Associative and segregative interactions between gelatin and low-methoxy pectin. Part 3. Quantitative analysis of co-gel moduli

The experimental moduli (G′ at 5 °C) reported in the preceding paper for gelatin–calcium pectinate co-gels (pH 3.9; 1.0 wt% pectin; stoichiometric Ca²⁺; 0–10 wt% gelatin) formed in the presence or absence of 1 M NaCl have been analysed using a single adjustable parameter, p, to characterise partition of solvent. The analysis of samples incorporating 1 M NaCl assumed complete segregation of calcium pectinate into dispersed particles in a continuous gelatin matrix, with p defined as the ratio of water/polymer in the gelatin phase divided by the corresponding ratio for the pectin phase. Relative phase volumes at each trial value of p were used to determine the polymer concentration in each phase, and the corresponding moduli were obtained from standard calibration curves. For solvent distributions where the calculated modulus of the continuous gelatin phase was higher than that of the dispersed calcium pectinate phase, co-gel moduli were derived using the Takayanagi isostrain model, and the isostress model was used for the converse situation. The p factors required to give perfect agreement with the moduli observed experimentally were tightly grouped around a single value (p=1.21) for all concentrations of gelatin studied, indicating that the assumption of complete segregation is reasonably valid. Calculated moduli for the gelatin phase were in good agreement with experimental values obtained by melting the gelatin network, centrifuging to sediment the dispersed calcium pectinate particles, and re-gelling the gelatin supernatant. The same p factor (1.21) was used to derive calculated moduli for co-gels formed in the absence of NaCl, where the mixed solutions remain monophasic, by application of the relationship proposed by Davies for bicontinuous composites. The modulus of the calcium pectinate gel, which is already present when the gelatin network forms, was calculated (i) on the assumption of dynamic cross-linking (i.e. using the concentration-dependence of G′ for calcium pectinate alone), and (ii) for permanent cross-linking (by application of deswelling theory). The experimental moduli moved from close agreement with the former model to close agreement with the latter as the gelatin concentration increased from 0 to 10 wt%, consistent with a progressive increase in the extent of rearrangement of the calcium pectinate network required to accommodate the compression introduced by gelation of gelatin.     

Effect of complexation of oxidised corn starch with mineral elements on physicochemical properties

The objective of this study was to determine the effect of complexation of oxidised starch with mineral elements on its physicochemical properties. Corn starch was oxidised with sodium hypochlorite and, afterwards, modified with ions of potassium, magnesium and iron. Thus, native and modified starches were analysed for: contents of mineral elements, colour parameters (L*a*b*), water binding capacity and solubility in water at temperature of 60 and 80 °C. Thermodynamic characteristics of gelatinisation by DSC, molecular weight distribution by GPC, intrinsic viscosity and pasting properties by RVA were studied. The efficiency of incorporation of metal ions into oxidised corn starch was about 30%, 20% and 20% for potassium, magnesium and iron ions, respectively. The complexation with potassium ions caused the greatest changes in the molecular weight distribution and the intrinsic viscosity of starches and viscosity of starch pastes. Only modification of starch with iron ions affected the colour parameters of the starch. Incorporation of metal ions into starch resulted also in changes in its water binding capacity and solubility in water.     

Associative and segregative interactions between gelatin and low-methoxy pectin: Part 2—co-gelation in the presence of Ca

