On food and cooking the science and lore of the kitchen ( PDFDrive ) 1155

cookshavetakenadvantageofthistomake
smallflavoredspheresandthreads:they
prepareacalcium-freealginatesolutionofthe
desiredflavorandcolor,andthendripor
injectitintoacalciumsolution,whereit
immediatelygels.Gellan,anindustrial
discovery,isacarbohydratesecretedbya
bacterium,andinthepresenceofsaltsoracid
formsverycleargelsthatreleasetheirflavor
well.
SaucesThickened
withFlourandStarch

Manysauces,fromlong-simmeredclassic
Frenchbrownsaucestolast-minutegravies,
oweatleastpartoftheirconsistencytothe
substancecalledstarch.Unliketheother
thickeningagents,starchisamajor
componentofourdailydiet.It’sthemolecule
inwhichmostplantsstoretheenergythey
generatefromphotosynthesis,andprovides


aboutthree-quartersofthecaloriesforthe
earth’shumanpopulation,mainlyintheform
ofgrainsandrootvegetables.It’stheleast
expensiveandmostversatilethickenerthe
cookhastoworkwith,aworthyadjunctto
gelatinandfat.Thecookcanchooseamong
severaldifferentkindsofstarch,eachwithits
ownqualities.

Agar:FromPuddingtoPetriDish
Solidgelsmadefromagarhavelongbeen
a standard tool in the study of microbes.
Scientistsmakethemuptoincludevarious
nutrients, and then grow colonies of
microbes on their surface.Agar gels have
several important advantages over the
original growth medium, which was
gelatin. Very few bacteria can digest the
unusual agar carbohydrates, so agar gels
remain intact and the bacterial colonies
separate, while many bacteria digest
proteins and can quickly liquefy a gelatin