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CHEM 181 (350)
David Harpp (107)
Lecture

Food 2

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Department
Chemistry
Course
CHEM 181
Professor
David Harpp
Semester
Winter

Description
World of Chem: Food January 17 – Food II What Sugar Does In The Body Fructose Issues Good news: - Low glycemic index – does not cause blood sugar to rise as much as sucrose – thus thought to be a good substitute for sucrose - Small amounts in food is okay Bad news: - Too much at once is not good and the modern diet can have ~10% fructose - When glucose enters the bloodstream, insulin regulates it but fructose is processed in the liver and if there is too much, it makes fats o Too much fat in the blood is a risk factor for heart disease o Fructose circumvents the appetite signaling system so being “filled up” is not triggered as well o Some evidence is accumulating that excess fructose causes insulin resistance leading to type 2 diabetes o Fructose promotes AGEs more than glucose Amount - A cup of chopped tomatoes 2.5g - A can of non-diet soda 23g - Super-size soda 62g - Diet soda 0g High fructose drinks linked with gout risk. - Gout is the crystallization of uric acid in the joints (often foot, sometimes hand) - More males than females - Results from too much meat eating - Diet drinks not associated with the risk of gout Study: Assumed 20 years of consumption and an average of 50 increased cases – the results suggest 1-2 added cases of gout per 100 persons because of drinking “sugar” sodas. Conclusion: among this cohort of women, consumption of fructose-rich beverages is associated with an increased risk of incident gout, although the contribution of these beverages to be risk of gout in the population is likely modest given the low incidence rate among women. World of Chem: Food January 17 – Food II Fructose in part goes to uric acid (this is its mechanism). Glucose does not follow in the mechanism path of fructose. Thus glucose does not cause gout. Sucrose Issues - Glycation o Sucrose splits into glucose and fructose and glycation happens o Amine end of an amino acid and a sugar join and a water is formed (under heat) o Reaction discovered in 1912 by Louis Maillard  Same reaction as when you make toast  Yellow colour is the maillard reaction  Product is called an amadori product  Protein chains are linked to sugar as a result, called Advanced Glycation End Products (AGEs). Not toxic product but is alien.  The product reorganizes its atoms and another amino acid chain can join with sugar to make water  Protein linked to a sugar, linked to a protein, etc.  Contributes to sagging skin and a variety of things  Blood sugar takes 80 minutes at 10 mM at age 70 to be processed. o Has an opportunity to connect with the proteins and thus more opportunity to connect with AGEs‟ o Exercise may help o Takes much less time for younger people; 6 mM in 80 minutes for 20 year old.  AGEs have a role in cataracts: about 40% of persons between 55 and 64 have some opaque areas whereas about 90% of persons between the age of 75 and 84 have some opaque areas. o Sometimes called “sugar cataracts” or “diabetes cataracts” o Clouded lens; light rays diffused into different directions by a cataract o Particulates in the lens of the eye o Cataract operation: lens is given a dose of vibration, shreds the lens, implants a new lens o The human eye lens consists of a mix of several proteins. Protective proteins prevent these proteins from aggregating. If this protective function fails, the lens blurs and the cataract forms. o Protein folding (why do they fold to create cataracts?) o Cataracts can give a yellowish tinge to objects. World of Chem: Food January 17 – Food II o Claude Monet developed cataracts  Painted a bridge distorted  AGEs also have a role in increasing o Atherosclerosis o Sagging skin Fats - For stored energy, insulation, padding - Structure: o 3 carbons o 3 oxygen atoms that connect the carbons o 3 C=O groups o 3 carbon chains o Tristearin: a saturated solid fat with 18 carbons in each chain  Much variation!  2 chains of 18 and 1 chain of 16: a saturated solid fat  Chains can vary in length and structure  Chains can align well – saturated fats are often solid materials like butter.  Most butter has mostly saturated fat o Chains can be bonded differently  An unsaturated solid fat has a double bond – angled turn  Often liquid (has no physical capacity to be solid)  If doubly bonded then the shape will change  If more than one double bond: polyunsaturated  9 cal/g as opposed to proteins and carbohydrates, which are 4 cal/g - Canola oil has very little saturated fat. It is mostly polyunsaturated fat and monounsaturated fat. (pours almost like water) - Coconut oil has mostly saturated fat. (80-90%) o Apparently studies are saying it‟s not so bad. - Olive oil is used in the Mediterranean so it apparently leads to long life and good health. Mostly monounsaturated fat, a lot less polyunsaturated fat. - Sunflower oil and corn oil have more polyunsaturated fats so pour more easily. - Some key products (with a lot of saturated fat): o Lard o Butter o Margarine - Cooking in Mongolia o Sheep fat then stir in noodles or rice and sometimes meat and consume – often twice a day o No vegetables due to lack of growth World of Chem: Food January 17 – Food II - Butter is mostly saturated fat – 20% water - Margarines have plant fats – 15 – 60% water o Invented in France by Napoleon Bonaparte‟s nephew  Promoted margarine for the army and the lower classes o Became popular during WWII because butter was not produced as much o White lard + colouring agent = margarine (coloured to look like butter) o Light products are popular: light margarine is 58% water.  Not a good idea for cooking because of the high water content – will spray out of pan  Heated and set cool results: 3 layers of unsaturated, saturated fat and water. o “Regular” margarine‟s first ingredient is liquid soya oil and partially hydrogenated soya oil. About 16% water; thus, more fat. o Gums are plant products designed to thicken the product and give it the „mouth feel‟ - How is margarine made? o Trans fat  Unsaturated fatty acid chain with one double bond (monounsaturated)  Unsaturated linkage  Hydrogens are on the same side – CIS  Hydrogens are on opposite sides – TRANS  They are locked in that position  Lead to higher cholesterol and do not process as well in the body  Made almost accidentally in the process of making margarine  Rotation about the C=C bond cannot take place.  To prepare a margarine it is usually necessary to hydrogenate many of the double bonds to single bonds (unsaturated to saturated)  Want to add hydrogen to the double bond and saturate it. (to make it solid)  This sometimes causes a partial reorganization of the bonding to give some TRANS double bonds (before the second hydrogen can be transferred, the carbon rotates and the first hydrogen rebinds to the other hydrogen)  Reaction is carried out in a catalyst: Pd or Pt  Trans double bonds appear to increase cholesterol levels.  Federal law requires labels on packaged foods to list trans fat amounts of a half gram or more. But the rule does not apply to most meat and dairy
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