Lecture 7 Flashcards
What is the different between the aldehyde and ketones structure?
Aldehyde: C attached to R,H, =O
Ketone: C attached to R, R’ and =O
What is the difference between D glucose and D fructose?
Glucose has an aldehyde
Fructose has a ketone
What is a furanose and pyranose?
Furanose is a 5 ring structure
Pyranose is a 6 ring structure
What is the difference between alpha and beta configuration of sugars?
Beta the OH group is pointing up
Alpha OH groups point down
What is the bond linkage between 2 glucose molecules?
alpha 1, 4 linkagee
What is the function of sugars?
Sweetness Mouth Feel Preservation and humectants Fermentable Caramelization Maillard Browning Crystallization
What is the order of sweetness of the sugars?
Fructose, Sucrose, Glucose, Maltose, Lactose
How can sugars contribute to mouth feel?
Dietetic Jello (Brittle)
Regular Jello (Rubbery)
How does sugar affect preservation to humectants?
↓ aw
↓Microorganisms
↓ Chemical Reactions
↑ Stability
What is the fermentation of sugar used in?
Bread Making: Sugar CO2
Pickles and Sausages: Sugar Acid
Wine and Beer: Sugar Alcohol
What is caramelization?
Direct Heating of Sugars
Used as colourants and flavourants
Cola Drinks
What is the Maillard browning?
Amino Acids + Reducing Sugars
Potato Chips, Roasted Meat, Bread Crust, Roasted Nuts
What is crystallization of sugar?
Sugar Cane Juice and evaporation leads to Concentration and when cooled leads to Crystallized Sugar
Sugar is hygroscopic, what does that mean?
Sugar has the ability to absorb moisture
What is the hydrolysis of sugar?
Breakdown of a disaccharide leads to an inverted sugar
What are the characteristics of inverted sugar?
Sweetness? ↑
Water Retention? ↑
Crystallization? ↓
What are the advantages of invertase?
Mild Conditions & Specificity
What are examples of inverted sugars?
Honey, Candies
Cherry Liquer Chocolate
What sugar has the same sweetness of sucrose?
Xylitol
What are alditols?
Sugar alcohol
- non carcinogenic/nutritive
- used in Candy for Diabetics, Chewing Gums, Hard Candies
What is cellulose?
the most abundant carb, a whole bunch of glucoses attached to each other via beta 1-4
-also the structural based of plants
what is starch?
polysaccharide is either straight or branched
What are the 2 kinds of starch and how are they linked?
Amylose : α (1-4)
Amylopectin: α (1-4) and α (1-6)
What re the functions of starch?
Thickening Agent
- Absorb H2O
- Swelling of Starch Granules
What is a starch granule?
Microscopic structure where starch is deposited, differ in shape and size
Starch found in layers within a Granule
Where is starch found in corn and wheat?
Corn in a circular form
Wheat in an X pattern
What is the composition of starch?
15-30% Amylose
70-85% Amylopectin
How do you modify starch?
Hydrolysis
-: Results in formation of smaller fragments of starch known as Dextrin
Addition of Phosphate (linkage)
-(Provides stability in Frozen Meals upon thawing and prevent syneresis)
Pre-gelatinization
-: Instant Pudding
What is granule solubility like?
Cold water? Reversible
Hot water? Irreversible
What is the change like in corn starch granules when heating in water?
Granule Swelling
Disruption of organized structure
What is retrogradation?
Rearrangement of starch molecules which results in tighter association of molecules
What is syneresis?
Expulsion of a liquid from a gel
What happens during gelatinization?
Amylose is leached out from granules
Bonding of amylose molecules
What is waxy starch?
100% amylopectin without amylose
**Thickening Agent (Pie filling, Salad dressing)
- *No Gel formation
- gotten from selective breeding
What is high amylose starch used in?
80% Amylose:
Used in making Edible Film
What does starch hydrolysis lead to?
Viscosity?? ↓
Acid ? No Specificity, Random Fragments
Enzyme ? Highly Specific
α – amylase ? Hydrolyze main branch of starch: α (1-4)
α – (1-6) Glucosidase ? Breaks off the side branch: α (1-6)
What is pectin and the linkage?
Structural Unit:
α – D – Galacturonic acid
α – (1-4) linkage
MW = 10 – 40, 000
What are other polysaccharides and their functions?
Plant Gums: Guar gum, Locust bean gum
Sea Weed Gums: Alginate, Carageenan
Functions : Thickening Age
What do poly saccharides differ in?
1) Distribution and type of monosaccharide
2) Site of glycosidic linkage
3) Sequence of monosaccharide
What are the functional properties of charbs in summary form?
Energy Preservative -(act as humectants and↓ aw) Flavour and Colour Sweetness -(Fru > Suc > Gluc > Mal > Lac) Viscosity Control Gelation Dietary bulk Fermentation
Where do your start counting Cs in a structures?
○ Most oxidized carbon is where you start counting
What is the difference between D and L sugars?
if OH is right then its D, left is L
○ Look at the highest number chiral carbon to determine L and D
If OH on anomeeric C is down its alpha, up is beta
What is an semi acetal?
• Hemi acetal for glucose ring structuree
○ C attached to hydroxyl group and ehter group
○ It would be a reducing sugar. Ebcasue of the hemi a cetal
How do you determine if OH will be alpha or beta?
• Ranomdom chance that when sugar ring closes the OH group will be up or down
What aree d and l sugars to each other?
mirror images
What are the reducing and non reducing sugars?
○ Maltose reducing sugar
○ Lactose iss reducing sugar
○ Sucrose is non reducing sugar
How doe sugar act as a humectant challenge?
• They bind free water decreasing water and increasing stability of final product, can keep for longer time, less free water for Mos and chemical rxns
What is the most hygroscopic sugar?
Fructose
How does sugar hydrolysis of sucrose work?
○ Sucrase/invertase break downs sucrose into glucose and fructose
○ Invert sugars (broken down disaccharide) have higher sweetness, hold more water and crystalization decreases
§ Pros: don’t need strong heat or acid for hydrolysis, can do it under normal conditions
How do you make a sugar alcohol?
• Alditols are sugar alcohols, when treat sugars with reducing agents you convert the aldehyde into an alcohol, rest of molecule remains the same
Do alcohol sugars contribute to kcals?
Yes but no cavities because they don’t cause bacteria in the mouth to ferment
Can humans break down cellulose?
Because Beta 1-4 linkage humans don’t have the enzymes to break it down
What is the difference between amylose and amylopectin?
○ Amylose is straight molecule polymer
○ Amylopactin is branched, main branch 1-4, and side branches are 1-6 (both are alpha)
What doesn’t really contribute to the thickness of products?
Amylose
Is pectin digestible?
No
does contribute to thickness and viscosity
