Rapid Visco-Analyzer (RVA) Pasting Profiles of Wheat,Corn, Waxy Corn,Tapioca and Amaranth Starches (A. hypochondriacus and A cruentus) in the Presence of Konjac Flour,Gellan, Guar,Xanthan and Locust Bean Gums

The Rapid Visco-Analyzer (RVA) 20min test was used to study the effects of different levels of konjac flour, guar, gellan, xanthan and locust bean gums on starch cooking properties. Wheat, corn, waxy corn, tapioca and A. hypochondriacus and A. cruentus starches were affected to different degrees by different levels of the gums. Peak viscosity increased at the higher gum concentrations, especially with locust bean gum at the 0.4 g level. The increase in viscosity was more pronounced with wheat and corn starches than with waxy corn and tapioca starches which consist mostly of highly branched amylopectin thus preventing close physical association between molecules. Amaranth starches showed much lower viscosity with all the gums than the other starches. Peak viscosity, time to reach the peak and maximum setback viscosity were affected by the gums. The increase in viscosity of starch/hydrocolloid systems is due to the release of amy-lose and low molecular weight amylopectin which promotes the formation of polymer complexes and significantly adds to the viscosity of the system.     

EFFECT OF SURFACTANT GEL AND GUM COMBINATIONS ON DOUGH RHEOLOGICAL CHARACTERISTICS AND QUALITY OF BREAD

Sodium stearoyl‐2‐lactylate (SSL), diacetyl tartaric acid esters of monoglyceride (DATEM), glycerol monostearate (GMS) and distilled glycerol monostearate (DGMS) surfactant gels were made with water. Addition of surfactant gels decreased water absorption by the bread while xanthan, karaya, guar and locust bean gums increased the same. Only DGMS or GMS and gum combinations further improved water absorption. All the gums except for guar along with surfactant gels improved dough stability. Both surfactant gels and gums improved the extensograph dough properties of wheat flour to varying degrees. Alveograph characteristics of wheat flour improved to varying extents with surfactant gels while the gums influenced the viscoelastic properties in differing ways. Different combinations of surfactant gels and gums showed varied influences on rapid visco analyzer characteristics of wheat flour. Both surfactant gels and gums improved the bread making quality. Among surfactants, SSL in combination with gums, and among gums locust bean in combination with surfactant gels improved the bread making quality of wheat flour to a maximum extent.     

Effect of dry heating with ionic gums on physicochemical properties of starch

Corn starch, potato starch, pea starch were impregnated with ionic gums (sodium alginate, CMC, and xanthan, 1% based on starch solids) and heat-treated in a dry state for 0, 2, or 4 h at 130 °C. Effects of the dry heating on paste viscosity (RVA), microstructure and thermal properties were examined. Dry heat treatment with ionic gums reduced the pasting temperature of the three starches. Heating with xanthan increased the paste viscosity of corn and potato starch. With heat treatment, the paste viscosity of all the starch-sodium alginate mixtures decreased. Heating with CMC increased the paste viscosity of potato starch, but decreased that of corn and pea starch. After dry-heating, To, Tp and Tc of potato starch with ionic gums decreased significantly. SEM of potato starch with CMC showed that the gel structure got compacter after drying-heating. Heat treatment obviously improved the functional properties of the three starches.     

Influence of selected hydrocolloids on triticale starch rheological properties

The aim of the study was to define the influence of selected nonstarch polysaccharides (guar gum, xanthan gum and arabic gum) on several rheological properties of triticale starch pastes/gels, at constant polysaccharide concentration (6.5 g/100 g). These included pasting characteristics, flow curves at 50 °C and mechanical spectra at 25 °C. It was found that the presence of a gum in a system modified the rheological properties of triticale starch gels/pastes, depending on the type and concentration of the gums. In the case of guar and xanthan gums, higher pasting viscosity was observed and the shear stress was increased compared with native starch. The presence of guar gum reduced the degree of thixotropy hysteresis, negative values for this being found for systems with xanthan in spite of their shear‐thinning behaviour. Systems containing arabic gum displayed lower values of pasting and flow viscosity. The type and concentration of gums added to the polysaccharide influenced the viscoelastic properties of the gels.     

