Post on 01-Jan-2016
Chocolate Pudding Lab
Aim: To study the effects of cornstarch in the preparation of a simple pudding
Pudding• A starch thickened
desert
– A starch is a polysaccharide made up of 2 fractions: amylose and amylopectin
• Amylose – linear molecule and gives gelling characteristics to cooked and cooled starch mixers
• Amylopection – highly branched and bushy; no gelling properties
Starch Gradules
• Stored in plant cells• Come in different
sizes and shapes depending on the type of starch– Potato: 10 - 100 um– Corn: 5 - 25 um
Potato Starch
Factors That Affect Starch
1. Moist Heat → Gelatinization
2. Temperature and Time of Heating
3. Agitation and Stirring
4. pH
5. Addition of Other Ingredients
Gelatinization
• As you heat the starch its granules absorb water and swell → increased viscosity and thickness
• After a period of time the granules gelatinize –
gets rigid and takes shape
Temperature and Time of Heating
• Starch paste is quickly prepared by boiling it for 1 minute – granules swell at high
temperatures
Agitation and Stirring
• Stir in the early stages of cooking with uniform consistency for a smooth product
• If agitation is too intense → rupture of granules and decreased viscosity
Other Ingredients
• Sugar – raises temperature at
which a starch gelatinizes
→ delays swelling of starch granules decreasing thickness of paste
– It competes with the starch for water
pH
• High acidity causes fragmentation of granules– Decreases the
thickening power
Other Ingredients
• Protein and Fat: – coat the starch
which delays swelling and lowers rate of viscosity development