A Study of the Mild Oxidation of Wheat Starch and Waxy Maize Starch by Sodium Hypochlorite in the Alkaline ph Range

Schmorak, J.; Mejzler, D.; Lewin, Menachem

doi:10.1002/star.19620140805

Cited by 27 publications

(6 citation statements)

References 27 publications

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“…The reaction rate of hypochlorite oxidation of amylopectin fractionated from corn starch has been shown to depend on pH, being most rapid at pH 7 and very slow at pH 11-13 [6]. Similar results have been obtained with granular wheat and waxy maize starches [4]. In potato starch oxidation the presence of bromine and cobalt * Epoo (Finland), ** Raisio (Finland).…”

Section: Introductionmentioning

confidence: 59%

“…The oxidizing agent has been claimed to penetrate deeply into the granule, acting mainly on the amorphous regions [2,3]. On the other hand the oxidation rate was reported to be considerably higher when oxidation was conducted in gelatinized starch dispersion as compared with granule suspensions, and it was suggested that only parts of the native granules are available for oxidation [4]. Greater modification was needed for high-amylose starch as compared with normal starch to produce stable dispersions [5].…”

Section: Introductionmentioning

confidence: 99%

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Hypochlorite Oxidation of Barley and Potato Starch

et al. 1995

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The oxidation of barley and potato starches was studied using sodium hypochlorite as oxidant. The degree of oxidation, depolymerization during oxidation and gel formation of barley starch was compared with the properties of potato starch. The effect of oxidation on gelatinization of starches as well as on amylose‐lipid complex of barley starch was also analyzed. Barley starch was not as easily oxidized as potato starch. In both starches depolymerization of amylopectin and amylose occurred during oxidation. Based on the dissociation enthalpy of amylose‐lipid complex, the lipid‐bound amylose in barley starch was readily oxidized. Oxidation decreased the gelling ability of barley starch. At high level of oxidation gel formation by potato starch was much slower and weaker than by barley starch.

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Section: Introductionmentioning

confidence: 59%

Section: Introductionmentioning

confidence: 99%

Hypochlorite Oxidation of Barley and Potato Starch

et al. 1995

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“…The factors affecting hypochlorite oxidation include pH, temperature, hypochlorite concentration, starch molecular structure, and starch origin [5]. The effects of starch molecular structure and starch origin on oxidation are still not well understood despite previous studies [7][8][9][10][11]. One study showed that rice starch consumed more hypochlorite but had a lower carboxyl group content and a higher apparent viscosity compared with corn starch in hypochlorite-oxidized reactions, possibly because of their differences in physical and molecular structure [12].…”

Section: Introductionmentioning

confidence: 99%

Characterization of Different Starches Oxidized by Hypochlorite

2001

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The effects of starch origin (potato, corn, and rice starches) and hypochlorite level (NaOCl, 0 .8% and 2% w/w) on the structures and physicochemical properties of oxidized starches were investigated. Carboxyl and carbonyl group contents of oxidized starches increased with increasing NaOCl level, with potato starch having the highest and corn starch having the lowest carboxyl groups content at both NaOCl levels. Oxidation generally reduced the pasting temperature and viscosity of native starches as demonstrated by using a Rapid Visco Analyser. The peak viscosities of oxidized rice and corn starches were higher than those of their native counterparts at 0.8% NaOCl. The morphology of starches was not altered and X-ray diffraction patterns of all the starches remained unchanged after oxidation. Oxidized starch batters exhibited greater adhesions than did native starch batters, with rice starch batter exhibiting the greatest adhesion. Carbohydrate profiles by high-performance size-exclusion chromatography indicated that both amylopectin and amylose were degraded during oxidation. The level of oxidation was largely dependent on the degree of crystallinity of starch and the degree of polymerization of amylose, whereas the adhesion property of oxidized starch was mainly attributed to its granular size and shape.

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“…Oxidation causes depolymerisation of the starch and introduces carboxyl and carbonyl functional groups. 7 Oxidised starch is produced by reacting starch with a specified amount of oxidising agent under controlled temperature and pH. 8 Many reagents such as periodate, chromic acid, permanganate, nitrogen dioxide and sodium hypochlorite have been used for oxidising starch.…”

Section: Introductionmentioning

confidence: 99%

Functional properties and retrogradation behaviour of native and chemically modified starch of mucuna bean (Mucuna pruriens)

2003

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Mucuna bean (Mucuna pruriens) starch was isolated and subjected to chemical modification by oxidation and acetylation. The proximate analysis of the non-starch components of the native starch on a dry weight basis was 92 g kg −1 moisture, 5 g kg −1 ash, 2 g kg −1 fat, 7 g kg −1 crude fibre and 19 g kg −1 protein. Chemical modification reduced the values for all the non-starch components except the moisture level. For all the samples, swelling power and solubility increased as the temperature increased in the range 50-90 • C. The swelling power of mucuna native starch (MNS) and mucuna acetylated starch (MAS) increased with increasing acidity and alkalinity, while that of mucuna oxidised starch (MOS) only increased with increasing pH in the acidic range. The maximal solubility of all the starches was observed at pH 12. All the starch samples absorbed more oil than water. The lowest gelation concentration followed the trend MAS < MNS < MOS. Chemical modification reduced the gelatinisation temperature (Tp), while peak viscosity (Pv), hot paste viscosity (Hv) and cold paste viscosity (Cv) decreased after oxidation but increased following acetylation. The setback tendency of the native starch was reduced significantly after chemical modification. However, the breakdown value of MNS, 65 BU (Brabender units), was lower than that of MOS (78 BU) but higher than that of MAS (40 BU). Differential scanning calorimetry studies of gelatinisation and retrogradation revealed that chemical modification reduced the onset temperature (T o ), peak temperature (T p ) and conclusion temperature (T c ). Oxidation and acetylation reduced the gelatinisation and retrogradation enthalpies of the native starch. The enthalpy of retrogradation of the starches increased as the length of storage increased.

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A Study of the Mild Oxidation of Wheat Starch and Waxy Maize Starch by Sodium Hypochlorite in the Alkaline ph Range

Cited by 27 publications

References 27 publications

Hypochlorite Oxidation of Barley and Potato Starch

Hypochlorite Oxidation of Barley and Potato Starch

Characterization of Different Starches Oxidized by Hypochlorite

Functional properties and retrogradation behaviour of native and chemically modified starch of mucuna bean (Mucuna pruriens)

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