C) Flavouring Agents
what are their functions
what are not their functions
Function(s):
(1) to render a food more acceptable and enjoyable (by masking objectionable taste characteristics [e.g. soy, artificial sweeteners]; or to enhance existing flavours);
(2) to impart a recognizable character to a food product when very little or none existed [e.g. JELL-O, beverages; association of flavor with colour]- eyes and our brain tell us what it should be, not our taste buds (3) to compensate for flavour losses during processing or to extend ‘freshness’ during storage.
(1) mask human errors (e.g. poor manufacturing practices [lack of GMP]); (overheated is bad processing – gives cooked flavor, example dole, sqeezing the orange too much and get taste of the white stuff on peel)
(2) mask the use of poor quality raw ingredients; and
(3) improve a poorly designed product, example
Flavouring Agent Definition:
“the property of a substance which causes a seemingly simultaneous sensation of taste in the mouth and odour in the back of the nose”
5 basic taste- talk about 4
bitter, sour, salty, sweet- all over our mouth - not on specific parts of the tongue
there are super tasters and not- have more taste buds
first flavouring agents were
- first flavouring agents were spices, herbs and essential oils (aromatic/odorous oily liquids obtained from plant materials such as mint)-> birth of food additives and their regulation
- access to, and ownership of these compounds were responsible for many world changes/conflicts (e.g. Roman Empire; Americas)Columbus (1942): looking for a direct water route from Europe to Asia-> food spices (pepper, cinnamon, turmeric); health (cloves, cardamom)
what are 2 Natural Flavours (examples)
what functional groups do they have
Natural Flavours (examples)
(a) acids: acetic and citric acids (“sour” taste response; non-volatile
compounds; functional group: -COOH)- pungeant
we can taste the bitter tast 10000 times better than sweet
carbohydrates and polyols (hydrophilic):
which is sweeter alpha-mannose or beta
what functional group do they have?
α-mannose is known as sweet
β-mannose is known as bitter) (6% bitter, 94% sweet taste the bitter because its stronger)
- functional group: -OH
- illustrates the important role of structure in human taste response and molecular flexibility
uti: e-coli- 90-80%- exude glycoprotein and stick to the cell wall- those that get it frquently and it competes with the glycoprotein- is a competition -example of carbohydrate treatment
) alcohols (isoprenoids; hydrophobic):
(b) alcohols (isoprenoids; hydrophobic):
these are just one of the flavor compounds in these products
citronellol (rose oil)
linalool (cinnamon)
L-menthol (peppermint)
- also act as insect repellents; GRAS status
(c) aldehydes
- Functional group =c-h
- GRAS; perfumes (up to 0.5%);
C) Flavouring Agents (Preparations)
(d) multiple functional groups (e.g. aldehydes + alcohol + ether):
vanillin (vanilla bean/pod; Orchidacae)
- very expensive flavour vanilla extract) ~$3,000/kg
- vanillin is also produced from lignin (by-product of the pulp and paper industry) and guaiacol (petroleum industry) ~85% of world supply; cost of $400-500/kg
- This material is called “nature identical”- exactly the same structure- never would think that it came from another source
- option of ‘artificial’ vanilla flavour: ethyl vanillin (2-4x more potent flavour; cost of $20-50/kg; LD50: 1590 mg/kg bwt)
natural flavours:
the flavouring compounds are isolated from naturally occurring raw materials by physical methods and cemical (grind it up and then treat it with a chemical so both (e.g. pressing, solvent extraction, distillation)
remove the water from the juice but also takes some of the flavor- evaporates the essence and can add it back to the juice or sell it as a flavor pack to ex. Jello, cosmetics
nature identical flavours:
the flavouring compounds are obtained by synthesis (chemical or enzymatic) or areisolated through chemical and physical processes from naturally occurring raw materials and are chemically identicalto a substance present in natural products intended for human consumption (e.g. vanillin from lignin)
(c) artificial flavours:
these are flavouring compounds that have not yet been identified in a natural product intended for human consumption (i.e. ethyl vanillin)
are natural,nature identical and artificial safe for conumption
((a) natural flavours: are natural constituents of foods so they are assumed to be safe
(b) Nature identical flavors: are also considered safe as long as they are not used in foods in/at concentrations significantly higher than is found naturally
(c) artificial flavours: undergo extensive toxicity testing (e.g. cmta)
A. Eugenol
Are all natural flavours safe?
