Inulin Solution Research Articles

Immobilised Inulinase from Aspergillus niger for Fructose Syrup Production: An Optimisation Model.

Fructose is a carbohydrate with essential applications in the food industry, mainly due to its high sweetness and low cost. The present investigation focused on optimising fructose production from commercial inulin using the enzymatic immobilisation method and applying the response surface methodology in a 12-run central composite design. The independent variables evaluated were the pH (-) and temperature (°C). The substrate consisted of a commercial inulin solution at a concentration of 1 g/L, while the catalyst consisted of the enzyme inulinase from Aspergillus niger (EC 232-802-3), immobilised in 2% m/v sodium alginate. A stirred vessel reactor was used for 90 min at 120 rpm, and quantification of reducing sugars was determined using DNS colorimetric and UV-Vis spectrophotometric methods at a 540 nm wavelength. After applying the response surface methodology, it was determined that the catalytic activity using the immobilisation method allows for a maximum total productivity of 16.4 mg/h under pH and temperature of 3.9 and 37 °C, respectively, with an efficiency of 96.4%. The immobilised enzymes' reusability and stability compared to free enzymes were evaluated, obtaining activity up to the fifth reuse cycle and showing significant advantages over the free catalyst.

Impact of Inulin on Self-Assembled Behavior of Anionic Surface Active Ionic Liquids: Conductometric, Spectroscopic and Antimicrobial Studies

The self-assembled behavior of greener anionic surface-active ionic liquids (SAILs), namely Tetrapropylammonium Dodecylsulfate (TPADS) and Tetrabutylammonium Dodecylsulfate (TBADS), in an aqueous solution of biocompatible saccharide inulin, has been extensively investigated using conductometric and fluorescence probe techniques at different temperatures. The critical micellar concentration (CMC) values have been determined by observing the breakage point in κ vs. [SAIL] plots. These values as obtained from fluorescence probe techniques have also been calculated. It has been found that the CMC values obtained through both conventional and spectroscopic techniques exhibited close agreement. Additionally, thermodynamic parameters of micellization, such as Gibbs free energy (ΔGmo), enthalpy (ΔHmo), and entropy (ΔSmo) were calculated using conductivity data as they play a crucial role in understanding the various interactions prevailing in the SAIL-inulin-water system. It was found that the micellization process for SAILs in the aqueous inulin solution occurs readily, as indicated by the Gibbs free energy of micellization. Furthermore, the antimicrobial properties of biocompatible SAILs in 0.2% w/w aqueous inulin solution were explored against bacterial strains, gram-positive i.e. B. cereus, S. aureus, and gram-negative namely P. aeruginosa. Molecular docking studies were also conducted to determine the binding energy and binding sites between TBADS and the proteins of the aforementioned bacteria. These investigations help to enhance the understanding of potential applications and interactions of SAILs in the presence of inulin.

Rheological properties of cross-linked inulin solutions as a function of cross-linker concentration and temperature

The purpose of this study is to determine the rheological properties of cross-linked inulin solutions in two different polymerization degrees (native and degree of polymerization of >23%). Thus, the effect of cross-linking, a new approach applied to support a specific property (stabilization) of inulin, which has many benefits, has been demonstrated. Sodium hexametaphosphate was used as a cross-linking agent at three different ratios (0.375%, 0.500%, and 0.750%). The cross-linked inulin solutions were lyophilized, and the lyophilized mixture was then reconstituted at 25 °C and 45 °C to obtain cross-linked inulin solutions with 1% and 5% (w/v) concentrations. The control samples (native and with a high degree of polymerization) were treated similarly without a cross-linking agent. The samples were subjected to a dynamic frequency sweep test in the range of 0.01–10 Hz as well as shear viscosity measurements at 1–500/s shear rates for the determination of rheological properties. The thixotropic curves were analyzed as the shear rate increased from 0.1/s to 300/s in the first 120 s (up curve), and then decreased to the same point in the subsequent 120 s. Results indicated that cross-linking increased inulin solution viscosity, particularly at 5% concentration, and solubility. Solutions with 5% inulin containing 0.750% and 0.375% cross-linker yielded the highest viscosities at 45 °C and 25 °C, respectively. Samples with 5% inulin concentration exhibited solid-like behavior in the oscillation test. Thixotropic curves revealed antithixotropy at low shear rates and thixotropy at high shear rates. The study demonstrated the impact of cross-linking on inulin stabilization, providing insights for future applications. Results indicated that cross-linking increased inulin solution viscosity, particularly at 5% concentration, and solubility. Solutions with 5% inulin containing 0.750% and 0.375% cross-linker yielded the highest viscosities at 45 °C and 25 °C, respectively. Samples with 5% inulin concentration exhibited solid-like behavior in the oscillation test. Thixotropic curves revealed antithixotropy at low shear rates and thixotropy at high shear rates. The study demonstrated the impact of cross-linking on inulin stabilization, providing insights for future applications.

