Potato Starch Samples Research Articles

MODIFICATION BY MICROWAVES OF READY COMMODITY ADHESIVES

Studies on the microwave modification of complex technical auxiliary materials - import adhesive compositions on the basis of native and modified samples of potato starch with various functional additives have been presented. The paper aims at the replacement of import technical production and the decrease in the consumption of the important materials which are used as wallpaper glues. Features of direct microwave effect on various water-soluble adhesive substances differing from each other in chemical composition and properties have been determined. A mechanism of absorption of microwaves using the air-dry adhesive compositions based on their specific effect on the water which is in the finished dry product has been offered. A possibility of change of the main technological properties of adhesive compositions (viscosity, adhesion) after a direct short-term effect of microwaves on them with the frequency of 2.45 GHz has been proved. It has been established that, in case of preliminary short-term influence of MR in the non-thermal mode, the kinematic viscosity and adhesive forces of various initial types of the glues on a starch basis having a different composition change differently and individually with various time of influence. The change of viscosity and adhesive forces of separate selected adhesive compositions after microwave processing provides a decrease in the cost of the gluing process. The found method of management of technological parameters of gluing has an important practical value and can be introduced in the construction industry for the internal finishing of ready apartments.

The Effect of Heat-acid Treatment on the Formation of Resistant Starch and the Estimated Glycemic Index in Potatoes.

Potatoes are generally regarded as high glycemic index (GI) foods. Resistant starch (RS) comprises the starch fraction that is not absorbed in the small intestine, thus controlling the glucose level and improving the intestinal environment. In this study, an analysis of the formation of RS of potato starch samples under different acetic acid-thermal treatment conditions was conducted. Additionally, the relationship between the rates of starch digestion, estimated GI (eGI), and the RS content was evaluated by employing in vitro enzymatic models. Compared with control samples, the RS content in the cold-stored samples after acid-boiling was higher, whereas that of samples after heating at 120 °C with acetic acid was decreased. The eGI was negatively correlated with the RS content in potatoes. Cold store after acid-boiling was effective in increasing the RS content. Furthermore, low eGI values may have resulted from higher levels of RS in potatoes.

Multivariate Optimization of Method of Slurry Sampling for Determination of Iron and Zinc in Starch Samples by Flame Atomic Absorption Spectrometry

A slurry sampling procedure has been developed for determination iron and zinc in starch sample by using flame atomic absorption spectrometry. The optimization step was performed using univariate methodology for mass of sample and multivariate methodology using Box-Behnken design involving the other variables: type extractor, final concentration of extracting solution, and sonication time. The established conditions were with 100 mg of sample, extracting solution composed of mixture (1:1) HCl:HNO3 at a final concentration of 2.0 mol L−1, sonication time of 17 min, and a slurry volume of 10.0 mL. This procedure allows the determination of iron and zinc with quantification limits of 5.68 and 1.36 mg kg−1, respectively, and a precision expressed as relative standard deviation (%RSD) of 6.1 and 4.7 % (both, n = 10) for the concentrations of iron and zinc of 19.5 and 2.9 mg kg−1. The accuracy of the procedure was confirmed by analysis of certified reference material wheat flour NIST 1567a. A statistical evaluation using student t test showed that there is no significant difference between the value obtained with the use of the proposed procedure and the certified value, at 95 % confidence level. The proposed procedure was applied for determination of iron and zinc in samples of corn starch, rice starch, potato starch, cassava starch, and starch mix of rice and corn. The obtained concentrations in samples analyzed varied between 17.2 and 152 mg kg−1 of iron and 1.6 and 23.8 mg kg−1 of zinc, and can conclude that these starches are an important source of iron and zinc.

