Irradiated Starch Research Articles

Influence of Heat Moisture, Ultrasonication, and Gamma Irradiation on Pasting, Thermal, Morphological, and Physicochemical Properties of Indian Teff (Eragrostis tef) Starch

AbstractThe present work is conducted to study the effect of heat‐moisture treatment (HMT), ultrasonication (US), and gamma‐irradiation (GI) on various properties of teff starch. Starch is subjected to HMT at 28% moisture level, US at a frequency of 20 kHz for 30 and 60 min, and GI at 5 and 10 kGy. US has an increased swelling power (8.22–9.39 g g−1) and solubility (9.5–10.5%). Water binding and Oil binding capacity are improved in modified starches than native. The highest amylose content (24.94–25.24%) is observed in US than native (20.82%). Thermal characteristics show an increment in the modified teff starches with enthalpies varied from 2.30 to 3.81 J g−1. Significant differences in starch gel textural properties are identified. Similar outcomes for native and modified findings are seen in Fourier transform infrared spectroscopy spectra. X‐ray diffraction shows a similar X‐ray pattern with crystallinity decreases for HMT (28.07%) and gamma irradiated starches (30.21%) and increases for ultrasonicated samples (32.23%). The morphological changes in teff starch are observed after physical modification. All in all, significant improvements have been reported in modified teff starch, which not only increases its industrial application but also improves the utilization of teff grain globally.

Fine molecular structure and digestibility changes of potato starch irradiated with electron beam and X-ray

The change of digestibility of starch irradiated with different types from the perspective of fine structure is not well understood. In this work, the change of internal structure, molecular weight and chain-length distribution, helical structure, lamellar structure, fractal structure and digestibility of native and treated potato starch with electron beam and X-ray was analyzed. Two irradiations caused the destruction of internal structure, the disappearance of growth rings and increase of pores. Irradiation degraded starch to produce short chains and to decrease molecular weight. Irradiation increased double helical content and the thickness and peak area of lamellar structure, resulting in the reorganization of amylopectin and increase of structure order degree. The protected glycosidic linkages increased starch resistance to hydrolase attack, thereby enhancing the anti-digestibility of irradiated starch. Pearson correlation matrix also verified the above-mentioned results. Moreover, X-ray more increased the anti-digestibility of starch by enhancing ability to change fine structure.

EPR study of irradiated starch: induced radicals and dose assessment

Irradiation of starch is of much importance to get rid of microbes and for disinfection. EPR study of the ionizing radiation-induced radicals can lead to the assessment of radiation doses delivered during irradiation. The EPR spectra properties, microwave power saturation behavior, short- and long-term temporal dependencies, and other significant factors are studied. Response of EPR spectra of irradiated starch over the range (0.5–10 kGy) was investigated. The time dependence study of the radiation-induced signal radicals of starch showed that variation of the EPR signal can be noticed within ±7.7% relative to the average value over 38 days following irradiation. Results obtained indicate that gamma irradiated starch can be identified and radiation doses can be determined accurately using EPR spectroscopic techniques.

Altered leaching composition of maize starch granules by irradiative depolymerization: The key role of degraded molecular structure

The molecular composition of starch leachates from starch-based foods has been recently recognised as a crucial determinant of food properties. However, there is limited knowledge on the regulation of this composition through irradiative depolymerization of starch. This research investigates the leaching behaviour of maize starch depolymerized by electron beam irradiation, and the relationship between the composition of leached starch and structures of modified starch granules. The analysis using 1H NMR spectroscopy confirmed a decrease in the degree of branching (from 4.4 % to 2.8 %), while size-exclusion chromatography identified a newly-derived amylopectin fraction of a smaller hydrodynamic radius (approximately 60–80 nm). The structural properties of the starch granules were also analysed, revealing an increased BET-area of granules and reduced total crystallinity after depolymerization. In the leachates of swollen granules, the bimodal distribution of starch molecules evolves into unimodal with the increase of the irradiative dosage, while modified starch leached more starch molecules with Rh < 10 nm. The results of principal component analysis and Pearson correlation analysis indicate that the degree of branching of degraded starch molecules, as well as the newly-derived amylopectin fraction, significantly correlates (p < 0.01) with the molecular size of leached starch molecules (Rh < 10 nm). It is thus proposed that the cleavage of α-1,6 linkage may be a critical factor in controlling the leaching process of irradiated starch granules. This study highlights the potential of irradiative degradation to control the molecular composition and structure of starch leachates, thereby optimizing the properties of starch-based foods.