Inulin for surimi gel fortification: Performance and molecular weight-dependent effects

Inulin is a prebiotic carbohydrate widely used in food industry due to its health benefits and unique rheological properties. For the first time, this study explores the potential of natural inulin as a sustainable food additive to enhance surimi gel characteristics, specifically focusing on understanding its molecular weight effects. The good solubility of inulin facilitates the conversion of α-helix to other secondary conformations which are favorable for protein denaturation and aggregation during gelation. Moreover, the abundant –OH groups at the surface of inulin can boost the chemical forces within surimi proteins to reinforce the gel network. Compared to short-chain inulin, long-chain inulin can alleviate proteolysis, enhance hydrophobic interactions and intertwine with myosin molecules, thereby reinforcing the gel network. A more viscous long-chain inulin solution formed within surimi gels fills the space between aggregated proteins and facilitates the lock of water molecules, improving the water-holding capacity (WHC). Thus, an addition of 12 % long-chain inulin leads to an enhanced hardness of surimi gel from 943 to 1593 and improved WHC from 72 % to 85 %. A new inulin-myosin interaction mechanism model is also proposed to provide useful guidelines for surimi processing and expanding the application of inulin within the food industries.

Sodium Alginate and Chitosan as Components Modifying the Properties of Inulin Hydrogels.

The aim of the study was to investigate the influence of addition of sodium alginate (SA) and chitosan (CH) on the properties of inulin hydrogels. Inulin hydrogels (20 g/100 g) containing various additions (0.0, 0.1, 0.3, and 0.5 g/100 g) of SA and CH were produced. The hydrogels’ properties were assessed based on the volumetric gel index, microstructure, yield stress, texture, stability, and color parameters. According to the findings, the inclusion of these polysaccharides had no influence on the gelation ability of the inulin solution. The physical properties of the hydrogels containing SA or CH differed from hydrogels containing only inulin (INU). The obtained microstructural pictures revealed that the addition of SA and CH resulted in the formation of hydrogels with a more compact, smooth, and cohesive structure. Consequently, they had higher yield stress, strength, and spreadability values than INU hydrogels. The addition of chitosan in comparison with sodium alginate also had a greater effect in strengthening the structure of hydrogels, especially at the level of 0.5 g/100 g. For example, the addition of this amount of SA increased the yield stress on average from 195.0 Pa (INU) to 493.6 Pa, while the addition of CH increased it to 745.3 Pa. In the case of the strength parameter, the addition of SA increased the force from 0.24 N (INU) to 0.42 N and the addition of CH increased it to 1.29 N. In the case of spreadability this increase was from 2.89 N * s (INU) to 3.44 N * s (SA) and to 6.16 N * s (CH). Chitosan also caused an increase in the stability of inulin hydrogels, whereas such an effect was not observed with the addition of sodium alginate. The gels with the addition of SA and CH also had significantly different values of color parameters. Inulin–alginate hydrogels were characterized by higher values of the color parameter a *, lower values of the color parameter b *, and in most concentrations higher values of the color parameter L * compared to inulin–chitosan hydrogels. Based on the collected data, it can therefore be concluded that through the addition of sodium alginate and chitosan, there is a possibility to modify the properties of inulin hydrogels and, consequently, to better adapt them to the characteristics of the pro-health food products in which they will be used.

