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Article: pH dependent amylase activity and pasting properties of sweet potato flour and wheat- Sweet potato composite flours

TitlepH dependent amylase activity and pasting properties of sweet potato flour and wheat- Sweet potato composite flours
Authors
KeywordsAmylase Activity
Composite Flours
Pasting Properties
Sweet Potato Flours
Issue Date1998
PublisherUniversity of the Philippines at Los Banos, College of Agriculture. The Journal's web site is located at http://www.uplb.edu.ph/journal/philagri/
Citation
Philippine Agricultural Scientist, 1998, v. 81 n. 3-4, p. 141-150 How to Cite?
AbstractDifferences in pasting profiles (measured with a Rapid Visco-Analyser, RVA) of sweet potato flour (SPF) of 4 different genotypes were due mainly to differences in diastatic activity. Furthermore, at 25% (w/w) substitution of SPF with wheat flour, the pasting of the composite flour was greatly altered compared to 100% wheat flour. Addition of 25% (w/w) CL-946-25 flour, an SPF with high amylase activity, decreased the peak viscosity (PV) by 60%, but addition of 25% CL-1489-89, an SPF with minimal amylase activity, lowered the peak viscosity by only 24%. This sensitivity of wheat starch to sweet potato amylases is a major constraint to its use in composite flours. Composite flours pasted over a pH range of 3 to 11 showed marked differences in the pasting parameters. At pH 4 and at pH 10-11, there were no significant differences in the pasting profiles of the SPF composite flours as compared to all-wheat flour, due to amylase inhibition under extreme pH conditions. Composite flours with added mercuric chloride (20 ppm) (an amylase inhibitor which did not alter the pH of the flour slurry) showed no significant differences in pasting profiles compared to composite flours to which various acidulants were added. Thus food additives such as ascorbic acid, HCl and lactic acid can be used in some cases to reduce the effect of amylases. Where end-product quality would be adversely affected by low pH, screening for sweet potato varieties with minimal amylase activity would be appropriate and can be done using the RVA. Screening for this purpose should be done at around pH 6 where the sweet potato amylase activity is at the optimum.
Persistent Identifierhttp://hdl.handle.net/10722/178896
ISSN
2015 Impact Factor: 0.266
2015 SCImago Journal Rankings: 0.142
References

 

DC FieldValueLanguage
dc.contributor.authorCollado, LSen_US
dc.contributor.authorMabesa, LBen_US
dc.contributor.authorCorke, Hen_US
dc.date.accessioned2012-12-19T09:50:31Z-
dc.date.available2012-12-19T09:50:31Z-
dc.date.issued1998en_US
dc.identifier.citationPhilippine Agricultural Scientist, 1998, v. 81 n. 3-4, p. 141-150en_US
dc.identifier.issn0031-7454en_US
dc.identifier.urihttp://hdl.handle.net/10722/178896-
dc.description.abstractDifferences in pasting profiles (measured with a Rapid Visco-Analyser, RVA) of sweet potato flour (SPF) of 4 different genotypes were due mainly to differences in diastatic activity. Furthermore, at 25% (w/w) substitution of SPF with wheat flour, the pasting of the composite flour was greatly altered compared to 100% wheat flour. Addition of 25% (w/w) CL-946-25 flour, an SPF with high amylase activity, decreased the peak viscosity (PV) by 60%, but addition of 25% CL-1489-89, an SPF with minimal amylase activity, lowered the peak viscosity by only 24%. This sensitivity of wheat starch to sweet potato amylases is a major constraint to its use in composite flours. Composite flours pasted over a pH range of 3 to 11 showed marked differences in the pasting parameters. At pH 4 and at pH 10-11, there were no significant differences in the pasting profiles of the SPF composite flours as compared to all-wheat flour, due to amylase inhibition under extreme pH conditions. Composite flours with added mercuric chloride (20 ppm) (an amylase inhibitor which did not alter the pH of the flour slurry) showed no significant differences in pasting profiles compared to composite flours to which various acidulants were added. Thus food additives such as ascorbic acid, HCl and lactic acid can be used in some cases to reduce the effect of amylases. Where end-product quality would be adversely affected by low pH, screening for sweet potato varieties with minimal amylase activity would be appropriate and can be done using the RVA. Screening for this purpose should be done at around pH 6 where the sweet potato amylase activity is at the optimum.en_US
dc.languageengen_US
dc.publisherUniversity of the Philippines at Los Banos, College of Agriculture. The Journal's web site is located at http://www.uplb.edu.ph/journal/philagri/en_US
dc.relation.ispartofPhilippine Agricultural Scientisten_US
dc.subjectAmylase Activityen_US
dc.subjectComposite Floursen_US
dc.subjectPasting Propertiesen_US
dc.subjectSweet Potato Floursen_US
dc.titlepH dependent amylase activity and pasting properties of sweet potato flour and wheat- Sweet potato composite floursen_US
dc.typeArticleen_US
dc.identifier.emailCorke, H: harold@hku.hken_US
dc.identifier.authorityCorke, H=rp00688en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.scopuseid_2-s2.0-23644447915en_US
dc.identifier.hkuros45636-
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-23644447915&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume81en_US
dc.identifier.issue3-4en_US
dc.identifier.spage141en_US
dc.identifier.epage150en_US
dc.publisher.placePhilippinesen_US
dc.identifier.scopusauthoridCollado, LS=6603767372en_US
dc.identifier.scopusauthoridMabesa, LB=6506652897en_US
dc.identifier.scopusauthoridCorke, H=7007102942en_US

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