Experimental Food Science

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Experimental Food Science Lab Excerpts
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• Virtual Lab Rules
• Follow on-screen
• Procedure by
• clicking the mouse.
• Each bulleted step
• represents one click.
• WAIT at least 3 seconds
• between clicks
• (steps) to ensure that
• operation is complete.
• (i.e., dont get trigger-happy!)

STOP . . . and read the rules
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Moisture Content of Foods

• Procedure
• Weigh (click) the apple slice and record weight.
• Place (click) in drying oven
• Dry overnight at 100oC to constant weight.
• Remove and reweigh record weight.
• Compute Moisture

Objects not drawn to scale
Oven
100oC
0.0g
10.0g
0.0g
1.3g
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Osmosis and Syrup Formation
Objects not drawn to scale

• Slice the strawberry
• Sprinkle sugar on the slices
• Let stand for 30 min
• 29. What is the liquid that formed on the
  strawberry slices?
• 30. Explain how it formed.
• 31. What is this process called?

0 min
10 min
20 min
30 min
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Experiment 2Measuring Liquids(Milk, Water,
juices, Syrups, etc.)

• Fill the liquid measure to the ½ cup line. Note
  the surface of the milk in the cup.
• 9. Is it level?
• a. Yes
• b. No
• 10. Why or why not?
• a. Milk fat sticks to sides of glass container
• b. Capillary action of liquid for glass container
• c. Attraction of milk solubles (proteins,
  lactose, water-soluble vitamins) for glass
  container

Nonfat Milk
1 Cup
3/4
2/3
1/2
1/3
1/4
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Standards of Identity, Quality Fill

• Open can
• Express contents into strainer
• (Allow contents to drain. Reserve packing
  medium for sugar analysis)

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Determination ofSyrup Strength

• Place some of the packing medium on the
  refractometer prism
• Close prism lid
• Read scale in sugar at line between light and
  dark areas. Record.

Eyepiece
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Determination ofSyrup Strength

• Place some of the packing medium on the
  refractometer prism
• Close prism lid
• Read scale in sugar at line between light and
  dark areas. Record.

Eyepiece
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Standards of Identity, Quality Fill of Container

• Remove container
• Separate each fruit variety
• Weigh each variety record.

• Fruit legend
• Peach
• Pear
• Grape
• Pineapple
• Cherry

0.0g
114.0g
0.0g
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Table 1Standards of Identity and Quality
Analyses of Canned Fruit Cocktail
Based on your findings, enter appropriate data in
Tables 1 2 on your Data Sheet.
21 CFR 145 Std of Quality range each fruit
variety 21 CFR 145 Std of Quality for packing
medium (sugar content) Lite, 10-14 Medium,
14-18 Heavy, 18-22
Table 2Standards of Identity and Quality
Analyses of Canned Fruit Cocktail
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Principles of Cooking Direct HeatUse of
Broiling Element
1 min
2 min
3 min
5 min
0 min
4 min
6 min
7 min
8 min
9 min
10 min
11 min
12 min
13 min
14 min
15 min
16 min
17 min
18 min
19 min

• Turn on broiler element
• Open door
• Insert pan containing two cups of water
• Insert temperature probe into water (record
  ambient temp.)
• Partially close oven door monitor record
  water temperature and time until 180oF endpoint
  is reached.
• 4. How was heat transferred from element to water
  in container?
• 5. Why was the door left ajar during the broiling
  period?

72oF
73oF
80oF
86oF
93oF
104oF
111oF
122oF
129oF
138oF
145oF
152oF
159oF
163oF
168oF
172oF
176oF
177oF
179oF
180oF
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Principles of Cooking Direct HeatUse of
Broiling Element
1 min
2 min
3 min
5 min
0 min
4 min
6 min
7 min
8 min
9 min
10 min

• Turn on broiler element
• Open door
• Insert pan containing two cups of water on top
  shelf
• Insert temperature probe into water (record
  ambient temp.)
• Partially close oven door monitor record
  water temperature and time until 180oF endpoint
  is reached
• 6. Why did this water sample heat faster than the
  previous one?
• 7. How is broiling temperature controlled?

72oF
87oF
100oF
113oF
125oF
138oF
149oF
159oF
168oF
177oF
180oF
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Factors Affecting Enzymatic Browning Acid

• Dip apple slice 1 in water and note browning
• Dip apple slice 2 in acid at pH 5 and note
  browning
• Dip apple slice 3 in acid at pH 2 and note
  browning
• 12. Which medium inhibited enzymatic browning
  best?
• Why?
• 13. Explain how pH inhibits enzyme function.

3
1
2
Acid pH 5
Acid pH 2
Water pH 7
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Crude Protein Analysis of Red BeansKjeldahl
Method

• Add 1.4g homogenized red bean sample to Kjeldahl
  flask
• Heat Kjeldahl flask until sample is digested
  (disappears)
• Add NaOH pellet to make digest alkaline (pink).
• Connect water-cooled condenser
• Distill NH3 into Erlenmeyer flask

Objects not drawn to scale
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Crude Protein Analysis of Red BeansKjeldahl
Method
0.0mL
12.5mL

• Red bean distillate from Kjeldahl digestion
  (previous) step
• Titrate with 0.1 M HCl to clear endpoint
• Read burette and record

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Crude Protein Content of Red BeansKjeldahl
Method

• 4. Based on titration data, compute crude
  protein for the red bean sample using the
  formula
• Nitrogen MHCl x VHCl x 14 x 100
• Sample wt. X 1000
• Protein N x 6.25

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Objective Determinationof Texture of Raw Beef
Roast
Front View
Side View
Objects not drawn to scale
20 lb Capacity

• Remove a 1 core sample of raw roast
• Place in triangular opening of shear tester.
• Activate shear tester and record maximum shear
  result in pounds.
• Read maximum deflection pointer value of raw
  sample and reset shear tester.

10.7 lb
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