Unit 10 Flashcards
A moisture sorption isotherm is a graph that plots the change in water
content of a food sample against …… (acronym, two capital letters)
RH
Reduction of …… enhances the efficacy of the drying process due to
the reduction of the boiling point of water
Pressure
…… is the process of soaking food in a sodium
bisulfite and water
solution for 10 to 30 minutes (one word, first capital letter)
Sulfiting
What affects the perception of the product by the client
Quality
What is food quality
the product meets (or exceeds) the
expectations of the consumer
Difference between QC and QA
Quality control (QC) involves testing (representative samples) of the
finished product to determine whether they meet the specifications
that have been set for the product.
Quality assurance (QA) involves taking measures to ensure that the
processing steps are properly performed, which should ensure that the
finished products are of consistent quality
As mentioned at the beginning of this section, QC involves testing
(representative samples) of the finished product to determine whether
they meet the specifications that have been set for the product.
QA involves taking measures to ensure that the processing steps (unit
operations) are properly performed, which should ensure that the
finished products are of consistent quality.
Plant sanitation.
Microbiological quality
Testing of the finished product to determine whether they meet
the specifications that have been set for the product
a.
Quality assurance
b.
Quality control
B
Two quality characteristics
Sensory quality characteristics
Hidden quality characteristics
Sensory characteristics can be divided into what categorizes
appearance attributes textural attributes flavor attributes
The consumer s initial perception of the quality of a product is largely
based on appearance attributes such as:
Color: often an indicator of ripeness, spoilage, or storage history
Size/shape: e.g., fruits & vegetables
Wholeness: e.g., cookies, nuts
Degree of damage: e.g., bruising of bananas
Consistency (visual perception of thickness): e.g., ketchup
Gloss: e.g., apples
Fat crystallization on the surface of the chocolate is called
Fat bloom
QC Measurement of Color
Human eye (comparison to colored tiles) A spectrophotometer (transparent liquids) A tristimulus colorimeter
What is a standard plate
QC generally uses color difference measurements to make color
measurements more sensitive.
For example, a standard plate is made to represent the desired color
of the product.
We sense texture by
We sense by touch, tongue, palate, and teeth.
What texture we expect from liquids and pastes
Viscous (thick): e.g., tomato ketchup Non viscous (thin): e.g., water Smooth consistency: e.g., mayonnaise, yogurt Creamy: e.g., margarine, icing
What texture is expected for solids
Crisp: e.g., lettuce, chips Chewy: e.g., granola bars Crunchy: e.g., chips Soggy: e.g., crackers
What is rheology
Rheology: the study of the deformation and flow of matter.
What instruments are used to objectively measure fluidity of products
A Bostwick consistometer measures the time it takes for a viscous fluid
product (e.g., ketchup, syrup) to flow down an inclined plane.
Numerical measurements of viscosity can be made using various types of
viscometers
What is the equipment to measure texture of solid and semi-solid products
Measuring texture is more complex than measuring viscosity.
It is based on measuring the force required for deformation of a
material.
Common forces include compression (squeezing), shear (cutting),
and tension (pulling) or combinations thereof (chewing).
What is universal testing machine
These instruments come with a wide variety of accessories: cutting
devices, pulling devices, and plungers to mimic forces imposed on food
products.
Examples how texture and viscosity can change
Meat becomes more tender with aging.
Starches gelatinize with heat/moisture.
Bread firms/stales over time (starch retrogradation).
Crackers become soggy with exposure to humid conditions.
Some instruments do exist that can objectively measure some flavor related
parameters:
Gas chromatography (measures volatile compounds associated with
Conductivity measurements (salt concentration)
pH meters (acidity)
Refractometers (sugar concentration)
Do we still need to do taste panels
However, no instrument has replaced humans as of yet, so taste panels
are commonly used to measure flavor as well as other quality
attributes of foods: sensory evaluation
Sensory evaluation is carried out routinely in most food companies for
QC purposes or to compare products against those of competitors.
What are Non
sensory (Hidden) Quality Attributes
For example, nutritional value has recently become much more
prominent in consumers ’ perception of quality.
What is done to determine best before date
Accelerated storage trials
What is included in materials handling section
Harvesting
Transport of agricultural/animal products to the processing plant
Pneumatic conveying of powders (e.g., milled flour, refined sugar) from
trucks/railroad cars to storage bins, etc.
Materials handling also include all types of in plant conveying of
materials, including pumping of liquids.
What should be fulfilled during materials handling section
sanitary
conditions, minimize losses of raw materials and maintain their quality,
and minimize microbial growth.
As an example, liquid nitrogen is used to cool fruits and vegetables at
harvest and during transport to reduce their rate of respiration.
What are should be done with pumps
Materials handling also include all types of in plant conveying of
materials, including pumping of liquids.
What is included in cleaning-related operations
All raw materials tend to be contaminated to some degree and require some type of
cleaning operation.
Cleaning operations range from purification of water for soft drinks to evisceration
(gutting) of animals
Cleaning related operations also include regular cleaning of processing equipment :
sophisticated clean in place (CIP) systems exist for automated liquid processing equipment
while many other types of equipment have to be completely disassembled.
Removal of mud from oysters
Removal of metal fragments from bulk grain (using a magnetic metal separator)
These are examples of what stage in production
Cleaning-related
What is done during separation-related operations (solid from solid, liquid from liquid, solid from liquid, liquid from solid
Solid from solid Peeling of potatoes: one of the most important steps in potato processing Shelling of nuts Liquid from liquid Separating cream from milk: centrifugation (fat has lower density than the aqueous phase)
Solid from liquid Separation of whey proteins from whey Liquid from solid Pressing juice from fruit Separating whey from curd (cheese production)
What is disintegration-related operations
These operations involve a reduction in size , e.g.: Slicing of potatoes for potato chips Grinding of meat Milling of wheat to produce flour Homogenization of milk (reduction in size of fat globules) Filleting of fish
Example of mixing-related operations with solid-solid
: Mixing of dry ingredients
e.g., ribbon blending of spices/soup mix
Example of mixing-related operations with solid-liquid
, e.g., sugar/water
All sorts of paddles and propeller designs are used.
Example of mixing-related operations with liquid-liquid
: e.g., oil/water (to produce
High pressure homogenizers are used.
Example of mixing-related operations with gas-solid
: e.g., incorporate air into ice cream
Various types of mixers and beaters are used.
Centrifugation of milk separates fat from the aqueous phase
due to difference in …… (one word, small letters)
Density
What operations involve in heat-exchange related operations
Cooling
Heating
Types of equipment that can be used for both types of heat exchange
Plate heat exchangers
Tubular scraped surface heat exchangers
Cooling processes encompass ___ and ___ and is done for
Cooling processes encompass refrigeration and freezing and most
often have the primary purpose of extending shelf life (not always the
case; e.g., ice cream).
