Introduction Flashcards
The primary goal of food processing is:
preservation
differentiate primary and secondary processing:
primary: post harvest/slaughter processing, focus on maintenence of fresh tissue
secondary: turning fresh into processed foods, focus on long term preservation
What are the fundamental unit operations of food processing? (5)
heating, cooling, mixing, drying, blending
What are some other objectives of food processing? (6)
Product diversification Value addition Convenience food marketing needs Ingredient isolation/synthesis non-conventional foods
What are the fundamental dimensions? (2 systems, list for each)
absolute: mass, length, time, temp
gravitational: mass, length, time, temp, FORCE
List the classifications of technologies for food processing:
heat removal/addition
non thermal (high pressure, pulse electric field)
irradiation (with or without heat generation)
environment control (MA, CA)
water removal
extraction (for concentration or separation)
composition control
preservatives
preparatory
what system of measurement is widely used in the industry today? What was it based on?
SI (Revised MKS)
metric
What are the two types of measurement units?
base, derived
How do the concepts of weight and mass differ?
weight: combination of gravity and mass (force exerted)
mass: amount of matter in the body
Velocity is a ____ unit, expressed as ____.
derived; distance per unit time
How are base and derived units different?
base: describes a single dimension (mass, length, etc)
derived: combination of dimensions (velocity, flow rate, etc)
True/False: the unit for time for imperial and metric systems is the same.
False: metric is (s), imperial is (hr)
lbs, F, inches, and poundals are units from the _____ system. Where are they used?
British/imperial
US
What is 0C in F?
32F
What is the unit for specific gravity? What is this a measurement of?
no unit
density
What is the conversion from C to F?
C *(9/5) +32
All energy is measured in:
Joules
What is “Cp?” What is the unit?
heat capacity - how much HEAT is needed to raise UNIT MASS by UNIT TEMPERATURE
kJ/(kg*C)
What is thermal conductivity?
quantity of heat that can be transferred by a given material of unit area cross section under unit temperature gradient in the direction of heat flow
Power is ____ and measured in:
Rate of producing energy; watts (J/s)
How do you determine specific heat? What are the units?
ratio of substance Cp to Cp of water
no unit
The unit of “k” is:
W/(min*C)
What is the heat transfer coefficient?
quantity of heat transferred between surface and fluid, when there is a unit temperature difference between the two
(h)
What does thermal diffusivity describe, and how is it calculated?
ability of material to respond to changes in temp
k/(specific heat x density)