韧化温度和时间对不同直链淀粉质量分数玉米淀粉物化性质的影响

为进一步探讨韧化处理对淀粉性质的作用机理,通过测定糊化性质、热特性、膨胀力、结晶特性及观察偏光十字现象和微观结构,研究了不同韧化温度和时间对不同直链淀粉质量分数玉米淀粉（普通玉米淀粉（normal corn starch,NCS）和蜡质玉米淀粉（waxy corn starch,WCS））物化性质的影响。结果表明,韧化处理主要作用于NCS和WCS淀粉颗粒的无定形区,对淀粉结晶类型没有影响;但韧化处理能够明显增强NCS和WCS的热稳定性和抗剪切能力,抑制淀粉老化和糊化,显著降低峰值黏度和膨胀力（P＜0.05）。韧化温度升高至60 ℃时韧化效果更加明显,糊化焓和相对结晶度明显降低,颗粒表面被明显破坏。但延长韧化时间对NCS和WCS老化的抑制效果和对糊化焓、膨胀力、颗粒形貌等的影响不明显。     

食品胶协同干热处理对马铃薯淀粉理化特性的影响

为了改善马铃薯淀粉加工特性,选用瓜尔胶、羧甲基纤维素钠和黄原胶3种食品胶分别与马铃薯淀粉复配后进行干热处理,研究食品胶协同干热处理对马铃薯淀粉糊化、老化和流变特性的影响。研究发现,中3种食品胶协同干热处理均能够降低糊化温度与糊化焓,并且均能增强淀粉体系稳定性,使其呈现出弹性流体性质,不仅如此还均能提高淀粉糊热稳定性以及耐剪切能力,此外均能增强淀粉凝胶的冻融稳定性。结果表明,3种食品胶协同干热处理均能起到改善马铃薯淀粉加工特性的作用,对其改善程度对比分析发现,黄原胶协同干热处理改善马铃薯淀粉特性效果最好。     

Corn Masa and Tortillas from Extruded Instant Corn Flour Containing Hydrocolloids and Lime

Extruded instant corn flour (EICF) samples with hydrocolloids (gums), such as gum arabic, carboxymethylcellulose (CMC), guar and xanthan and with different concentrations of lime (0.1, 0.2 and 0.3% w/w) were prepared by extrusion. The gums were added before or after thermal processing. The dehydration process followed through the weight loss (WL) in masa, the physicochemical (water absorption capacity (WAC) and WL during cooking) characteristics of masa were optimized to give longer dehydration times and tortillas with good textural (rollability, tensile strength and cutting force) properties. The lowest effective moisture diffusion coefficient (D*) was found in masa samples containing 0.2% (w/w) of lime and 0.5% (w/w) of the xanthan gum added before extrusion. These masas produce tortillas with optimum textural characteristics and highest yields.     

Comparison of the effects of gums on dynamic rheological properties of acetylated sweet potato starch

Dynamic rheological properties of acetylated sweet potato starch (ASPS) pastes mixed with 3 commercial gums (guar gum, locust bean gum, and xanthan gum) were investigated at different gum concentrations. The dynamic moduli of the ASPS-gum mixtures were higher than those of the control, and they increased with an increase in gum concentration. In particular, the G′ value of xanthan and G″ value of guar gum at a 0.6% gum concentration were much higher as compared to those of other mixtures. Tan δ values of ASPS-xanthan mixtures were much lower than those of other samples, indicating that the elastic properties in the ASPS-gum mixture systems were strongly affected by the additions of xanthan. These results suggest that the presence of gums in ASPS modifies the viscoelastic properties, and that these modifications are dependent on the gum type and gum concentration.     

直链淀粉含量对玉米淀粉/瓜尔胶复配体系糊化和流变特性的影响

为考察直链淀粉含量对淀粉/瓜尔胶复配体系性质的影响,以不同直链淀粉含量的玉米淀粉(蜡质玉米淀粉、普通玉米淀粉和高直链玉米淀粉)为原料,加入瓜尔胶,研究复配体系的糊化、流变及凝胶特性。结果表明:瓜尔胶与直链淀粉之间的相互作用是引起淀粉复配体系黏度和稠度系数增加、成糊温度和流体指数降低的主要原因。动态流变实验结果表明淀粉中直链淀粉含量不同对复配体系的动态模量的影响也不同。在糊化过程中,随着直链淀粉含量增加,直链淀粉分子与瓜尔胶间的相互作用增强,阻碍了直链淀粉分子间的聚集重排,使得复配体系硬度值减小,3种玉米淀粉形成了质地更为柔软的凝胶。     