Avaliação reológica e sensorial de espessantes domésticos em diferentes líquidos como alternativa na disfagia

O objetivo desse estudo foi analisar as propriedades reológicas e a aceitabilidade de espessantes domésticos em diferentes líquidos, além de comparar os custos e o valor energético desses espessantes. Avaliaram-se no viscosímetro de Brookfield amostras à base de farinha de fécula de batata, de amido de milho, de polvilho doce e de farinha de arroz, além de dois espessantes comerciais, diluídos em líquidos. Foi realizada, com a participação de 30 avaliadores, a investigação de aceitabilidade dos espessantes em água, leite e suco para os atributos: aparência, consistência, odor, sabor e aceitação global. A viscosidade em água dos espessantes comerciais, do amido de milho e da farinha de arroz não teve diferença estatística significativa entre si. Um dos espessantes comerciais atingiu a consistência “rala”. Os resultados de leites e sucos foram semelhantes quando classificados por consistência. Na aceitabilidade dos atributos odor e sabor para água, o espessante comercial, a fécula de batata, o polvilho doce e a farinha de arroz não apresentaram diferença significativa entre si. No leite, para os atributos odor e sabor as amostras não tiveram diferença significativa entre si e para sucos, o espessante comercial, a fécula de batata e o polvilho doce não apresentaram diferença significativa. A viscosidade de um dos espessantes comerciais não estava adequada para o consumo por pacientes com disfagia, obtendo consistência “rala”. O espessante comercial E.C1F e o amido de milho (AM) apresentaram consistência “mel”, sendo apropriado para o consumo em líquidos. As amostras com leites foram as que apresentaram maiores viscosidades, a maioria obteve consistência “pudim”. A aceitabilidade da E.C1F e da fécula de batata (FB) em leite foram as que mais se destacaram promissoras.

Molecular characterization of acid‐thinned wheat, potato and pea starches and correlation to gel properties

Molecular parameters and gel properties of systematically prepared acid‐thinned starch products (wheat, potato, and pea) were investigated. The impacts of acid type (HCl, H2SO4), acid concentration (0.36 and 0.72 N), and hydrolysis time (4 and 24 h) were found to be statistically significant on weight‐average molar mass (Mw) of the starch as revealed by analysis of variance (ANOVA). Especially for potato starch samples, the blue value (BV) was found to increase after short‐time hydrolysis and decrease after longer modification, indicating a reduced amount of polysaccharide chains able to complex with iodine, which was found for all products. Simultaneously, the wavelength of the absorption maximum (λmax) decreased systematically with an increasing degree of modification, giving evidence for decreasing length of linear polymer chains. Enzymatic debranching of amylopectin and dextrins and molecular characterization by means of size exclusion chromatography‐multi angle laser light scattering (SEC‐MALS) enabled the detection of Mw and the amount of amylose fraction. Generally, declining Mw of amylose was accompanied by a mass‐specific loss. Starch pastes with very good solution states were prepared in general. Pastes of the acid‐thinned starches showed dominant viscous behavior, whereat storage and loss modulus decreased with increasing degradation. Additionally, a significant reduction of the sol‐to‐gel‐transition temperature was found applying oscillation measurements. Increasing gel strength of the starch samples was detected due to acid‐thinning up to a certain degree of modification and optimal molecular parameters of the starch as well as the amylose fraction were determined resulting best strength properties. The gel clarity was reduced due to acid modification in general.

Effect of simultaneous cooling on microwave-assisted wet digestion of biological samples with diluted nitric acid and O2 pressure

The present work evaluates the influence of vessel cooling simultaneously to microwave-assisted digestion performed in a closed system with diluted HNO3 under O2 pressure. The effect of outside air flow-rates (60–190m3h−1) used for cooling of digestion vessels was evaluated. An improvement in digestion efficiency caused by the reduction of HNO3 partial pressure was observed when using higher air flow-rate (190m3h−1), decreasing the residual carbon content for whole milk powder from 21.7 to 9.3% (lowest and highest air flow-rate, respectively). The use of high air flow-rate outside the digestion vessel resulted in a higher temperature gradient between liquid and gas phases inside the digestion vessel and improved the efficiency of sample digestion. Since a more pronounced temperature gradient was obtained, it contributed for increasing the condensation rate and thus allowed a reduction in the HNO3 partial pressure of the digestion vessel, which improved the regeneration of HNO3. An air flow-rate of 190m3h−1 was selected for digestion of animal fat, bovine liver, ground soybean, non fat milk powder, oregano leaves, potato starch and whole milk powder samples, and a standard reference material of apple leaves (NIST 1515), bovine liver (NIST 1577) and whole milk powder (NIST 8435) for further metals determination by inductively coupled plasma atomic emission spectroscopy (ICP-OES). Results were in agreement with certified values and no interferences caused by matrix effects during the determination step were observed.

