120 terms

Food Science1120

Process and Storage of cereal
composition of legumes
protein, phytoestrogen
explain emulsion
droplets of milk dispersed in watery milk serum
composition of meat
protein, phosphorous, vitaB6, B12, zinc, Mg, thiamin, niacin, iron
composition of vegetables
carbs,fibre, minerals, vitamins, antioxidants
what causes anaemia?
iron deficiency
1 effect of anaemia
affects brain function
what causes goitre?
iodine deficiency
what is the affect of folic acid deficiency?
megaloblastic anaemia
what leads to xerophthalmia?
vitaA deficiency
list the three types of carbohydrates
monosaccharide, disaccharides, oligosaccahrides/ploysaccharides
list three types of monosaccharides
fructose, glucose, galactose
what is a glycosidic bond?
bond between 2 monosaccharides forming a disaccharide
list three types of disaccharides
sucrose, lactose, maltose
3 functions of carbs in food
sweetner, thickner, stabilizer
list two types of fiber and a source for each
soluable fiber: oatmeal
non-soluable fiber: whole wheat bread
what are polypeptides
polymers of amino acids
list structure of amino acid
amine group, acid group, carbon atom attached to H and R
what is a peptide bond? dipeptide
form amino acids; two or more amino acids joined together
3 functions of proteins in food
color, texture, flavour
3 functions of fats in food
caloric density, essential fatty acids, flakiness
2 reasons to add organic acids to food
tartness, lower pH to preserve food
5 reasons for process efficiency in microorganisms
1. identify species and strain
2. understand growth
3. correlate growth
4. correlate safety
5. link info to ensure quality
2 ways to classify organisms
1. classic
2. molecular
3 ways how MOs contaminate foods
soil, air,surfaces
4 nutrients MO need for growth
1. carbon source
2. nitrogen source
3. vitamins
4. minerals
3 phases of microbial growth curve
lag, stationary, and death
microbial growth in food can be beneficial (1) or detrimental (2) list ways
beneficial through fermentation
detrimental through quality and safety
5 factors affecting microbial growth
type of food, processing, storage, type of microorganism, interaction
4 impacts of MO on food properties
appearance, texture, odour, flavour
define spoilage
no longer acceptable to consumer
give an example of infection
define intoxication
food acts as a growth for organism and chemical created which is bad for consumer
3 factors contributing to outbreaks
1. food contaminated with pathogen
2. foods obtained from unsafe sources
3. inadequate processing
list 3 foodborne illnesses
gastroenteritis, abortion, cancer
list the pH for stomach acids and small intestines
2-3pH and 4-5pH
what is the main cause of pathogenicity
microbial toxins
what are exotoxins and how are they produced
proteins, produced by metabolic activity
what are endotoxins and how are they produced?
lipo-polysaccharides, released when the cell dies
3 mechanisms of foodborne illnesses
1. intoxication
2. non-invasive infection ex salmonella
3. invasive infection
difference b/w non-invasive and invasive infection
non-invasive grows in small intestine
invasive grows in cells
what are factors to infective dosage
# of organisms to produce exotoxin and enable colonization
list 3 reasons to ferment food
preservation, safety, increased benefits
list 3 roles of bacteria
flavour, texture, nutritional enrichment
list 4 complex microbial associations
list 4 things preservation protects
physical damage, chemical reactions, microbial activity, contamination
list 6 ways to control growth of microorganisms
time, temperature, moisture, pH, addition of preservatives, limiting oxygen
list the normal fridge and freezing temperature
4degrees and -12degrees
list one way adding preservatives helps
to reduce browning
the most effective way to control growth of MOs
combination, 'hurdle technology'
define commercially sterile
heating all the MOs that can multiply until they are killed
2 ways to reach commercial sterilization
canning or UHT treatment
6 steps in canning
prepare ingredients,fill container, seal, heat process, cool, label
UHT plus aseptic packaging steps -4
sterilize by heating, sterilize packaging, fill under aseptic conditions, seal
list four types of filtration and which packaging style utilizes it
micro, ultra, nano and reverse osmosis
aseptic packaging
list 2 types of chemical reactions
enzyme catalyzed, non-enzymic
how can enzymes be denatured
heat, chemicals
how can enzyme reaction be retarded
refrigeration, freezing, blanching
list 5 types of physical damage
breakage, package puncture, moisture uptake, insect damage, rodent damage
define contamination
something that should not be in the food, may not be harmful
list 5 types of contamination
dirt, broken glass, metal, taints, adulteration
list 3 freezing processes
refrigerated surface, cold air, cryogenic `
why should freezing be quick
cuz slow freezing allows for bigger crystals to form and allows dehydration
list 2 things about freezer burn
causes off flavour, woody appearance
freezing is the combination of what two things
reduced temperature
removal of water as ice
list the steps in freezing peas
harvest, quality check, washed, blanched, chilled, tested, de-watered, quick freeze, packed, distributed
difference between wet food and dry food
wet food: MOs grow, enzyme reactions
dry food: MOs dont grow, chemical reactions
what are the two categories of water chemistry?