Irradiation effects on characteristics and ethanol fermentation of maize starch

Maize starch was irradiated by a Co60 irradiator with different doses. The morphology and physicochemical properties of native and irradiated starches were investigated. Scanning electron microscopy showed that the shape and size of starch granules did not change after irradiation. However, the irradiated starch granules were easily destroyed by dissolution. Irradiation also caused the change of starch color, the decrease in the pH value, light transmittance, stability index, degree of polymerization, total sugar content, and the increase in the swelling index and the reducing sugar content. In this study, irradiated maize starch was also used as material for ethanol fermentation to investigate its potential as a pretreatment method. Results showed that the ethanol yield of cooked and raw starch fermentation using irradiated starch increased by 20.41 % and 5.18 %, respectively, and the ethanol concentration increased by 3 % and 2 %. This finding indicated that irradiation effectively improved the utilization rate of maize starch, making it an effective pretreatment method for ethanol fermentation.

Understanding how electron beam irradiation doses and frequencies modify the multiscale structure, physicochemical properties, and in vitro digestibility of potato starch

To optimize the properties of native potato starch and to broaden its application in the food field, it was treated by electron beam irradiation (EBI) with different irradiation doses (6, 12, and 24 kGy) and frequencies (1, 2, 4, and 8 times), and the effects on the multi-scale structure, physicochemical properties, and in vitro digestibility were investigated. The results indicate that the increased dose aggravates starch degradation, generating more short chains and fragments, and reducing molecular weight, viscosity, and swelling power. Also, the higher dose facilitated the relative crystallinity, enhancing the ΔH and improving the RS content of potato starch. Furthermore, the repeated irradiation exhibited a cumulative dose effect: the short-range order, molecular weight, solubility, and swelling power improved after multiple irradiations. In addition, irradiation doses and frequencies neither destroyed starch's surface nor changed the polarized cross and growth ring. Also, all irradiated starch preserved starch's FT-IR spectrum and crystalline type. Moreover, multiple low-dose irradiations can not only improve the starch properties, but also achieve energy-saving purposes. Thus, as a rapid, green, non-thermal modification technology, EBI can impart low molecular weight, low viscosity and high solubility processing properties to starch, and improve its RS content without destroying the starch granular appearance.

Impact of gamma irradiation on structural, thermal, and rheological properties of talipot palm (Corypha umbraculifera L.) starch: a stem starch

Talipot palm (Corypha umbraculifera L.) is a non-conventional source of stem starch. The starch obtained from the trunk of the talipot palm was subjected to various doses of irradiation (20 kGy, 50 kGy, 80 kGy, and 100 kGy). The effect of this high dose irradiation on functional, pasting, thermal and rheological properties was studied. The irradiation considerably decreased the amylose content, pH, swelling index, and relative crystallinity, and it increased the carboxyl content and solubility. The L* value, water absorption capacity, and oil absorption capacity were also increased by irradiation. The pasting parameters like pasting temperature, peak viscosity, and final viscosity were considerably decreased by irradiation. The paste clarity and light transmittance of irradiated starches were high at any point of storage. The gel hardness was decreased by γ-irradiation up to a radiation dose of 50 kGy. The FTIR analysis did not show any evidence for the formation of new functional groups. The gelatinization properties, storage modulus, and loss modulus were decreased by irradiation. The principal component analysis showed a good relationship among the different parameters studied.

A new pre-gelatinized starch preparing by spray drying and electron beam irradiation of oat starch

As a green and safe physical technology, irradiation is increasingly used to improve starch properties. In the study, oat starch was pre-gelatinized at 70 °C followed by spray drying. Subsequently, the spray-dried starch (SDS) was exposed to electron beam (e-beam) irradiation at different doses to obtain new pre-gelatinized starch. Spray drying caused a decrement in the ratio of long B3 chains and the molecular weight of starch. Spray-dried starch (SDS) slightly increased solubility and swelling power than native starch. When SDS was subjected to e-beam irradiation, its solubility and swelling power increased dramatically, but the pasting viscosities, gelatinization temperatures, apparent viscosity, storage modulus (G′) and lost modulus (G″) reduced. The depolymerization of starch molecules and the breakage of amylopectin chains might be responsible for changing the physicochemical properties of e-beam irradiated starch. These results showed that spray drying combined with e-beam irradiation would potentially produce new pre-gelatinized starch.

