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Understanding how starch constituent in frozen dough affected bread quality would be valuable for contributing to the frozen products with better quality. To elucidate the underlying mechanism, starch was fractionated from multiple freezing-thawing (F/T) treated dough and reconstituted with gluten. Results showed that F/T treatment destructed the molecular and supramolecular structures of starch, which were more severe as the F/T cycle increasing. These structural disorganizations made water molecules easier to permeate into the interior of starch granules and form hydrogen bonds with starch molecular chains, which elevated the peak, breakdown, setback and final viscosity of starch paste. In addition, F/T treatment resulted in decreased specific volume (from 1.54 to 0.90 × 103 m3/Kg) and increased hardness (from 42.98 to 52.31 N) for steamed bread. We propose the strengthened water absorption ability and accelerated intra- and inter-molecular rearrangement of starch molecules and weak stability of “starch-gluten matrices” would allow interpreting deteriorated bread quality.

Native starch is an important raw material used in the industry. Rheological, pasting, and textural properties of starch are the major functional properties to determine its applications. Key rheological properties of starch include rheology of starch during heating, viscosity of starch paste, and rheological features of starch gel. The pasting properties of starch are commonly quantified by measuring changes in viscosity during the heating and cooling of starch dispersions. The textural characteristics of starch gels have an important role in the classification of sensory and quality of foods. In this this chapter, the rheological, pasting, and textural properties of starch from different botanical sources are compared, and the impacts of other ingredients (sugars, salts and lipids) on the properties are summarized. The relationship of starch functionalities with food quality is also summarized. The information provided will be useful for the applications of starch in the industry.

Pongamia pinnata seed (PPS) starch was studied for its physicochemical, thermal, rheological and morphological properties. As PPS starch is a novel starch, it was compared with corn, mung bean, potato, pearl millet and mango kernel starches. Peak, trough and final viscosity of PPS starch was found the lowest as compared to other starches. Plots of shear stress versus shear rate for starch pastes were plotted and fitted to Herschel-Bulkley model. Yield stress and consistency index value of starch pastes varied between 6.5 and 58.9 Pa and 1.4–10.6 Pa s, respectively. During frequency sweep testing, G′ and G′′ values of starch pastes varied between 33 and 484 Pa and 18–71 Pa, PPS starch paste had the lowest values. Transition temperatures (Tο, Tp, Tc) for PPS starch was 61.5, 72.1 and 82.9 °C, respectively. Scanning electron microscopy of PPS starch showed small to large and round to oval shape starch granules with small pitches on their surface.

Improve the consumption of millet to vermicelli promoted for food diversification. Millet starch less stable of stirring and heating. Starch modification can improve the quality. In this research to evaluate pasting character of millet starch modified by heat moisture treatment which suitable for vermicelli. Heat moisture treatment conditioned at 25% moisture content and heating 100, 130 and 150 0C for 3, 5 and 7 hours with oven. Crystalline and starch paste properties of modified starch were analyzed and then selected to vermicelli. The suitable starch for vermicelli which stable paste of stirring and heating and high gel strength. The results show modified starch with 100 °C for 7 hours has an ideal for vermicelli. Shown by lower peak viscosity and viscosity breakdown (2951 cP and 71 cP), high final viscosity (3695 cP).Keyword : Heat moisture treatment, millet starch, RVA, pasting properties

In this study, we aimed to examine the effects of different low concentrations of alcohol solution (5%–20%) on the gelatinization and pasting properties of pea starch. A rapid visco analyzer revealed that when the starch concentration was fixed, the viscosity of the starch paste decreased with increasing alcohol concentration. In addition, the texture analyzer results showed that compared to the hydrogel formed in water, the hardness of the gel formed by 15% starch in 10% alcohol increased approximately 2-fold (1696.4 g versus 928.1 g). Furthermore, the rheological results showed that the tan δ value of the gel formed under this condition was second only to that of 20% starch in water, which indicated the gel had a strong network structure. X-ray diffraction analysis showed an increased relative crystallinity of 15% starch gels formed in 10% alcohol (13.2%) compared to the hydrogel formed in water (12.2%). Our study will expand the knowledge of the gelatinization properties of starch in low concentrations of alcohol.