Experimental Analysis of Structural Change and Rheological Behavior of Macromolecular Solutions with Guar and Xanthan Gums in Crossflow Microfiltration Processing

The present paper reports on the structural change and rheological behavior of mixtures of macromolecular suspensions (guar and xanthan gums) in crossflow microfiltration processing. Mixtures in suspension of guar and xanthan gums at low concentrations (1,000 ppm) and different proportions were processed by microfiltration with membrane of nominal pore size of 0.4 μm. The rheological behavior of the mixtures was investigated in rotational viscometers at two different temperatures, 25 and 40 °C, at the beginning and at the end of each experiment. The shear stress (τ) in function of the shear rate (γ) was fitted and analyzed with the power-law model. All the mixtures showed flow behavior index values (n) lower than 1, characterizing non-Newtonian fluids (pseudoplastic). The samples of both mixtures and permeates were also analyzed by absorbency spectroscopy in infrared radiation. The absorbency analysis showed that there is good synergism between xanthan and guar gums without structure modifications or gel formation in the concentration process by microfiltration.     

Viscosity of guar gum and xanthan/guar gum mixture solutions

The viscosity of diluted guar gum solutions and the viscosity of xanthan and guar gum mixture solutions have been studied. Guar gum solutions showed pseudoplastic behaviour. Apparent viscosity increased with gum concentration and decreased with the temperature at which viscosity was measured. A maximum in the plot of viscosity versus increasing dissolution temperature was observed at 60 °C. This behaviour was related to differences in molecular structure of the polymers solved at different temperatures. Mixtures of xanthan and guar gum showed a higher combined viscosity than that occurring in each separate gum. This synergistic interaction was affected by the gum ratio in the mixture and dissolution temperature of both gums. The effect of polysaccharide concentration (1.0, 1.5 and 2.0 kg m⁻³), xanthan/guar gum ratio (1/5, 4/2, 3/3, 4/2 and 5/1) and dissolution temperature (25, 40, 60 and 80 °C for both gums) on the viscosity of solutions of mixtures were studied. The highest viscosities were observed when 2.0 kg m⁻³ gum concentration was used together with a ratio of xanthan/guar gum of 3/3 (w/w) and dissolution temperature of 40 and 80 °C for xanthan and guar gum, respectively. © 2000 Society of Chemical Industry     

Rheological interactions between Lallemantia royleana seed extract and selected food hydrocolloids

BACKGROUND: Lallemantia royleana (Balangu) is a mucilaginous endemic plant which is grown in different regions of world. The flow behaviour of Balangu seed extract (BSE) and its mixture with xanthan, guar and locust bean gums at 1:3, 1:1 and 3:1 ratios, in addition to control samples (0% BSE), were evaluated. To describe the rheological properties of samples, the power law model was fitted on apparent viscosity–shear rate data. To evaluate the interaction between BSE and selected hydrocolloids in dilute solutions, the relative viscosity was also investigated. RESULTS: There was no significant difference between the consistency coefficient of guar and locust bean solutions and their blends substituted with 250 g kg^?1 BSE. The BSE–xanthan mixture at 1:3 and 1:1 ratios had consistency index equal to xanthan solution. BSE–locust bean gum at all ratios, BSE–xanthan at 1:3 ratio and BSE–guar gum at 1:1 and 3:1 ratios indicated relative viscosity lower than values calculated assuming no interaction. The intrinsic viscosity value of BSE was determined 3.50 dL g^?1. CONCLUSION: The apparent viscosities of BSE, selected hydrocolloids and their blends were the same at a shear rate of 293 s^?1 and the commercial gums can be substituted by 250 g kg^?1 and 500 g kg^?1 BSE. Copyright © 2011 Society of Chemical Industry     

Dielectric and Thermal Properties of Rice Cake Formulations Containing Different Gums Types

In this study, dielectric properties of rice cake formulations containing different gum types (xanthan, guar, locust bean, HPMC, and kappa-carrageenan) were determined at temperatures between 25 and 90°C at 2450 MHz. Moreover, thermal properties of these formulations were determined by using differential scanning calorimeter (DSC). Dielectric properties of cake batters were found to be dependent on cake formulation. Xanthan and guar gum containing cake batters had the highest dielectric constant and loss factor values at 25°C. Temperature dependence of dielectric properties was not significant until temperature of 85°C. Gelatinization enthalpy of batter increased with the addition of gums.     