Effects of Annealing on the Properties of Gamma-Irradiated Sago Starch.

The increase in health and safety concerns regarding chemical modification in recent years has caused a growing research interest in the modification of starch by physical techniques. There has been a growing trend toward using a combination of treatments in starch modification in producing desirable functional properties to widen the application of a specific starch. In this study, a novel combination of gamma irradiation and annealing (ANN) was used to modify sago starch (Metroxylon sagu). The starch was subjected to gamma irradiation (5, 10, 25, 50 kGy) prior to ANN at 5 °C (To-5) and 10 °C (To-10) below the gelatinization temperature. Determination of amylose content, pH, carboxyl content, FTIR (Fourier Transform Infrared) intensity ratio (R1047/1022), swelling power and solubility, thermal behavior, pasting properties, and morphology were carried out. Annealing irradiated starch at To-5 promoted more crystalline perfection as compared to To-10, particularly when combined with 25 and 50 kGy, whereby a synergistic effect was observed. Dual-modified sago starch exhibited lower swelling power, improved gel firmness, and thermal stability with an intact granular structure. Results suggested the potential of gamma irradiation and annealing to induce some novel characteristics in sago starch for extended applications.

Gamma radiation modification of cassava starch and its characterization

AbstractRadiation technology has been recognized as a potential tool to modify starches in order to enhance their solubility and enzymatic digestion, hence improving their applicability in food industry. In the present study, the local cassava starch was irradiated under 60Co gamma source with the absorbed dose ranging from 1 to 10 kGy, and the obtained radiation‐modified starches were characterized. The microstructure of the initial cassava starch was not much changed although several starch granules were deformed or even fragmented by gamma irradiation as observed in the scanning electron microscopy images. Water solubility of the irradiated starch was significantly increased, and their viscosity was much reduced by radiation degradation. Gamma radiation broke glycosidic bonds in starch chains into smaller molecules with lower molecular weight, whereby increased the water solubility of cassava starch. Radiation scission also partly decreased the crystallinity of the starches irradiated with dose higher than 5 kGy as indicated in their X‐ray diffraction patterns. The Fourier transform infrared spectra of irradiated starches revealed the reduction in intensities of stretching vibration characterized for OH, CH, and COC groups of starch molecules. Thus, gamma irradiation can be used to modify cassava starch for further applications.

A comparitive study on morphology, solution properties of electron beam and gamma irradited edible starch

Comparison in solution and morphology properties of electron beam and gamma irradiated potato starch are investigated. In the present work, the authors investigated the changes in solution properties, morphology, granular size and blue value on radiation dose of both electronbeam, gamma radiations. The studies indicate that surface morphology of granules is altered by both the radiations but damage is more in electronbeam irradiation. Viscosity of un- irradiated starch solutions appears to have non – Newtonian behavior; while irradiation led the solutions to have Newtonian nature. This is attributed to the damage in chemical structure caused by both the radiation. Blue index of non-irradiated and irradiated starches are measured and the changes are assigned due to variations in amylose content brought by radiation.

Investigation of physico-chemical properties of native and gamma irradiated starches

Starch is one of the most abundantly found carbohydrates in cereals, roots, legumes and fruits located in amyloplasts of plants. Native starch comprises of amylose, a linear α-glucan with α-1,4-linkage and amylopectin, a branched polysaccharide with both α-1,4-linkage and α-1,6-linkage. In food industries, the native starch is modified to manufacture the desired quality of starchy foods by means of physical, chemical, and enzymatic modification techniques. Gamma irradiation technique is one among the physical modifications of starch which is extensively used for the modification of native starch as it is rapid, less toxic and cost-effective technique. When starch is radiated with gamma rays, it is observed to produce free radicals owing to cleavage of amylopectin branches and exhibit variation in their physicochemical properties. In this study, commercially available corn, rice, and potato starch were irradiated with 10 kGy dose of gamma radiation and changes in their physicochemical properties were investigated. Native and irradiated starch was subjected to enzymatic hydrolysis with bacterial α-amylase (150 U/mL). The highest starch hydrolysis was observed for irradiated rice starch (17.03%). Amylose content of irradiated starch decreased by 3–4 %. The optical microscopic images showed the surface erosions of the irradiated starch and differential scanning calorimeter (DSC) revealed the thermal transition temperatures. Overall, starch hydrolysis and amylose content showed inverse correlation between them. Further studies regarding the effect of storage on gamma irradiated starch can help to gain new insights into the usage of modified starches in the manufacture of processed foods.

