Clean label starches as thickeners in white sauces. Shearing, heating and freeze/thaw stability

The linear viscoelastic properties and syneresis of freshly prepared and freeze/thawed white sauces prepared with different native starches (corn, waxy corn, potato and rice) at different shearing speeds were studied. Viscosity changes during processing were also measured using a starch pasting cell attached to a rheometer. The freeze/thaw cycle produced a significant increase in the viscous and elastic modulus and the appearance of syneresis in the corn and potato starch sauces, while the waxy corn and rice starch sauces were only slightly affected. Syneresis was significantly reduced upon subsequent heating. Greater shearing speed produced a significant decrease in viscoelasticity. Viscosity profiles revealed that the increase in shearing speed decreased the starch gelatinization temperature and swelling capacity and increased starch breakdown.     

Influence of corn starch type in the rheological properties of a white sauce after heating and freezing

The freeze/thaw and heating stability of white sauces prepared with two modified waxy corn starches (hydroxypropyl distarch phosphate and acetylated distarch adipate) and two native corn starches (waxy and normal) are compared.     

Study of emulsions stabilized with Phaseolus vulgaris or Phaseolus coccineus with the addition of Arabic gum, locust bean gum and xanthan gum

The properties of o/w emulsions stabilized with 1%w/v common bean (Phaseolus vulgaris L.), V or scarlet runner bean (P. coccineus L.), Coc extracted by isoelectric precipitation or ultrafiltration, at pH 7.0 and 5.5, with the addition of Arabic gum, locust bean gum, xanthan gum and a mixture of xanthan gum–locust bean gum (0.1 %w/v and 0.25 %w/v) are studied. The stability of emulsions was evaluated on the basis of oil droplet size, creaming, viscosity and protein adsorption measurements. The addition of Arabic gum, caused an increase in D[4,3] values and a decrease in the amount of protein adsorbed at the interface. The addition of locust bean gum in some emulsions reduced the amount of protein adsorbed. The addition of xanthan and to a less extend of the polysaccharide mixture, promoted a decrease in D[4,3]. So, emulsion stability was affected by the polysaccharide nature. Differences were also observed with respect to the protein nature, the method of its preparation and emulsion's pH. All polysaccharides enhanced the emulsions viscosity with xanthan and xanthan–locust bean gum exhibiting the higher values. V isolates and isoelectricaly precipitated isolates of both V, Coc showed higher viscosity values. The stability was enhanced by the increase of the viscosity of the continuous phase and the creation of a network, which prevents the oil droplets from coalescence.     

Structure and rheology of the κ-carrageenan/locust bean gum gels

The structure and interaction of κ-carrageenan and locust bean gum (LBG) has been studied using rheology, cryo-SEM, conductivity and syneresis characterization. The rheological behaviour of the binary system has been characterized using both compression and shear measurements. Elimination of slip in the shear measurements yields G′ values of the order 10,000–30,000 Pa for a 1% κ-carrageenan gel in 0–0.2 M added KCl. These values are higher than previously reported. No synergistic peak was found with the addition of LBG as has been previously reported. The measured modulii for these gels yields a Poisson's ratio of 0.5. Compression rupture stress and strain were also monitored. The rupture measurements do show a synergistic peak indicating that the interaction does occur and is important at high strain amplitudes. The gel points as determined by conductivity for these systems show a decrease in temperature with increasing LBG concentration, which is consistent with rheological measurements. Syneresis results are reported for the range of κ-carrageenan/LBG ratios. The syneresis shown by the mixtures is the same as that shown by the same concentration of κ-carrageenan. Structures of the gels as determined by cryo-SEM are also reported. Characteristic length scales in these systems are of the order of tens of microns and show little change with LBG concentration. The reduction in the characteristic length scale with increasing LBG concentration is discussed in terms of the rheological behaviour.     

Rheological behaviour of pullulanase-treated guar galactomannan on co-gelation with xanthan

The present study involves the use of non-specific enzyme pullulanase (from Bacillus acidopullulyticus) to remove galactose residues from guar galactomannan to obtain modified guar galactomannan mimicking the functional properties of locust bean gum. The modified guar galactomannan blended with xanthan exhibited the rheological behaviour of elastic modulus (G′) greater than viscous modulus (G″) with a decrease in tan δ value similar to locust bean gum/xanthan blend. Also a twofold increase in the magnitude of elasticity compared to xanthan alone suggested the synergistic interaction with formation of three dimensional networks. The modified guar galactomannan with galactose content of 21% and M:G ratio 1:3.8, almost akin to locust bean gum, showed a better interaction with xanthan. Dynamic stress sweep study of modified guar galactomannan/xanthan blend with increased yield stress of 800 dynes/cm² also indicated the synergistic behaviour. Modified guar galactomannan also revealed the maximum synergistic interaction with xanthan at a mixing temperature of 60 °C than at 20 °C, 30 °C, 40 °C and 50 °C, respectively. Modification of guar galactomannan by pullulanase is an alternative route to produce galactose-depleted guar galactomannan with enhanced rheological functionalities on co-gelation with xanthan, as a cost effective replacement to locust bean gum.     

