Lab report

Equipment

1 cup glass graduated measure cup 1-quart sauce pan Balloon whip Digital thermometer with probe and clip Ice bath Glass pie plate

Line spread chart 2” hollow cylinder (for line spread) Small straight spatula Timer Metal skewer 6” ruler

Basic Formula

16 grams Starch

240 ml Cold water

1. Measure 240 ml cold water and transfer to saucepan.

2. Using a wire balloon whip, mix assigned starch in cold water to hydrate starch and prevent lumping.

3. Heat to a boil stirring to occasionally to prevent lumping. Boil for one minute. Turn off heat and immediately read temperature of paste. Record temperature reading in table provided.

4. Using an ice water bath, cool to 140 °F (this is minimum holding temperature for TCS foods) and complete line spread test.

a. Position glass plate over diagram of concentric circles so that the center of the circles is directly under the center of the plate.

b. Place hollow 2” wide cylinder over the smallest circle and fill with starch paste.

c. Level with straight spatula.

d. Lift the cylinder and allow the past to spread for 2 minutes.

e. Quickly take four readings at the four numbered points on the circumference of the circle. Record readings in table provided.

f. Average the four readings and record in table provided.

5. Cool remaining paste further in ice water bath to 80 °F. Perform a percent sag test as directed below.

a. While the gel is in the 2” hollow cylinder, insert a metal skewer into the center of the gel.

b. Remove the skewer and measure the depth of penetration to the nearest millimeter.

c. Remove the 2” cylinder and immediately insert the metal skewer into the center of the gel. Measure the depth of penetration to the nearest millimeter.

d. Calculate percent sag:

% Sag=Height in container – Height out of container x 100

Height in container

Experiment Variation

1. Corn Starch (control)-Follow the basic formula as directed.

2. Waxy Corn Starch- Follow the basic formula as directed.

3. Rice starch - Follow the basic formula as directed.

4. All-purpose flour- Follow the basic formula as directed.

5. Dextrinized flour- Follow the basic formula as directed with the following adjustment: place flour in a pan and dry heat it until it noticeably changes color to a light brown or tan. Then add this treated flour to the cold water and begin at step 2.

References

1. Brown A. Understanding Food Principles and Preparation, 5th ed. Stamford, CT: Cengage Learning; 2015

2. McWilliams M. Introductory Foods A Laboratory Manual, 9th ed. Upper Saddle Rive, NJ: Pearson Education; 2017.

3. Walter J and Beathard, K. Understanding Food Principles and Preparation Lab Manual, 5th ed. Stamford, CT: Cengage Learning; 2015.

Introduction

The purpose of the Starch Pastes and Gels laboratory exercise was to observe the different type of starches, we will examine how temperature and different ingredients affect the gelatinization of cooked starch paste.

Result

Unit	Starch Type	% Sag	Line Spread	Description
			140 °F	80 °F	Hot Paste	Cooled Paste
9	Corn Starch (control)	65%	3.5	3	Thick, light milk color, semi clear	Light, milk color, semi clear
2	Waxy Corn Starch	49.1%	6.5	5.75	Very thick,	Thinner, more translucent
3	Rice Starch	50%	8.5	7.25	Thinner, opaque	Thicker, opaque
4	All Purpose Flour	68.7%	13.25	13.38	Little lumpy, Milk color, relativity Thin	Still clumps, opaque, seems to be same thickness
7	Double All Purpose Flour 32g	73.5%	9.13	8.38	Hair gel consistency, yellow milk color, thick	Less liquid, some clumps, pancake milk like
8	Double volume Dexrinization 32g	62.9%	7.5	6.28	Tan, light brown, very thick	Tan, lumpy, very thick top layer