Exam 2 Flashcards
Why is water the most important food component?
Because it is in everything
what is the smallest and simplest of food components?
Water
Bond angle of water?
104.5
how many hydrogen bonds are formed with ice?
4
what happens when water freezes?
Density increases and volume increases.
why does ice float?
because it is less dense than water.
How do Cp, Lf and Lv compare between water and other compounds?
All 3 are fairly low
what is sublimation?
when water skips the liquid state
List the 3 major sensory characteristics that relate to the influence of water on food.
Appearance, texture, and flavor
why do supermarkets use water misters in the produce section?
to keep vegetables nice and crisp.
What is formed where a molecules charged surfaces (like carrageenan or pectin) provide repulsion necessary to keep particles dispersed?
Dispersion
Which types of water are the most important in food science?
Free and Entrapped
What is the measure of the water that is not bound to food molecules and is available for reactions and microbial growth?
Aw (Water Activity)
Which method isn’t a method to manipulate Aw?
Adding fruit juice
How do bacteria divide?
Binary Fission
Why is bacteria population with a short generation time and a high initial load of concern?
Food spoilage can occur in a few hours.
In which phase of the microbial growth curve are the vegetative cells actively growing?
Log Phase
In the death phase, division is no longer possible and if bacteria can, they take on a tough, dormant form called what?
Endospore
F A T T O M
Food, Acid, Temperature, Time, Oxygen, Moisture
Which microbes are most likely to spoil slightly acidic, fruit based foods?
Yeats and Molds
How is microbial growth interrupted?
Alter greater than or equal to 1 growth factor
An additive changes the oxidation/reduction potential. How does this impact microbes?
Inhibits or prevents growth.
The smoking process, curing agents and preservatives are all examples of which growth?
Additive
MAP and vacuum packaging are examples impacting which growth factor?
Oxygen
What is the function of enzymes?
Control all chemical reactions in living organisms.
Enzymes are often called catalysts. How do catalysts impact reactions?
Speed up reactions
Major portion of enzyme
Protein part
Minor portion of enzyme, responsible for activity
non-protein part
Coenzyme responsible for activity
usually vitamin
Cofactor responsible for activity in enzyme structure
usually mineral
Why did the gelatin dessert with the canned pineapple gel and the gelatin dessert with the fresh pineapple remain liquid?
Canned pineapple takes some of the acid away while the fresh still has everything in it causing the acid to not allow gelling.
2 desirable foods related to enzymatic browning reactions
tea, coffee
2 undesirable foods related to enzymatic browning reactions.
apple, bananna
how would you define tyrosinase oxidation of tyrosine in mushrooms?
undesirable but harmless
what type of non-enzymatic browning occurs when bread is cooked into toast?
Maillard Browning
Water soluble vitamins
B vitamins, Vitamin C
identify the fat soluble vitamins
Vitamin A,D,E,K
Define a pro vitamin
a substance that is converted into a vitamin w/in an organism.
example of a provitamin and the associated vitamin
B carrotene, vitamin A
Compounds used to fortify milk
Vitamin A,D
Vitamin D is essential in the absorbing of what compound?
Calcium
name the 2 vitamin deficiencies associated with early ocean travel.
Rickets-Vitamin D skeleton structure weakens
Scurvy-Vitamin C-connective tissue breaks down
Sunshine vitamin
Vitamin D
What compound is necessary for blood clotting?
Vitamin K and Calcium
Which compounds are associated with optimal immune health?
Zinc, Vitamin C, Viamin A, Iron
Proteins are _______ machinery of life.
active
What bond joins amino acids and what is produced when 2 amino acids join?
Peptide bonds, Protein Structure
Describe the primary (1 degree) structure of proteins.
Linear arrangement of Amino Acids
List 5 functions of protein in food
Form gels, texturize, emulsify, form foods, develop gluten
Differentiate between reversible and irreversible protein denaturalization including the impact on biological activity.
Reversible-contains all essential AA’s. Supports maintenance and growth, meat, poultry, and fish.
Incomplete-Lack certain AA’s-support only maintenance. Plants.
