This presentation highlights the flavor developed during cooking of meat. Meat flavor development is a complex process which involves formation of multiple kinds of chemical compounds. So check out this presentation to know more about those savory, mouth watering flavors of meat that you can't resist!

1. FLAVOR DURING
COOKING OF MEAT
13FET1003 : MOKSHA CHIB
13FET1004: AMEYA PATHAK

2. Cooking of meat
• Meat is cooked using different media for heat transfer like dry heat methods, moist heat
methods, microwave cooking or a combination of both
• The cooking method chosen should be appropriate to the type of meat, the amount of connective
tissue and the shape and size of the meat
Core temp
increases from
0°C to as much
as 85°C
Proteins get
coagulated
Browning
begins at 90°C :
Concentration
of sugars
Water is lost as
cooking loss
Fat melts and cell
membrane ruptures;
fat is spread
throughout the tissue
Fat becomes
available for
chemical
reaction
Change in
texture and
flavor

3. Heating Process in meat
• The rate of heating in meat depends upon
 the coefficient of conductivity in meat
 the surface temperature of meat: affected by the temperature of the heating source, air circulation
& relative humidity
• Increasing air circulation improves heat conduction & increases evaporation from the surface of meat
• Heat absorbed in the meat causes a temp rise by heat conduction through meat from the surface to
the center

5. Cooking methods
• Three main factors differing in cooking techniques:
o Temperature at the surface of meat
o Temperature profile through meat
o Method of heat transfer (contact, air, steam, microwave)
Dry Heat Cooking Moist Heat Cooking Combination
Grilling/ broiling Steaming Stewing
Barbecuing Poaching Braising
Roasting/ baking Simmering
Sauteing Boiling
Pan frying
Deep fat frying
Heat has applications:
• Flavor formation from precursors &
homogeneous mixtures of water
soluble & fat soluble compounds
• Releases flavor (precursor) from fatty
structures
• Enable mixing of fat soluble & water
soluble compounds ( fat melts &
becomes part of meat juices)
• Favors browning reactions through
evaporative & exudative dehydration
& through protein degradation

6. Effect of cooking on flavor
• Amino acids and reducing sugars react when heated MAILLARD REACTION
• Fatty acids get oxidized and degraded to create volatile flavor compounds
• Thiamine is a source of meat flavor generated on heating THIAMIN DEGRADATION
• INTERACTION BETWEEN LIPID OXIDIZED PRODUCTSWITH MAILLARD PRODUCTS
• Vitamin gets degraded during cooking VITAMIN DEGRADATION
LIPID DEGRADATION

7. Meat Flavor Aroma
• Meat flavour comprises mainly the two sensations of taste and smell
• Other sensations such as astringency, mouthfeel and juiciness may also play a part. Receptors in
the mouth can recognize four main taste sensations (sweet, salt, sour and bitter)
• In contrast, many hundreds or even thousands of different odours can be distinguished by the
human nose
• The sensation of odour is produced by volatile chemical substances which stimulate the
receptors in the nasal epithelium

8. Aroma Flavor Precursors
Flavor precursors Names in detail
Free amino acids Cystine; cysteine; glycine; lysine; alanine; valine; isoleucine; leucine; threonine;
serine; proline; asparagines; aspartic acid; methionine; glutamic acid;
phenylalanine; glutamine; ornithine; histidine; tyrosine; tryptophan; arginine.
Reducing sugars Ribose; glucose; xylose; starch; mannose; fructose; maltose; mannose 6-
phosphate, glucose 6-phosphate; fructose 6-phosphate; ribose 6-phosphate.
Fats/ lipids Triglycerides and phospholipids, Oleic acid (C18:1n-9), Linoleic acid (C18:2n-6),
Linolenic acid (C18:3n-3) and etc.
Vitamin Thiamine
Nucleotides and peptides Glutathione; carnosine inosine; inosine monophosphate; inosine 5’-
monophosphate; guanosine 5- monophosphate; creatinine; Hypoxanthine and
etc.
The low molecular weight, water soluble compounds and fats in meat constituents are the most important
precursor of aroma flavor characteristics of cooked meat.

