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More Fun In the Food Science Classroom

More Fun In the Food Science Classroom. Welcome! Presenters: Patti Rambo, Director, The Curriculum Center for Family and Consumer Sciences, Texas Tech University, Lubbock, TX

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More Fun In the Food Science Classroom

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  1. More Fun In the Food Science Classroom Welcome! • Presenters: • Patti Rambo, Director, The Curriculum Center for Family and Consumer Sciences, Texas Tech University, Lubbock, TX • Leslie Thompson, Ph.D., Chair and Professor, Department of Animal and Food Sciences International Center for Food, Texas Tech University, Lubbock, TX • Sandra Duke, Family and Consumer Sciences Education Graduate Research Assistant, Texas Tech University, Lubbock, TX

  2. Fun In the Food Science Classroom Molecular Motion

  3. Fun In the Food Science Classroom Molecular Motion TEKS (14) The student explains how food provides energy. The student is expected to: • (A) discuss molecular motion and temperature • (D) compare various temperatures on rates of reaction

  4. Fun In the Food Science Classroom Molecular Motion • Objective: Student will demonstrate and explain the effect temperature has on molecular motion.

  5. Fun In the Food Science Classroom Molecular Motion • Color Changing Milk Experiment • One cup of milk on plate • Place food coloring in milk • Place a drop of food coloring • Variables • Hot milk • Cold Milk • Hypothesis?

  6. Fun In the Food Science Classroom Molecular Motion Brownian Motion • Random movement of atoms and molecules suspended in a liquid or gas • Motion is caused by collisions with molecules of the surrounding medium • Heat energy determines how fast molecules move

  7. Fun In the Food Science Classroom Molecular Motion Kinetic Theory • Matter is composed of small particles - atoms and molecules • Particles of matter are in constant vigorous motion • Helps explain: • Transfer of heat • Relationship between temperature, pressure and volume of gases

  8. Fun In the Food Science Classroom Molecular Motion Diffusion • Spontaneous spreading out of something • Random in nature • Matter moves constantly!

  9. Fun In the Food Science Classroom Foaming and Whipped Cream

  10. Fun In the Food Science Classroom Foaming and Whipped Cream TEKS (19) The student understands coagulation and coalescence process associated with milk protein and cheese. The student is expected to: (F) Identify the factors that affect the ability of cream to form a foam.

  11. Fun In the Food Science Classroom Foaming and Whipped Cream Objective: Students will demonstrate and explain the effects temperature and agitation have on foams formed from cream

  12. Fun In the Food Science Classroom Foaming and Whipped Cream Whipped Cream Experiment • Half-cup whipping cream (or other dairy product of varying fat content) • Place in screw cap plastic container • Shake container vigorously • Check consistency of foam approximately every 2 min • Continue agitation until foam breaks and butter forms

  13. Fun In the Food Science Classroom Foaming and Whipped Cream Potential variables • Fat content of dairy product (evaporated milk 7.25% fat, half and half 10 to 18%, light cream 18 to 30%, light whipping cream 30 to 36%, heavy whipping cream >36%) • Temperature of heavy whipping cream • Time of agitation • Age of whipping cream • Addition of sugar (when added, gradual addition or dump method)

  14. Fun In the Food Science Classroom Foaming and Whipped Cream Foam: Dispersion consisting of a continuous liquid phase and a discontinuous gas phase Examples: Ice cream, angel food cake, meringues, whipped toppings, soufflés

  15. Fun In the Food Science Classroom Foaming and Whipped Cream • Foams are formed when whipping or agitation unfolds (denatures) proteins creating a stable network that traps air • Agitation unfolds proteins and incorporates air • Fat in whipping cream helps stabilize the foam

  16. Fun In the Food Science Classroom Foaming and Whipped Cream The most stable dairy foams are produced at lower temperatures.

  17. Fun In the Food Science Classroom Egg Foams

  18. Fun In the Food Science Classroom Egg Foams TEKS (4) The student analyzes the role of acids and bases in the food sciences. The student is expected to: • (E) Discuss ways pH is related to the properties of food, its safety and its freshness

  19. Fun In the Food Science Classroom Egg Foams TEKS (18) The student describes the properties of proteins and amino acids. The student is expected to: • (F) List factors that affect the stability of egg foam

  20. Fun In the Food Science Classroom Egg Foams Objective: The student will assess how pH affects the physical properties of eggs.

  21. Fun In the Food Science Classroom Egg Foams • As shell eggs age they loose water and CO2 • This cause the loss of the carbonate buffer • As the buffer is lost the pH of the egg increases • As pH of albumen increases the thick albumen becomes thinner • As the albumen thins it foams more easily but is much less stable

  22. Fun In the Food Science Classroom Egg Foams • As eggs are stored the pH increases from about 7.2 to 9.5 • pH changes affect foamabilty and foam stability • Ovomucin is the primary protein in eggs responsible for foaming and foam stability

  23. Fun In the Food Science Classroom Egg Foams • Freshly laid eggs are USDA Quality Grade AA • As eggs are stored the quality grade decreases from AA A B • Foam stability decreases as quality grade decreases

  24. Fun In the Food Science Classroom Egg Foams • Lipids interfere with egg foaming and foam volume • Factors such as temperature, age of the egg, presence of sugars, presence and types of lipids, pH and other ingredients affect foam volume and stability

  25. Fun In the Food Science Classroom Curds and Whey

  26. Fun In the Food Science Classroom Curds and Whey TEKS (6) The student studies the chemical properties of food. The student is expected to: • (H) Analyze the occurrence of specific chemical reactions • (I) Analyze chemical and physical changes in food

  27. Fun In the Food Science Classroom Curds and Whey Objective: The student will generate a physical change of a substance from a liquid state to a solid state

  28. Fun In the Food Science Classroom Curds and Whey The two major milk proteins are casein and whey. When milk is acidified to a pH of 4.6 casein becomes insoluble precipitating out of solution forming curds. Whey proteins remain soluble (do not denature) at low pH and are found in the liquid that is separated from the solid curds.

