Enzymeconcentration
Owing to the comparabilityof the preparationsSavinase,Properase L and
Esperase (concerning theircharacterization,production and also efficiency) the
influence of the enzymeconcentrationon the scaling-offof the foulingwas only
analyzedfor Savinase.For the trial seriesdisplayed in Fig. 32.7,0.25,0.50,1.0,
2.5 and 5.0 mL of the liquidenyzmeconcentrate(corresponding to 0.0025%,
0.005%, 0.01%, 0.025%and 0.05%) wereaddedto the solutionused(10 L,
60 ÎC, pH 9.5).
A cleardependence of the kineticsuponthe depositremoval, or of the
remaining soiling, after45 minutes on the test surfacewas seen,as longas the
test surfacedid not havea metallic brightappearancebeforethe expirationof a
45-minute trial.Whetheran increase exceeding 0.05%bringsabouta further
enhancementin deposit removalhas not beeninvestigated as for a possible
applicationof the enzymatic cleaningprocess in practice,the costs of the
chemicals havealso to be takeninto account, apart fromotherparameters.For a
comparison witha conventionalcleaning process, 0.05%as a justifiable upper
limitseemsto be reasonable.
pH
Figure32.5(Esperase)indicatesa dependenceof the deposit-removingeffect of
the enzymeuponthe pH valueof the solution.However, thereis no unam-
biguous proofas to whether the increase of the deposit-removing kineticscan be
deduced fromthe enzyme, or primarily fromthe NaOH,as the pH valueof 12.0
corresponds to a 0.5%NaOHsolution, whichalso has a deposit-removaleffect
Fig. 32.7 Influenceof enzymeconcentrationon depositremovalwithSavinase’.Enzymatic cleaning in foodprocessing 529