On food and cooking the science and lore of the kitchen ( PDFDrive ) 755

chemicals.Onegroup,thethiocyanates,are
formedinmustardplantsandtheirrelatives,
horseradishandwasabi,whentheplantcells
aredamaged.Mostthiocyanatesaresmall,
light,water-repellingmolecules—adozenor
twoatoms—thatreadilyescapefromthe
foodintotheairinourmouth,andupour
nasalpassages.Inboththemouthandnose
theystimulatenerveendingsthatthensenda
painmessagetothebrain.Thesecondgroup
ofpungentchemicals,thealkyl-amides,are
foundpreformedinanumberofunrelated
plants,includingthechilli,blackpepper,
ginger,andSichuanpepper.Thesemolecules
arelargerandheavier—40or50atoms—
andthereforelesspronetoescapethefood
andgetupournose;theymostlyaffectthe
mouth.Andtheiractionturnsouttobevery
specific.Theybindtoparticularreceptorson
certainsensorynervesandessentiallycause
thosenervestobecomehypersensitiveto
ordinarysensations—andthustoregisterthe


sensationofirritationorpain.Themustard
thiocyanatesappeartoactinasimilarwayin
themouthandnose.
WhyPainCanBePleasurable

Whyshouldirritatingspicesbeourfavorites?
PsychologistPaulRozinhasproposeda

coupleofdifferentexplanations.Perhaps
spicyfoodsaretheedibleequivalentofriding
arollercoasterorjumpingintoLakeMichigan
inJanuary,anexampleof“constrainedrisk”
thatsetsoffuncomfortablewarningsignalsin
thebody.Butsincethesituationsarenottruly
dangerous,wecanignorethenormalmeaning
ofthesesensationsandsavorthevertigo,
shock,andpainfortheirownsakes.The
sensationofpainmayalsocausethebrainto
releasenaturalpain-relievingbodychemicals
thatleaveapleasantglowwhentheburning
fades.