Impact of chemical composition of xanthan and acacia gums on the emulsification and stability of oil-in-water emulsions

Xanthan gum (GX) and acacia gum (GA) are widely employed in food industry, indeed xanthan gum is used for its thickening properties of aqueous solutions and acacia gum for its emulsifying ability. The present work aims to study the effect of GX–GA mixtures on the stability of oil-in-water (o/w) emulsions; attention is particularly focused on the impact of the chemical structure of each gum. Emulsion stability has been evaluated by monitoring the evolution of droplet size and viscometric properties over time when submitted to accelerated ageing conditions. On the one hand results show that the higher the ArabinoGalactanProtein (AGP) content the more stable the emulsion as observed when GA is used alone. On the other hand, we proved, unexpectedly, that the most viscous aqueous phase does not exhibit the best emulsion stability. Besides, we clearly evidenced the presence of specific interactions between GX and GA in both emulsion and aqueous solution, these interactions being governed by the gums chemical composition.     

The effect of electrostatic interactions on pasting properties of potato starch/xanthan gum combinations

The effects of electrostatic interactions on pasting properties of potato starch (PS)/xanthan gum (XG) combinations were investigated. The RVA peak viscosity of combinations was decreased firstly and then increased with the adding of XG. The analysis and regression model performance of RVA measurement showed that there was the relationship between pasting properties of combinations and XG concentrations. Electrostatic repulsions between native potato starch or anionic modified potato starches (AP) and XG could be present by decreasing peak viscosity, but the pasting temperatures showed increasing trend. However, electrostatic attractions between cationic modified potato starch (CP) and XG showed the opposite effect. Negative zeta potential determination for combinations (− 54.6 mv) was higher than PS (− 35.2 mv) illustrated that combinations had more electronegativity and stability, in addition a phase-separated microstructure was exhibited in the combinations determined by Zeta potential results. SEM micrographs presented that XG film attached to the surface of PS granules, which inhibited the starch granules destruction and leaching of amylase. The electrostatic repulsion leaded to more stability of the three dimensional network structures of combinations. The strong electrostatic interactions between PS and XG were found to play an important role on the pasting properties of the combinations.     

Rheological and structural characterization of gels from whey protein hydrolysates/locust bean gum mixed systems

The gelling ability of whey proteins can be changed by limited hydrolysis and by the addition of other components such as polysaccharides. In this work the effect of the concentration of locust bean gum (LBG) on the heat-set gelation of aqueous whey protein hydrolysates (10% w/w) from pepsin and trypsin was assessed at pH 7.0. Whey protein concentrate (WPC) mild hydrolysis (up to 2.5% in the case of pepsin and 1.0% in the case of trypsin) ameliorates the gelling ability. The WPC synergism with LBG is affected by the protein hydrolysis. For a WPC concentration of 10% (w/w), no maximum value was found in the G′ dependence on LBG content in the case of the hydrolysates, unlike the intact WPC. However, for higher protein concentrations, the behaviour of gels from whey proteins or whey protein hydrolysates towards the presence of LBG becomes very similar. In this case, a small amount of LBG in the presence of salt leads to a big enhancement in the gel strength. Further increases in the LBG concentration led to a decrease in the gel strength.     

Oil-in-water emulsions stabilized by sodium caseinate: Influence of pH,high-pressure homogenization and locust bean gum addition

The effect of pH, addition of a thickening agent (locust bean gum) or high-pressure homogenization on the stability of oil-in-water emulsions added by sodium caseinate (Na-CN) was evaluated. For this purpose, emulsions were characterized by visual analysis, microstructure and rheological measurements. Most of the systems were not stable, showing phase separation a few minutes after emulsion preparation. However, creaming behavior was largely affected by the pH, homogenization pressure or locust bean gum (LBG) concentration. The most stable systems were obtained for emulsions homogenized at high pressure, containing an increased amount of LBG or with pH values close to the isoelectric point (pI) of sodium caseinate, which was attributed to the size reduction of the droplets, the higher viscosity of continuous phase and the emulsion gelation (elastic network formation), respectively. All the studied mechanisms were efficient to decrease the molecular mobility, which slowed down the phase separation of the emulsions. In addition, the use of sodium caseinate was also essential to stabilize the emulsions, since it promoted the electrostatic repulsive interactions between droplets.     

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.     

