch Understand the structure and nomenclature used for starch polysaccharides Appreciate some of the structural features of starch granules Recognition that starch is only one component of storage organs Modified starches Starch Sandra Hill Nov 2004

2. Starch Major food for animals Usage in the paper industry Bioethanol production Filler component for many pharmaceuticals Building material Some times eaten by people

3. Food Beverage Animal Feed Plastic Pharmacy Building Mayonnaise Soft drinks Pellets Biodegradable plastic Tablets Mineral fibre tiles Baby food Beer By products Dusting powder Gypsum board Bread Alcohol Concrete Buns Coffee Gypsum plaster Confectionery Agriculture Textile Paper Various Meat sausages Jelly gums Seed coating Warp Corrugated board Foundries Meat rolls and loaves High-boiled sweets Fertiliser Fabrics Water treatment Ketchup Jellies Yarns Cardboard Coal Marchmallows Soups Marmalade Paper Detergent Snacks Jam Fermentation Non-Wowen Printing paper Oil drilling Pizza sauces Ice cream Vinegar Hygienic diapers Stain remover Sauces Dairy cream Enzymes Baby diapers Packaging material Glue Low fat foods Fruit fillings Sanitary napkins Foamed starch Noodles

4. Given the right crops and new technology, bioethanol could make a real contribution to world fuel needs, writes Giuliano Grassi. Bioethanol plant in Nebraska, USA, processes corn to produce 925 litres per day (Minnesota Corn Producers). http://www.jxj.com/magsandj/rew/2000_ 03/bioethanol.html

5. Starch based products • High proportion of human requirement for energy supplied by starch • potatoes • crisps • chips • maize • extruded products • rice • variety and preference • wheat • (bread and cake and the bubble) • cassava • a staple for much of the world

6. Starch Starch the chemical Starch the macromolecule Starch the supermacromolecule Starch the granule Starch the stuff that comes in a sack

7. In Europe a starch factory consumes between 1,000 and 2,000 tonnes of cereals each day. http://www.aac-eu.org/html/everydayuses.html

8. Carbohydrates C H O H O H H O H H O H H O H O H H C H O H H 2 O H O H O H H O H O H H O • sugar components • open chains • ring structures o chair Starch the chemical

9. Linking sugars • link a (1-4) • example maltose • glucose -glucose

10. multiple links (ribbons and helices)

11. Amylose and Amylopectin

12. link a (1-6) • example amylopectin • glucose -glucose

13. Double helix, association of 2 left handed helices Amylose helix Pitch 0.8nm 6 residues per turn

14. Starch • carbohydrate reserve • seeds • roots • tubers • stem • Native starch always is: • glucose polymers • amylose ( a1-4) and amylopectin (a1-4 and a1-6) • packed into granules • different size and shape depending of the botanical source • semi crystalline structures

15. How starch is laid down in the plant Smith, Denyer & Martin, 1993

16. Starch • complex assembly of two macromolecules • amylose Glucose units linked (mostly) 1-4 Number of glucose units ~ 250-5,000 15-30% weight

17. Amylopectin 70-85% by weight number of glucose units ~ 10,000-100,000 branch chains ~20 glucose units only one reducing end Racemose model Glucose units linked 1-4 and some  1-6 linkage

18. Diagram of the starch granule organisation

19. Glucose chains form helices Two types in native starch A and B mixture of A and B known as C differ in the amount of water in the helix

20. Can tell the structure of the helices by X-ray X-ray wavelength 10-10 m

21. Packing of the molecules to form a starch granule

22. Polarised Light-optical microscope

23. Measurement of the amount of crystallites DSC (Differential scanning calorimetry) Temperature at which the crystallites melt Amount of energy required to melt them NMR (nuclear magnetic resonance) FTIR (Fourier transform infra red) Endothermic heat flow 65C

24. Growth ring Wheat starch granule, erosion during germination

25. (Gallent et al, 1997)

26. Size shape and morphology of the granules is characteristic of the botanical source 10mm shoti wheat lentil potato avacado rice green pea rye maize

27. Starch Storage polysaccharides examples cereal wheat rice oat barley seeds pea tuber potato cassava / tapioca /manioc stem sago

28. Different starches Starch granule Amylose Degree polymerisaton DP(amylose) um % Corn regular 5--25 26 800 waxy 5--25 ~1 - Potato 15--100 22 3000 Rice 3--8 17 Sago 20--60 25 Cassava 5--35 17 3000 Wheat 2--35 25 800 Molecules per granule 10*10-12 0.01*10-12 10*10-12 4*10-12 5*10-12 From Pomeranz 1991 Swinkels,1985

29. Remember that with the starch can come other components within the granule Internal components wheat maize potato Amylose 26-31 24-32 23 Lipids 0.48-1.12 0.6-0.8 0.09 Protein 0.20-0.33 0.27-0.39 0.05 Ash 0. 2 0.1 0.4 Phosphorus 0.06 0.02 0.08* Note : the amount of amylose depends on the method used to measure

30. Amylose : a)the straight chain portion(but there are often some 1-6 linkages)b)the portion that incorporates iodine (chains of less than 10 glucose units -no colour colour goes from red, red-purple, purple, blue depending on chain length) 645nm d.p. 366 or higher but long chains of the amylopectin, often B1 chains, can do this) c)hot water soluble fraction (amylose not water soluble at above 2mg/ml, it precipitates)

31. Remember that with the starch can come other components from outside the granule External components Maize: starch in protein matrix

32. Texture Cell walls Starch RAW RAW Cooking Cell/cell adhesion Properties of the starch

33. Modified starch

34. Starch and Water • starch is biosynthesised in an aqueous environment • drying starch can cause shrinkage and cracks • most water goes to the amorphous phase or to the surface of the crystallites • material up to 1000 daltons can enter the starch granule-might be pores • dry starches in water can absorb up to 50% of its weight -will expand 30-100%, this is reversible.