Novel aggregation induced emission materials from natural Helianthus tuberosus, sustainable of inulin for room temperature phosphorescence

It is really needed for novel sources of aggregation-induced emission (AIE) biomaterials from nature, which with good biocompatibility and biodegradability. Inulin (IUL), a very rich polysaccharide existed in nature, it has enhanced emission in powder and concentrated solution state of AIE effect. In addition, room temperature phosphorescence (RTP) can be observed in the solid powder of IUL, which is also rare in pure organic materials. IUL can emit various multicolor light, thus, it has excellent multi-color imaging capabilities. In addition, the IUL solution has quenching reaction to Fe3+, it can be used as a biosensor to detect the concentration of Fe3+ within the normal human serum. These results shown that IUL has potential prospects as new biosensor and multicolor cell imaging.

Ultrasound affects physical and chemical properties of Jerusalem artichoke and chicory inulin.

Jerusalem artichoke (Helianthus tuberosus L.) and Chicory (Cichorium intybus L.) have a heterogeneous collection of fructose polymers, known as inulin. This study was aimed to explore the effects of ultrasound (US) and autoclave (AC) on inulin physico-chemical properties as well as investigate structural characterizations and relationships with inulin physico-chemical properties. More specifically, Jerusalem artichoke powder (JA, 69.99% inulin in dry basis), purified inulin from Jerusalem artichoke (PJAI) and chicory inulin (CI) were studied to determine the effects of both treatments on reducing sugar contents, degree of polymerization (DP), water-holding capacity (WHC) and particle size. US (90W, 20 KHZ) treatments had increased reducing sugar content up to 12.27% for PJAI, 10.86% for JA powder and 2.18% for CI. HPLC analysis showed that the DP of inulin decreased for PJAI after 2min US treatment. WHC analysis showed that both treatments did not have significant effects (p>.05) on WHC for JA powder. This study suggests that US can be a preferable treatment for reducing the DP of inulin from JA for designing variety of food formulations. PRACTICAL APPLICATIONS: Ultrasound treatments could result in more inulin breaking down into reducing sugars, and in the decrease of inulin DP. This research suggested that the DP of inulin might be a very important factor in ultrasound treatment for their affect in the absorption of energy from ultrasound. Therefore, ultrasound can be a desirable treatment for changing the degree of polymerization of inulin from JA for designing different food products. Future studies need to investigate the relationship between the viscosity of inulin solution and the de-polymerization of inulin caused by ultrasound treatment.

Improved Heat Stability of Whey Protein Isolate by Glycation with Inulin

Glycation between proteins and sugars via the Maillard reaction has been shown to improve the heat stability of proteins. In this study, inulin, a healthy dietary fiber, was glycated with whey protein isolate (WPI), and the effects of reaction conditions were investigated. Conjugates were prepared by freeze-drying mixed WPI and inulin solutions at 1:1 to 6:1 WPI-to-inulin weight ratios followed by dry heating at 70, 75, or 80 °C for 12 to 72 h under uncontrolled, 44%, or 80% relative humidity. Heat stability was evaluated by turbidity, particle size, and rheological measurements. Degree of glycation was assessed by quantifying the loss of amino groups and the formation of the Amadori compounds. Results showed that conjugation led to improved heat stability, as shown by decreased turbidity and particle size as well as the ability to maintain the viscosity compared to control samples. Based on the loss of amino groups, the optimum glycation conditions were achieved with WPI–inulin mixtures at 2:1, 4:1, and 6:1 weight ratios and 80 °C temperature for 12 to 72 h without controlling the relative humidity. The improved heat stability could be due to an increase in negative charge as well as increased structural stabilization of the proteins. Under a limited degree of glycation, glycated WPI–inulin conjugates have great potential to be utilized as food ingredients, especially in the beverage industry.

