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FoodFood preference preferences of vertebrates s of vertebrates and humansand humans
• food choice depends on tastetaste and smellsmell regardless its nutritive value
• lack of reliable experiments
• expensive research in domestic animals
• unreliable data in wild animals
• all vertebrates significantly prefer sweet taste
HumansHumans - - 55 basic types of tastebasic types of taste
• sweet (tip of tongue)• bitter (root of tongue)• sour (sides of tongue)• salty (tip and edge of tongue)• umami (meet taste)
• threshold for perception of salty taste - 0,05 %• bitter taste - 0,0001 %
Chemical basis of some aromaChemical basis of some aromaCH3
H3C CH3
OHCHO
Terpenes
thymol (mandarines)
citral (lemon)
CHO
OCH3
OH
OH
OCH3
CH2
Aromatics
vanillin (vanilla)
eugenol (banana)
O O O OLactones
-nonalactone(coconut)
undecalactone(peach)
SS
S
SS
SS
Sulfur-containing compounds
di-2-propenyldisulfide (garlic)
lenthionine(mushrooms)
Green leaf odourGreen leaf odourOH
OH
O
O
2- a 3-hexen-1-ol
fresh leaf odour
2- a 3-hexenal
intense grass odour
myrcenehops odour
Flower odourFlower odour
OH
OH
O
OH
O
COOH
1- and 2-fenylethanol, fenylacetaldehyde
rose hyacinth
geraniol
2- and 3-methylbifenylrose
methyl jasmonatejasmín odour
FruitFruit odourodourO
O
1,1-diethoxyethane
O(2E,6Z)-2,6-nonadienalmelon odour
OH
pent-1-en-3-olfresh fruits(strawberries, blackberries)
O
citronellallemon odour
aliphatic ketones - peach, bananaalkanes C11-C15 - light fatty fruit odour
Vegetable odourVegetable odour
CH3
H3C
CH3
CH3
humulenetomatoes
OH
oct-1-en-3-olmushrooms
(E)-2-hexenal ..... raw potatoes(E)-2-nonenal ..... fresh cucumber odourdimethylsulfide ... fresh cabbage
Nut odourNut odourOH O CN
benzylalcohollight almond
odour
2-methylbenzaldehydebitter almond odour
fenylacetonitrilhoney almond odour
O O-nonalactone
coconut
N
-picolinenut and rhum odour
Chemical basis of hot (spicy)Chemical basis of hot (spicy) tastetaste
OCH3
OH
O
OCH3
OH
O OH
zingerone (ginger) gingerol(artefact)
OCH3
OH
HN
O
N
OO
O
capsaicin (chilli peppers)
piperine (black and white pepper)
Chemical basis of sweet tasteChemical basis of sweet taste
O
HO
O
OH
CH2OH
HO O
OH HOCH2OH
CH2OH
OS
O NH
O-
NH
O
NH2
HOOC
O OCH3
O
HNS
O O
sucrosesweetness 1
cyclamatesweetness 30
aspartamesweetness 200
saccharinesweetness 500
DL-xylitolsweetness 1
HO
OH
OH
OH
OH
HO
OH
OH
OH
OH OH
D-glucitol (sorbitol)sweetness 0,6
Lapčík et al.: Chem. Listy 2007, 101, 44-54 (in Czech).
Natural sweetenersNatural sweeteners
H
H
CH3CH2
OHO
OH
O
OH
HO
OHO
OH
HO
O
OHO
OH
OH
HOCH3
O
O
stevioside(Stevia
rebaudiana)sweetness 300
proteinsproteins – from seeds of different plants; sweetness 103
amino acids derivatives:amino acids derivatives: terpenes:terpenes:
NH
OH
O
NH2OH
O OH
monatinroots of South African bush
sweetness 103
Natural sweetenersNatural sweeteners
H3C COOH
H
CH3CH3
O
H CH3
CH3
HHO
CH3H3C
O
OO
Oglycyrrhetinic acidCOOH
COOH
OH
HO
OH
OH
HO
glycyrrhetinnic acidglycyrrhizic acid
triterpentriterpeneses:liquorice
Bitter agentsBitter agents
• bitter plant products without further pharmacological activity
• common occurrence, limited use• different structural types (often glycosides)• in some of them, chemical structure is not
known• bitterness numberbitterness number – the lowest
concentration of a compound or extract that has a bitter taste
• used in the form of extracts, tincture, or wine
• bitter agents - amaraeamarae – in small doses increase the appetite, secretion of gastric juice and influence its acidity
• cholagoguescholagogues – stimulate secretion of bile or the gall bladder contraction to promote the bile flow
• used in food industry for production of liquors, aperitifs, and other bitter drinks
Bitter agentsBitter agents
• Gentiana luteaGentiana lutea (hořec žlutý) – perennial plants (up to 60 years old)
• roots harvested from 4th year• protected, grown for medicinal effects• dried roots• content - glykosidic bitter agents – pyrane
derivatives - gentiopicrin (bitterness number 12 000), amarogentin (bitterness number 58 millions), and gentiamarin, essential oil, tannins, and sugars (gentiobiose and sucrose)
• yellow pigment gentisin (xanthone derivative)
• the drug stimulates secretion of gastric juice and digestion of nutrients, division of blood cells
• gentiopicrin, erythaurin and its aglycone erythrocentaurin are present in Centaurium Centaurium erythraea erythraea (zeměžluč menší), annual or biannual herb (harvest of flowering aerial parts)
OO
O
GlcOCH=CH2
gentiopikrin
• Absinthe wormwoodAbsinthe wormwood (Artemisia absinthium, pelyněk pravý) - perennial (South and Middle Europe)
• harvest of flowering aerial parts in full sun
Absinthe wormwoodAbsinthe wormwood
• content - 2 % essential oil (more than 20 components)
• main component - β-thujone (60 %)
• toxic, causes irreversible neurodegenerative damage (overestimated earlier)
• other components – bitter agents absinthin and artabsin, bitterness number 10 mil.
