Transcript Slide 1
Fat Structure Fatty acids are either saturated, monounsaturated (contain one C=C double bond) or polyunsaturated (contain two or more C=C double bonds) Saturated fatty acids stack closely and are more solid. Unsaturated fatty acids are more fluid. “Hydrogenating” unsaturated fatty acids makes them more rigid. Cis and trans hydrogens Trans fats “look” more like saturated fats. “Partially hydrogenated” fats. Trans fats “look” more like saturated fats. Polyunsaturated > monosaturated “Attempt” to hydrogenate 4 cis double bonds succeeds with 2, leaves one alone, creates one trans double bond. Talk Show Schlock – Apples, arsenic, Alar Timely vs “on topic” Transition: Top Ten Lessons I Learned In College 10. Success is 1% inspiration and 99% cramming the night before the exam. 9. Roommates can be pretty harsh if you're still sleeping with your Big Bird doll. 8. Laughing at the professor’s jokes brings up the curve. 7. The best way to learn biology is in the woods behind Heylar House. 6. On Microsoft Word, if you drag down the format window and click on paragraph, adjusting the line spacing can make your papers look a lot longer. 5. Do your laundry every six months, whether you need it or not, (or take it home and have Dad do it.) 4. Do I have to think of another? 3. Um...sorry, I'm drawing another blank. 2. My parents wasted about 80 grand. 1. If you major in some lightweight field, goof off and get bad grades, you could become rich like that dropout Bill Gates. Sugars, Starches, Gums and Fibers Outline 1. Video 2. Uses in foods 3. Structure and function 4. “Artificial Sweeteners” Aspartame Smear 5. Starches, Pectins and Gums 6. Fiber and Diet 7. Metabolism of Sugars 8. Energy 9. Diet and Exercise 10.Production of honey, sugar, maple syrup and molasses Uses of Carbohydrates in Foods • Sweetener • Structure • Bulk (sugar substitutes) • Water Binding • “Mouth feel” • Color • Nutrition - Calories - Soluble and Insoluble fiber - Intestinal transit time, cholesterol bile binding • Special uses of gums, starches and pectins: gelation, viscosity, emulsification Structure of Carbohydrates Cartoon Chemistry High Fructose Corn Syrup, What is it? How is it made? Is it natural? Is it good for you? Glucose Glucose Fructose Glucose Glucose Glucose Starch Sucrose Fructose Glucose Glucose Glucose Glucose Glucose Glucose Fructose Glucose Fructose Corn Syrup Glucose Glucose High Fructose Corn Syrup Attributes of High Fructose Corn Syrup •Its liquid form and dust-free nature make it easy to handle. •The glucose and fructose in HFCS contribute to the desirable brown colors in baked. •HFCS has greater water binding capacity than sucrose. •HFCS has sweetening, thickening, and water binding properties and can balances tartness. • HFCS is more stable than sucrose in acid products. • HFCS is more stable than some artificial sweeteners. •Its sweetness can be manipulated by varying the fructose: glucose ratio. •HFCS is not as likely as sucrose to form crystals, which can impart a “gritty” defect. Is HFCS healthy? HFCS has the same 4 Cal/g as sucrose. HFCS is not the culprit for obesity. The over consumption of calories in sweetened beverages plays a large role in the obesity problem. Sedentary life style and lack of exercise also play a large role. Excess calories can come from sucrose, corn syrup, high fructose corn syrup or fat. Over consumption of calories is not healthy. Guess the calories Guess the calories 1,443 Calories 1,500 Calories Law suits against Snapple and Arizona “Not natural” What is the legal definition of a natural ingredient? “Sugar is Back on Food Labels, This time as a Selling Point” The New York Times March 21, 2009 By Kim Severson - The quiet rivalry between sugar and highfructose corn syrup appears to have a winner. - “ The first lady, Michelle Obama, has said she will not give her children products made with it (high-fructose corn syrup).” It’s a choice, market segmentation •HFCS consumption is at a 20 year low (37 lbs per person, 44 lbs for sucrose). •“Sugar is sugar, HFCS has been highly disparaged and highly misunderstood.” •Analogy to the renaming of other foods – “Rapeseed oil”. •Even CSPI (and AMA) says sugar and HFCS are the same and have same health effect. •“Corn sugar” more easily understood and eliminates the negative connotation. Relative sweetness of sweeteners “Sugars” Sucrose 1 Fructose 1.7 Glucose 0.7 Lactose 0.16 Maltose 0.32 Galactose 0.32 Artificial Sweeteners Cyclamate Banned in U.S “Delaney Clause” Saccharin 500 Aspartame 100 Sucralose 600 Acesulfame K 200 Sugar alcohols* Sorbitol 0.5 Mannitol 1 Xylitol 1 *bind water, laxative effect, gassy (caloric) 0.2 Cal/g Stevia from plant extract Truvia based on Stevia Neotame based on Nutrasweet 300 times sweeter than sucrose 7,000 – 13,000 sweeter Sugar and Sweeteners: a Molecular View A SHORT REVIEW Trans fats “look” more like saturated fats. “Partially hydrogenated” fats. Trans fats “look” more like saturated fats. Polyunsaturated > monosaturated “Attempt” to hydrogenate 4 cis double bonds succeeds with 2, leaves one alone, creates one trans double bond. Hydrogen bonding and solubility in water “Hydrogen bonding” is nothing more than the attraction of positive and negative. Structure of sucrose Fat Structure Fatty acids are either saturated, monounsaturated (contain one C=C double bond) or polyunsaturated (contain two or more C=C double bonds) Saturated fatty acids