Starches+Group+3

= = __ STARCH __ =

**Amylose and amylopectin are different forms of starch.**

Plant starch comes in two different forms: amylose (20-30%) and amylopectin (70-80%), each with their own physical and chemical properties: Properties of amylopectin such as water solubility and bonding capacity make it more useful for technical applications in the food, paper, and chemical industries. It is well suited for use in pastes, adhesives, and lubricants. The food industry also takes advantage of its properties. Usually, amylose and amylopectin must be separated or modified by chemical, physical, or enyzmatic means. http://www.gmo-compass.org/eng/glossary/
 * Amylopectin consists of large, highly-branched molecules, making up the majority of the starch found in plants.
 * Amylose consists of long, chain-like molecules.



Starch is composed of multiple links glucose


=4 Forms That Gel Can Undergo:=

*Weakens hydrogen bonds so the starch can take up water **Gel Formation**- This is when the gelatin in the substance forms a sol. *Gel formation is dependent on the amount of amylose present. **Retrogradation**- This is when after the starch has cooled water droplets form on the top of the starch substance and the surface begins to crack and pull away from the sides of the container. *Bonds form between the amylose molecules. **Dextrinization**- This is when the glucose molecules of starch loose their ability to form gel because they have been denatured due to things such as high/dry heat, for example toasting a piece of bread, or browning of the flour. *Starch breaks down into dextrin molecules (contributes to browning). This is how toast is made! []
 * Gelatinization ** - when starch is put under the stress of heat and water it becomes gelatinized

Results from Class Lab:


 * **Starch** || **Viscosity Hot** || **Viscosity Cold** || **Appearance** || **Notes** || **Concentration**
 * Amylopectin** ||
 * **Tapioca** || **Thick, gummy, cloudy/ gray** || **Glossy, thick, sticky** || **Cloudy and gray** || **8 average on viscosity chart** || 83% ||
 * **Arrowroot** || **Thick cloudy** || **Sticky** || **Gray with white swirls** || **9** || 70-75% ||
 * **Cornstarch** || **Thick, jelly, cloudy and white** || **Gummy, white** || **Cloudy white and thick** || **7** || 70-75% ||
 * **Rice** || **Grainy, thick, white** || **White grainy thick** || **Gummy, white, thick** || **6.5** || +90% ||
 * **Wheat Flour** || **Yellow, white, grainy** || **Thick, thick and gummy** || **Whitish yellow, thick** || **7.5** || 75% ||
 * **Browed Flour** || **Thin** || **A little thicker** || **Thin, brown and cloudy** || **12** || Dextrinization* ||
 * **Potato** || **Clear, extremely thick** || **Still clear and thick** || **Clear** || **7.75** || 80% ||
 * Dextrinization occurs when the flour is browned. Amylopectin starts to lose its gelling ability and the substance turns a brown color.

﻿ Results!
Some of our starches looked like this! This is after the process of gelatinization. The color indicates that there was a high concentration of amylose. Starches low in amylose work well in foods that needs less of a solid form such as gravy thickeners.
 * Tapioca and Rice yielded expected results. Because there was a higher concentration of amylopectin, these starches were thick, cloudy and gummy.
 * Wheat and Arrowroot also yielded expected results. Because there was less amylopectin, there was a higher concetration of amylose. This resulted in a more sticky substance that was less cloudy.
 * Cornstarch and Potato starch did not yield the exact results expected but these starches, however, gelatinization did happen because the sol began to gel when cooled.

Effect of sugar and acid on starch Pastes and Gels:

 * **Modification** || **Appearance** || **Viscosity** || **Texture** || **Notes** ||
 * **Sugar** || **Cloudy gel** || **8** || **Shinny and sticky** ||  ||
 * **Acid** || **White, shinny, cloudy** || **7.25** || **Kind of gummy** || **﻿** ||
 * Acid weakens starchs' ability to thicken, this is why many modified starches are resistant to acid!**
 * Sugar is hydrophillic and competes with the starch for water.

Modified Starches

 * ===Altered to increase usefulness===
 * ===Cross linked starches are more resistant to heat because of stronger bonds===
 * **Oxidizers are modified with chemical oxidizers and are less viscous**
 * **Pregelatinized starches do not need heat to gel.**