  29. Fun In the Food Science Classroom Curds and Whey • Casein exist in milk in the form of soluble micelles. • Casein consists of three primary forms • Alpha, beta and kappa • Some portions of the micelle are hydrophillic others are hydrophobic. • Colloidal CaPO4 is within the micelle.

  30. Fun In the Food Science Classroom Curds and Whey • When pH is 4.6 or lower • Colloidal CaPO4 within the micelle is disrupted and micelle structure changes • The micelle is no longer soluble • The casein proteins then aggregate forming a gel

  31. Fun In the Food Science Classroom Curds and Whey • Cheese making - rennet (chymosin and pepsin, two enzymes) is used • Kappa casein is cleaved from the casein molecule • Micelles are destabilized losing solubility • Casein proteins aggregate forming a gel (curds)

  32. Fun In the Food Science Classroom Chemical Leavening

  33. Fun In the Food Science Classroom Chemical Leavening TEKS (6) The student studies the chemical properties of food. The student is expected to: • (H) Analyze the occurrence of specific chemical reactions • (I) Analyze chemical and physical changes in food

  34. Fun In the Food Science Classroom (10) The student discusses how leavening agents are used in baking. The student is expected to: • (A) describe the purpose of leavening agents in baked goods. • (B) Identify and describe major leavening agents. • (C) explain why baking soda is used with an acid in baked goods • (F) discuss how air and steam act as leavening agents

  35. Fun In the Food Science Classroom Chemical Leavening Objective: The student will assess the effectiveness of various types of leavening systems.

  36. Fun In the Food Science Classroom Chemical Leavening Chemical leavening systems consist of a leavening agent (produces CO2 gas) and a leavening acid (provides H+ ions that cause the release of CO2)

  37. Fun In the Food Science Classroom Chemical Leavening • Common leavening agent • Sodium bicarbonate or “baking soda” (NaHCO3) • Common leavening acids • Acetic acid (vinegar) • Lactic acid • Sodium aluminum sulfate • Monocalcium phosphate

  38. Fun In the Food Science Classroom Chemical Leavening • Baking powder contains • Sodium bicarbonate (leavening agent) • Sodium aluminum sulfate (leavening acid) • Monocalcium phosphate (leavening acid) • “Double acting” baking powder

  39. Fun In the Food Science Classroom Chemical Leavening Leavening reaction in an aqueous system: HCO3- + H+ H2CO3 H2O + CO2 Equilibrium is pH-dependent

  40. Fun In the Food Science Classroom Chemical Leavening Carbonic acid-bicarbonate equilibrium H2CO3 HCO3- + H+ pKa = 6.35 Thus, below pH 6.35 bicarbonate is converted to carbonic acid which in an aqueous system can produce CO2 and water.

  41. Fun In the Food Science Classroom Browning Reactions: Maillard Reaction, Caramelization, and Enzymatic Browning

  42. Fun In the Food Science Classroom Browning Reactions - The Maillard Reaction (non-Enzymatic), Caramelization and Enzymatic Browning TEKS (6) The student studies the chemical property of foods. The student is expected to: • (H) analyze the specific occurrence of specific chemical reactions. • (I) analyze chemical and physical changes in foods.

  43. Fun In the Food Science Classroom Browning Reactions - The Maillard Reaction (non-Enzymatic), Caramelization and Enzymatic Browning TEKS (8) Student understands the functions of enzymes. The student is expected to: • (A) describe how enzymes act as catalysts. • (D) identify factors that affect enzyme activity. • (E) explain how enzyme reactions are involved in food preparation.

  44. Fun In the Food Science Classroom Browning Reactions - The Maillard Reaction (non-Enzymatic), Caramelization and Enzymatic Browning TEKS (18) The student describes the properties of proteins and amino acids. The student is expected to: • (C) explain what happens during denaturation of protein and how the process occurs.

  45. Fun In the Food Science Classroom Browning Reactions - The Maillard Reaction (Non-Enzymatic), Caramelization and Enzymatic Browning Objective: The student will summarize the browning reactions.

  46. Fun In the Food Science Classroom The Maillard Reaction (Non-Enzymatic) Substrates: Amino acids + Reducing sugars Products: Brown pigments + Flavor and odor compounds Reaction is favored by: • higher pH’s (add baking soda) • intermediate water activity

  47. Fun In the Food Science Classroom The Maillard Reaction (Non-Enzymatic) “In other words” Amino acids + Reducing sugars (Amine groups) (Carbonyl groups) -NH2 H | - C = O or – C = O | |

  48. Fun In the Food Science Classroom N-substituted glycosylamine ketosamines aldehydes + ketones (flavor and odor compounds) + Melanodin pigments (Brown pigments) Amadori rearrangement

  49. Fun In the Food Science Classroom • Responsible for browning and flavor in: • Roasted coffee • Cooked meat • Sautéed onions

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