stack closely and are more solid. Unsaturated fatty acids are more fluid. “Hydrogenating” unsaturated fatty acids makes them more rigid. Carbohydrates Structure Importance of glucose Relative sweetness Lo/no cal sweeteners High fructose corn syrup No definition of “natural” My nuanced opinion of “Is HFCS good or bad?” It all depends… “Bias” A Tale of Four Sodas Component Rec’d Amt Cal/ g Cal Carbohydrate 120 g 4 480 Protein 56 g 4 224 Fat 30% of total 9 300 Required “Nutrient Calories” 1004 “Elective” Calories 540 Total Caloric Requirement 1,544 Add 4 cans soda (150 Cal/can) 600 Activity Couch potato Runner 0 -800 Cal Total Cal = 2,154 Total Cal = 1,334 HFCS Bad HFCS Good Discuss web rants -Dr Oz - more -Best and worst sugars- new Other items: •How can you know? •Questions about the extra credit? •Questions about lipids, or carbs thus far? •Comments on the “Knowledge Assessment Opportunity” •Attendance Function of Starches Food Function Benefits Pies, tarts, fillings Stabilize and thicken Resistant to weeping Instant puddings Instant thickening Creamy texture, smoothness and fast meltaway Gravy and sauces Thickening without lumping Texture and cling Jelly gums Setting and gelling agent Clarity, easy processing Baked or fried puffed snacks Volume control, crispness No need for cooking during forming process Breakfast cereal Texture enhancement Excellent expansion and bowl life French fries Form, crisp coating, internal binder Crispier more appetizing product Amylose and Amylopectin – Two forms of starch Structure of Starch Amylose = 30% of the starch, tightly packed, less digestible, insoluble in water. Amylopectin = 70% starch, soluble in water, many endings, crystalline Starch retrodegration Gluten, good or bad? Selling point? Survey: Do you think gluten is “bad”? Are you more likely to buy a product advertized as “gluten free”? Gluten Protein from wheat, barley, and rye (rice and corn different) Associated with starch Gliadin + gluteline Important global protein source Plasticity, shape, chewiness Celiac disease < 1.0 % of population Gums Gums - hydrocolloidal suspensions that don’t gel, aren’t soluble, but bind lots of water. Most important are non digestible soluble fiber. Source Gum Seeds Guar and Locust bean Plants Arabic (soluble in cold water) Microbes Xanthan and gelan Sea weed Alginate, carrageen, agar Chemical synthesis micro-crystalline cellulose, carboxy methyl cellulose Soluble and Insoluble Fibers Sources of Fiber Foods Rich in Insoluble Fiber Foods rich in Soluble Apples Citrus fruits Beets Oatmeal Cauliflower Potatoes Seeds Cherries Nuts Corn Green beans/peas Seeds Wheat bran Barley Health problem Fiber type Obesity Both Possible Health Benefits Replaces calories from fat, provides satiety, prolongs eating time because of chewiness Constipation Insoluble Provides bulk and aids intestinal motility: binds bile acids Diabetes Soluble May improve blood sugar tolerance by delaying glucose absorption Hemorrhoid Insoluble Provides bulk and aids intestinal motility: binds bile acids Colon Insoluble Speeds transit time through intestines and may Cancer protect against prolonged exposure to carcinogens Carbohydrate Characteristics Simple Sugars and Starches Soluble Complex Fibers Insoluble Complex Fibers Digested like glucose Nondigestible High glycemic index Provokes insulin response No insulin response Provides 4cal/g No calories May lower cholesterol Decreases intestinal transit time Decreases risk of heart “keeps you loose” disease Decrease diabetes Protects against colon cancer Protects against digestive disorders Glucose Metabolism Glycemic index of foods Low (Used slowly) Apples Medium bananas High (Used rapidly) Carrots Beans High-fructose corn syrup Dry dates Chickpeas Honey Glucose Grapefruit Ice cream Instant white rice Green leafy vegetables Oatmeal cookies Jelly beans Soy milk Strawberries Sucrose Sweet corn Potatoes White bread Glycemic index – the impact on blood glucose levels The glycemic index, glycaemic index, or GI is a measure of the effects of carbohydrates on blood sugar levels. Carbohydrates that break down quickly during digestion and release glucose rapidly into the bloodstream have a high GI; carbohydrates that break down more slowly, releasing glucose more gradually into the bloodstream, have a low GI. A lower glycemic response usually equates to a lower insulin demand but not always, and may improve long-term blood glucose control[2] and blood lipids. The glycemic index of a food is defined as the area under the two hour blood glucose response curve (AUC) following the ingestion of a fixed portion of carbohydrate (usually 50 g). The AUC of the test food is divided by the AUC of the standard (either glucose or white bread, giving two different definitions) and multiplied by 100. The current validated methods use glucose as the reference food, giving it a glycemic index value of 100 by definition. GI values can be interpreted intuitively as percentages on an absolute scale and are commonly interpreted as follows : Insulin Response to Glucose Metabolism The Effect of Diet on Physical Endurance White Sugar Production Raw Sugar Mixed with saturated sugar syrup Package Centrifuge to remove impurities* Screen for size Dissolve water and raise pH Dry Heat to 180°F Centrifuge and Wash Supernatant Filter through diatomaceous earth and charcoal Crystallize in Vacuum Pans *“Impurities” become molasses “The three moles.”