9. Flavor Active Volatiles
Compound name:
ALDEHYDES
Aroma flavor characteristics
Methional caramel, sweet, alcoholic, “cooked”, broth, spicy
Propanal Cooked potato, meaty
Butanal smoky, fish, amylic, aldehyde-enal or dienal
Hexanal Sweet, fatty, green, fruity
Heptanal Sweet, fatty, fruity, oil
Octanal Green, lemon, citrus, aldehyde
Nonenal Sweet,fatty,green
Decanal Sweet, fruity, like aldehydes, roasty
Undecanal, E,2-undecenal Sweet, pungent, green
E,2-nonenal, E,2-hexenal Fatty, Green
Benzenacetaldehyde Sweet, honey
2-methylbutanal Pungent, sweet, roasty
acetaldehyde-like 3-
methylbutanal
Meaty, fish, rotten, aldehyde,valeric acid, fatty

10. Flavor Active Volatiles
Compound name: KETONES Aroma flavor characteristics
2-octanone, decanone, decanone Fruity, musty
1-octen-3-one Fresh, mushrooms, pungent, rubbery
3-octanone Fruity, nutty, moldy, fatty, earthy
2,5-dimethyl-4-hydroxy-3(2H)-
furanone
Roasted almonds, sweet
4,5-dihydro-5-propyl-2(3H)-
furanone
Fruity, fatty, sweet, pungent, roasty
2,3-butanedione Sweet, buttery
2-heptanone Citrus grapefruit, limonene, floral, cheese
2-nonanone Hot milk, soap, green, fruity, floral
6-Methyl 2-heptanone Cloves, menthol
2,2,6-Trimethylcyclohexanone Mint, acetone

11. Flavor Active Volatiles
Compound name:
ALCOHOLS
Aroma flavour characteristics
1-octen-3-ol
Mushroom
Cyclobutanol Roasted
1-heptanol Fragrant, woody, oily, green, fatty, winey, sap
2-Ethyl-1-hexanol Resin, flower, green
1-octanol Penetrating aromatic odor, fatty, waxy, citrus, oily

12. Compound name:
HYDROCARBONS
Aroma flavour characteristics
Ethenylbenzene Pungent, aromatic, fragrant, roasty
1-undecen Fatty, burnt, nutty, rubbery
Hexane Faint peculiar odor
(Z)-3-Octene Fruity, old apples
Pentane Very slight warmed-over flavor, oxidized
Flavor Active Volatiles

13. Compound name:
PYRAZINES
Aroma flavour characteristics
2-ethyl-3,5-
dimethylpyrazine
Burnt, fragrant, meaty, green
2-ethenyl-3,6(5)-
dimethylpyrazine
Sweet, cooked rice, fatty
2,3-diethyl-5-
methylpyrazine
meaty, roasty, fragrant, sweet
2,5-dimethylpyrazine Fried rice, popcorn, pungent, green
2-ethenyl-5(6)-
methylpyrazine
Roasty break-like, cooked rice, coffee-like
2-ethenyl-5(6)-
methylpyrazine
Smoky, roasty, break-like, cooked rice, popcorn
2-isopentyl-3,6-
dimethylpyrazine
Sweet, fragrant, fatty, fruity, pungent
2,3-diethyl-5-
methylpyrazine
Meaty, roasty, fragrant, sweet
Flavor Active Volatiles

14. Compound name: S and N
CONTAINING COMPOUNDS
Aroma flavour characteristics
2-fufurylthiol, 2-acetylthiazole Roasty
2-acetyl-1-pyrroline Roasted, sweet
2-formyl-5-methylthiophene, Benzylthiol Sulfurous
2-methyl-3-furanthiol Meaty, sweet, sulfurous
2,4-dimethylthiazole Rubbery, moldy, fruity, pungent, onion-like
Dimethyltrisulfide Fragrant, musty, roasty, rubbery
Bis(2-methyl-3-furyl)disulfide Meaty-like
Benzothiazole Metallic
4,5-dimethylthiazole Smoky, roasty, fragrant, nutty
2-methylchinoxaline Aromatic, roasted, nutty, sweet, fruity, fatty
3-mercapto-2-butanone Fried onion, sulfury, cooked meat
2-mercapto-3-pentanone Brothy, mashed potatoes meaty, roast meat
3-[(2-furanylmethyl)dithio]-2- butanone onion, burnt rubber, burnt wood
Flavor Active Volatiles

15. Maillard Reaction
STEP A
STEP B
STEP C
STEP D
STEP E
STEP F
STEP G
STEP H
Condensation of CO group of a reducing sugar
(aldose) with a free amino group of an amino
acid, which loses a molecule of water to form
N-substituted glycosylamine
Undergoes the "Amadori rearrangement" to
form "1-amino-1-deoxy-2-ketoses"
Dehydration (loss of 2 water molecules)
into reductones & dehydro reductones
(caramel products)
Production of short chain hydrolytic
fission products such as diacetyl,
acetol, pyruvaldehyde, etc
"Strecker degradation" with amino
acids to aldehydes
or they may react in the absence of
amino compounds, to give aldols
and high molecular weight,
nitrogen-free polymers
Formation of brown nitrogenous
polymers and copolymers called
melanoidins
Direct route to fission products
from N-substituted
glycosylamines, without the
formation of an ARP