EFFECTS OF HYDROCOLLOIDS AND ASPARTAME ON SENSORY VISCOSITY AND SWEETNESS OF LOW CALORIE PEACH NECTARS

Effects were studied of interactions between each of three hydrocolloids-xanthan gum, guar gum and methylcellulose- and aspartame on sweetness intensity and sensory viscosity of low-calorie peach nectars (60% fruit purée with no sucrose added). The flows of the nectars were characterized as near Newtonian without hydrocolloids, as Bingham plastic at lower hydrocolloids concentrations and as pseudoplastic at higher concentrations (Ostwald flow for guar and methylcellulose, and Herschel-Bulkley for xanthan). Hydrocolloids concentrations were selected to cover viscosity range of commercial whole nectars: 0.10 and 0.20% xanthan or guar, and 0.15 and 0.30% methylcellulose. Aspartame concentrations tested were derived from the calculation of equisweet concentration as referred to a control nectar sample with sucrose (14°Brix) and of the upper and lower limen value: 0.216, 0.360 (equisweet), 0.502, and 0.644 g/L. Addition of either guar or methylcellulose did not alter the perceived sweetness in aspartame-sweetened peach nectars. Xanthan addition, even at 0.10%, significantly lowered sweetness of samples sweetened with the highest aspartame concentration (0.644 g/L). Addition of aspartame did not modify the perceived viscosity in samples thickened with either xanthan or guar gums. At all methylcellulose concentrations tested, samples with the lowest aspartame concentration (0.216 g/L) were perceived as less viscous.     

Effect of physico‐chemical properties of tropical starches and hydrocolloids on rice gels texture and noodles water retention ability

The links between the physico‐chemical properties of rice flour (RF), cassava (CS), sago (SS), canna (CaS), sweet potato (SPS), and mung bean (MS) starches, and the gelling properties of rice flour blends with these starches in different proportions (0, 20, 40, 60, 80, and 100% pure starches) and with xanthan (XG) and carrageenan (CG) gums were studied. Water retention ability of starches and hydrocolloids blends in noodle systems during drying at 40°C was also investigated. The mean granule diameter and AM content values of RF, CS, SPS, SS, CaS, and MS were in the range of 12.8–41.0 µm and 21.9–39.4%, respectively. Thermal properties showed significant differences (p < 0.05) between the starches in terms of gelatinization temperature and enthalpy, as well as retrogradation tendency. Different starches produced gels with a wide range of textural properties. Results confirmed the role of AM content in determining the gel strength, and indicated a possible role of retrogradation in increasing the dissipation of mechanical energy during compression and relaxation tests, which can have an effect on mouth feel. Blends of RF with other starches and hydrocolloids generally improved the characteristics of RF‐based gels, by increasing gel strength. In particular, the use of MS markedly increased the strength of RF‐based gels. Addition of hydrocolloids significantly reduced the drying rate of noodles, although overall water retention ability was reduced only to a limited extent. This may be used to produce starch‐based products, especially noodles, in a range of desired characteristics.     

微波处理对普通玉米淀粉和蜡质玉米淀粉理化性质的影响

为探讨微波处理对普通玉米淀粉(CCS)和蜡质玉米淀粉(WCS)理化性质的影响,采用快速黏度分析法、差示扫描量热法、流变分析法,研究了不同时间或功率微波处理后CCS、WCS的理化性质。结果表明,微波处理时间和功率影响CCS、WCS的理化性质。60~90 s或462~700 W的微波处理增加CCS、WCS的糊化难度,使其起糊温度升高。微波处理导致CCS淀粉糊稠度、糊化焓降低,WCS的膨胀度降低。微波处理使WCS淀粉糊储能模量、损耗模量升高,增加其在外力作用下的稳定性,但只能形成弱凝胶。不同时间、不同功率的微波处理对CCS、WCS的短期老化和长期老化均有一定的抑制作用,使CCS、WCS的回生值、老化率均降低。     

Rheological behaviors of hydroxypropylated sweet potato starches influenced by guar,locust bean,and xanthan gums

