Other Sweeteners - Sweeteners: Nutritional Aspects, Applications, and Production Technology - page 181

7.1.3.3 Denaturation

Sugarextractisstoredindenaturationtanks,whichareappropriatelyinsulatedtokeepthetem-
peratureoftheproductconstant.
Denaturationiscarriedoutwiththeadditionof0.02%phenolphthalein.Phenolphthaleinmakes
staidinrapidlydetectablewhenaddedtoproductswhereitsuseisnotallowed,e.g.,towines,to
increasethealcoholicgrade.

7.1.3.4 Evaporation

Followingdenaturation,theextractisreadyforevaporation.Thisisdoneinanevaporatorina
thinlayerunderavacuum.Thistypeofevaporatorissuitablefortheevaporationofliquidproducts
withhighviscosity,suchasraisinjuiceconcentrate.
Aschematicoftheevaporatorshowstheintroductionoftheextracttothetankthroughapump
in the separator, which is illed with extract until it reaches two-thirds of its height. The extract
passesthroughatubetotheheatexchanger,becausetheseparatorandheatexchangerarecontact
vessels.Steaminsertioniscarriedoutatapoint,andcondensatesexitatthedownwardpointofthe
exchanger.Insidetheevaporator,vacuumingisdonewithavacuumpump.Theextractisheatedin
theheatexchangerandisboiled,discardingwaterintheformofvapors,whicharecollectedonthe
uppersideofthesystem.Productsintheformofdropletsduringheatingarecarriedthroughthe
tubetotheseparator,wheretheyaremixedwiththeinitialextract.Thecirculationoftheevaporated
productfromtheheatexchangertotheseparatortakesplaceasaresultofthedifferenceinvapor
pressureexistingbetweentheseparatorandtheevaporator.
Whenthelevelintheseparatorreachesacertainheightsothatthenaturallowinthesystem
isnotpossible,anewquantityofextractisaddedthroughasecondvalve.Atanotherpoint,there
isaglassvalvethroughwhichlevelcontrolisachieved.Fromthesecondvalve,asamplingofthe
productisreceivedtocontroltheBaume(°Be),sotherequiredevaporationisachieved.Whenthe
productreaches42°Be,evaporationstops,andtheinalproductistakenbeforepackaging.
Thecharacteristicsoftheproductduringevaporationarelistedasfollows:

• Initialtemperature—40°C

• Finaltemperature—67°C

• Initialconcentration—15°Be

• Finalconcentration—42°Be

• DegreesBrixoftheinalproduct—70°Bx

Theproduct'sphysicalcharacteristicsarelistedasfollows:

• Color—Brown

• Taste—Fruity,raisinjuice

• Acidity—pH2.0-3.5,bestforconfections

• Sweetness—Highconcentrationofmonosaccharides,suchasglucoseandfructose(85%-95%dry

solids)

• Viscosity—Approximately260cpsor42°Beat42°C

7.1.4 Manufacture of Staidin

InFigure7.3,themanufactureofstaidinisshown.Initially,theproductisapureextractofstai-
din.Itismanufacturedwiththeextractionofraisinsusinghotwater(Figure7.3b).Then,theproduct
isevaporatedundervacuumandisstoredwithnopreservatives(Figure7.3c).Theinalproductwith
approximately74%dissolvedsolidsispackagedanddistributed.