Lecture 2: Food Chemistry Flashcards
What is a Proxumate Analysis of food?
The chemical constituents in food.
True or False:
Food Products are mostly made up from biological origin.
True.
What is food?
Food is a chemical mixture of carbohydrates, protiens, water, fats and miscellanenous atoms
What are the some of the most common elements found in food?
C
H
N
O
What are the five major categories of distinctly different chemical compounds described in food composition (Proximate composition)
- lipids
- Carbohydrates
- Proteins
- Water
- Minerals/Ash
What is the unit used to express Proximate composition.
% of whole.
What is important about Proximate composition?
- It helps us know the storage or shelf life if a food item
- conform to legal definitions of foods
- Directs processing parameters
- Determine energy value of foods
(Caloric content)
Why do use a “dry-weight basis”
This is due to the fact that water has no nutritional value, they take it out to only look at the primary components.
Once you take out the mostuire, what will happen to the weight of the rest of the percentages?
They will increase.
What are Carbohydrates?
Hydrates of Carbon
Acting as the main energy source of energy for animals and humans.
How do you classify Carbohydrates?
Classified according to the number and type of molecules contained
What are Monosacchrides?
Pentoses (5C) and Hexoses (6C)
- Glucose, Fructose, Glactose.
What are Disaccharides?
Two monosaccharides linked
- Sucrose
- Lactose
- Maltose
What are the two components of Sucrose?
Glucose + Fructose
What are the two components of lactose?
Glucose + Galactose
What are the two components of Maltose?
Glucose + Glucose
What is the function of Sugar in foods?
- Provides Sweetness & enhances flavor
- Crystallization leads to characteristic products
- provides body and mouth feel (Viscosity)
- Attracts and holds water (Hygroscopic)
- Preservation effect at high levels
What is the process of Caramelization?
Sugar decomposition at high temperatures creates brown polymers
What is the Maillard reaction?
Reducing sugar & A.A react with heat.
Creates brown pigment Polymers.
What are Oligosaccharides?
A combination of more than two disaccharides
What are Polysaccharides?
A large chain of oligosaccharides such as starch, cellulose, pectin, some hydrocolloids.
What are the 6 main reasons why you would add complex carboydrates are added to food?
- Increase dietary fiber content (nutrition)
- Thickens food
- form gels
- Bind water
- Stabilize proteins
- Serve as Prebiotics
What is Starch?
A polysaccharide with Long chains of glucose units linked together (500 to >100,000)
What is Amylose?
A Starch with linear chains (Gel formation)
What is Amylopectin?
A Starch with branched chains (viscosity)
True or false:
Starch is involved in Gelatinization and retrigradation
True
What is Cellulose?
- Major Component of plant cell walls
- It is a Polysaccharide
- Long chains of Glucose molecules linked together with 1-4 linkages
What is Pectin?
- Functions as an intercellular cement and provides texture o fruits and tubers.
What are Gums?
Agar
True or false:
- Carbohydrates cannot be digested by humans, and are only used as dietary fibers
True.
What is high fructose Corn Syrup?
Derived from corn starch
- Varies fructose contents are used by the food industry (soft drinks, pasta sause)
What is another name for High Fructose Corn Syrup?
Glucose-Fructose
What are the Building blocks of Proteins?
Amino Acids
How many Amino Acids are there?
There are 20 different ones.
What is it called when you break down proteins?
Hydrolyzation
What are the major things that change the properties of Proteins in foods
- pH
- Heat
Just small changes in there two things can cause MAJOR and dramatic changes in the protein molecules.
What are the four types of structures in proteins?
- Primary
- Secondary
- Tertiary
- Quaternary
What are the functions of proteins in food?
- Emulsifiers and foaming agents: Amphiphilic properties (polar and non-polar)
What is a Protein Emulsifier?
Egg yolk protiens & casein in milk
What is a protien foaming agents?
Egg whites
What is the function of Texture with proteins in food?
- thickening agents
- binding agents
- gelling agents
What is the flavor additive of proteins?
- Specific amino acids can contribute to food flavor.
What is the isoelectric point?
The pH at which there is not net change on proteins
What happens to proteins when they are isoelectric point?
Proteins percipiate at their isoelectric point.