Effects of non-starch hydrocolloids on the physicochemical properties and stability of a commercial béchamel sauce

The aim of this study was to investigate the effects of non-starch hydrocolloids (NSH) on the physicochemical properties and stability of a béchamel sauce. Three different NSH (guar gum, xanthan gum and carboxymethylcellulose) were added at two concentrations (0.10 wt.% and 0.25 wt.%) hereby replacing an equal amount of modified starch. Sauce batches were stored at refrigerated temperatures during four weeks and were rheologically characterized at day 2, 16 and 30 after preparation. The addition of all hydrocolloids caused a marked increase of the consistency index compared to the model system whereas this parameter decreased for all sauces during refrigerated preservation. The yield stress was also increased by the NSH. Furthermore all studied NSH reduced the amount of syneresis, with xanthan gum being the most effective. Besides, sensory tests demonstrated that there were no significant differences in taste and general preference between the hydrocolloid sauces and the model system.     

白芸豆淀粉与小利马豆淀粉理化性质的比较研究

本实验以白芸豆和小利马豆为原料,采用碱法提取淀粉,对白芸豆淀粉和小利马豆淀粉的理化特性进行分析研究。结果表明,白芸豆和小利马豆的淀粉颗粒均呈表面光滑、无棱角及裂痕的特征,且2种淀粉的微晶结构均为A型;2种豆类淀粉的溶解度和膨胀度均随温度的升高而增加。小利马豆淀粉和白芸豆淀粉在冻融稳定性、透明度和成糊特性等方面存在显著差异,小利马豆淀粉的膨胀度、溶解度及淀粉糊的冻融稳定性和透明度更好,而白芸豆淀粉呈现起糊温度、峰值黏度、破损值和回生值较低的成糊特性,易成糊、抗剪切。     

Microwave heating effect on rheology and microstructure of white sauces

The microstructure and rheological properties of white sauces formulated with different starches were analyzed after being microwave-heated for different times. Significant differences (P < 0.05) in rheological parameters analyzed-storage modulus (G'), loss modulus (G″), and loss tangent (tanδ)-were obtained for sauces made with different starches. Microwave reheating did not affect G' and G″ values until water evaporation became significant. In addition, tanδ values did not change significantly (P < 0.05) even during long reheating times showing that sauce viscoelastic properties did not change after microwave irradiation. However, microstructure assessed by confocal laser scanning microscopy showed changes in fat globule and protein. These microstructural changes did not seem to have a significant effect on rheological measurements since starch and ι-carrageenan are mainly responsible for the viscoelastic behavior of the sauces. Practical Application: The development of products appropriate to microwave heating is constantly rising in food industry. It is necessary to understand the behavior of the ingredients and the final product to microwave heating in order to choose those ingredients which will develop the best performance. Starches are common ingredients in industrial sauces, and rheological and microstructural techniques have shown their usefulness in characterization of starch-based systems.     

Acid gelation of native and heat‐denatured soy proteins and locust bean gum

The effects of protein concentration and locust bean gum (LBG) addition on the mechanical properties, microstructure and water holding capacity of acidified soy protein (SPI) gels were studied. The protein was employed in two different states: (i) native and (ii) heat denatured. A slow acidification rate was induced in both systems by applying glucono‐δ‐lactone (GDL). The results indicated that the gels of native SPI were weaker, less deformable and showed lower water holding capacity than the gels of heat‐denatured SPI. The LBG addition led to an increase in the strength and water holding capacity of SPI gels, independent of the protein state (native or denatured). These results indicated that the properties of texture and water holding capacity of the SPI acid gels can be modulated by the process conditions or by the addition of other ingredients, such as polysaccharides.     

Surface tension of Phaseolus vulgaris and coccineus proteins and effect of polysaccharides on their foaming properties

The surface tension of protein isolates from common bean (Phaseolus vulgaris L.) and scarlet runner bean (Phaseolus coccineus L.), prepared by isoelectric precipitation and ultrafiltration was evaluated, with respect to protein concentration (0.001–0.1% w/v) and pH (pH 4.5, 5.5, 7.0 and 8.0). Surface tension was most reduced, and with a higher rate of reduction at higher protein concentration and at pH 8.0. Foams (1, 2% w/v protein), at the same pH values, with and without the addition of polysaccharides, were studied. The proteins’ foaming behaviour was related to their adsorption behaviour. Arabic gum, locust bean gum (0.1% and 0.25% w/v), xanthan gum and a xanthan/locust bean gum mixture (0.1% w/v) had a positive effect on foam creation. All polysaccharides increased foam stability, probably due to the viscosity increase and to the creation of a network, which prevents the air droplets from coalescence. Isolates from P. coccineus and isolates obtained by ultrafiltration seemed to exhibit better foaming properties.     

