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On food and cooking the science and lore of the kitchen ( PDFDrive ) 1505

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unsaturatedfatopensaspaceunprotectedby
hydrogenatomsononesideofthechain.This
exposesthecarbonatomstoreactive
moleculesthatcanbreakthechainand
producesmallvolatilefragments.
Atmosphericoxygenisjustsuchareactive
molecule,andisoneofthemajorcausesof
flavordeteriorationinfoodscontainingfats.
Waterandmetalatomsfromotherfood
ingredientsalsohelpfragmentfatsandcause
rancidity.Themoreunsaturatedthefat,the
moreproneitistodeterioration.Beefhasa
longershelflifethanchicken,pork,orlamb
becauseitsfatismoresaturatedandsomore
stable.
Somesmallvolatilefragmentsof
unsaturatedlipidsactuallyhavedesirableand
distinctivearomas.Thetypicalaromaof
crushedgreenleavesandofcucumberboth
comefromfragmentsofmembrane
phospholipidsgeneratednotjustbyoxygen,
butbyspecialplantenzymes.Andthe


characteristicaromaofdeep-friedfoods
comesinpartfromparticularfatty-acid
fragmentscreatedathightemperatures.
SaturatedandUnsaturatedFattyAcids
inFoodsandCookingFats
Proportions of fatty acids are given as a
percentageofthetotalfatty-acidcontent.



Fat Saturated
Monounsaturated Polyunsaturat
or
Fatty
FattyAcids
FattyAcids
Oil Acids
Butter 62 29 4
Beef 50 42 4
Lamb 47 42 4
Pork 40 45 11
Chicken 30 45 21
Coconutoil 86 6 2
Palmkerneloil 81 11 2
Palmoil 49 37 9



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