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© 2006 Ralph Lane. © 2006 Ralph Lane Virtual Lab Rules Follow on-screenFollow on-screen Procedure by clicking the mouse. clicking the mouse. Each bulleted.

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Presentation on theme: "© 2006 Ralph Lane. © 2006 Ralph Lane Virtual Lab Rules Follow on-screenFollow on-screen Procedure by clicking the mouse. clicking the mouse. Each bulleted."— Presentation transcript:

1 © 2006 Ralph Lane

2 © 2006 Ralph Lane Virtual Lab Rules Follow on-screenFollow on-screen Procedure by clicking the mouse. clicking the mouse. Each bulleted stepEach bulleted step represents one click. represents one click. WAIT at least 3 secondsWAIT at least 3 seconds between clicks (steps) to ensure that (steps) to ensure that operation is complete. (i.e., don’t get trigger-happy!) STOP... and read the rules

3 © 2006 Ralph Lane Procedure: Weigh (click) the apple slice and record weight. Place (click) in drying oven Dry overnight at 100 o C to constant weight. Remove and reweigh; record weight. Compute % Moisture 0.0g 10.0g 0.0g 1.3g 100 o C Moisture Content of Foods Objects not drawn to scale

4 © 2006 Ralph Lane Experimental Food Science Virtual Laboratory Manual Instructor’s Manual (Excerpt) Water: Moisture Content of Foods Slide 18 13. How much moisture was lost. (show work) 10.0 -1.3 = 8.7g moisture which evaporated in the moisture oven. 14. % Moisture = 10.0 -1.3 = 8.7/10.0 = 87% contained in the apple 15. Compare your moisture value with the value obtained from a food composition handbook such as Pennington’s Bowes and Church or USDA’s Ag. Handbook No. 8 or online at: http://www.nal.usda.gov/fnic/foodcomp/search/index.html This value was obtained and integrated into the moisture analysis using the old USDA Handbook #8. A more recent reference (on-line) is: http://www.nal.usda.gov/fnic/foodcomp/search/index.html. Of course all nutrients vary depending on plant (apple) variety, time of harvest, time held during storage, sampling, sample weighing, drying oven temperature, time in oven, etc. http://www.nal.usda.gov/fnic/foodcomp/search/index.html Experimental Food Science Virtual Lab Instructor’s Manual Experimental Food Science Virtual Lab Instructor’s Manual

5 © 2006 Ralph Lane Osmosis and Syrup Formation 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? 0min10min20min 30min Objects not drawn to scale

6 © 2006 Ralph Lane Experimental Food Science Virtual Laboratory Manual Instructor’s Manual (Excerpt) Osmosis and Syrup Formation Slice the strawberry. Sprinkle sugar on the slices. Let stand for 30 minutes. 29. What is the liquid that formed on the strawberry slices? Syrup. 30. Explain how it formed. Sprinkled s ugar dissolves in surface sap creating an osmotic pressure gradient with higher osmotic pressure outside the slices which withdraws water from the strawberry cells creating the syrup on the surface of the strawberry slices. 31. What is the process called? Osmosis (Type 2)

7 © 2006 Ralph Lane Nonfat Milk Experiment 2 Measuring 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 1 Cup 3/4 3/4 1/4 1/4 1/3 1/3 2/3 2/3 1/2 1/2

8 © 2006 Ralph Lane Experimental Food Science Virtual Laboratory Manual Instructor’s Manual (Excerpt) Weights & Measures Laboratory Fill the liquid measure to the ½ cup line. Note the surface of the milk in the cup.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 Since water molecules of milk are polar, they have an affinity for the silicate of the glass and form hydrogen bonds and thus adhere to the sides of the glass measure forming a concave surface (meniscus). Experimental Food Science Virtual Laboratory Manual Instructor’s Manual (Excerpt) Weights & Measures Laboratory Fill the liquid measure to the ½ cup line. Note the surface of the milk in the cup.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 Since water molecules of milk are polar, they have an affinity for the silicate of the glass and form hydrogen bonds and thus adhere to the sides of the glass measure forming a concave surface (meniscus).

9 © 2006 Ralph Lane Standards of Identity, Quality & Fill Open can Express contents into strainer (Allow contents to drain. Reserve packing medium for sugar analysis) Mrs. Kirby’s Fruit Cocktail In Heavy Syrup 15oz (426g)

10 © 2006 Ralph Lane Determination of Syrup Strength Eyepiece % 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 Refractometer, handheld 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.