Thermodynamic properties of starch and glucose

Heat capacities were measured for two samples of potato starch. The experimental results allowed us to obtain the accurate values of thermodynamic properties for this material. Energies and enthalpies of combustion for starch and α-d-glucose were determined by combustion calorimetry. The saturated vapour pressure of α-d-glucose was measured by the integral Knudsen effusion method. The values of standard sublimation entropy of α-D-glucose obtained on the basis of vapor pressure data and evaluated from quantum chemical calculations and combustion calorimetry are in a satisfactory agreement.

Determination of Melamine and Derivatives in Foods by Liquid Chromatography Coupled to Atmospheric Pressure Chemical Ionization Mass Spectrometry and Diode Array Detection

Two liquid chromatographic methods based on atmospheric pressure chemical ionization mass spectrometry (LC-APCI-MS) and diode array detection (DAD) are evaluated for the rapid determination of melamine (MEL) and structurally related compounds, including ammeline (AMN), ammelide (AMD), and cyanuric acid (CA) in foods. Both procedures used ion-exchange LC and isocratic elution. Samples were extracted by homogenization with acetonitrile/water/diethylamine. Specificity was demonstrated for LC-MS by the retention characteristics and MS spectra, by comparing with commercial standards. Specificity was only demonstrated in the case of LC-DAD for MEL and AMN, considering the retention characteristics and UV spectra. The recoveries obtained for spiked samples were satisfactory for all the analytes with LC-MS. The proposed procedure, LC-APCI-MS, was successfully applied to the analysis of different baby foods, including infant formula and breakfast cereal, and samples of rice flour, potato starch, soya drink, and coconut drink.

Structure, Physico-chemical and Microbiological Properties of Ozone-oxidized Wheat, Corn, Potato and Rice Starches

A limited number of studies have been conducted on the effects of ozone use on cereal and its components. Starch, an important natural macromolecule, is an essential component of cereals. In present study, the effects of ozone on the structure, physico-chemical and microbiological properties of wheat, corn, potato and rice starches were investigated. Wheat starch, corn starch, potato starch and rice starch water mixtures were prepared in the ratio of 1:9 (dry sample to water ratio) and treated with ozone at a rate of 60 g/h for 1 hour, while unozonated samples were used as controls. Light microscopy represented that the structures of corn and potato starch samples were affected by 1 hr ozonation rather than the structures of wheat and rice starch samples. Colour of ozone-oxidized wheat, corn and potato starch samples could meet the consumer preference due to the higher lightness, higher whiteness and lower chroma value. However, high chroma, high yellownes and low whiteness values of ozonated rice starch is not adequate for consumer desire. Microbiological analysis showed that 1 hr ozonation reduced the total bacteria and mould/yeast counts significantly for all wheat, corn, potato and rice starch samples (P ＜ 0.05) due to most probably the reduced pH of samples. Ozonation can be an alternative modification technique, but further research is needed to understand the certain benefits and limitations of ozone applications on starch oxidation for human safety and health.

Characterization of remaining granules of acetylated starch after chemical surface gelatinization

One acetylated waxy potato starch and three acetylated normal potato starch samples were treated with aqueous calcium chloride (4 mol/L) for surface gelatinization. The remaining granules after removal of gelatinized starch were investigated on size distribution and level of acetylation. Their crystal structure, thermal property and morphological change were studied with X-ray diffractometry, differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Greater proportions of the acetyl groups were present at the periphery than at the core of the granule. Remaining granules obtained after higher degree of gelatinization showed greater relative crystallinity and gelatinization temperature. Morphology of gelatinized starch and remaining granules differed for acetylated waxy and normal potato starch samples. The results suggest that structural divergence exists not only between acetylated waxy and normal potato starches, but also within one granule.