Materials used in this research were residual oat flour and starch isolated from it, and wheat flour and starch were used as reference. Pasting temperature of the starch present in flour or isolated starch increased with increasing syrup concentration, depending on material and syrup concentration. The maximum values of oat flour and starch paste viscosity were achieved at 30–40% syrup concentration, and at 50% for wheat pastes. Oat flour and starch pastes were pseudoplastic shear thinning fluids. In presence of syrup they revealed lesser deviation from Newtonian properties. Mechanical spectrum analysis of oat flour and starch pastes revealed stronger elastic than viscous properties. The hardness of flour gels prepared in syrup was higher than aqueous ones, and was increasing with increasing syrup concentration. It was stable during 7 days of storage. Adhesiveness of oat flour gels with syrup were lower than aqueous ones, reverse situation was observed for wheat flour gels. During storage, oat gels showed an increase of adhesiveness, in contrast to wheat gels, that were characterized by only initial increase of adhesiveness.

Selected physicochemical properties of native and modified water chestnut starch (Trapabispinosa) were studied. Single- and dual-modifications were carried out by pregelatinization, acetylation and acid-thinning methods. Chemical modification created unevenness on the surface of starch granule. Swelling power, solubility, and water retention capacity were improved by all modification techniques used. The peak viscosity was reduced in all modified starches as compared to native water chestnut starch. The setback value which is an indication of retrogradation (re-association of starch molecules) tendency in the starch paste was reduced after pregelatinization and acid-thinning but increased by acetylation.

The novel hyperbranched poly(trimellitic glyceride) (PTG) starch plasticizer synthesized in our previous study was neutralized with different alkaline metal hydroxides. Mixed with starch, the effects of different alkaline metal cations, M+, on gelatinization of starch suspensions and thermal behaviors of the films were analyzed using RVA and DMA, respectively. The structures of the starch suspensions, films and freeze-dried samples (S/PTG-M) were investigated using DSC, XRD and FTIR spectroscopy, respectively. M+ increased the gelatinization temperature of starch suspensions in the order of S/PTG-Li > S/PTG-Na > S/PTG-K. The formation of a complex between M+ and starch in the films observed using FTIR spectroscopy improved the stability of the starch paste and gel, and increased the gel temperature of starch dispersions. The corresponding starch gel was relatively thermostable, but not shear-resistant. PTG decreased the Tg of starch films with different paired M+. PTG-Li and PTG-K, but not PTG-Na, strengthened the mechanical properties of starch films.

The modification greatly improved konjac glucomannan (KGM) characteristics and expanded its application range. For this purpose, the combination of acidolysis with oxidation was chosen to modify KGM in a heterogeneous system. In this study, we mainly discussed the effect of acidolysis and oxidation on the structure and properties of KGM. The experimental results indicated that the acidolysis and oxidation destroyed the structure of KGM particles, and reduced its crystalline degree. The size of derivatives was greater than that of KGM, and their surface became very rough. The acidolysis and oxidation decreased obviously the swelling capacity of KGM, but increased the acid and alkali resistance. The thermal characteristic parameters of KGM such as onset decomposition temperature, onset temperature, peak temperature, enthalpy change, and so on were affected by the acidolysis and oxidation. The oxidation of hydrogen peroxide did not led to any carboxyl groups being introduced into KGM molecular chains, whereas it resulted in the reduction in the viscosity of KGM. There is no synergistic effect between KGM or its derivatives and starch paste.

Native and modified starches are important raw materials used in the industry. Gelatinization and rheological properties of starch are primary physicochemical properties to determine its applications. Starch gelatinization refers to a process that starch loses the native order and crystalline structure of the granules and becomes amorphous. Key rheological properties of starch include pasting property, viscosity of starch paste, and rheological features of starch gel. In this review, gelatinization and rheological properties of native starches from different botanical sources are compared and impacts of other ingredients, including sugars, salts, and lipids, on the properties are summarized. The review also covers current understandings of the gelatinization and rheological properties of modified starches with different structures. The information provided will be useful for the applications of starch in the industry as well as fundamental research in this field.