11 © 2006 Ralph Lane Determination of Syrup Strength Eyepiece % 32 30 28 26 24 22 20 18 16 14 12 10 8 6 4 2 0 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.

12 © 2006 Ralph Lane Experimental Food Science Virtual Laboratory Manual Instructor’s Manual (Excerpt) Standards of Identity, Quality and Fill of Container Place some of the packing medium on the refractometer prism and read scale in % sugar at line between light and dark areas. Record: 18%Place some of the packing medium on the refractometer prism and read scale in % sugar at line between light and dark areas. Record: 18% A refractometer is a device that measures very accurately the concentration of dissolved sugar (irrespective of the particular sugar) in solutions by determining the degree of refraction of light through the sugar solution with the refractive index of the solution calibrated in percent sugar. For fruit cocktail packed in heavy syrup, percent sugar ranges from 18-22% according to 21CFR, § 145. Experimental Food Science Virtual Laboratory Manual Instructor’s Manual (Excerpt) Standards of Identity, Quality and Fill of Container Place some of the packing medium on the refractometer prism and read scale in % sugar at line between light and dark areas. Record: 18%Place some of the packing medium on the refractometer prism and read scale in % sugar at line between light and dark areas. Record: 18% A refractometer is a device that measures very accurately the concentration of dissolved sugar (irrespective of the particular sugar) in solutions by determining the degree of refraction of light through the sugar solution with the refractive index of the solution calibrated in percent sugar. For fruit cocktail packed in heavy syrup, percent sugar ranges from 18-22% according to 21CFR, § 145.

13 © 2006 Ralph Lane 0.0g 0.0g Standards of Identity, Quality & Fill of Container Fruit legend Peach Pear Grape Pineapple Cherry Remove container Separate each fruit variety Weigh each variety & record. 114.0g 0.0g 0.0g

14 © 2006 Ralph Lane Table 1 Standards of Identity and Quality Analyses of Canned Fruit Cocktail BrandStandard % Peaches30-50* % Pears25-45* % Grapes6-20* % Pineapple6-16* % Cherries2-6* % Solute** Mrs. Kirby’s * 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 2 Standards of Identity and Quality Analyses of Canned Fruit Cocktail BrandNet Wt. of Contents gm Drained Wt. of Fruit gm % FillLabelActualLabel Standard Mrs. Kirby’s42627765 Based on your findings, enter appropriate data in Tables 1 & 2 on your Data Sheet.

15 © 2006 Ralph Lane 0min 1min2min3min 4min 5min 6min7min8min9min10min11min12min 13min14min15min16min17min18min19min 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 180 o F 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? Principles of Cooking: Direct Heat Use of Broiling Element 72 o F 72 o F 73 o F 73 o F 80 o F 80 o F 86 o F 86 o F 93 o F 93 o F 104 o F 104 o F 111 o F 111 o F 122 o F 122 o F 129 o F 129 o F 138 o F 138 o F 145 o F 145 o F 152 o F 152 o F 159 o F 159 o F 163 o F 163 o F 168 o F 168 o F 172 o F 172 o F 176 o F 176 o F 177 o F 177 o F 179 o F 179 o F 180 o F 180 o F

16 © 2006 Ralph Lane Experimental Food Science Virtual Laboratory Manual Instructor’s Manual (Excerpt) Heat Penetration Laboratory Use of Broiling ElementUse of Broiling Element Turn on broiler elementTurn on broiler element Open doorOpen door Insert pan containing two cups of waterInsert pan containing two cups of water Insert temperature probe into water (record ambient temperature)Insert temperature probe into water (record ambient temperature) Partially close oven door & monitor & record water temperature and time until 180*F endpoint is reached.Partially close oven door & monitor & record water temperature and time until 180*F endpoint is reached. 4. How was heat transferred from element to water in container? Radiation. 5. Why was the door left ajar during the broiling period? To prevent the high-limit oven switch from automatically turning the element off.