Effects of pulsed electric fields (PEF) treatment on physicochemical properties of potato starch

Abstract Potato starch–water suspensions (8.0%, w/w) were subjected to pulsed electric fields (PEF) treatment at 30 kV·cm − 1 , 40 kV·cm − 1 and 50 kV·cm − 1 , respectively. The physicochemical properties of PEF-treated potato starch samples were investigated using scanning electron microscopy (SEM), laser scattering technique, X-ray diffractometry (XRD), differential scanning calorimetry (DSC), and the Brabender rheological method, with native potato starch as reference. It has been concluded from SEM analysis that dissociation and damage of PEF-treated potato starch granules appeared. Some granules aggregated with each other and showed gel-like structures. It was revealed from particle size analysis that there was an obvious increase of the granule size after PEF treatment. This has been attributed to the aggregation among granules. It was also demonstrated from other analysis that relative crystallinity, gelatinization temperatures, gelatinization enthalpy, peak viscosity as well as breakdown viscosity of modified samples all decreased with increasing electric field strength. Industrial relevance In this study, the effect of PEF treatment (up to 50 kV·cm − 1 ) on physicochemical properties of potato starch has been investigated. The results from SEM images showed that dissociation, denaturation and damage of potato starch granules had been induced by the PEF treatments. Some of granule fragments showed gel-like structures, and congregated with each other or with other starch granules. Laser scattering measurements of particle size revealed that an obvious increase of granule size under electric field strength of 50 kV·cm − 1 , which was attributed to the aggregation of the starch granules. The X-ray diffraction pattern showed an obvious loss of crystalline structure after the PEF treatment at 50 kV·cm − 1 , which induced a trend of transformation from crystal to non-crystal in potato starch granules. DSC analysis showed a decrease in gelatinization temperatures ( T o and T p ) and gelatinization enthalpy (Δ H gel ) with increasing electric field strength. Brabender rheological method has been used to show that the peak viscosity and breakdown viscosity decrease with increasing electric field strength of PEF treatment. All the results reveal that the PEF treatment can lead to an intragranular molecular rearrangement of potato starch granules, which induces changes of various physicochemical properties of the treated starch thus may endow it some new characteristics and functions. This phenomena may warrant further more detailed study.

Light Scattering and Viscosity Investigation of Dilute Aqueous Solutions of Carboxymethyl Starch

AbstractThree samples of corn starch and three samples of potato starch were transformed to carboxymethyl starch (CMS) using a two‐step etherification with sodium monochloroacetate in ethanol as the reaction medium. The degree of substitution (DS) of the synthesized samples was between 0.40 and 1.10. The structure parameters – solution properties relationships of the CMS samples were investigated by static light scattering and dilute solution viscometry in water and sodium‐chloride aqueous solutions of different concentrations at 25°C. The values of the mass average molar mass, MW, radius of gyration, Rg, and second virial coefficient, A2, were determined for all samples together with the limiting viscosity number. The results indicated that the Mw ‐ Rg correlation was independent of the origin of the starch, as well as the exponent aη and constant Kw from the Kuhn–Mark–Houwink equation. Values of the exponent ν for CMS in all sodium‐chloride aqueous solutions were between 0.450 and 0.472, while for the CMS samples in aqueous solution the value of ν was 0.580. The values of the exponent aη were around 0.3, which is typical for branched macromolecules.

Interaction of Moisture with Sodium Starch Glycolate

The relationship between the apparent moisture content and moisture sorption of modified starches was investigated. Samples of sodium starch glycolate (SSG), pregelatinized starch (PGS) and potato starch (PS) were stored for various times at 44% or 75% relative humidity (RH) to produce samples with moisture contents of up to 14%, as determined by loss on drying (LOD). Evaluation of LOD and mass gain data suggested that measured mass gain equated to predicted LOD values for PGS and PS. However, in SSG there was a nonstoichiometric relationship between mass gain and predicted LOD. In addition, samples of SSG displayed hysteresis during dynamic vapor sorption (DVS) cycling in that an apparent mass loss of about 2–3% was observed for two of the SSGs, with PS and PGS exhibiting reversibility. In some cases, SSG exhibited an apparent mass loss during the DVS cycle at with 50% RH. These observations suggest that one or more of the components of SSG “interact” with moisture. Because X-ray diffraction suggested there was no dramatic change in the crystallinity of SSG, an exchange of residual SSG solvent, alcohol, with moisture may, in part, explain the moisture sorption behavior of SSG.