O
-thujon
O
O
O CH3
CH3
OH
CH3O
CH3
H
CH3OH
H
HH H
absinthin
O
HCH3
CH3
OH
H
CH3O
artabsin
CH3
CH3
CH3
chamazulen
Components of absinthe wormwoodComponents of absinthe wormwood
Essential oil of absinthe wormwoodEssential oil of absinthe wormwood
• hydrodistillation – decomposition chamazulencarboxylic acid decarboxylation, the final product is chamazulene (blue colour)
• drug stimulates secretion of gastric juice (digestive)
• essential oil is toxic, causes nausea, dizziness, spasm, heady state, congestion of organs in pelvis (misused for illegal abortions)
• in low concentration additive in absinth or vermouth (nowadays prohibited in almost all countries)
• Achillea millefoliumAchillea millefolium (řebříček obecný) – flowering aerial part contains 0,3 % essential oil (40 % chamazulene)
O
O
O
achillin
Bitter agent achillin oxidizes on air to chamazulencarboxylic acid that decarboxylizes to blue chamazulene
Achillea millefoliumAchillea millefolium
• use - amarum, stomachikum and cholagogue
• in traditional medicine as anti-inflammatory agent
Acidic bitter agentsAcidic bitter agents
• HopsHops (Humulus lupulus, chmel otáčivý)
• drug - female burs, source of lupulin
• essential oil (1-3 %) consists of myrcene, caryophyllene, farnesene, humulene, and other components
HopsHops• resin forms up to 80 % mass, contains mainly
bitter agents (50 %), α- and β-bitter acids• humulone (2–6 %) and lupulone (8–12 %)
R
O
O OHOH
OH
-kyseliny
O
R
O
OHOH
OH
humulon
kohumulon
adhumulon
R
CH2-CH(CH3)2CH(CH3)2
CH(CH3)CH2CH3
R
O
O OH
OH
-kyseliny
O
R
O
OH
OH
lupulon
kolupulon
R
CH2-CH(CH3)2CH(CH3)2
Bitter acidsBitter acids
• chemically instable, degradation in light and air (storage max. 1 year)
• taste and bacteriostatic effect - isocompounds arise from bitter acids in brewing process
• sedative effect, sleepiness, aphrodisiacs, amarum and stomachics
• hops extract has antibiotic and estrogenic effect
• Acorus calamusAcorus calamus (puškvorec obecný) spread from Asia to Europe; grows in wetlands, harvest of rhizome
• content – essential oil (2–4 %)• β-asarone and minor α-asarone
OCH3
H3CO
OCH3
CH3
H
H
OCH3
H3CO
OCH3 H
H
CH3
-Asarone -Asarone
• Acorus calamusAcorus calamus
• bitter agents acorine and acoretine; choline
• stimulates metabolism
• used for production of stomachic liquor (Acorus +Gentiana+Angelica+ Centaurium+fennel+caraway)
• asarone is suspected cancerogene, prohibited use in USA
• Juniper Juniper (Juniperus communis, jalovec obecný) – evergreen bush occurring in all Northen temperate zone, protected in CR
• drug – dried fruits, contains essential oil (2 %, terpenes - pinenes, cadinene, terpineol), up to 30 % invert sugar, inositol, 9 % resin, phytoncides, and bitter agent glycoside juniperin
CH2
H3C CH3
CH3
longifolene (juniperene)
JuniperJuniper• effect - diuretics, stimulates metabolism,
external application – skin congestion
• use in food industry (liquors, spice)
• DandelionDandelion, , Taraxacum officinale (smetanka lékařská – pampeliška)
• flowers - honey
• leaves – spring salad
• drug – root, leaves and unopened flowers; strong bitter taste – bitter agent taraxin (taraxacin), complex of water-soluble compounds
• other compounds - lactucopicrin (sequiterpenic lactone, guajanolide), bitter, sedative effect
OH OHtaraxasterin taraxasterol
OH
OH
O
O
OO
laktukopikrin
DandelionDandelion
DandelionDandelion• other compounds - phytosterols, terpenic
alcohols (taraxasterin, taraxasterol), organic acids and fatty acids
• leave – high content of vitamin C
• flowers - vitamin B2
• cations - sodium, potassium, manganese
• drug stimulates digestion, heals urinary tract inflammations, kidney stones, liver and metabolic issues
• supporting drug in diabetes