Download P4 3 Off flavor - e

OFF FLAVOR FORMATION IN FOODSTUFFS
OBJECTIVES
1. Formation of aroma compounds via enzymatic mechanism;
2. Transformation of carbohydrates, lipids and amino acids;
3. Transformation of other compounds.
OFF FLAVOR FORMATION IN FOODSTUFFS
Off-flavor – a flavor that is not natural or up
to standard owing to deterioration or contamination
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OFF FLAVOR FORMATION IN FOODSTUFFS
Off-flavor
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OFF FLAVOR FORMATION IN FOODSTUFFS
Off-flavor
1. As a result of chemical and biochemical processes
1.1. Fishy / mushroom smell in butter (octa-1-en-3-on) –
degradation of phospholipids; otherwise – smell of mushrooms, found
in Camembert cheese
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OFF FLAVOR FORMATION IN FOODSTUFFS
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Off-flavor
1. As a result of chemical and biochemical processes
1.2. Soybean oil – presence of 3-methyl-2,4-nonadion and diacetyl:
bean and oily aroma;
1.3. In the dry sterilized milk – sometimes is felt pockety and stale smell;
the reason is oxidation of lipids and formation of Z-nona-6-enal; Other
reason might be presence of о-amino acetophenone – potato and animal
odor
(interestingly at higher concentrations this compound have grape odor
notes!)
OCH3
OH
Cl
Cl
Cl
Cl
Cl
f ungicides
molds
Cl
Cl
Cl
odor of molds, stale
2,4,6-trichloroanisole (TCA)
The main factor for
formation of smell of
molds and stale – cork
taint.
OFF FLAVOR FORMATION IN FOODSTUFFS
Off-flavor
1. As a result of chemical and biochemical processes
1.3. Off-flavor formation during carrot treatment – sterilized or dried;
reason – formation of ionones (α-, β-) having floral aroma
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OFF FLAVOR FORMATION IN FOODSTUFFS
Off-flavor – due to degradation of carotenoids
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OFF FLAVOR FORMATION IN FOODSTUFFS
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Off-flavor
1. As a result of chemical and biochemical processes
Tryptophan
oxidative
deamination
decarboxylation
It’s formed in the mammalian digestive
tract – in higher concentrations has
strong fecal odor. In low concentrations
has flowery smell (found in some flowers,
used as fragrance and fixative in perfumes.
Skatole
Smell in the Emmental
Off-flavor in processed
peppers
о-aminoacetophenon
(animal, potato smell);
Found in tortilla, taco
(in dairy products –
gives off-flavor)
OFF FLAVOR FORMATION IN FOODSTUFFS
Off-flavor
2. As a results from external contamination of foodstuffs
2.1. Geosmin in water, vegetables (beets) and fishes – smell of soil, earth
produced by gram-positive bacteria Streptomyces.
2.2. Formation of acrid taste and burnt
smell in dairy products – from the milk of
animals consumed Coronopus
didymus (swinecress); reason –
formation of benzylmethyl sulfide and
benzylthiocyanate; losses for the
producers.
Coronopus didymus (swinecress)
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OFF FLAVOR FORMATION IN FOODSTUFFS
Off-flavor
2. As a results from external contamination of foodstuffs
2.3. Allium ursinum – known as ramsons,
buckrams, wild garlic; Animals which has consumed it
gives milk with garlic off-flavor.
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