BACKGROUND Functional properties of wheat starches with different particle size distribution were investigated. RESULTS A-granules displayed a disc shape and B-granules displayed a spherical shape. A-granules had the highest conclusion temperature (Tc, 80.28 °C) and gelatinisation enthalpy (3.268 J g−1) and B-granules had the highest peak temperature (Tp, 66.00 °C) and the lowest gelatinisation enthalpy (2.237 J g−1). The gelatinisation onset temperature (To), the peak temperature (Tp), Tc and retrogradation of mixed starches increased with the increase of the ratio of B-granules, while the enthalpy, all the viscosity parameters and syneresis of mixed starches decreased with the increase of the ratio of B granules. B-granules had a higher pasting temperature. The sample of B/A = 0.5/10 had the highest peak, breakdown and final viscosity. The percentage of water separated from B-granule gels was minimal, indicated that B-type gels were more stable than other samples. The ΔH2 of A-granules was obviously higher than that of B-granules. However, during storage, the ΔH2 of the starch paste was dramatically increased and the ΔH2 of B-granules was obviously higher than that of A-granules. CONCLUSION B-granules were easier to age than A-granules and most of the properties of wheat starches varied significantly with the ratio of B-granules. The relationship between structure and functionality of wheat starch received further verification. © 2013 Society of Chemical Industry

The objectives of this work were to determine the gelatinization temperature of jackfruit starch and to compare the effect of pH on the viscosity and density of different botanical sources of starch pastes. The study was conducted according to a three × four factorial design with three repetitions, being three levels for the starch paste (jackfruit seed, corn and cassava) and four levels for pH (3.4; 4.4; 5.4 and 7.0). The results showed a gelatinization temperature (GT) of jackfruit seed starch ranging from 75 to 80 °C, superior to GT range of common starch sources. Density of all starch pastes increased with pH. The effect of the kind of starch was not significant (P > 0.05). Viscosity of corn and cassava starch pastes varied with pH according to quadratic models. The viscosity of seed starch paste from jackfruit did not significantly vary with pH, indicating acid resistance.

Acid-thinned cornstarch was monophosphorylated by reaction with orthophosphates to obtain an agent for sizing heat-sensitive viscose warp yarns under reduced temperature. Influences of the modification and sizing temperature on paste behavior, adhesion to viscose fibers, and properties of sized viscose yarns were studied for a range of substitution of 0.021-0.082 and temperatures from 60°C to 95°C. The modification resulted in an increase in viscosity stability of the starch paste, enhancement of the adhesion to the viscose fibers, improvement of mechanical properties of the sized viscose yarns, and a decrease in hairiness of sized yarns even if the temperature of the starch paste was lowered to 60°C. The modification is capable of improving the sizing properties of starch for viscose yarns at 60-80°C when the degree of substitution with phosphate groups is about 0.05.

The study was carried out in order to determine and establish the functional characters of starch extracted from yam bean (Pachyrhizus erosus (L) Urban) compared with cassava starch. Yam bean is a tropical tuber legume easily grown and holds a great potential as a new source of starch. Yam bean starch shows functional properties which are peculiar to those of most starch root crops. Gelatinization temperature (53-63 degrees C) and the pasting temperature (64.5 degrees C) are less than those of cereal starch, however, the swelling power is high (54.4 g gel/g dried starch). Yam bean starch paste presents a high viscosity profile, high retrogradation tendency and low stability on cooking. The functional properties of yam bean starch, similar to those of cassava starch, allows yam bean to be used as a potential new source of starch.

The removal of old glue from paper artworks is of paramount importance for the preservation of its integrity during the restoration process. Wet cleaning is one of the traditional methods, although it may cause damages on artworks. In this work, an advantageous alternative method, based on the use of a rigid hydrogel, for a simple and localized removal of starch paste from paper supports is presented. The use of an appropriate hydrogel allows to overcome many of the problems faced by restorers minimizing damages, through a controlled release of water to the artwork, and a simple and not invasive application and removal. At the same time, the specific and targeted enzyme activity leads to a significant reduction in the application time of the cleaning procedure. In this context, experiments were carried out applying Gellan hydrogel carrying α-amylase enzyme on several paper samples soiled with starch paste. To assess the cleaning efficacy of the proposed hydrogel, we have used a multidisciplinary approach, by means of spectroscopic techniques, scanning electron microscopy, chromatographic analysis, and pH investigations.

