Quality Control of Sweeteners: Production, Handling, and Storage - Sweeteners: Nutritional Aspects, Applications, and Production Technology - page 273

Fortestcompletion,holdthesampleandcontrolsidebyside.Viewthetesttubesfromthetop.
Rhodamine B Test Results Evaluation .Whenviewingthetesttubesfromthetop,evaluatethe
solutionsaccordingtothefollowingguidelines:

• Apositivetestgivesavioletcolortothesamplesolution.Thecolorwillconcentratemostlyinthe

foam(producedfromshaking).Ifyouseeavioletcolorinthesample'sfoam,performthequinine
hydrochloridetest(below).

• Anegativetestgivesasimilarredcolortothesampleandthecontrol.

9.16.3 Quinine hydrochloride test

Thequininehydrochloridetestrequiresthefollowingequipment:

• 10-mlgraduatedcylinder

• 100-mlgraduatedcylinderwithstopper

• 10-mlpipette

• 20-mltesttube

• Timer

• 400-mlbeaker

• Hotplateorburner

• Spectrophotometerwith1-cmcells

Forreagents,6%w/vquininehydrochlorideordistilledwatercanbeused.
Samplepreparationisdescribedasfollows:

1. Measure 50-ml HFSS in a 100-ml graduated cylinder with a stopper. Add 50-ml distilled water,
stopperthecylinder,andmix.

2. Pipette10-mlHFSSsolutionintoa20-mltesttube,add2-ml6%w/vquininehydrochloride,andmix.

3. Allowthemixturetostandfor30min.

4. Placethetesttubeinaboilingwaterbathfor5min.

5. Coolthesampleimmediately.

Samplereadingisconductedasfollows:

1. Filla1-cmcellwithsample.

2. Fillanother1-cmcellwithdistilledwater.

3. Setthespectrophotometerat720nmandreadthesample'stransmittanceagainstadistilledwater
blank.

Forresultsinterpretation,anysamplereadinglessthan90%Tisunacceptable.

9.17 SaMpLe preparatION

Sample preparation for the determination of high-intensity sweeteners is relatively simple.
Carbonatedsoftdrinksaredegassedpriortoanalysis.Liquidbeveragesandtabletopsweetenersare
dilutedordissolvedinwater.Sweetenersincomplexfoodsareextractedwithwateroranappropri-
atesolvent.Then,theextractcanbeclariied,centrifuged,orcleanedbyusingsolid-phaseextrac-
tion(SPE)techniques.
Thephysicochemicalpropertiesoffoodsvary.Variabilityinthecompositionofagivenfood
samplecanbeminimizedwithpropersamplepreparation.Ingeneral,preparationoffoodsamples
iscarriedoutinfoursteps:(1)homogenization;(2)extraction;(3)cleanup;and(4)preconcentration.