chappter one starch

1. Starch and Extrusion Technology
(Ftpe 4153)
By:- Chernet T.

2. Chapter 1: Starch in Foods
• Introduction
• Development of Specialty Starches
• Other Products from Starch
• Modern Use of Starch in Foods
• Improvement of Starch Sources

3. Introduction
What is starch?
Carbohydrate

4. Cont…
• Carbohydrate – major sources of energy
– Simple carbohydrates
• Naturally occurring sugars
• Added sugars
–Monosaccharides
–Disaccharides
• Quick energy
sources

5. Cont…
– Complex carbohydrates
• Starch
• Fiber
– Insoluble fiber Vs. soluble fiber
longer lasting energy + nutrients + fiber

6. Cont…
• Sources of carbohydrate
• whole grains,
• flour,
• legumes,
• nuts,
• vegetables and fruits

7. Starch in Foods
• Starch
– a common constituent of higher plants,
– major form in which carbohydrates are stored
– nutritive reserves of many plants
• Forms of storage
– in chloroplasts - transitory
• accumulates during the light period and is
utilized during the dark
– Storage starch
• accumulates in reserve organs during one
phase of the plant’s lifecycle and is utilized at

8. Cont…
• Starch biosynthesis
– complex process
– Summarized
green leaves collect energy from the sun,
energy is transported as a sugar solution to the starch
storage cells
enzymes
sugar is converted into starch (tiny granules)

9. Organization of Starch Granules
• Starch is synthesized in granules inside amyloplasts
Starch granule
• basic physical structural unit of starch
• distinctive microscopic appearance for each
botanical source
• The common starches are readily identifiable by
using a polarizing light microscope to
– determine their size,
– shape, and
– form

10. Cont…
• Starch is synthesized in granules inside amyloplasts
• Starch granules
– botanical sources and
– Organs
• Diameters of starch granules
– vary from submicrons to more than 100 μm
• potato starch 15 to 75 μm
• maize starch 5 to 20 μm,
• rice starch 3 to 8 μm, and
• amaranth starch 0.5 to 2 μm
different shapes and
sizes

11. Cont…
• Starch granules display
– spherical,
– oval,
– disk,
– polygonal,
• Leaf starch
– flat-shaped small granules that are submicron in
diameter
• Wheat, barley and rye starches display
– bimodal granule size distributions:
• disk-shaped, large A-granules and
• the spherical, small B-granules
- elongated,
- kidney, and
- lobe shapes

12. Cont…
• Rice and oats starches
– are known as compound starches,
– multiple granules synthesized within a single
amyloplast
• starch granules are tightly packed together and
• develop into polygonal irregular shapes

13. Size and morphology of granules
wheat lentil
rice
rye
maize
potato
shoti
avacado
green pea

14. Amaranth starch
(Bar: 1 µm)
Arrowroot starch
(Bar: 20 µm)
Buckwheat starch
(Bar: 5 µm)
Cassava starch
(Bar: 10 µm)
Corn starch
(Bar: 10 µm)
Oat starch
(Bar: 5 µm)
Potato starch
(Bar: 50 µm)
Rice starch
(Bar: 2 µm)
Kidney bean starch
(Bar: 20 µm)

15. Chemical Composition of Starch
Granules
• Starch granules
– composed of two types of alpha-glucans,
• Amylose and
• Amylopectin
• ratio of the two varies according to the botanical
origin of the starch
• starch classification
– ‘waxy’ starches contain less than 15% amylose,
– ‘normal’ 20–35% and
– ‘high’ amylose starches greater than about 40%
98–99% of the dry weight

16. Cont…
• Amylose
– Linear a-1,4 glucose chain
– DP: 180-320,
– MW~106
– Branch approximately every 200 glucose units

17. Cont…
• Amylopectin
– Linear a-1,4 chain with an a-1,6 branch
approximately every 20 glucose units
– MW~108

18. Amylose and Amylopectin

19. Other components within the
granule
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*

20. Products from Starch
1. Sweeteners
• Kirchoff ’s discovery of starch hydrolysis
– led eventually to today’s modern starch
sweetener industry
– The original starch-derived sweeteners
–produced by acid-catalyzed hydrolysis of
starch
–contained varying amounts of
dextrose,other saccharides and
polysaccharides,
Glucose syrups

21. Cont…
2. Ethanol
• Glucose syrups are easily fermented by yeast to
ethanol
– beverage ethanol has been produced from many
sources of sugar and starch for countless
centuries,
– Large scale production of fuel-grade ethanol by
fermentation is attributed to a demand for
combustible motor fuel additives

22. Cont…
3. Polyols
• Hydrogenation of sugars produces a class of
materials known as sugar alcohols or polyols
• Major commercial sugar alcohols include
– mannitol,
– sorbitol (D-glucitol),
– malitol, and
– xylitol and
– syrups related to these products
• obtainable from starch

23. Cont…
4. Organic Acids
• Organic acids are found throughout nature
• Citric,
• lactic,
• malic and
• gluconic acids
• have become large-scale food and industrial
ingredients
• Originally produced from fermentation of sucrose or
sugar by-products,
• now mainly produced from fermentation of dextrose

24. Cont…
5. Amino Acids
• During the 1980s, advances in fermentation
technology allowed the economic production of a
number of amino acids from starch hydrolyzates
• Examples are
• lysine,
• threonine,
• tryptophan,
• methionine and
• cysteine
• Starch-derived amino acids are generally
• used as animal nutrition supplements

25. 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