DSC studies of the influence of gamma irradiation on the structural properties of the complexes formed with cetyl-trimethyl-ammonium bromide

The effect of irradiation carried out for potato starch on further transformations taking place in the starch-CTAB-water system (10:1:11) was studied using differential scanning calorimetry (DSC). Native solid starch and dense (25 wt%) starch gels were irradiated with 60Co gamma rays using doses in the range 1–30 kGy. DSC studies were carried out in heating-cooling-heating cycles (3 heating and 3 cooling cycles) with rates of 10 and 5 °C min-1. The differences were discovered between the amylose-lipid complex transition taking place in the case of the non-irradiated and the irradiated starch. The results are discussed in terms of modification the structural properties of the complex formed by the non-irradiated starch and the species irradiated using various doses. The structural changes were confirmed by FTIR spectroscopy and viscosity data. It can be concluded that the complexes formed using the irradiated starch have revealed decreased symmetry in comparison to the complex formed using the non-irradiated starch. In general, subsequent thermal treatment in the calorimeter induces further deterioration of the structure of the complex formed in the cases of the irradiated samples, while none or the opposite effect was noticed in the case of the non-irradiated starch. In the case of granular starch the changes of the complex structure were detected when the doses in the range 2–30 kGy were applied. Irradiation with a dose of 5 kGy causes easily noticeable modification of the complex.

Development of Bioplastic Films from γ − Irradiated Kithul (Caryota urens) Starch; Morphological, Crystalline, Barrier, and Mechanical Characterization

AbstractImportant properties of bioplastic film made from γ − irradiated kithul starch such as crystalline, morphological, mechanical, and barrier properties are studied. The films are made from native and irradiated kithul starch using the casting method. Relative crystallinity is higher for the film made from irradiated kithul starch. The film made from 100 kGy irradiated starch shows the highest relative crystallinity (2.26%) among the starch films. The film prepared from irradiated kithul starch exhibits lower water vapor permeability (WVP). The solubility of film made from irradiated starch decrease with an increase in irradiation dose. Irradiation of starch cause higher surface compactness, which decrease the oxygen permeability of the films. The decrease in WVP and oxygen permeability indicates the improved barrier properties of films made from irradiated starch. Mechanical properties increase in films made from irradiated kithul starch. Moreover, it shows lower surface roughness as compared with native starch film. The research reveals that films made from γ − irradiated kithul starch exhibited better mechanical and barrier properties due to their higher crystallinity and surface homogeneity.

Dual Modification of Starch Via Gamma Irradiation and Subsequent Chemical Treatment with Urea for the Development of Adhesives

This research evaluates achira starch modification via gamma radiation, chemical modification and the subsequent adhesives formulation. Native starch was irradiated using a linear accelerator; the mean dose rate used was 19.5 kGy/min at ambient temperature and normal pressure. The chemical modification of irradiated starch consisted of a hydrolysis process, followed by the obtention of carbamates from the hydrolyzed starch with urea, sulphuric acid and ethanol. In order to prepare adhesives; native, modified and dual-modified starches were tested in different proportions with a polyvinyl alcohol (PVA) solution. Fourier Transformed Infrared Spectroscopy (FTIR) analysis showed all modified starches had a lower intensity in the band between 1100 and 900 cm-1 due to the damage in the glycosidic bonds. Only single modified starches evidenced a characteristic band at 1715 cm-1, which corresponds to the group carbonyl (C=O) of carbamates. The viscosity of native starch adhesives increased with the starch-PVA, unlike, single and dual-modified starch adhesives. The shear bond strength did not change significantly in the adhesives formulated either with starch modified by urea or electron beam irradiation. The combination of hydrolysis with gamma radiation caused strong damage in the starch structure. However, despite the molecular destruction of polysaccharide, the adhesion capacity for non-irradiated starches is similar in all cases.

