title: Effect of alkali and oxidative treatments on the physicochemical, pasting, thermal and morphological properties of corn starch.
abstract: BACKGROUND
  Few studies on starch modifications using different chemical agents are available in the literature, and no reports were found on the combined effect of oxidation and alkaline treatment of corn starch. Thus this work evaluated the physicochemical, pasting, morphological, cystallinity and thermal properties of chemically modified corn starch, after either the isolated or combined action of alkaline (sodium hydroxide) and oxidative (sodium hypochlorite) treatments.
  
  
  RESULTS
  The highest values for the sum of carbonyl and carboxyl and enzymatic hydrolysis occurred in starches submitted to oxidative treatment at high active chlorine concentrations. The alkali treatment in isolation modified the pasting properties, reduced the paste temperature and increased the peak viscosity, breakdown, final viscosity and setback of starches. Starch modified by the action of sodium hypochlorite and hydroxide in combination presented more severe damage on granule surfaces.
  
  
  CONCLUSIONS
  The results show that corn starch modified by the combined action of oxidative and alkaline treatments should be studied more, especially at the concentration limit of sodium hydroxide where gelatinization occurs. Under these conditions the effect of oxidation can be more intense and thus allow the production of starches with different properties and an increase in their industrial applications.
authors: Department of Agroindustrial Science and Technology, Federal University of Pelotas, 96010-900, Pelotas, RS, Brazil. franciela@ibest.com.br
authors: Franciela
authors: F
authors: Spier
authors: Elessandra da Rosa
authors: Eda R
authors: Zavareze
authors: Ricardo
authors: R
authors: Marques e Silva
authors: Moacir Cardoso
authors: MC
authors: Elias
authors: Alvaro Renato Guerra
authors: AR
authors: Dias
mesh_terms: D002424:Caustics / Q000737:chemistry*; D055598:Chemical Phenomena; D003460:Crystallization; D005511:Food Handling; D005782:Gels; D006358:Hot Temperature; D006868:Hydrolysis; D008855:Microscopy, Electron, Scanning; D009994:Osmolar Concentration; D016877:Oxidants / Q000737:chemistry*; D010084:Oxidation-Reduction; D012639:Seeds / Q000737:chemistry*; D012972:Sodium Hydroxide / Q000737:chemistry; D012973:Sodium Hypochlorite / Q000737:chemistry; D013213:Starch / Q000737:chemistry* / Q000648:ultrastructure; D013535:Suspensions; D044366:Transition Temperature; D014783:Viscosity; D003313:Zea mays / Q000737:chemistry*
chemical_list: D002424:Caustics; D005782:Gels; D016877:Oxidants; D013535:Suspensions; D012972:Sodium Hydroxide; D013213:Starch; D012973:Sodium Hypochlorite