NDFS 250 exam 1

• Food Science is
• the multidisciplinary study of food Disciplines such as chemistry, microbiology and engineering are used to study the nature of food.

Engineering, Chemistry, Microbiology, Law, Statistics, Nutrition, Physics, horticulture and animal science 

Appearance  

Odor  

Taste  

Texture  

Nutrition

Safety

Discipline used to evoke, measure, analyze and interpret responses that are perceived by sight, smell, taste, touch, and hearing.

Tests that do not rely mainly on human senses.

Attribute ideality (Just About Right or JAR)

• Consumer panelists are asked to focus on
• a single attribute and determine if is at an
• appropriate level

• Are
• the samples the same or different?

• Select the sample that matches the reference. 

• Select the odd/different sample

science dealing with the deformation and flow of matter

• Viscosity
• resistance to flow.

Elasticity

Stability to recover size and shape after deformation.

Elasticity

• Plasticity
• to retain a shape attained by deformation

• TA-XT2
• Texture Analyzer

measures viscosity of fluids

• Consistometer measures the distance a given volume of
• product flows during a specified time.

The heat needed to cause a change of state in water.  ( ice --> water 80 cal and water -->steam 540 cal.)

No change in temperature

•Ions or small molecules

• •< 1nm in diameter
• •Very stable

•Transparent

• •Usually can not form
• gels

•Macromolecules or small groups of molecules

•Usually 1-100 nm in diameter

• •Visible under electron
• microscope

•Moderately stable

•Translucent or opaque

•Form gels

•Large groups of molecules

•> 100 nm

• •Visible under light
• microscope

• •Do not pass through
• filters

• •Unstable; i.e., settle
• out

•Opaque

•Can not form gels

Dispersed phase solid

continuous phase liquid

• Dispersed phase liquid
• continuous phase liquid

• Dispersed phase gas
• continuous phase liquid

• Dispersed phase gas
• continuous phase solid

• Dispersed phase liquid
• continuous phase solid

calcium and magnesium ions

Change in temperature produced by heat

Can be measured with a thermometer

Absorbs heat.

Example: Melting ice

Releases heat.

Example: Freezing water

•Concentration (moles) of solute per kg of solvent

•Concentration (moles) of solute per liter of solution

• Properties that depend upon the number of molecules
• present, not upon their nature or size.

• Examples:
•    Vapor pressure
•    Boiling point
• Freezing point
• Osmotic pressure

Boiling point of that solution is raised 0.52 ºC

Freezing point is lowered 1.86 ºC

elevation/960

• One means of determining microbial
• stability of food

• Related to the rate of some
• chemical reactions in food, e.g., vitamin loss, lipid oxidation, browning

• State in which amorphous material is so viscous that it does not flow under its own
• weight and molecules are practically immobile

Physically hard, brittle and able to shatter…like a glass window

The temperature at which a substance changes from a rubbery state to a glassy state (or vice versa)

Related to stability of some foods, especially dry foods and frozen foods.

The non-polar tail is attracted to the oil (discontinuous phase) and the polar head is attracted to the water (continuous phase).

D-Glucose

• The carbon which becomes assymetric when the open-chain structure closes to form the ring structure

Fructose

Galactose

Sucrose

Maltose

Lactose

Equimolar mixture of D-glucose and D-fructose   formed by hydrolysis of sucrose

It is the product when acid is added to a sucrose ans water mixture and heated

it can be commercially produced without bees

The term "invert" refers to change in sign + to - on the degrees of rotation of plane polarized light.

Invert sugar has a lower water activity than that of sucrose, so it provides more powerful preserving qualities (a longer shelf life) to products that use it.

• A carbohydrate that can reduce Fehlings
• Reagent or Benedicts Reagent

• Most simple sugars are reducing
• sugars, except sucrose

maillard browning - typically a reaction between a reducing sugar and an amino group

F,S,G,M,G,L

Amylose

Amylopectin

Cellulose

Pectin

Carbohydrates (and lignin) that cannot be broken down by human digestive enzymes

Complex polysaccharides that typically impart high viscosity at low concentrations.

• Food uses of vegetable gums
• Inhibit crystallization

Whipping aid

Foam and emulsion stabilizer

Adhesive and binding agent

Coating agent

Prevent gel breakdown (syneresis)

Suspend solids

Flavor carrier

Fat replacer

Measures concentration of solutes in the syrup. 

Advantage: objective

Disadvantage: must take into account the presence of other substances and altitude

Measures consistency of the syrup

Advantage: takes into account all variables

Presence of substances other than sucrose

Altitude, barometric pressure

Disadvantage:  subjective

Substance in which molecules fit together into a regular  geometric arrangement (crystal lattice).