17 © 2006 Ralph Lane 0min 1min2min3min 4min 5min 6min7min8min9min10min 72 o F 72 o F 87 o F 87 o F 100 o F 100 o F 113 o F 113 o F 125 o F 125 o F 138 o F 138 o F 149 o F 149 o F 159 o F 159 o F 168 o F 168 o F 177 o F 177 o F 180 o F 180 o F 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 180 o F endpoint is reached 6.Why did this water sample heat faster than the previous one? 7.How is broiling temperature controlled? Principles of Cooking: Direct Heat Use of Broiling Element

18 © 2006 Ralph Lane Experimental Food Science Virtual Laboratory Manual Instructor’s Manual (Excerpt) Heat Penetration Laboratory Use of Broiling ElementUse of Broiling Element Turn on broiler elementTurn on broiler element Open doorOpen door Insert pan containing two cups of waterInsert pan containing two cups of water Insert temperature probe into water (record ambient temperature)Insert temperature probe into water (record ambient temperature) Partially close oven door & monitor & record water temperature and time until 180*F endpoint is reached.Partially close oven door & monitor & record water temperature and time until 180*F endpoint is reached. 6. Why did this water sample heat faster than the previous one? Water closer to heat source. Water closer to heat source. 7. How is broiling temperature controlled? Distance from heat source to material (water) being heated. Distance from heat source to material (water) being heated.

19 © 2006 Ralph Lane 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. 1 Water pH 7 2 3 Acid pH 5 Acid pH 2 Factors Affecting Enzymatic Browning: Acid

20 © 2006 Ralph Lane Experimental Food Science Virtual Laboratory Manual Instructor’s Manual (Excerpt) Factors Affecting Enzymatic Browning: Acid Dip apple slice 1 in water and note browningDip apple slice 1 in water and note browning Dip apple slice 2 in dilute acid at pH 5 and noteDip apple slice 2 in dilute acid at pH 5 and note browning browning Dip apple slice 3 in dilute acid at pH 2 and noteDip apple slice 3 in dilute acid at pH 2 and note browning browning 32. Which medium inhibited enzymatic browning best? pH 2 33. Why? Changes the surface of the enzyme such that binding to the substrate does not occur as readily, and minimal or no browning results.

21 © 2006 Ralph Lane Crude Protein Analysis of Red Beans: Kjeldahl 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 NH 3 into Erlenmeyer flask Objects not drawn to scale

22 © 2006 Ralph Lane Crude Protein Analysis of Red Beans Kjeldahl Method Red bean distillate from Kjeldahl digestion (previous) step Titrate with 0.1 M HCl to clear endpoint Read burette and record 0.0mL 12.5mL

23 © 2006 Ralph Lane Experimental Food Science Virtual Laboratory Manual Instructor’s Manual (Excerpt) Proximate Analysis Laboratory Kjeldahl Method Titrate with 0.1 M HCL to clear endpoint.Titrate with 0.1 M HCL to clear endpoint. Read burette and record: 12.5 mLRead burette and record: 12.5 mL Based on titration data, compute % crude protein for the red bean sample using the formula: 4. % Nitrogen = MHCL x VHCL x 14 x 100 Sample wt x 1000 Sample wt x 1000 = 0.1 x 12.5 x 14 x 100 = 1.25 1.4 x 1000 1.4 x 1000 5. % Protein = % N x 6.25 (protein factor for mixed diet) = 1.25 x 6.25 = 7.8%

24 © 2006 Ralph Lane % Crude Protein Content of Red Beans Kjeldahl Method 4.Based on titration data, compute % crude protein for the red bean sample using the formula: % Nitrogen = M HCl x V HCl x 14 x 100 Sample wt. X 1000 % Protein = % N x 6.25

25 © 2006 Ralph Lane Objective Determination of Texture of Raw Beef Roast 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. Front View Side View 20 lb Capacity 20 lb Capacity 10.7lb Objects not drawn to scale

26 © 2006 Ralph Lane Experimental Food Science Virtual Laboratory Manual Instructor’s Manual (Excerpt) Meats Laboratory Remove a 1” core sample of raw roastRemove a 1” core sample of raw roast Place in triangular opening of shear tester.Place in triangular opening of shear tester. Activate shear tester and record maximum shearActivate shear tester and record maximum shear result in pounds. result in pounds. Record maximum deflection pointer value of rawRecord maximum deflection pointer value of raw sample & reset10.7 lb sample & reset10.7 lb Shear tester device is based on the Warner-Bratzler Shear Tester that measures the amount of force, in pounds, applied in order to shear, in this case, a one-inch core of meat. The device is spring-loaded and elongates a spring within the instrument face housing that is calibrated to record the load applied, much like a dietetic scale, until the core is sheared which releases the load and the (black) pointer attached to the spring returns to zero (no load) leaving the maximum load (red) pointer to indicate the amount of force required to shear the core sample, 10.7 lb..


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