Chemistry of Food. Fresh baked bread Would you like some butter on it? Or margarine? Or Benecol? ...
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Transcript of Chemistry of Food. Fresh baked bread Would you like some butter on it? Or margarine? Or Benecol? ...
Chemistry of FoodChemistry of Food
Fresh baked breadFresh baked bread
Would you like some Would you like some butter on it?butter on it?
Or margarine?Or margarine? Or Benecol?Or Benecol? Or Smart Balance?Or Smart Balance?
LipidsLipids
Organic substance Organic substance found in living found in living systems that is not systems that is not soluble in watersoluble in water Fats & oils 95% of Fats & oils 95% of
lipids in diet are theselipids in diet are these Steroids Extremely Steroids Extremely
important in cell important in cell function, hormonesfunction, hormones
WaxesWaxes
Fats solidsFats solids Oils liquidsOils liquids
Lipids and HealthLipids and Health
Diets that are high in Diets that are high in saturated fats are saturated fats are associated with an associated with an increased risk of increased risk of coronary artery coronary artery diseasedisease
Saturated fatsSaturated fats
Found in animal derived fatsFound in animal derived fats Usually solidsUsually solids Butter is a saturated fat, also high in cholesterolButter is a saturated fat, also high in cholesterol
ciscis Unsaturated fats Unsaturated fats
Naturally occurring unsaturated fatNaturally occurring unsaturated fat Found in plant derived fatsFound in plant derived fats About 30% of our daily calories should be from fatAbout 30% of our daily calories should be from fat
TransTrans unsaturated fats unsaturated fats
Formed from hydrogenation of unsaturated fatsFormed from hydrogenation of unsaturated fats This is done to make the fat more solid, ex. Peanut This is done to make the fat more solid, ex. Peanut
butterbutter TFA associated with increased heart diseaseTFA associated with increased heart disease
MargarinesMargarines
Margarines do not have cholesterol, they are made from plant derived Margarines do not have cholesterol, they are made from plant derived fatty acids, originally unsaturatedfatty acids, originally unsaturated
To give them solid consistency, they are hydrogenated, resulting in To give them solid consistency, they are hydrogenated, resulting in trans fatty acids (TFA)trans fatty acids (TFA)
Can’t believe Can’t believe has 1g of TFA per 10 g total fat in 1T servinghas 1g of TFA per 10 g total fat in 1T serving Blue bonnet has 2 g of TFA per 7 g total fat in 1 T servingBlue bonnet has 2 g of TFA per 7 g total fat in 1 T serving
““Health” SpreadsHealth” Spreads
These spreads are made from unsaturated vegetable These spreads are made from unsaturated vegetable oils, no cholesterol, lower saturationoils, no cholesterol, lower saturation
Also do not have trans fatty acidsAlso do not have trans fatty acids Better for you?Better for you?
Fake fatsFake fats Olestra (Proctor & Olestra (Proctor &
Gamble)Gamble) Replaced glycerol with Replaced glycerol with
sucrose, 6 to 8 fatty acidssucrose, 6 to 8 fatty acids No calories, not digestedNo calories, not digested Removes oil soluble Removes oil soluble
vitamins & cartenoidsvitamins & cartenoids Severe gastrointestinal Severe gastrointestinal
problemsproblems
Carbohydrates Carbohydrates Good or Bad?Good or Bad?
CarbohydratesCarbohydrates
Carbohydrates: Hydrates of carbon Have Carbohydrates: Hydrates of carbon Have general formula: Cx(H2O)y in which x general formula: Cx(H2O)y in which x and y are whole numbersand y are whole numbers
Carbohydrates consist of:Carbohydrates consist of: MonosacchadridesMonosacchadrides DisaccharidesDisaccharides StarchStarch CelluloseCellulose
Carbohydrates in DietCarbohydrates in Diet
Typically half the Typically half the calories in the human calories in the human diet are made up of diet are made up of carbohydratescarbohydrates
The Atkins diet limits The Atkins diet limits the amount of the amount of carbohydrates in carbohydrates in your dietyour diet
MonosaccharidesMonosaccharides
What is the difference What is the difference between these between these sugars?sugars?