This study examined the steady flow and dynamic rheological behaviors of hydroxypropylated sweet potato starch (HPSPS) pastes mixed with guar gum (GG), locust bean gum (LBG), and xanthan gum (XG) at different concentrations (0, 0.3, and 0.6%). The HPSPS–gum mixtures had higher shear‐thinning fluid characteristics than the control (0% gum) at 25°C. The addition of the gums resulted in an increase in the consistency index (K) and apparent viscosity (η_a,100). The dynamic moduli (G′, G″) and complex viscosity (η*) values of the HPSPS–gum mixtures were higher than those of the control, and they increased with an increase in gum concentration. In particular, the presence of XG at 0.6% in the HPSPS–gum mixture systems gave rise to the greatest viscoelastic properties among the gums examined at different concentrations. The tan δ (ratio of G″/G′) values (0.35–0.57) of the HPSPS–GG and HPSPS–XG mixtures were much lower than those of the control (0.82) and HPSPS–LBG (0.88–1.06), indicating that the elastic properties in the HPSPS–gum mixture systems were strongly affected by the additions of GG and XG. These steady flow and dynamic rheological parameters indicated there were synergistic interactions between the HPSPS and gums. The synergistic effects of the gums and modified starch were hypothesized by considering the molecular incompatibility and molecular interactions between the gums and HPSPS.     

Moisture absorption characteristics of food thickeners used for the management of swallowing dysfunctions

Six commercial food thickeners, based on starch, and guar and xanthan gums, were investigated for their moisture absorption properties. The thickeners were exposed to 100% relative humidity as well as soaked in water for selected time periods. The gum-based thickeners dissolved in water to yield 100% water solubility index. The water absorption index of the starch-based thickeners ranged from 14.7 to 18.0 g/g dry solids of thickener. The starch-based thickeners sorbed less moisture than the gum-based ones, with the xanthan gum-based thickeners having the highest sorptive ability on mass basis. The Peleg model was the most suitable (r ²=0.966–0.997) of the sorption models investigated to describe the sorption data. The diffusion rate constant of the thickeners ranged from 8.7 to 13.5 day%⁻¹, while the equilibrium moisture content was between 35.7 and 46.8%. The sorptive ability explained viscosity development in some of the thickeners, but was unsuitable in fully describing comparisons of the solutions viscosities of starch-based and xanthan gum-based thickeners.     

Comparison of 3D printed and molded carrots produced with gelatin,guar gum and xanthan gum

This study examined the effects of different hydrocolloids (guar gum, xanthan gum and gelatin) on the sensory and textural properties of pureed carrots. There were eight products involved in the study; 3D printed carrots and molded carrots without the addition of gums and with guar gum, xanthan gum and gelatin. All products were evaluated using trained panelists (n = 12) and underwent a texture profile analysis. No significant differences were found between the molded and 3D printed pureed carrots; instead, the samples were grouped based on the gum used in their production. The samples made with gelatin and xanthan gum were the hardest (texture profile analysis) and the densest samples when evaluated by the trained panelists. The 3D printing did not affect the taste properties of the pureed carrots, as they were evaluated to be similar to that of the molded carrots (p > .05). This study demonstrated that 3D printing did not affect the textural and sensory properties of pureed carrots when compared to molded carrots. However, changes in the printing parameters (infill percentage, nozzle diameter, flow rate, nozzle height) need to be evaluated to determine their effect on the sensory properties of 3D printed pureed carrots.     

Influence of Gluten and Gum Additives and Cryogenic Treatment on Some Properties and Morphology of Wheat Starch Complex Gels

The influence of gums (guar and xanthan) and gluten additives on the physicochemical properties and structural features of wheat starch gels (8%, w/w) subjected to cryogenic treatment at various temperatures (−9°C, −20°C, −40°C) was studied. Shear modulus and breaking stress of the gels were measured, the gels' morphology was studied with optical microscopy and the local mobility of water in the gels was determined with ESR. The total concentration of polysaccharide additives did not exceed 1% (w/w), and a 65:35 (w/w) mixture of guar and xanthan gums proved to be the optimal additive, which caused a noticeable increase in rigidity and strength of the resulting complex gels. Shear modulus and breaking stress of the gels decreased with lowering the temperature of the cryogenic treatment. The heterogeneous morphology of thin sections of the gel samples was revealed via optical microscopy. ESR studies showed that the local mobility of water was much lower in the gels than in pure water.