The effect of segregative interactions with gelatin (type B; pI=4.9; 0–10 wt%) on the networks formed by low-methoxy pectin on cooling in the presence of stoichiometric Ca²⁺ at pH 3.9 has been investigated by rheological measurements under low-amplitude oscillatory shear. Samples were prepared and loaded at 85 °C, cooled (1 °C/min) to 5 °C, held for 100 min, and re-heated (1 °C/min) to 85 °C, with measurement of storage and loss moduli (G′ and G″) at 10 rad s⁻¹ and 2% strain. The final values of G′ at 5 °C for mixtures prepared at the same pH without Ca²⁺ were virtually identical to those observed for the same concentrations (0.5–10.0 wt%) of gelatin alone, consistent with the conclusion from the preceding paper that electrostatic (associative) interactions between the two polymers become significant only at pH values below 3.9. Increases in moduli on cooling in the presence of Ca²⁺ occurred in two discrete steps, the first coincident with gelation of calcium pectinate alone and the second with gelation of gelatin. Both processes were fully reversible on heating, but displaced to higher temperature (by 10 °C), as was also observed for the individual components. The magnitude of the changes occurring over the temperature range of the gelatin sol–gel and gel–sol transitions demonstrates that the gelatin component forms a continuous network; survival of gel structure after completion of gelatin melting shows that the calcium pectinate network is also continuous (i.e. that the co-gel is bicontinuous). On progressive incorporation of NaCl (to induce phase separation before, or during, pectin gelation) the second melting process, coincident with loss of calcium pectinate gel structure, was progressively abolished, indicating conversion to a gelatin-continuous network with dispersed particles of calcium pectinate. These qualitative conclusions are supported by quantitative analyses reported in the following paper.     

The influence of Cu(II) ions on physicochemical properties of potato starch oxidised by hydrogen peroxide

The study investigates the influence of Cu(II) ions used as a catalyst on the effectiveness of potato starch oxidation by hydrogen peroxide, and compares the physicochemical properties of the modified starches. The starch was oxidised by H₂O₂ alone and with the addition of Cu(II) ions at three concentrations: 0.1, 0.2 or 0.3 g per 100 g d.m. of starch. The oxidised starches were examined for the content of carboxyl groups, carbonyl groups, amylose and copper, and for water‐binding capacity and water solubility at temperatures of 60 and 80°C. Colour parameters (L*a*b*), susceptibility to retrogradation, thermodynamic characteristics of pasting, intrinsic viscosity and pasting characteristic by RVA were also determined. The results indicate that the concentration of Cu(II) ions added as a catalyst has an effect on both the effectiveness of the oxidation process and the physicochemical properties of starch.     

Production of short‐chain fatty acids following in vitro fermentation of saccharides,saccharide esters,fructo‐oligosaccharides,starches, modified starches and non‐starch polysaccharides

A range of carbohydrates including modified starches and short‐chain fatty acid esters of di‐, tri‐, tetra‐ and polysaccharides were subjected to an in vitro fermentation using human‐derived faecal bacteria. The production of the short‐chain fatty acids (SCFAs) acetate, propionate and butyrate was monitored at 6, 12, 24 and 36 h for all substrates; however, it was found that the proportions of acids produced were reasonably constant after 6 h. Between substrates there was variation in both the proportions and quantities of acids produced. Relative substrate fermentability as measured by total acid production at 24 h was: sucrose octa‐acetate > sucrose > stachyose > pregelatinised starch > Raftilose^® > verbascose > raffinose > starch acetate > bleached starch > phosphated distarch phosphate > locust bean gum > corn starch > oxidised starch = starch sodium octenyl succinate > di‐starch phosphate > acetylated di‐starch adipate = gum arabic > acid‐treated starch > gum tragacanth > gum guar > acetylated di‐starch phosphate = hydroxypropyl di‐starch phosphate > hydroxypropyl starch > pectin > raffinose undeca‐acetate > stachyose acetate > gum karaya = cellulose propionate > cellulose acetate > cellulose > cellulose butyrate > hydroxypropyl methyl cellulose > carrageenan > methyl cellulose. Chemically modified starches were similar to corn starch in the amounts of total SCFAs produced at 24 h. Synthetic sugar esters could have potential application as vehicles to deliver supraphysiological amounts of SCFAs during in vivo studies of colonic fermentation. © 2000 Society of Chemical Industry     

Physicochemical properties of cassava,potato and jicama starches oxidised with organic acids