They are isomers of They are isomers of one another. one another. Isomer:Isomer: Same formula but Same formula but different arrangement different arrangement of the connectivity/ of the connectivity/ geometry of the geometry of the molecule.molecule.
DisaccharidesDisaccharides
These are 2 simple sugars These are 2 simple sugars combined together (with combined together (with elimination of 1 Helimination of 1 H22O)O)
General formula: CGeneral formula: C1212HH2222OO1111
Average daily Western Average daily Western consumption of simple consumption of simple sugars is 170gsugars is 170g
Density DemonstrationDensity Demonstration
Density = Mass/ VolumeDensity = Mass/ Volume The density of water is 1g/mLThe density of water is 1g/mL Why do the two kinds of pop behave Why do the two kinds of pop behave
differently?differently? Different densitiesDifferent densities Majority of both pops is composed of water Majority of both pops is composed of water
but the added sugar in the sweetened pop but the added sugar in the sweetened pop increases the density and causes it to sinkincreases the density and causes it to sink
Carbohydrates & HealthCarbohydrates & Health
Simple sugars are Simple sugars are responsible for dental responsible for dental cavitiescavities
Simple sugars Simple sugars contribute to obesitycontribute to obesity
Simple sugars are Simple sugars are thought to be thought to be important in the important in the development of Type development of Type II DiabetesII Diabetes
Artificial SweetenersArtificial Sweeteners
1
180
300
0
100
200
300
sugar aspartame saccharin
Relative Sweetness of Different Common Sweeteners
Saccharin: Not Saccharin: Not digested, no caloric digested, no caloric value, bitter aftertaste, value, bitter aftertaste, possible carcinogen, possible carcinogen, not used as muchnot used as much
Aspartame Aspartame (NutraSweet): Does (NutraSweet): Does have caloric value but have caloric value but more sweetness per more sweetness per gram than sucrosegram than sucrose
AspartameAspartame Decomposes10% per month at Decomposes10% per month at
room temperatureroom temperature How is rate affected by How is rate affected by
temperature?temperature? Increased Temp. Increased RateIncreased Temp. Increased Rate Cooking rapidly decomposes Cooking rapidly decomposes
NutraSweetNutraSweet
PolysaccharidesPolysaccharides
Consist of many Consist of many sugars bonded sugars bonded togethertogether
Polymer: A large Polymer: A large molecule with a molecule with a repeating unitrepeating unit
Common Common polysaccharides polysaccharides include: cellulose, include: cellulose, glycogen, and starchglycogen, and starch
Biomolecules GeometryBiomolecules Geometry
ChiralityChirality Chirality = Chirality =
HandednessHandedness Molecules that cannot Molecules that cannot
be superimposed on be superimposed on their mirror images are their mirror images are called chiral.called chiral.
Molecules that can be Molecules that can be superimposed on their superimposed on their mirror images are mirror images are achiralachiral
ChiralityChirality
Which of the following objects is chiral?Which of the following objects is chiral? A table knife, a pencil, a pair of gloves, a A table knife, a pencil, a pair of gloves, a
shirt that has buttons, a TV setshirt that has buttons, a TV set A table knife, a pencilA table knife, a pencil, , a pair of glovesa pair of gloves, , a a
shirt that has buttonsshirt that has buttons, , a TV seta TV set
ChiralityChirality
Enantiomers: Chiral pair of molecules, Enantiomers: Chiral pair of molecules, have same exact formula but are have same exact formula but are different moleculesdifferent molecules
Racemic: Equal portions of both Racemic: Equal portions of both enantiomersenantiomers
Examples: Aleve, thaliomide, ibuprofinExamples: Aleve, thaliomide, ibuprofin