Effect of γ-radiation on physico-chemical, morphological and thermal characteristics of lotus seed (Nelumbo nucifera) starch

Native and gamma (γ) irradiated lotus seed starches were studied for their physicochemical, thermal, pasting and morphological properties. Upon gamma irradiation of 5, 10, 15 and 20 kGy, amylose content of starches was decreased as the dose of irradiation was increased. Lotus seeds starch granules had bimodal size distribution varying in size from small to large. Observation under scanning electron microscope (SEM) showed that at low dose of irradiation (5, 10kGy), no significant changes were observed in shape and size. However, minor alterations were notice during treatment of 15kGy and 20 kGy, which included roughness. Irradiation significantly decreased the pasting properties (peak, trough, final and setback viscosities) of the starch. For native starch, To, Tp, and Tc of 137.44 °C, 138.29 °C and 143.21 °C and 169.51 °C, 169.72 °C, and 177.73 °C respectively was observed for first and second peak. Upon irradiation, the gelatinization temperatures were decreased. The irradiated starch showed no change in diffraction pattern compared to native lotus seed starch but a dose-dependent decrease in relative crystallinity was observed.

Irradiation as a tool for modifying tapioca starch and development of an active food packaging film with irradiated starch

Effect of irradiation on the properties of tapioca starch was studied. Apparent carboxyl content increased, while pH and bulk density decreased as the dose of radiation increased. A dose dependent increase in solubility and light transmittance was observed while there was decrease in swelling capacity. Radiation processing of starch reduced syneresis. Irradiated starch was blended with gelatin and lime juice to develop active films. Films prepared with starch (20 kGy)/gelatin blend had the best mechanical properties. Addition of lime juice (LJ) resulted in the films having antioxidant and antibacterial properties. Minced chicken meat packed in starch/gelatin films without LJ spoiled within 2 days while that packed in LJ containing films had a shelf life of 12 days during chilled storage. Lipid peroxidation of minced chicken packed in active films was also less. Development of functional food packaging films with irradiated starch-gelatin-LJ is an environmentally viable option for the food industry.

Electron beam irradiated maize starch: Changes in structural, physicochemical properties, and digestibility

Electron beam irradiated maize starch: Changes in structural, physicochemical properties, and digestibility

Effect of moisture on technological properties of corn starch modified by the electron beam irradiation

Electron beam irradiation is one of the most effective starch modification methods. Moisture is one of the factors that is affected by the irradiation via the free radical formation. The effect of the moisture content on the technological properties of irradiated starch samples was studied. The moisture content of corn starch samples in this study was adjusted at 9.08, 12.96, 15.06, 20.39 and 29.09% (w w). Corn starch samples were irradiated at 5 kGy. Color, free acid, solubility, swelling, transparency, syneresis and starch gel structure were studied to elucidate the effect of the moisture on technological properties of corn starch treated by electron beam. The results showed that electron beam radiation caused starch samples at different moisture to break into small molecules due to the separation of the glycosidie bonds. Thus, free acid, swelling, solubility of irradiated starch samples were higher than those of natural starch samples and were increased with low moisture content. The results also indicated that electron beam treatment increased the syneresis of irradiated starch samples. The texture profile analysis (TPA) of starch gel structure showed that textural properties such as hardness, elasticity and chewiness of irradiated starch samples were higher than those of natural starch samples.

Physicochemical, structural and functional properties of native and irradiated starch: a review.

The world population has crossed seven billion and such a huge population has increased the pressure and considerably affects our ability to feed ourselves. It has now emerged as a new challenge for policy makers, food scientists and other associated people to make food available to everyone. To achieve this, underutilized crops/plants that act as good sources of starch need to be explored. Starch in its native form have certain limitations in its functional properties to be used for different applications. Therefore, it becomes important to explore certain technologies which could be used for modification of properties of starch. During the last decades gamma irradiation has emerged as an efficient processing technique for the modification of starch when compared to the other available processes. This review, aims to summarize the effects of gamma irradiation on various properties of starch such as physicochemical and rheological properties, functional characteristics, thermal behaviour etc. so as to make the starch suitable for various applications in different industries including the food industry.