17. Strecker Degradation
1. Amino acids
undergo oxidative
deamination &
decarboxylation
in the presence of
dicarbonyls
2. Lead to formation
of aldehyde
(e.g.furfural)and
amino ketone

18. Strecker Degradation
3. Sulphur
containing amino
acids such as
Cysteine or cystine
form H2S , NH3
etc by Strecker
Degradation

19. Flavor Compounds formed from the
Maillard Reaction
Flavor class Characterized Flavor/aroma Remark
Pyrazines Cooked, roasted, toasted, baked
cereals
Alkylpyrazines Nutty, roasted
Alkylpyridines Green, bitter, astringent, burnt Unpleasant flavor
Acetylpyridines Caracker-like
Pyrroles Cereal–like
Furan, furanones,
pyranone
Sweet, burnt, pungent, caramel-like
Oxazoles Green, nutty, sweet
Thiophenes Meaty Formed from heated meat by the reaction of cystein and
ribose
6-Methyl 2-
heptanone
Cloves, menthol
2,2,6-
Trimethylcyclohexan
one
Mint, acetone

20. Lipid Oxidation
• The oxidation of unsaturated acyl chains of the lipids accompanied with thermal conditions.
• Auto-oxidation of these unsaturated fatty acids associated with phospholipids is responsible for the
undesirable flavors associated with rancidity.
• Hundreds of volatile flavor compounds derived from lipid degradation have been found in cooked
meat including aliphatic hydrocarbons, aldehydes, ketones, alcohols, carboxylic acids and esters.
The degradation of lipid is catalyzed by Iron.
 The oxidative breakdown of unsaturated alkyl chains of lipids involves a free radical mechanism to
form hydroperoxides.The reaction is initiated when a labile hydrogen atom is abstracted from a site
on the lipid with the production of lipid radicals.
RH  R· + H·
 Reaction with oxygen yields peroxy radicals which is followed by abstraction of another hydrogen
from lipid molecule
R·+ O2  ROO·
ROO·+ RH  ROOH + R·

21. • The resulting radical can undergo rearrangement prior to reaction with oxygen, giving rise to a
number of hydroperoxides. The degradation of hydroperoxides formed leads to the formation of
various volatile components.
• The degradation of hydroperoxides initially involves homolysis to give an alkoxy radical (RO·) and a
hydroxy radical (OH·).
• The nature of the volatile product for a particular hydroperoxide depends on composition of alkyl
chain and the position where the cleavage of the chain takes.
 Hydroperoxides containing a diene system will give a complex mixture of volatiles such as dienals and
alkylfurans
 The other classes of volatiles including long chain alkylthiophenes and alkylpyridines are produced
from the interaction of lipid degradation products with ammonia and hydrogen sulphide.

22. Thiamin Degradation
• Primary product: 4-methyl-
5-(2-hydroxyethyl)thiazole &
other flavor compounds like
5-hydroxy-3-
mercaptopentan-2-one
which then gives some sulfur-
containing compounds such
as thiophenes and furans as
well.
• Some of those compounds
at low concentrations in
themselves smell like cooked
meat and some of them
contribute significantly to the
aroma of cooked meat

23. Interaction of Maillard browning and
Lipid oxidation products

24. Effect of cooking
temperature
Cooking
Dry
Cooking
Aqueous
Cooking
Roasting, Broiling, Pan
frying: 150°C-160°C
Subjecting aroma
precursors to heating
Boiling, Stewing,
Braising : 100°C

25. Dry Cooking
• Due to low Aw, high temperatures & dried surfaces, there is an increased production of flavor compounds
which give roasted odor notes & flavor
• Amounts of most volatile flavor compounds increase with cooking temperatures
• Amino acids & reducing sugars react when heated above 110°C MAILLARD REACTION
• Sugar melts & decomposes at temp above 170°C and produce “burnt sugar” flavor
• Fatty acids get oxidized and degraded to create volatile flavor compounds
CARAMELIZATION
LIPID DEGRADATION

