part 3a

Question 1

what are major classes of food additives?

Answer 1

preservatives/antimicrobial agents, antioxidants, flavouring agents, flavour enhancers, sweeteners, emulsifiers, fat replacers, colouring agents, misc.

Question 2

examples of misc?

Answer 2

phosphates, polysacc, bleaching/dough conditioners, glazing/polishing agents

Question 3

what are preservatives/antimicrobial agents?

Answer 3

function to preserve food products from detrimental effects of microorg

Question 4

consumers expect food:

Answer 4

available year round, free of pathogens, long shelf life, consistent

Question 5

most foodborne illness come from ___ food

Answer 5

unprocessed

Question 6

examples of natural antimicrobial agents for food preservation:

Answer 6

polypeptides (bacteriocins), proteins/enzymes, polysacc, lipids (dha)

Question 7

prob of natural antimicrobial?

Answer 7

expensive and lipophilic

Question 8

what are factors influencing selection of antimicrobial agent?

Answer 8

1) knowledge of microbiological variety (bioburden) 2) chem and phys properties of antimicrobial comp and food must be known 3) processing/packaging/storage 4) safety and legality of antimicrobial must be known 5) follow GMP

Question 9

antimicrobials incorporated into interior packaging not required on ingredients list in Canada, why?

Answer 9

minimal leakage

Question 10

benzoic acid/sodium benzoate naturally present in:

Answer 10

berries, fruits/veg, spices

Question 11

is comp or salt more soluble?

Answer 11

salt

Question 12

where else is sodium benzoate found?

Answer 12

naturally in rain by pollution, groundwater by animal excretion

Question 13

how is benzoic acid produced?

Answer 13

oxidation of toluene

Question 14

benzoate can cause allergy:

Answer 14

orofacial granulomatosis (disfigured lip swelling, gingivae)

Question 15

benzoate is ___ agent

Answer 15

antimycotic (against yeasts and moulds lvls 0.05-0.1%)

Question 16

____ form of benzoic acid has antimicrobial activity

Answer 16

undissociated

Question 17

mech of action for benzoic acid?

Answer 17

not known really, disrupt major energy production system of org

Question 18

want pka > or < ph?

Answer 18

>

Question 19

benzoic used in

Answer 19

bev, jam, margarine, baking, condiments, pharmaceuticals, cosmetics

Question 20

what is ld50?

Answer 20

will kill 50% pop

Question 21

how does enzymatic conjugation work?

Answer 21

benzoic acid with l-glycine makes comp more acidic so anionic, more H bounding site, more water sol.

Question 22

what are sorbates/

Answer 22

calcium, potassium, sodium salts of sorbic acid

Question 23

where sorbates/

Answer 23

rowanberry fruit, other berries in low lvl

Question 24

how sorbate made/

Answer 24

rxn crotonaldehyde and ketene

Question 25

sorbic acid is ___ agent, significant activity against _____

Answer 25

antimycotic; clostridium botulinum (gram -)

Question 26

___ form of sorbic acid is only form has antimicrobial activity

Answer 26

undissociated

Question 27

sorbic acid mech of action

Answer 27

sulfhydryl enzyme inhibitor (protease), lipophilc comp interfere w/ chem transport across cyto mem

Question 28

food uses of sorbic acid?

Answer 28

lots, plus packaging and cured meats as nitrite replacement, salads, choc syrup, wine

Question 29

which is more toxic--sodium benzoate or sorbates?

Answer 29

benzoates

Question 30

organic acids present naturally almost all fruits and veg

Answer 30

short chain fatty acids

Question 31

acetic acid found in:

Answer 31

figs, bananas

Question 32

fumaric acid from :

Answer 32

mushrooms, carrots

Question 33

SCFA produced via:

Answer 33

fermentation

Question 34

___ form of SCFA mainly responsible for antimicrobial activity

Answer 34

undissociated

Question 35

SCFA are ____ so have ability lower pH OF FOOD TO INHIBIT microbe growth

Answer 35

weak acids

Question 36

acetic acid active against ___, moderate against ___

Answer 36

yeasts/bacteria; moulds

Question 37

citric acid is __

Answer 37

ANTIMYCOTIC

Question 38

fumaric acid is __

Answer 38

antimycotic and c. botulinum (for bacon shelf life)

Question 39

lactic acid has ___ action

Answer 39

antibacterial

Question 40

mech of action for SCFA?

Answer 40

undissociated, cross cyto mem and dissociate to produce charged anion and H+-->inhibit growth by mem disruption, inhibit metabolic rxns, intracellular pH stress, accumulation toxic anion

Question 41

other food uses of SCFAs?

Answer 41

flavour, pH control, firming agent, clarifying agent, black spot prevention, improve stability/shelf life of veg oils, radioactive comp removal

Question 42

alkyl esters of p-hydroxybenozoic acid

Answer 42

parabens

Question 43

parabens found in:

Answer 43

berry fruits, alcohoic bev, water pollution/usage

Question 44

how make parabens?

Answer 44

esterification by proper alcohol

Question 45

phys. properties of parabens/

Answer 45

WATER SOL decrease as alkyl chain length increase, colourless/odourless/tasteless

Question 46

what bad about parabens/

Answer 46

NOT VERY BIODEGRADABLE

Question 47

Activity spectrum of parabens?

Answer 47

broad, gram +

Question 48

mechanisms of action for parabens

Answer 48

solubilize cyto mem-->neg. impact transport across membrane, electron chain disruption

Question 49

___ parabens used with Gras status

Answer 49

methyl / propyl

Question 50

parabens used in:

Answer 50

food packaging, alcoholic bev (heptyl)

Question 51

possible toxicity of parabens/

Answer 51

male repro issues