Ten rice starches with a fairly narrow range of amylose content, but wide variation in RVA pasting curves, were selected to study a possible relationship between amylopectin fine structure and RVA paste viscosity parameters. Amylopectin fine structure was found to significantly correlate with paste breakdown. Proportion of long chains of amylopectin (FrI) was negatively correlated (r=0·84, p

The mechanical behavior of cowpea starch gels (10%, w/v) at small and large deformations were investigated in comparison with acorn, corn, and potato starches in storage at 4°C for seven days. The rapid viscograms of starch paste (7%, w/v) revealed that cowpea starch had a larger setback (1,135 cP) than other starches (465–830 cP), although peak viscosity (1,723 cP) and pasting temperature (76°C) were between those of corn and potato starches. Texture profile analysis of cowpea starch gel showed exceptionally higher values for hardness, gumminess, chewiness and initial modulus than other starch gels. Cowpea starch gel also exhibited higher G′ and smaller tan δ compared with other starch gels, regardless of the storage time. A creep test revealed that the cowpea starch gel could remain highly resistant to stress, showing the least deformation among the tested starch gels during storage up to seven days. The overall results disclosed that cowpea starch was capable of forming exceptionally strong an...

クラスターデキストリンは,重量平均重合度900(分子量,約146000)で,構造的にアミロペクチンのクラスター単位を保持し,さらに環状構造を形成している.このクラスターデキストリンにはデンプン糊化液の粘度を低下させ,透明度を上昇(すなわち白濁度を降下)させる効果があることを見出した.また,これらの現象はデンプン糊化液の調製方法に関係なく生じ,さらに同じグルコースの重合体であるマルトースにはこれらの効果が顕著に見られなかった.

Starch paste viscosity plays an important role in estimating the cooking, eating, and processing quality of rice. The inheritance of starch paste viscosity in glutinous rice remains undefined. In the present study, 118 glutinous rice accessions were collected, and the genotypes of 17 starch synthesis-related genes (SSRG) were analyzed by using 43 gene-specific molecular markers. Association analysis indicated that 10 of 17 SSRGs were involved in controlling the rapid visco analyzer (RVA) profile parameters. Among these, the PUL gene was identified to play an important role in control of peak viscosity (PKV), hot paste viscosity (HPV), cool paste viscosity (CPV), breakdown viscosity (BDV), peak time (PeT), and paste temperature (PaT) in glutinous rice. Other SSRGs involved only a few RVA profile parameters. Furthermore, interactions between SSRGs were found being responsible for PeT, PaT, and BDV. Some of the RVA parameters, including PKV, HPV, CPV, CSV, and PaT, were mainly governed by single SSRG, whereas other parameters, such as BDV, SBV, and PeT, were controlled by a few SSRGs, functioning cooperatively. Further, three near-isogenic lines (NIL) of a japonica glutinous cv. Suyunuo as genetic background, with PUL, SSIII-1, and SSIII-2 alleles replaced with those of indica cv. Guichao 2, were employed to verify the genetic effects of the various genes, and the results were consistent with those obtained from the association analysis. These findings indicated that starch paste viscosity in glutinous rice had a complex genetic system, and the PUL gene played an important role in determining the RVA profile parameters in glutinous rice. These results provide important information for potentially improving the quality of glutinous rice.

Indica rice starch and japonica rice starch were used in the study. The protein contents of the two rice variety were respectively 0.43%, 0.62%, 0.84%, 1.08%, 1.25%. The pasting and rheological properties of samples were determined with Rapid Visco Analyzer and dynamic rheometer. The results indicated that, with the increase of protein content, the peak viscosity, breakdown viscosity and final viscosity of rice starch paste decreased, the setback viscosity increased and the pasting temperature did not change significantly. With the increase of protein content, the consistency coefficient of starch decreased, the corresponding yield stress also decreased, however, the flow behavior index increased with the decrease of consistency coefficient. At same temperature, the storage modulus G’ was greater when the protein content was higher.

