Lecture 1: Introduction Flashcards by Fiona Kao

What is the primary objective of food processing?

preservation

How well did you know this?

Not at all

Perfectly

What are two main objectives of preservation?

prevent undesirable changes (maintain wholesomeness, nutritive value, sensory qualities)
control activities (chemical, biochemical, physiological, microbiological)

How well did you know this?

Not at all

Perfectly

What are other objectives of food processing besides preservation?

product diversification
value addition
convenience foods
marketing needs
ingredients isolation and synthesis
non-conventional foods

How well did you know this?

Not at all

Perfectly

what are fundamental unit operations of intermediate moisture foods?

heating
cooling
drying
mixing
blending

How well did you know this?

Not at all

Perfectly

what is considered primary processing?

and secondary processing?

primary: harvest/slaughter and post harvest processing
secondary: maufacturing of processing food products

How well did you know this?

Not at all

Perfectly

what technologies are involved in primary processing and secondary processing?

primary: post harvest storage technology and handling
secondary: food processing technologies

How well did you know this?

Not at all

Perfectly

what are food processing methods that use addition of heat?

pasteurization and sterilization

How well did you know this?

Not at all

Perfectly

what are food processing methods that use removal of heat

refridgeration and freezing

How well did you know this?

Not at all

Perfectly

what are food processing methods that use high pressure and pulse electric field

non thermal technologies

How well did you know this?

Not at all

Perfectly

what are food processing methods that use radiation and heat?

IR
MW
RF

How well did you know this?

Not at all

Perfectly

what are food processing methods that use radiation without heat generation?

irradiation

How well did you know this?

Not at all

Perfectly

what are food processing methods that use control of environment

CA/MA storage and packaging (controls respiration rate to extend shelf life)

How well did you know this?

Not at all

Perfectly

what are food processing methods that use removal of liquid water

evaporation
concentration
membrane

How well did you know this?

Not at all

Perfectly

what are food processing methods that use concentration by extraction

SCFE: super critical fluid extraction

How well did you know this?

Not at all

Perfectly

describe SCFE

uses CO2 to bring food into a super critical state, where it will act like a liquid which is more powerful than gas in heat processing

How well did you know this?

Not at all

Perfectly

what are food processing methods that use separation of constituents?

extraction

How well did you know this?

Not at all

Perfectly

what are food processing methods that use composition control

dissolved oxygen
fermentation
salting
smoking

How well did you know this?

Not at all

Perfectly

what are food processing methods that use preparation

washing
grinding
mixing

How well did you know this?

Not at all

Perfectly

what are the 3 most widely used commercial processes of food preservation?

thermal processing
freezing
dehydration

How well did you know this?

Not at all

Perfectly

what are fundamental dimensions?

dimensions used to characterize a physical quantity under consideration

How well did you know this?

Not at all

Perfectly

what are the two types of fundamental dimensions?

absolute: mass, length, time, temp

2. gravitational systems: mass, length, time, temp, force

How well did you know this?

Not at all

Perfectly

what is a unit used to determine?

magnitude or size of a dimension

How well did you know this?

Not at all

Perfectly

what are 2 types of units?

base units: dimensionally independent and used for one dimension (eg. mass and time)
derived units: used for combinations of various dimensions (eg. velocity and flow rate)

what is the metric system designated with?

c g s system

``` what are the metric units for: length mass time temperature force ```

``` length = cm mass = g time = s temp = celcius or kelvin force = dyne ```

what are the british units?

lb, ft, hr, farenheit, poundal used in US

what is the MKS system

derived from the CGS system

what does SI stand for? What is it?

system international a revised version of MKS system m, kg, s, celcius or kelvin, newton

what are the units of force in metric and in SI?

metric: dyne SI: newton

what is the conversion of Fdegrees to C degrees?

C deg = (F-32) x 5/9

what is the conversion of C to Kelvin?

K = C + 273

what is the conversion of F to R?

R = F + 460

100C is ____ F?

180

what are the units of density?

M/L^3 or kg/m^3

what is the equation of work (energy)? what unit is work in?

F x distance unit: joule

what is one joule?

work done by 1N force resulting in a displacement of 1m or one joule required to raise the temperature of 1kg of water by 1degC

equation of potential and kinetic energy?

potential: m*g*h kinetic: M*v^2 / 2

what is sensible heat?

Qs = energy that results in a change in temperature Q = m*Cp* (T2-T1)

what is latent heat

energy that results in a change of state at constant temp Q = m * lambda

what is the latent heat of ice?

heat required to melt 1kg of ice or freeze 1kg of water at 0degC

what is the latent heat of steam?

heat required to boil 1kg of water or condense 1kg of steam at 100degC

what is heat capacity?

Cp = heat required to change the temperature of au nit mass by a unit of temperature difference Q = m * Cp * delta t

what is the unit of heat capacity?

Kg/Kg - C BTU/lb - F cal/g - C

what is specific heat? what is the unit?

ratio of heat capacity of the substance to that of water no unit because it is a ratio

what is power? what are the units?

P = rate of producing energy units: J/s or W or BTU/h

what is thermal conductivity (k)? what are the units? what is the equation?

quantity of heat a given material of unit area of cross section can transfer under a unit temperature gradient in the direction of heat flow units: W/m*C BTU/hr*ft*F cal/s*cm*C Q = (k*A*delta t)/x

what is the heat transfer coefficient of convection heat transfer? what are the units? what is the equation?

the quantity of heat transferred across an unit surface area to a fluid when a unit temperature gradient exists between the surface and the fluid unit: Q/m^2 * C equation: Q = h * A * delta t

a higher heat transfer coefficient means a ____ heat transfer (better or worse?)

better

what is thermal diffusivity? what does it describe?

ratio of the thermal conductivity divided by the specific heat and the density it describes the ability of a material to respond to changes in temperature

what is the equation of thermal diffusivity? what is this the ratio of?

alpha = k / p * Cp ratio of heat conducted to heat absorbed

what is absolute pressure? equation and units?

force per unit area P = F/A units: N/m^2 or Pa (pascal) or psia

what is gauge pressure? equation and units?

apparent pressure above the atmospheric pressure (aka the difference between absolute and atm pressure) units: Pa(g) or psig equation: gauge pressure = absolute pressure - atmospheric pressure

what is vacuum pressure

the pressure below the atmospheric pressure and measured on a vacuum gauge vacuum = atmospheric pressure - absolute pressure

how much is atmospheric pressure usually?

101.3kPa or 760 mmHg

what's the difference with precision and accuracy?

accuracy: how close the measured value is to the real value precision: how reproducible your experimental values are (implies how many significant digits there are)

are the zeroes significant in: 1. 100056 2. 2.300 3. 23000 4. 0.00056

1. yes 2. yes 3. yes 4. no