Chemistry Reference
In-Depth Information
8.9.7 Maillard reactions
Atoventemperatures,sugarchemicallyreactswithproteinsinthebakingproduct,contributing
tothefood'sbrownedsurface.
TheseMaillardreactionsarethesecondwayinwhichbreadcrusts,cakes,andcookiesgettheir
familiarbrownsurfaces.Duringthebakingofbreads,cakes,andcookies,Maillardreactionsoccur
amongthesugarandaminoacids,peptides,orproteinsfromotheringredientsinthebakedproduct,
causingbrowning.Thesereactionsalsoresultinthearomaassociatedwiththebakedgood.The
higherthesugarcontentofthebakedgoodis,thedarkergoldenbrownthesurfaceappears(Ponte
1990;TheSugarAssociation1992).
Alargenumberofreactions,suchastheMaillardreaction,caramelization,andchemicaloxida-
tionofphenols,maycontributetobrowning(Manzoccoetal.2001).Inthecaseofsugarsyrups,
browning is a consequence of the Maillard reaction, which results from an initial reaction of a
reducingsugarwithanaminocompound,followedbyacascadeofconsecutiveandparallelreac-
tionstoformavarietyofcoloredandcolorlessproducts(Hodge1953;Maillard1912;Martinsand
VanBoekel2005).
Aspartame, alitame, thaumatin, and glycyrrhizin participate in Maillard browning reactions
but, at typical usage levels, do not impart a brown color, and sweetness is lost after the reaction
(Nelson2000a).
8.9.8 Surface Cracking
Sugarhelpsproducethedesirablesurfacecrackingofsomecookies.Becauseoftherelativelyhigh
sugarconcentrationandthelowwatercontentincookies,sugarcrystallizesonthesurface.Assugar
crystallizes,itgivesoffheatthatevaporatesthewaterthatitabsorbedduringbakingandmixing.At
thesametime,leaveninggasesexpandandcausecrackingofthedrysurface(Godshall1990).
8.9.9 heat Stability
Mosthigh-intensitysweetenerscanwithstandheatandprovidesweetnessafterbaking.Alitame
has shown some losses during baking, but higher than 80% is retained in most baked goods
(Freeman1989).
AcesulfameKshowsexcellentheatstabilityincookiesandcakeswithexcellentrecoveryrates
(Peck1994).
Sucraloseisalsoheatstable,andperformancetestshaveshown100%recoveryinbakedgoods,
suchascakes,cookies,andgrahamcrackers(BarndtandJackson1990).
Aspartame is not heat stable; however, it is available in a more stable encapsulated form.
Recovery rates after baking in cookies and cakes are 95% and 79%, respectively. Glycyrrhizin
andsteviosideareheatstable;however,theyarenotusedinbakedgoods,becausetheyimpartoff
lavors.
8.9.10 Bakery products: Yeast-raised Breads, rolls, Bagels, and Sweet rolls
Yeastbreadsrequiresugarinitiallytospeeduptheyeastinproducingcarbondioxideforthe
leaveningofdough.Duringthemixingphase,sugarabsorbsahighproportionofwater,delaying
glutenformation.Thedelayedglutenformationmakesthebreaddough'selasticityidealfortrapping
gasesandformingagoodstructure(Ponte1990).
SugarinMaillardreactionscontributestothebrowncrustanddeliciousaromaticodorofbread.
Inaddition,someoftheyeastfermentationby-productsandproteinsfromthelourreactwithsugar,
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