A. Eugenol-major flavor components in cloves (50%)
active flavour compound in cloves (~0.2 g/10 g of dried cloves 37 chemical components) and bay leaf (also present at low levels in many herbs and spices (e.g. cinnamon and nutmeg)
- Listed as a carcinogen (not on the current CA Proposition 65 list)
dietary studies: kidney and liver damage in animal studies (1% of diet)
analgesic (pain relief [e.g. toothache]) and anesthetic (e.g. fish)
- GRAS (USA; not in Canada) [ LD50: 2.650 mg/kg bwt
C) Flavouring Agents (Preparations)
Final Comments
flavour addition to foods is generally conducted under GMP
-the term “flavors” on the ingredient label indicates natural
flavor compounds/preparations
no distinction is made between ‘natural’ and ‘nature identical’ when labeling foods
Food flavor market: $11.5 billion (2015; predicted growth of
1.3%/year
Synthetic flavors: on their way out
Coumarin
present (≤10 ppm) in vanilla, sweet clover (forage crop), fruits (e.g. apricot, cherry, strawberry)
feeding trials (1%) resulted in serious liver damage in laboratory animals (i.e. hepatotoxin)
- Banned as a flavoring agent in Canada and the USA (1954)
Safrole
present (≤10 ppm) in black pepper, basil, nutmeg, cinnamon, camphor and sassafras (tree)
feeding trials (rats; 1%) resulted in: weight loss, testicular atrophy, bone marrow depletion and liver tumors (human carcinogen)-> on CA Proposition 65 list
- Banned as a flavoring agent in Canada and USA (1960)
- Popular ingredient in herbal teas [LD50: 1.950 mg/kg bwt]
What is a flavor enhancer
what is an example of one
Function: a flavour enhancer is a substance( chemical compound/group of compounds) which is/are intentionally added to a food to enhance/supplement its original taste/flavor(bring in their own flavor) (Code of Federal Regulations Title 21; USA)
(1) Monosodium glutamate (monosodium L(S)- glutamate; MSG)- SALT OF A NATURALLY OCCURING AMINO ACID –not enough mass to be allergicable, scientific impossibility
MSG
first isolated (seaweed) in 1908; with commercial production by Ajinomoto Corporation in 1909
annual production of ~2 million tonnes:
acid (HCl) hydrolysis of wheat gluten (glutamic acid rich)
chemical synthesis from acrylonitrile (nature identical)
fermentation (Corynebacterium glutamicum) of sugar beet molasses (bacteria produced)100g per litter because of GMO
has been used in/added to foods since the 8th century
Flavour Enhancers Mechanism(s) of Action
- initially hypothesized that glutamate enhanced the intensities of the basic taste sensations animal and human studies have shown that this is not true
- New hypothesis is that it has its own receptors (or is a neurotransmitter) and is therefore a primary taste sensation called umami” (deliciousness”)
Combined impact- has its own flavor but can boost other flavors
MSG Physical Properties
- white solid (no food colour issues); also available in liquid form
- excellent water solubility: 74.0 g/100 mL (very good)
- Heat stable
- Reacts with reducing carbs to produce colour (yellow-brown): maillard reaction) (crust on the bread
MSG Food Uses and Concentrations (legal)
- not considered to be a food additive in Canada/USA (EU: E621–number); used under GMP (www.hc-sc.gc.ca/fn-an/securit/addit/msg_qa-qr-eng.php)
- foods where MSG has been added must be clearly labelled
- MSG is used worldwide in soups, sauces, gravy, spice blends, canned/frozen meat & poultry, vegetables, heat and serve products/meals, etc.
M (salt: 0.0007Taste threshold: 0.01M; sucralose: -0.01 M)
Typical usage levels: 0.05-0.08% (based on food weight) for best enhancement of natural flavors [MSG consumption figures:550mg/day (general population; USA); 4.68 g/day (extreme consumer])
MSG Toxicity
- LD50 (mice): 18.0 g/kg bwt (LD50 for salt: 3.8 g/kg bwt)
- long term (1-2 years) and multigenerational animal (dogs, chickens, mice, rabbits, and rats) at high dosage levels (up to 4% of total diet no cmta
Glutamate crosses the blood/brain barrier-> daily doses (rats) at 4g/kg bwt showed a spike (about 8% increase) in brain glutamate levels – see higher level but no brain damage seen or anything Single dose (12,000x maximum anticipated food level) injections into the blood stream -> significant increase (65%) in brain lesion (rats)-> importance- never will have that much, injectionin blood stream is not how we consume food anyway
MSG Toxicity (cont. - free glutamate concentration in the brain is ~2 mg/g (neurotransmitter and for CO/CO2 fixation/mobilization-important for normal brain)
- Glutamate is synthesized in brain cells upon demand
- glutamate crosses the placental barrier at high dose levels (up to 70x normal) can result in fetal plasma glutamate levels increasing to ~10x normal levels
Human breast milk-> broad normal range (about 8to 21 mg/100 ml) [ 10x as much free glutamate inbnhuman milk as in cows milk]
ADI: not specified” (JECFA)
-“CRS” (Chinese Restaurant Syndrome; Kwok’s Disease):
Dr. Robert Ho man/Mon Kwok wrote a letter to the editor of the New England Journal of Medicine in 1968 about a patient/himself who reported symptoms of: “burning, numbness, and upper abdomen tightness” following a meal at a Chinese restaurant extensive media attention CRS was born
- scientists jumped into studying this 'phenomena': carried out double blind studies in 1972, 73, 78, 79, 1980 (x3), 1986 (x3) each study reported "no correlation between MSG and postprandial (events [medical] occurring after meal consumption) claims”- all had same outcome- none
in 1986 Kenney challenged patients who were positive that they were effected by MSG-CRS and subjected them to a double blind test: 85% had no response, and 15% had a mild response to MSG, however, the later subjects also had the same response to the placebo(Food Chem. Toxicol. 24:240-244) [food intolerance? Idiopathic]
- bottom line: “studies have failed to demonstrate that MSG is the casual agent in provoking the full range of symptoms or CRS” - recent (2014): MSG metabolism slowdown obesity IN ANIMALS