Starch paste is used in cooking and processing as a viscosity enhancer and viscosity stabilizer.1,2 But few studies have been conducted on its spinnability, which is a visco-elastic phenomenon. We have jointly developed a Rheoner RE-33005 with Yamaden Co.3 to assess spinnability. The area of the tip of the rod in this equipment is a very small cross-sectional area to minimize the effects of surface tension. The spinnability of various starch pastes was compared with this apparatus, and the results suggest that the characteristics of spinnability are important indicators of viscoelastic behavior. The relationship between spinnability and dynamic viscoelasticity was developed, and the stress relaxation was investigated.

Unmodified cassava starch paste was characterized on the basis of its paste viscosity as affected by drying, cooking, and paste temperatures at different paste concentrations The paste exhibited plastic fluid flow with high hot-paste peak viscosity. The temperature of the peak viscosity decreased with increasing concentration. Drying temperature had statistically significant effects on the paste viscosity; the higher the temperature at which the starch was dried, the lower was the paste viscosity over the levels of concentration and cooking temperature. Starch drying temperature and paste concentration significantly affected the paste stability as measured by freeze-thaw tests and paste retrogradation tendencies.

The mechanism of the separating effect of fatty acid ester (FAE) has been studied in frozen starch noodles (FSN). This was examined by FAE adsorption on the starch surface and by FAE effects on viscosity, adhesive force, syneresis and iodine-affinity of starch paste. The present and previous results indicate that separating effect of FAE has a close relationship to the interaction of FAE with starch. The following factors are at least important in the separating effect of FAE; (a) adsorption of FAE on starch surface and (b) the subsequent action of FAE to reduce the viscosity and adhesive force of starch paste. The reason for FAE, especially sorbitan sterate or glycerin sterate, being effective in the separating action of FSN probably lies in the FAE ability to satisfy the above requirements.

The dynamic mechanical behaviour of starch pastes has been investigated over a frequency range of 0.02 to 5.0 radian sec−1. The influence of concentration of starch, source of starch and method of paste preparation on rheological properties have been studied. The results suggest that under the conditions examined differences in the dynamic rigidity and viscosity of pastes may be attributed to differences in the number fraction of large granules and the volume fraction of swollen starch particles they contain.

澱粉,とくにアミロペクチン(Ap)と界面活性剤との相互作用を明らかにすることを目的とし,B型粘度計を用いて,モチトウモ・コシ澱粉(WCS)希薄糊の粘度に及ぼすドデシル硫酸ナトリウム(SDS)の影響を調べた.その結果,WCS糊の粘度はSDSを添加すると著しく増加した.この粘度増加は,イオン強度を増加させると抑制され,また,糊調製時の加熱温度,加熱時間にも影響された.糊化澱粉中の膨潤澱粉と溶解澱粉とではSDSの結合量に差がないと考えられたが,糊の粘度増加は主として膨潤澱粉とSDSとの相互作用によるものであった.あらかじめWCS糊をβ一アミラーゼ処理すると,粘度増加は認められなかった.これらの結果から,WCS希薄糊の粘度がSDSを添加すると著しく増加したのは,主として,SDSが膨潤澱粉のAp外部鎖と相互作用することにより,すなわち,ApがSDSと複合体.(包接化合物)を形成することにより,硫酸イオンを持ったAp分子の隣接鎖間での静電的反発による分子の広がりが生じ,これが膨潤澱粉の一層の膨潤をもたらしたためではないかと推察した.