Determination of the phosphorus content in potato starch using an energy-dispersive X-ray fluorescence method

Potato starch is unique because of its high starch phosphorus content. The textural characteristics of potato starch change due to the presence of the starch phosphate. Thus, the measurement of phosphorus in potato starch is needed, but conventional methods require a considerable amount of time and labour. In this investigation, a simple and fast analytical procedure has been developed for the determination of the phosphorus content of potato starch with a non-destructive energy dispersive X-ray fluorescence (ED-XRF) technique. Potato starch samples were analyzed as pressed pellets using detection times of 200 s. Reference values, measured by a conventional method, namely, wet chemical analysis, were used to calibrate the ED-XRF. Calibration was done using 20 potato starch samples, and the results were validated using a second set of 15 samples. The results indicated the validity of ED-XRF as a rapid and non-destructive method for the quantitative determination of phosphorus content of potato starch. Based on the combined results of ED-XRF and Rapid Visco-Analyzer (RVA), ED-XRF is promising for predicting the peak viscosity, by RVA, of potato starch paste through the measurement of starch phosphorus content.

Rheology of starch–clay nanocomposites

The effects of incorporating various montmorillonite nanoclays into wheat, potato, corn, and waxy corn starch samples were examined by rheology and X-ray diffraction. The nanoclays included the hydrophilic Cloisite Na+ clay as well as the more hydrophobic Cloisite 30B, 10A, and 15A clays. Frequency sweep and creep results for wheat starch–nanoclay samples at room temperature indicated that the Cloisite Na+ samples formed more gel-like materials than the other nanoclay samples. X-ray diffraction results showed no intercalation of Cloisite Na+ clays at room temperature, suggesting that starch granules interacted only with the clay surface and not the interlayer. When the various wheat starch–nanoclay samples were heated to 95 °C, the Cloisite Na+ samples exhibited a large increase in modulus. In contrast, the more hydrophobic nanoclay samples had comparable modulus values to the neat starch sample. These results suggested that during gelatinization, the leached amylose interacted with the Cloisite Na+ interlayer, producing better reinforcement and higher modulus values. X-ray diffraction results supported this interpretation since the data showed greater intercalation of Cloisite Na+ clay in the gelatinized samples. The samples containing wheat and corn starch showed comparable elastic modulus values during gelatinization. However, the potato and waxy corn samples had modulus values that rapidly decreased at higher temperatures.

Properties of Starches from Potato Varieties Grown in Hokkaido

Using potato cultivars grown in Hokkaido, the starch properties in potato tubers were characterized. The starch properties determined in this study were the contents of amylose and phosphorus, granule size distribution, and pasting properties using a rapid visco-analyzer. There were wide variations in starch parameters among the 96 potato starch samples used. A high phosphorus content of starch was closely associated with high peak viscosity and breakdown and low peak viscosity temperature. Although the amylose content also had an effect on pasting properties, the correlation coefficients between the phosphorus content and pasting properties were higher than those between the amylose content and pasting properties.

The influence of various small plasticisers and malto-oligosaccharides on the retrogradation of (partly) gelatinised starch