The oxidising effects of organic (acetic, citric and lactic) acids on the physicochemical properties of starches from cassava, potato and jicama were investigated. Cassava starch oxidised with lactic and citric acids had the highest carbonyl contents (5.43 and 5.84 g kg^?1 respectively), while oxidised potato starch had the highest carboxyl contents. Oxidised jicama starch showed the lowest carbonyl and carboxyl contents. Oxidation increased the maximum viscosity of cassava starch (from 426.61 to 670.11 relative viscosity units (RVU)) and jicama starch (from 160.17 to 561.50 RVU) but decreased that of potato starch (from 669.44 to 206.92 RVU). When carbonyl and carboxyl groups were incorporated into jicama starch granules, the resistance of these granules to stirring at constant temperature (holding) increased, as did their final and retrogradation viscosities. However, the behaviour of oxidised cassava and potato starches, as indicated by a Rapid Visco Analyser, was different. The highest values of endotherm enlargement were found for native and oxidised jicama starch, while the lowest values were found for native and oxidised cassava starch. Native and oxidised potato starch had the highest enthalpy values (14.30–18.30 J g^?1), while jicama starch had the lowest (9.50–11.9 J g^?1). The high intrinsic viscosity of native potato starch was attributed to B‐type starch with a longer‐than‐average amylopectin chain length and a lower degree of crystallinity. Oxidised granules showed little erosion in the form of grooves; on the contrary, oxidation left the grains with a very smooth surface. Copyright © 2007 Society of Chemical Industry     

Retention of apple starch in production of pectin by the aluminum pectinate procedure]

Apple pectin produced by means of the aluminum pectinate procedure contains less starch than apple pectin obtained by precipitation with ethanol. The degradatin of the starch which occurs during production depends to a great extent upon the conditions of pomace digestion. The absorption maxima of the amylose-iodine complexes range in general from 550 to 570 nm. Model experiments with highly esterified pectin and partially degraded (by mechanolysis) apple starches were performed to establish favourable conditions for fractionating the pectin and starch components which are obtained when the pectin is precipitated as aluminum pectinate and when the granular coagulate is washed with water.     

Interactions of starch with a cyanidin–catechin pigment (vignacyanidin) isolated from Vigna angularis bean

A cyanidin–catechin pigment isolated from adzuki bean (vignacyanidin) interacted with starch. The pigment had absorption maxima at 530 and 540 nm at pH 2.0 and 6.8, respectively, and starch (10 and 100 mg ml⁻¹) increased the absorbance, shifting the absorption maxima to longer wavelengths. Nitrite oxidised vignacyanidin at pH 2.0, and the oxidation resulted in the production of nitric oxide (NO). Rates of the oxidation and the NO production were enhanced by starch. Vignacyanidin inhibited α-amylase-catalysed digestion of starch at pH 6.8, and amylose digestion was more effectively inhibited than amylopectin digestion. The above results suggest (i) that binding of the pigment to starch increased the accessibility of nitrous acid to the pigment, and (ii) that the binding reduced the digestibility of starch by α-amylase. Possible functions of the pigment in the stomach and the intestine are postulated, taking the above results into account.     

A Gel Chromatographic Study of Molecular Weight Distribution in Native Wheat Starch and Its Oxidation Products

The distribution of molecular size of the native starch prepared according to a new method and of oxidised products of starch has been investigated with the help of agarose gel filtration. It has been noticed that the curve of the molecular distribution of the native wheat starch (product A) shows a big peak excluded by the gel with M̄_W > 2 · 10⁶ comprising about 58% of the sample and a part fractioned by the gel within the area 1 · 10⁴ < M̄_W < 2 · 10⁶. Comparative gel filterings of native maize, tapioca and potato starch have shown that the distribution of molecular size of wheat starch (A) most resembles that of maize starch. Tapioca starch and especially potato starch have a somewhat lower percentage of molecules within the part fractioned by the gel than wheat starch (A). Native wheat starch, product B has a somewhat higher percentage of molecules within the area 1 · 10⁵ > M̄_W > 2 · 10⁴ than the other native types of starch. Heat-treatening and oxidation of native starch causes a decrease or a disappearance of the macromolecular excluded part of the sample and instead increases the molecules within the fractioning area of the gel, M̄_W < 2 · 10⁶. The used gel chromatographic method is thus very suitable when investigating the distribution of molecules of oxidised starch products and in product control.     