26. Changes in flavor compounds on dry
cooking
• LIPID OXIDATION: High temp increase oxidation processes in meat.
Volatile compounds generated by lipid oxidation: Pentanal, hexanal, 2-hexanal, heptanal, benzaldehyde,
octanal, nonanal
Trend for hexanal : Roasted > Microwaved > Fried > Grilled
Hexanal is dominant in the flavor profile as it can be generated from oleic acid, linoleic acid & arachidonic
acid, and through degradation of other unsaturated aldehydes such as 2,4-decadienal.
Lipid oxidation increase the number of free radicals which attack other less susceptible fatty acids, favoring
synthesis of heptanal, octanal & nonanal.
Roasting at 200°C for 12 min > Frying at 140-180°C for 4 min

27. Changes in flavor compounds on dry
cooking
• ESTERS: Generated from esterification of alcohols & carboxylic acids, their content decrease on cooking.
This is because thermal treatment degrades the esters & this decrease is higher in roasted treatments as
compared to grilled and fried treatments.
• ALKANES: Alkane content was found to be higher after microwaving than after grilling.
The most abundant alkanes: Undecane, nonane, 2,2,4,4,6,8,8-heptamethyl and octane
• AROMATIC HYDROCARBONS: Highest increase in roasted meats when treated for long time.
The most abundant aromatic hydrocarbons: Toluene and p-xylene
• FURANS: Highest increase in furans after microwaving.
Furans in microwaving: Furan, 2-ethyl, furan, 2-n-butyl and furan, 2-pentyl; roasting: furan, 2-ethyl and
furan, 2-pentyl; frying & grilling: furan, 2-pentyl

28. Changes in flavor compounds on dry
cooking
• KETONES: Aroma imparted by methylketones, which are products of β keto acid and are derived from
triglycerides on heat treatment.There is an increase in the ketone level with an increase with the lipid
oxidation.
• ALCOHOLS: 1-hexanol,2-ethyl is found in raw samples, while only one alcohol (1-pentanol) is present in
roasted steaks.
• PYRAZINES &THIAZOLES: Production increases with increased roasting
Correlation Hexanal Aldehydes Furans Esters Total volatile
compounds
Lipid oxidation + + + - +

29. Comparison of flavor compounds in different
methods of cooking
Flavor Compounds (%) Fresh Fried Roasted Grilled Microwave
Alcohols 0.56 - 0.71 - -
Furans - 0.29 0.49 0.64 0.83
Lineal Alkenes - 0.32 0.33 - 0.21
Aldehydes 3.2 53.21 65.19 54.31 59.99
Cyclic Hydrocarbons 2.33 1.37 0.52 0.48 0.34
Other compounds 3.01 1.15 0.97 1.01 0.71
Aromatic Hydrocarbons 15.83 6.96 9.89 10.17 8.00
Ketones 6.63 1.47 0.85 1.32 0.43
Esters 39.86 7.59 2.59 8.90 3.82
Lineal Alkanes 28.58 27.64 18.46 23.18 25.66

31. Wet Cooking
• While collagen softens in moist heat, muscle fibers firm as their proteins unfold and form new
linkages during cooking.Various proteins in meat fibers coagulate over a range of temperatures from
40°C-90°C, temperatures that are far below boiling point 100 °C
• Wet cooking prevents Maillard Reaction
• As lipid degradation can take place at lower temperatures, therefore flavor compounds can be
produced on the surface and throughout the meat
• No caramelization takes place as temperatures do not reach greater than 100°C
• Except pressure cooking, interior of the pieces of meat cannot rise above 100°C until all water has
been driven off, thus it will have little flavor in comparison with exterior where high temperature and
less moisture produces various substances
• Unless cooking is pressurized, browning doesn’t take place; no roasting flavor & appearance
• Low heating yields homogeneous appearance but less distinct layers of doneness

32. Wet Cooking
• Well cooked boiled beef has major amounts of Benzenoids
Well cooked, boiled Underdone, boiled
HIGH MW HYDROCARBONS
Tetra-, penta-, hexa- and hepta- decanes
LOW MW HYDROCARBONS
Heptane, octane, decane, undecane,
hept-1-ene, undec-1-ene
BENZENOIDS
Benzene, n-propylbenzene, toluene, o
and p-xylenes, ethylbenzaldehyde
PYRAZINES
Dimethyl-, ethyl- and dimethylethyl
pyrazines
FURANS
2-ethyl and 5-n-pentyl furans
MISC
3-methylbutanol, pyridine, 2-
metylthiophen
MISC
Acetone, methylbutanol