The analysis of crude and purified locust bean gum: A comparison of samples from different carob tree populations in Tunisia

The crude and purified locust bean gum (LBG) from seven areas of the north and centre of Tunisia (Bouarada, Bargou, Kessra, Haffouz, Borj Toumi, Ben Arous and INRGREF) were analyzed for moisture, ash, protein, acid-insoluble matter and mannose/galactose ratio. The purified samples exhibited higher mannose/galactose ratios and lower amounts of ash, protein and acid-insoluble matter than the crude gum. The purified LBG from different regions had 3.43–6.99% moisture, 0.87–2.06% ash, 0.61–2.46% protein, 0.00–1.20% acid-insoluble matter and 3.55–4.32 mannose/galactose ratios. Statistical analysis revealed that purification significantly affected (P < 0.05) moisture, ash, protein, insoluble matter contents and mannose/galactose ratios of the crude LBG and purified LBG for all samples from different areas. The rheological properties of the different carob gum samples were determined, the best rheological properties are those of spontaneous carob trees of Bargou, Bouarada and Kessra areas. The climatic and geographic origin of carob and the cultivation mode influence the chemical and rheological properties. The purification of crude galactomannan samples by precipitation with isopropanol gave a clear and more stable solution, due to the elimination of impurities and endogenous enzymes.     

The effects of the combined use of stabilizers containing locust bean gum and of the storage time on Kahramanmaraş-type ice creams

This study was aimed primarily at determining the suitability of locust bean gum and various stabilizers in the production of Kahramanmaraş-type ice creams, the physical, chemical and sensory properties of the ice creams produced, and the stabilizer combination that could produce the best quality ice cream. With a total amount of stabilizer of 1.0%, ice creams of four different combinations containing locust bean gum, carboxymethyl cellulose, guar gum and sodium alginate were produced and their properties during a 6-month storage period compared with the control sample produced using only salep extract ( Orchis orchida ).
  The ice cream produced using only the salep extract had significantly higher ( P  < 0.05) levels of titratable acidity, lower pH and viscosity values, and were harder and less resistant to melting compared to those produced with the stabilizer combinations. The stabilizer mixtures containing locust bean gum yielded better results than those with the salep extract. An analysis of the effect of storage time on the properties of the ice creams indicated that, of the physical properties examined, only the decrease in the penetrometer values was significant ( P  < 0.05). Apart from the difference observed in the third month during the storage of the ice creams produced with the salep extract, the differences during the storage time were not found to be significant ( P  > 0.05).     

Impact of xanthan gum,sucrose and fructose on the viscoelastic properties of agarose hydrogels

Mixed carbohydrate systems are of special interest for the food and non-food industry as they offer a versatile range of unique and novel functional properties. However, intense research is required to understand the complex processes occurring in such systems on a molecular level and to be able to modify them aim-oriented. In food, characteristic properties are based on the physicochemical functions of the biopolymers added. Thus, small deformation tests and moisture analysis have been applied to study the impact of xanthan gum and two types of sugar on the viscoelastic properties, the sol–gel transition and the water holding capacity of 1% agarose hydrogels. Agarose gels are very elastic, turbid and prone to synaeresis, which impinges on their mouth feeling. Additions of xanthan gum revealed less elastic gels with an unaffected water holding capacity. Progressive addition of two different types of up to 40% of sugar yield an increase of the elasticity of agarose gels, whereby sugar concentrations of 60% partially result in a structural breakdown and thus a significant lower network structure but better water holding. In ternary systems, the effect of the sugar concentration and sugar type used is diminished by xanthan gum. The gelation mechanism of agarose gels with a distinct amount of co-solutes is presumably mainly affected by the water shortage evolved from the competition for it of all solutes present.     

Effects of waxy maize and potato starches on the stability and physicochemical properties of model sauces prepared with fresh beef meat

Stability and physicochemical properties of model sauces containing 2.5 wt% fresh beef meat (related to raw material), 30 wt% rapeseed oil and native waxy maize starch (WMS) or potato starch (PS) at concentrations ranged from 0.5 to 4.0 wt% were assessed. Sauces thickened with WMS showed a significantly (P < 0.05) higher stability than respective ones made with PS. All studied systems exhibited non‐Newtonian, pseudoplastic behaviour. The Ostwald–de Waele and Herschel–Bulkley models were used to describe the flow properties of model sauces. In comparison with control sample (prepared without starch), addition of this polysaccharide (WMS or PS) increased consistency index, yield stress and apparent viscosity and decreased flow behaviour index of model sauces. The Arrhenius equation was used to determine the effects of temperature (20–50 °C) on the apparent viscosity. The activation energy values were in ranges 7.66–10.59 kJ mol^?1 and 8.87–11.82 kJ mol^?1 in sauces prepared with WMS and PS, respectively. The instrumentally detected changes in consistency and whiteness of model sauces were found, which may be used as the good predictors of the perceived sensory consistency and whiteness.