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

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. Copyright © 2003 Society of Chemical Industry     

Scanning Electron Microscopy of Chemically and Enzymatically Treated Black Gram (Phaseolus mungo) and Ragi (Eleusine coracana) Starch Granules

Amylolysis of chemically - treated starch granules of black gram and ragi was followed colorimetrically and by scanning electron microscopy. From the percent hydrolysis values it was evident that oxidation with periodate resulted in considerable resistance, whereas urea treatment resulted in granule susceptibility towards in vitro amylolysis. The action of α-amylase and/or glucoamylase on periodate oxidised black gram starch showed on SEM sufficient enlargement of the granules and hollow craters as well; whereas similar treatment on oxidised ragi starch resulted in folded, distorted and deformed granules. Treatment with 8M urea resulted in the total loss of characteristic granular shape and formation of the socalled amylopectin “sacs”. Like waxy starches the latter showed an increase in enzymic activity. Particularly, the synergistic action of α-amylase and glucoamylase on ureatreated starches virtually collapsed the granules, forming innumerable “flat” ribbon like fragments.     

Development of oxidised and heat-moisture treated potato starch film

This study investigated the effects of sodium hypochlorite oxidation and a heat-moisture treatment of potato starch on the physicochemical, pasting and textural properties of potato starches in addition to the water vapour permeability (WVP) and mechanical properties of potato starch films produced from these starches. The carbonyl contents, carboxyl contents, swelling power, solubility, pasting properties and gel texture of the native, oxidised and heat-moisture treated (HMT) starches were evaluated. The films made of native, oxidised and HMT starches were characterised by thickness, water solubility, colour, opacity, mechanical properties and WVP. The oxidised and HMT starches had lower viscosity and swelling power compared to the native starch. The films produced from oxidised potato starch had decreased solubility, elongation and WVP values in addition to increased tensile strength compared to the native starch films. The HMT starch increased the tensile strength and WVP of the starch films compared to the native starch.     

Effect of Asian sea bass bio-calcium on textural,rheological, sensorial properties and nutritive value of Indian mackerel fish spread at different levels of potato starch

Effect of potato starch (2%–4%) and Asian sea bass bone bio-calcium (BC) (0%–10%) on characteristics of Indian mackerel fish spread was investigated. Starch levels had higher impact than bio-calcium concentration on characteristics of fish spread (P < 0.05). Firmness, consistency and cohesiveness of fish spread were raised with increasing starch and BC levels (P < 0.05). Highest lightness (L*) was found in fish spread added with 2% starch and 10% BC (P < 0.05). Highest a*, b*, C*-values but lowest hue angle were obtained in fish spread added with 4% starch and 10% BC (P < 0.05). Higher G' and viscosity were observed in sample added with 4% starch when BC was incorporated at higher level. All fish spreads generally showed shear thinning flow behaviour. Higher acceptability was attained for fish spread containing 4% starch and 10% BC without grittiness. This fish spread showed higher ash with lower moisture, protein and lipid contents than those without BC. Calcium solubility of fish spread was augmented after in vitro gastrointestinal tract system when fortified with 10% BC, and higher solubility of calcium was also noticeable, compared to BC itself. Overall high PUFA, acceptable PV and TBARS value were attained for fish spread fortified with 4% starch and 10% BC.     

Creation of reduced fat foods: Influence of calcium-induced droplet aggregation on microstructure and rheology of mixed food dispersions

The impact of calcium-induced fat droplet aggregation on the microstructure and physicochemical properties of model mixed colloidal dispersions was investigated. These systems consisted of 2 wt% whey protein-coated fat droplets and 4 wt% modified starch granules heated to induce starch swelling (pH 7). Optical and confocal microscopy showed that the fat droplets were dispersed within the interstitial region between the swollen starch granules. The structural organisation of the fat droplets within these interstitial regions could be modulated by controlling the calcium concentration: (i) at a low calcium concentration the droplets were evenly distributed; (ii) at an intermediate calcium concentration they formed a layer around the starch granules; (iii) at a high calcium concentration they formed a network of aggregated droplets. Paste-like materials were produced when the fat droplets formed a three-dimensional network in the interstitial region. The properties of fat droplet–starch granule suspensions can be modulated by altering the electrostatic interactions to alter microstructure.     