dilute solutions- water activity
concentrated solutions- molecular mobility
which is the strongest interaction of water bonds?
dipole ion, dipole dipole, hydrophobic hydration
define Relative Vapour Pressure
the vapour pressure of a solution relative to vapour pressure of pure water
define water activity
RVP, approximately equal to RVP,
why is water content unhelpful to determine microbial growth?
cuz microbes respond to availability not amount
what is the effect on water activity and water content after an increase in temperature?
water activity increased, water content same
what is the result of moisture migration in frozen foods?
in-package dessication
list 4 things water activity depends on
water content, food composition, previous treatment, temperature
define molecular mobility
useful where moisture is low, little or no mobility when frozen since there is high micro-viscosity
explain glassy state
low water content, low temperature, high concentration of solids
explain rubber
if at the glassy state, temperature is raised or water removed
where did the food industry come from? 3 things
early man, society, civilization
what are the 4 big discoveries
tools, wheel, agriculture, fire
list 2 effects of cultivation
settlement, specie modification
3 aspects of the agricultural revolution of the 70s
fertilisation, hybridisation, irrigation
challenges to food industry -2
adulteration, food poisoning
list 2 characters of canned food
no MO growth, commercially sterile
4 steps of canning process
container, hermetically sealed, heat processed, cans cooled and labeled
canning achieves to destroy what 3 things
vegetative cells, spores, and enzymes
#1 concern in canning
clostridium botulinum
acid food vs low acid foods
acid= pH<4.5 mild treatment needed
low acid= pH>4.5 must destroy spores
3 containers for canned food
tinplate cans, glass jars, flexible pouches
3 advantages to flexible packaging
less waste, less weight, rapid heating
does canned food have preservatives?
no preservatives allowed
list the canning process- 10 steps
1. inspection
2. food preparation
3. blanching
4. filling
5. exhausting
6. sealing
7. heat processing
8. cooling
9. incubation and quality control checks
10. labeling and dispatch
list 4 methods of blanching
steam, hot water, microwaves, hot gasses
list 3 things blanching does to the food
expels gases, shrink products
list 3 methods of exhausting
1. heat
2. steam
3. mechanical
list 2 things exhausting does
1. removes oxygen
2. removes gas from headspace
what machine is used for heat processing
what temp must the product be cooled to
list 3 methods of heat transfer
convection, conduction, radiation
list 3 factors of heat rate penetration
nature of food, packaging, # and arrangement of cans
T/F : properly canned foods do not undergo spoilage unless maltreated
underprocessed cans lead to ...
thermophilic sporing ogranisms
not-processed canning leads to...
massive contamination
cooling water leakage into can leads to...
one/few types of vegetable MOs
what facilitates tinplate corrosion -5
oxygen, nitrates, nitrites, acids, sulphur
list 2 types of retorts in heat processing
batch and continuous
does aseptic processing produce a commercially sterile product?
3 steps of aseptic processing
1. product is heat treated
2. package is sterilized
3. aseptic filling and sealing
T/F aseptic packaging is used for solids and liquids?
FALSE just liquids or suspensions
T/F final aseptic product does not require refrigeration
list three things food additives are used for
improve taste, improve shelf life, maintain acidity
define acceptable daily intake
the amount of a food additive that can eb eaten every day for an entire lifetime with no adverse effect
list 3 things FSANZ does
protect health
provision of info
promotes fair trading
cooling saturated solutions causes crystallization or makes ----- solutions
3 functions of protein in the body
amino for tissue, forms enzymes, supporting roles in development
difference b/w food deterioration and food spoilage
food spoilage: undesirable consequence of chemical biological or physical action
food deterioration: change in composition or process becoming undesirable
what are the major groups of nutrients microorganisms need for geowth?
vitamins and minerals
4 areas which MOs can affect food supply
food safety, fermented foods, probiotic benefits, contamination
how did the green revolution affect production capacity
new technology and processes
list 5 factors to retard microbial growth
time, temp pH, oxygen, moisture