modified starch -revisited

modified starch -revisited PowerPoint PPT Presentation

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Modified Starches - Substituted. Starch estersAcetate StarchStarch phosphateSuccinylatedStarch etherscarboxy methyl starchhydroxyl propyl starch. Substituted Starches. Made from starch in granule formLow level subsitution interupts linearity and

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modified starch -revisited

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1. Modified Starch -Revisited Substituted (Derivitized) Cross Linked Substituted and Cross Linked

2. Modified Starches - Substituted Starch esters Acetate Starch Starch phosphate Succinylated Starch ethers carboxy methyl starch hydroxyl propyl starch

3. Substituted Starches Made from starch in granule form Low level subsitution interupts linearity and – retards retrogradation, increase water binding capacity, lowers gelation temperature, introduction of hydrophobic groups impart emulsification properties Alters clarity

4. Acetate starch Class: Substituted starch Acetylated starch. Granular starch ester with a CH3CO-group introduced Improves paste stability and clarity. The acetate groups act as pegs on the amylopectin chains to reduce or prevent retrogradation. Acetate starches are used in chilled or frozen preparations such as icecream cheesecakes etc. The level of acetelation can be altered to tailor the properties.

5. Phosphate starch There are two classes of phosphate starches.   Substituted starch phosphate esters. eg. monostarch phosphate. Similar in function to starch acetate. The phosphates act as pegs to prevent retrogradation.  Improves paste stability and clarity Crosslinked starch esters. Crosslinks starch chains to stabilize viscosity and reduce shear thinning.  

6. This is a substituted starch ester  Retards retrogradation Increases hydrophobicity and can assist in emulsification

7. Substituted starch ether General term for three classes of starch ether substitution are: Anionic (Carboxy methyl starches), cationic (Quaternery ammonium) and Non-Ionic (Hydroxy alkyl starches).

8. Substituted starch ether (cont) Substituted starch ethers have improved clarity, better resistance to retrogradaion and improved viscosity The substituted starch ethers (carboxy methyl starch and hydroxyl propyl starch) are generally preferred as they offer improved functionality compared with the substituted starch esters (starch acetate and monostarch phosphates). Crosslinked hydroxyl-propyl starches are among the most functional of the food grade modified starches.

9. Hydroxypropyl starch. The hydroxyl-propyl groups act as pegs to prevent retrogradation. Similar to the starch acetates above but the substituted group is larger,

10. Cross linked Starches Vary in degree of cross linking May be double modified – substituted starches Reduce elasticity found in native starches More tolerant to high shear in processing Less effected by acid, sugar More resistant to heat

11. Cross Linked Starch

12. Substituted or Cross Linked? Crosslinking protects against high shear, acid processing and prolonged heating. It depends on the food or other use, processing conditions and the cost of the modified starch. Most modified starches are BOTH crosslinked and substituted, It is the level of each of these processes that is used to adjust functionality. The levels of both crosslinking and substitution are adjusted depending on end use.

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