New insights on the characteristics of starch network

This study investigated the roles of granule-associated proteins (0.16% w/w d.b.) in mungbean starch (MBS, Vigna radiata (L) Wilczec) on the microstructural and thermo-mechanical properties of MBS gel and thermoplastic. Gelatinization at high water content (9–13% w/w) and intermediate water content (40–60% w/w) ranges generated microscopic multi-phase structure of swollen MBS granules, separated starch-rich phase and separated protein-rich phase. The presence of 50 mM calcium lactate plus 25 mM cysteine lowered the compressive stress of MBS gels at high water content range, increased T_o, T_p and T_e of MBS slurries at intermediate water contents, and lowered the storage modulus of the protein-rich phase in thermoplastic MBS at its T_g (P < 0.05). This study revealed the new insights on the significance of granule-associated proteins in the regulation of the envelope permeability, the leaching of starch and the thermo-mechanical characteristics of starch network over a wide range of water contents.     

Conformational ordering and gelation of gelatin in mixtures with soluble polysaccharides

Previous studies have shown that conformationally disordered, soluble biopolymers cause large enhancements in self-association of calcium pectinate, thermally denatured whey protein and gelling maltodextrin under conditions where the pre-gel solutions remained as a single phase. The purpose of the present work was to screen for similar enhancements in gel strength and rate of conformational ordering of gelatin on incorporation of soluble, disordered polysaccharides. Type B gelatin was used at a fixed concentration of 5.0 wt%, at a pH well above its isoelectric point of ∼4.5. Mixtures were prepared at 45 °C, where the gelatin is in the disordered coil form. Gel strength was characterised as Young's modulus (E), derived from the initial slope of compression curves for gels formed by holding for 16 h at 5 °C. Rate of conformational ordering of gelatin (triple-helix formation) was monitored by changes in optical rotation during and after rapid quenching from 45 to 5 °C. The polysaccharides studied were carboxymethylcellulose (CMC), hydroxypropylmethylcellulose (HPMC), guar gum, gum arabic, dextran and inulin, all of which were used in compression testing. Combinations of gelatin with HPMC and guar gum became immediately turbid on mixing and could not, therefore, be included in the samples characterised by optical rotation. The other mixtures remained homogeneous (i.e. single-phase) on holding at 45 °C. The results obtained were entirely negative. Incorporation of the soluble polysaccharides caused no significant changes in Young's modulus, and optical rotation values remained within ∼10% of those for gelatin alone. It is suggested that the enthalpic advantage of segregation is sufficient to overcome the small reduction in entropy from association of conformationally immobile subunits in gelation of calcium pectinate, whey protein and maltodextrin, but not sufficient to overcome the much greater loss of entropy from conversion of flexible gelatin coils to rigid triple helices.     

Comparative study on nutrient and anti‐nutrient changes in Ikivunde and Inyange,two Burundian traditionally processed cassava products

A comparative study on nutrients and anti‐nutrients in Ikivunde and Inyange and a correlation of nutrients and anti‐nutrients with fermentation time during processing of both products were carried out. In Ikivunde, all nutrients and anti‐nutrients had high negative correlations with fermentation time, except for crude fibre, fats and calcium, which showed high positive correlations. In Inyange, all nutrients and anti‐nutrients were positively correlated with fermentation time, except for starch, ash, zinc, magnesium, calcium, glutamine and alanine. Analysis of variance showed that Ikivunde and Inyange differed significantly (P < 0.05) in reducing sugar, protein, ash, cyanide, phytic acid and tannin contents at various fermentation times. There were also significant differences (P < 0.05) between Ikivunde and Inyange in starch and fat contents at 48, 72, 96 and 120 h, while for crude fibre a significant difference was observed from 72 h until the end of fermentation. At the end of the fermentation period (120 h), Inyange had higher starch, protein, amino acid, reducing sugar, ash, iron, zinc, potassium, sodium, magnesium, fat, cyanide, phytic acid and tannin contents but lower crude fibre and calcium contents than Ikivunde. The results from this study showed that Inyange contains more nutrients and anti‐nutrients than Ikivunde. Copyright © 2006 Society of Chemical Industry     