Substance in which molecules have aggregated in a random, disordered fashion.

• Darn Boys Came Cause Kiss
• 1.Dissolve sucrose in water, then
• heat  (Solution is unsaturated)

• 2.   Boil  (112 -115°C) away excess water  (Inversion occurs; solution is near
• saturation)

• 3.  Cool
• to 40ºC (it becomes supersaturated)

• 4.  Crystallize
• by continuous, rapid beating until kneadable

5.   Knead  (it becomes less glossy and lighter in color)

• 1. Combine
• corn syrup,  sugar and water, and heat to
• 118ºC.

2.  Add evaporated milk slowly.

• uInterfering
• compounds prevent crystallization

• 1.Caramelization   (CHO  +  dry
• heat --> Ascorbic acid

• 2.
• Maillard Reaction  C=O + NH2 -->Ascorbic acid

(or French ice cream)

Contains eggs

Animal or vegetable fat

No dairy ingredients

• Brain power helps pasteurization so serve
• and help

Emulsifier/milk fat - (suspension, if homogenized-colloidal)

Collodial

Foam

collodial

true solution

colloidal or suspension

• Overrun (%): a measure of the
• amount of air incorporated (by volume or by weight)

Browning

Thering opens up the aldehyde is available and it will react

React=browning 

• Cooling the ice cream mix a minimum of four hours
• Mix becomes more viscous and whipping quality improves

Ingredients

• Agitation
• Freezing rate - The faster the freezing rate, the
• greater the number and the smaller the size of ice crystals

Temperature fluctuations

Carboxylic acid

Ascorbic Acid

Carbonic

Lactic Acid

Phosphoric Acid

Have at least one H+ that does not completely ionize

Examples:  most food acids

Have at least one H+ that completely ionizes

Examples:  hydrochloric, nitric, phosphoric, sulfuric

measure of Ionized or free H+ at a given time

• Measured electronically (pH meter) or by color change (e.g.,
• litmus paper)

Measures both ionized H+ and nonionized H+; total H+ available for donation in free and bound state

Measured by titration with a base, e.g., NaOH to colorimetric endpoint

Developed from one ovary in one flower

• simple fruit containing a core plus seeds
• Apple, Pear

• simple fruit containing a stone or pit
• enclosing a seed

• Cherry
• Plum
• Peach

Fleshy fruit developed from several ovaries in one flower

Raspberries    Strawberries    Blackberries

Developed from a cluster of several flowers

Pineapple      Figs

Contains cellulose, hemicellulose, lignin and pectic substances

• Contains water soluble compounds,
• including water soluble pigments

• The protoplasm of a cell, excluding
• the nucleus

• Contains plastids, mitochondria,
• and water soluble compounds, e.g., salts, sugars

uDifferent types contain fat soluble pigments (chloroplasts, chromoplasts), starch (amyloplasts) and oils (elioplasts) 

• A thin layer of viscous
• intercellular material that “cements” cells together

• Composed of pectic
• substances, calcium, cellulose, and other polymers

Primary structural component in cell walls of plants.  Linear polymers of glucose with thousands of subunits. Does not soften when heated, even in acid.

Branched polymers of xylose and glucose with minor amounts of other compounds

Softens when heated in acidic or basic solution

Polymers of galacturonic acid and its esters

Binds with hemicellulose and cellulose to form a fibrous network for structural support of plant tissues

Softens during ripening and on heating

Protopectin    to        pectin  to        pectic acid

Polymers containing benzene derivatives

Does not soften even when heated; contributes woody characteristics to plants

Woody, fibrous material in mature broccoli and asparagus stems is lignin

Color:  chlorophyll decreases, other pigments predominate

Texture:  softens

Acidity:  decreases , pH goes up slightly

Pectic substances:  remain constant – pectin decreases and pectic acid increases

Flavor/Aroma:  flavor volatiles increase

Form of carbohydrate: starch decreases and sugars increase

Polyphenols + O_{2 -phenolase> Quinones -polymerization> Brown pigments}

Avoid oxygen

Add salt

Keep product cool

Alter pH


Blanch


Add reducing agent

• lettuce, cabbage, brussel
• sprouts, chard, kale

peas, beans, corn

carrots, rutabaga, sweet potato

Short thickened fleshy part of an underground stem

onion, garlic, leek

• broccoli, cauliflower, globe
• artichoke

cucumber, okra, tomato, squash, egg plant, green beans, zucchini

asparagus, celery

• formation of garlic odor
• onion tears

Limit to 1/8 teaspoon/cup of legume

Too much soda causes dark color, mushy texture and increases thiamin loss

tomatoes, watermelon

berries