Degradation of Corn Starch under the Influence of Gamma Irradiation

Saadany, R. M. A. El; Saadany, F. M. El; Foda, Y. H.

doi:10.1002/star.19760280605

Cited by 10 publications

(7 citation statements)

References 7 publications

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“…1B) were similar to that of the flour. The result was in agreement with the previous reports of the effects of irradiation on pasting viscosities of various starches [2,8,13,[18][19][20][21][22]. The reduction in viscosity indicated that gamma irradiation caused molecular degradation to starch granules.…”

Section: Pasting Viscositysupporting

confidence: 92%

“…Crystallinity of irradiated starch increases with increasing radiation dosages in wheat and rice starches [10,13], and decreased in potato starch [15]. Increase in irradiation dosage decreases viscosity and increases water solubility and acidity of starches [8,13,[18][19][20][21][22]. The gelatinization enthalpy was reported to increase [16,17] or decrease [2,11,15] gradually with increasing irradiation dosage.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Physical Properties of Flour and Starch Obtained from Gamma-Irradiated White Rice

2005

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Physical and structural characteristics of rice flour and starch obtained from gammairradiated white rice were determined. Pasting viscosities of the rice flour and starch, analyzed by using a Rapid Visco Analyser, decreased continuously with the increase in irradiation dosage. Differential scanning calorimetry showed that gelatinization onset, peak and conclusion temperatures of rice flour and starch changed slightly but the enthalpy change decreased significantly with increase of irradiation dosage. All irradiated starch displayed an A-type X-ray diffraction pattern like the native starch. Gel permeation chromatography showed that the blue value ratio of the first peak (amylopectin) to the second one (amylose) decreased with the increase of the irradiation dosage. The weight-average molecular weight (M w ) and gyration radius (R z ) of amylopectin analyzed by using HPSEC-MALLS-RI (high-performance size-exclusion chromatography equipped with multiangle laser-light scattering and refractive index detector) decreased gradually from 1.48610 9 (M w ) and 384.1 nm (R z ) of native rice starch to 2.36610 8 (M w ) and 236.8 nm of 9 kGy-irradiated starch. The branch chainlength distribution of amylopectins determined by HPAEC-ENZ-PAD (high-performance anion-exchange chromatography with amyloglucosidase post-column on-line reactor and pulsed amperometric detector) showed that gamma irradiation had no significant effect on the amylopectin branch chains with 13DP24 and 37DP, but produced more branch chains with 6DP12 when the irradiation dosage was less than 9 kGy. It might be deduced that gamma irradiation caused the breakage of the amylopectin chains at the amorphous regions, but had little effects on the crystalline regions of starch granules, especially at low dosage irradiation.

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Section: Pasting Viscositysupporting

confidence: 92%

Section: Introductionmentioning

confidence: 99%

Characterization of Physical Properties of Flour and Starch Obtained from Gamma-Irradiated White Rice

2005

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“…Much research has been done on the effects of γ-irradiation on starch properties from various sources (4,(6)(7)(8)(9)(10)(11)(12). There are some reviews available on the properties of irradiated starches (13,14).…”

Section: Introductionmentioning

confidence: 99%

“…The crystallinity of irradiated starch becomes higher with increasing radiation doses in corn and rice starches (7,16). Increased radiation dose is invariably associated with lower viscosity and higher water solubility and acidity of starches among various studies (4,(7)(8)(9)(10)(11)13). Swelling power is generally lowered (7,9), but may become higher under 20 kGy treatment, and then declines rapidly (8).…”

Section: Introductionmentioning

confidence: 99%

Pasting Properties of γ-Irradiated Rice Starches as Affected by pH

Bao

Corke

2001

J. Agric. Food Chem.

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Changes in the viscosity properties of gamma-irradiated rice starches (from 1 to 25% amylose content) from four genotypes (JY293, Jiayu 293; XS, Xiushui; ZF504, Zhefu 504; and ZXN, Zaoxiannuo) during pasting in water (pH 7) or in different pH solutions were studied using a rapid visco analyzer. Peak viscosity (PV) of all native rice starches was little affected at pH 4 and 10, while hot paste viscosity (HPV) and cool paste (final) viscosity (CPV) were generally lower at pH 4 and higher at pH 10 as compared with that at pH 7. The PV, HPV, and CPV of gamma-irradiated starches were higher at pH 4 and lower at pH 10 than pH 7. All viscosity characteristics of native rice starches were reduced in stronger alkali (pH 11.5) or acidic (pH 2.5) solutions. However, the gamma-irradiated starches were substantially higher at pH 2.5 but lower at pH 11.5, indicating that the effect of irradiation was highly pH dependent. The swelling volume of irradiated ZF504 and JY293 starch at all irradiation levels was higher at pH 4 than pH 7, while the values were lowest at pH 2.5. The irradiated ZXN and XS starches had higher swelling volumes at pH 4 and pH 2.5 than pH 7. Differential scanning calorimetry analysis showed that gamma-irradiation caused progressively lower gelatinization peak temperature (T(p)) and higher gelatinization range (T(r)) at pH 7. T(p) was higher and T(r) was lower at a much stronger acidic condition (pH 1) for both native and irradiated starches. The possibility of using viscosity changes in low pH for the detection of irradiated starch was discussed.

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“…Starch is degraded by ionizing radiation, resulting in decrease in viscosity (El-Saadany et a!., 1976;Nene et al, 1975;Roushdi et al, 1983). The viscosities of black and white peppers which contain high amounts of starch are lowered by irradiation, and measurement of viscosity has been proposed as a method to detect irradiated black and white peppers (Farkas et al, 1990a, b;Heide and Boegl, 1990;Mohr and Wichmann, 1985).…”

Section: Introductionmentioning

confidence: 99%

Irradiation Effects on Pepper Starch Viscosity

Hayashi

Todoriki

Kohyama

1994

Journal of Food Science

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Viscosity of irradiated black and white peppers decreased depending upon dosage, and viscosity was not lowered by other decontamination treatments such as super-heated steam or fumigation with ethylene oxide gas. Viscosity values of unirradiated pepper varied with the lot and harvesting locality. A normalized parameter, viscosity/starch amount, of a 10% suspension of unirradiated pepper was always higher than 190 mPa.s/g of starch and that of irradiated pepper (5 kGy) was always lower than 180 mPa.s/g of starch, irrespective of lot and harvesting locality.

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Degradation of Corn Starch under the Influence of Gamma Irradiation

Cited by 10 publications

References 7 publications

Characterization of Physical Properties of Flour and Starch Obtained from Gamma-Irradiated White Rice

Characterization of Physical Properties of Flour and Starch Obtained from Gamma-Irradiated White Rice

Pasting Properties of γ-Irradiated Rice Starches as Affected by pH

Irradiation Effects on Pepper Starch Viscosity

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