Effects of starch on nitrous acid-induced oxidation of kaempferol and inhibition of α-amylase-catalysed digestion of starch by kaempferol under conditions simulating the stomach and the intestine

Kaempferol glycosides can be hydrolyzed to their aglycone kaempferol during cooking under acidic conditions and in the oral cavity and the intestine by glycosidases. Kaempferol was oxidised by nitrite under acidic conditions (pH 2.0) to produce nitric oxide (NO), and the nitrite-induced oxidation of kaempferol was enhanced and inhibited by 10 and 100 mg of starch ml⁻¹, respectively. The opposite effects of starch were discussed by considering the binding of kaempferol to starch and starch-dependent inhibition of the accessibility of nitrous acid to kaempferol. Kaempferol inhibited α-amylase-catalysed starch digestion by forming starch/kaempferol complexes, and the inhibitory effects increased in the order of amylopectin < soluble starch < amylose. The different effects of kaempferol were discussed to be due to the difference in binding sites of kaempferol between amylose and amylopectin. From the present study, dual-function of kaempferol became apparent in the digestive tract.     

Nutrients and antinutritional factors in faba beans as affected by processing

 The influence on the nutrients content (soluble sugars, starch, dietary fibre and calcium) and antinutritional factors (α-galactosides and phytic acid) of faba beans (Vicia faba, L. major) of soaking in different solutions (distilled water, citric acid, and sodium bicarbonate solutions), cooking the presoaked seeds, dry-heating and germination have been studied. Soaking brought about a decrease in starch, sucrose, fructose, α-galactoside, dietary fibre and calcium content. Glucose was detected in soaked faba beans and soaking did not modify the phytic acid content. Cooking the presoaked faba beans produced a slight decrease in starch, and caused a general drop in α-galactosides, dietary fibre, calcium and phytic acid, with the exception of seeds presoaked in sodium bicarbonate in which cooking did not cause any appreciable changes in comparison with the unprocessed faba beans. Germination caused a sharp reduction in α-galactoside and phytic acid content after 6 days, whilst starch and dietary fibre decreased slightly. Calcium, however, enjoyed a slight increment during germination which was related to the decrease in the content of hemicellulose and phytic acid. Dry-heating caused a noticeable reduction in all the nutrients and antinutritional factors investigated. Of all the treatments studied, germination appears to be the best processing method to obtain nutritive faba bean flour, since it caused a minor decrease in starch content (15% loss), the largest α-galactoside and phytic acid removal (94% and 45%, respectively) and provided an appreciable amount of dietary fibre. Received: 21 December 1997 / Revised version: 19 February 1998     

Physicochemical, crystallinity, pasting and morphological properties of bean starch oxidised by different concentrations of sodium hypochlorite

The effect of bean starch oxidation at different active chlorine concentrations (0.5%, 1.0% and 1.5%) on the physicochemical, crystallinity, pasting and morphological properties of starch was investigated. The carbonyl content, carboxyl content, starch colour, swelling power, solubility, gel hardness, X-ray crystallinity, pasting properties, gelatinisation characteristics and morphology of the starches were evaluated. The bean starch oxidised with 0.5% active chlorine had the characteristic of a slightly crosslinked starch. As compared to the native and 0.5% active chlorine-oxidised starches, active chlorine at 1.0% and 1.5% increased the carbonyl content, carboxyl content and solubility of the starches. Moreover, these concentrations of active chlorine decreased the swelling power, gel hardness, relative crystallinity, breakdown, peak viscosity and setback, as compared to the native and 0.5% active chlorine-oxidised starches. The starch granules oxidised with 1.5% active chlorine had imperfections in their structure, and its surface appears to be rougher than the other granules.