Ageing of gelatinised and partly gelatinised potato starch and wheat starch were investigated in the presence of plasticisers with increasing size and number of OH groups (ethylene glycol, glycerol, threitol, xylitol, glucose, and for potato starch also maltose). The influences of these plasticisers and of granular remnants (ghosts) on recrystallisation were determined by using X-ray diffraction. Recrystallisation of potato starch samples in the presence of plasticisers resulted in crystallinity indices of ∼0.5. The largest reduction in potato starch recrystallisation is found for threitol (4 OH) and xylitol (5 OH). In the plasticiser range examined, the crystallisation inducing effect of granular potato starch remnants is reduced better when the plasticiser contains more OH groups. Wheat starch recrystallises to a lesser extent than potato starch, resulting in crystallinity indices of ∼0.4. The results for wheat starch do not show clear trends for the influences of plasticiser size and of ghosts. The difference in behaviour of the two starches is probably caused by wheat starch having shorter amylopectin chains. Resulting from these shorter amylopectin chains, the remaining structure in wheat starch ghosts may resemble A-type crystallinity, making it more difficult to form B-type crystals. Alternatively, the trends as found for potato starch may occur, but are less manifest for wheat starch, due to the lower total extent of recrystallisation. Solid state CP/MAS NMR spectra of the wheat starch samples containing ethylene glycol were obtained, in order to compare completely and partly gelatinised systems. The spectra were identical, confirming that the ghost structures do not influence wheat starch recrystallisation. Apparently, wheat starch ghosts do not act as nuclei for crystallisation. Similarly, the influence of various malto-oligosaccharides in combination with granular remnants (ghosts) was investigated on wheat starch ageing. Gelatinised and partly gelatinised wheat starch were plasticised with maltose, maltotriose, maltotetraose, maltopentaose or maltohexaose. This resulted in crystallinity indices of ∼0.2, with the largest reduction in recrystallisation for maltotriose and maltotetraose. No trend was found for the influence of ghosts. The presence of ghosts did not influence the 13C solid state HP/DEC NMR spectra. Less recrystallisation took place than with the previously mentioned smaller plasticisers that resulted in crystallinity indices of ∼0.4. The finding that maltose was able to reduce retrogradation better than glucose could be of practical importance.

NIR Spectroscopy and Partial Least Squares Regression for the Determination of Phosphate Content and Viscosity Behaviour of Potato Starch

A set of 97 potato starch samples with a phosphate content corresponding to a phosphorus content between 0.029 and 0.11 g per 100 g dry matter was analysed using a Rapid Visco Analyzer (RVA) and near infrared (NIR) spectroscopy, (700–2498 nm). NIR-based prediction of phosphate content was possible with a root mean square error of cross-validation ( RMSECV) of 0.006% using PLSR (partial least squares regression). However, the NIR/PLSR model relied on weak spectral signals, and was highly sensitive to sample preparation. The best prediction of phosphate content from the RVA viscograms was a linear regression model based on the RVA variable Breakdown, which gave a RMSECV of 0.008%. NIR/PLSR prediction of the RVA variables Peak viscosity and Breakdown was successful, probably because they were highly related to phosphate content in the present data. Prediction of the other RVA variables from NIR/PLSR was mediocre (Through, Final Viscosity) or not possible (Setback, Peak time, Pasting temperature).

Preliminary Studies Using Differential Scanning Calorimetry of Radiation-Induced Transformations in Starch and Flour

Differential scanning calorimetry was applied in studies of the effect of gamma irradiation on the potato starch and wheat flour. Essential differences were noticed between endothermal effects observed in concentrated suspensions of the initial and irradiated potato starch and wheat flour heated at a rate of 2.5°C min-1, while only small differences were noticed between gelatinization thermal effects recorded for ca. 20% suspensions of the initial and irradiated potato starch samples heated at a rate 10°C min-1. Moreover, in the case of wheat flour, a decrease of decomposition temperature of the amylose-lipid complex was concluded.

MECHANICAL PROPERTIES OF AN IMMERSION FRIED POTATO STARCH‐GLUTEN GEL DURING POSTFRYING PERIOD

ABSTRACTMoisture profiles in fried samples of potato starch with different gluten contents were determined during postfrying storage. Over time, moisture migrated from the core to the crust of the sample, and the moisture content of the crust region increased. The addition of gluten caused a significant increase in oil uptake in the crust. The initial hardness of the crust significantly decreased as the gluten content increased to 10 and 30%, during the first 30 min of storage. With longer storage time (> 240 min), the crust hardness tended to increase, due to an increase in firmness of the starch sample. This behavior was less pronounced for samples with 10 and 30% gluten. The range of linear viscoelastic behavior (up to 14% strain) was determined from the initial linear zone of the stress‐strain curves. Stress relaxation tests were performed in the linear and nonlinear viscoelastic regions, with a strain level of 5% and 40%, respectively. According to stress relaxation curves, samples became less elastic with the addition of gluten and more elastic with the time of storage.