On Determination of Shearing Stability of Starch Pastes. Test conditions for the shearing stability test of starch pastes are not sufficiently outlined in existing publications. In the present paper, first of all a determination of optimum parameters (type of paste production, type of stirrer, stirring time, stirrer revolutions, viscosity measurement etc.) for a shearing stability test was attempted. It became apparent that shearing treatment of 5 min by means of a blade stirrer at a number of stirrer revolutions of 1800 r.p.m. with a 5% paste concentration is sufficient to determine shearing stability of a starch paste. For viscosity measurement which as well as pasting and shearing stress is carried out a 95 °C, a Brookfield viscosimeter is used. Provided measuring conditions (type of spindle, spindle revolutions) are kept constant before and after shearing stress, shearing stability can be expressed as remaining viscosity as a percentage of the initial viscosity. Furthermore, reproducibility of paste production as well as that of the whole shearing stability test were determined. Finally, a test was carried out as to wether there is a connection between shearing and heat stability of paste. Values obtained from 11 commercial products made such a connection between the two criteria apparent.

Observations on Viscosity Properties of Low-Substituted Starch Acetates. It was shown that with low-substituted starches dispersibility in water increases with increasing content of acetyl groups and increasing temperature. This fact becomes evident in lower temperatures at the beginning of pasting and at maximum of „viscosity”-graph. This has confirmed and extended earlier observations. Viscosity of starch acetate pastes is lower in cold as well as in hot state as that of native starch paste. Viscosity decreases down to an acetyl content of 2.36% and it changes only unnoticeably above that point. The decreasing gel forming ability can be expressed by the ratio of paste viscosities in cold and hot state. The rotation viscosimeter Rheotest proved well applicable for studies of viscosity and rheological properties of starch and of low-substituted acetates.

The critical concentration of a starch paste is the limiting concentration above which structural flow is apparent. The inverse of the critical concentration, termed the effective volume, is the minimum volume of solution per gram of starch below which structural flow is apparent. The critical concentrations and effective volumes have been measured for series of pastes of acid-modified corn and potato starches, and the effective volume has been shown to decrease with increasing degree of modification. The specific viscosities per unit concentration of these pastes, at concentrations below the critical, increases linearly with the effective volume, and the proportionality constants found are compared with those derived from the equations of Einstein and of Hatschek. The effects of phase-volume ratio and ease of deformation of the dispersed phase on the viscosity of a system are discussed, and previous relations applied to experimental data obtained in the present instance. Residual structure below the critical concentration is discussed. Above the critical concentration, the viscosity is dependent on the rate of shear, and the equation F = KPn expresses the experimental data well, where F is the flow, P is the pressure, K and n are constants. For two starches investigated, within the range of concentrations used n has been found to increase linearly with the concentration c, dn/dc being dependent on the elasticity or deformability of the granules.The form of lyophilic colloids in solution is discussed and agreement is expressed with the conception of Haller that the long-chain molecules, owing primarily to the free rotatability of the valence linkages, are irregularly bent and tangled in solution, as opposed to Staudinger's conception of straight rigid chains. These molecules occupy on the average a form approximating to the spherical, and solvation is due chiefly to immobilization. A dextrin in solution was found to have a [Formula: see text] ratio close to that of a pasted starch, and the forms of the two are probably similar. A lyophilic sol is considered heterogeneous and similar in many respects to an emulsion, with a very highly deformable discontinuous phase. The viscosity of such a system is due to phase-volume relations, modified by the ease of deformation of the dispersed phase, and the particular characteristics of these important sols admit of explanation on this basis.

Starch has an abundant use in the food industry because it is a thickening, stiffening or gluing agent. Also, nowadays there is an emphasis on the need to develop mild non thermal methods for food processing and in this view ultrasound has great potential. Therefore it is interesting to determine the effect of high intensity ultrasound on functional properties of the most common carbohydrate in the human diet. In this study we reviewed the effect of one and two minute treatment of rice and corn starch pastes with 24 kHz probe, 400 W of nominal output power, at 20%, 60% and 100% amplitude. The results showed that 60% and 100% ultrasound treatments increase the swelling power of starch pastes but increase the resistance to refrigeration of only corn starch pastes while leaving the rice starch paste unchanged. Apparent viscosity measured at three different temperatures, as well as the hardness of starch pastes differ depending on the conditions of the ultrasound treatment. By reviewing the influence of ultrasound on the starch pastes, it was determined that no deteriorating effect occurred and this treatment could be helpful for freezing of food stuffs.