The effect of osmotic dehydration conditions on the calcium content in plant matrice

Osmotic dehydration is used as a pre-treatment before drying. This process can also be used as a method of modulation of the sensory values of plant components and fortifying them with selected components. The aim of this study was to examine the effect of osmotic dehydration as a method of pumpkin flesh 'Melon Yellow' (Cucurbita maxima) fortification with calcium. The studies showed for the first time that by selecting the appropriate process conditions it is possible to significantly increase the level of calcium in plant matrice. The highest calcium content was found in the pumpkin pulp dehydrated in 50% xylitol and inulin solutions with a calcium carbonate (5%), where the process was conducted for 120 min at 30 °C (1,380.4 and 1,328.4 mg Ca/100 g). Therefore, study has shown an innovative application of the osmotic dehydration process for the design of food with health-promoting properties, including for those at risk of osteoporosis.

Acacia gum fluidized bed agglomeration: Use of inulin as a binder and process parameters analysis

AbstractThis work aimed to investigate the use of inulin as an alternative binder in fluidized bed agglomeration to improve both acacia gum functional and handling properties. Acacia gum was agglomerated in fluidized bed with inulin solution (18.0% wt/wt) at two different fluidizing air temperature (65 and 85°C) and binder feed rate (1.5 ml/min and 3.0 ml/min). The granule growth kinetics and system stability were monitored by a spatial filter velocimetry probe. The influence of process parameters on process yields and product characteristics: final particle size, wettability, and flowability were also evaluated. We observed an increase in particle size and the agglomerated particles showed a short wetting time, indicating that inulin can be successfully used as an alternative binder adding both nutritional and functional value to the acacia gum. Low binder feed rate provided better system stability and larger particle size.Practical ApplicationsThis paper presents inulin as an alternative binder for application in powder food agglomeration processes. The use of inulin has provided improved flowability and wetting properties. Moreover, the inulin may also add functional value to agglomerated foods. Besides, it was possible to monitor particle growth and process stability through a relatively new technique that measures the particle size, spatial filter velocimetry. In this way, it is possible to establish which conditions of temperature and binder feed rate are the most suitable for the agglomeration process.

Dielectric, thermal, and rheological properties of inulin/water binary solutions in the selected concentration

AbstractInulin—a prebiotic has many applications in the food and pharmaceutical industries for texture modification and replacement of fat/sugar. In this study, thermal, rheological, and dielectric properties of inulin solutions were studied in a wide range of concentrations (5–50% w/v). Inulin is readily dissolved in water in low concentrations (< 20%), and exhibited Newtonian flow behavior, and the dielectric spectra were close to the pure water. The dielectric constant, ε′ of concentrated inulin (40–50%) showed frequency independency (500–1,150 MHz) whereas the loss factor, ε″ increased with frequency. Oscillatory rheology of concentrated inulin solutions at selected temperatures showed solid‐like behavior (G′ > G″), and the mechanical rigidity increased exponentially with the concentration. During thermal scanning of inulin concentrates (30–50%), two glass‐like transitions were detected (−74.98 to −72.28 °C;−24.25 to −23.45 °C), which were independent of the concentration. The obtained information will be useful for product development and structural characterization of inulin‐incorporated food products.Practical applicationsIncorporation of soluble fiber like inulin into food products has proven health effect. Knowledge of flow behavior and glass transition temperatures of inulin at selected concentrations will provide a better understanding of food formulation, transport, and storage. Dielectric properties of inulin solutions would help to employ microwave/radiofrequency heating of formulated foods. The information presented in the present work should be useful to the food and pharmaceutical industries for early prediction of food quality and process engineering.

An Efficient Method for Decoloration of Inulin from Jerusalem Artichoke by Macroporous Resin

The decoloration method for Inulin from Jerusalem artichoke with activated carbon andmacroporous resin was investigated in this manuscript. Six resins (D113, D301, 001×7, 201×7,DA201-C and activated carbon) with same diameter were studied through static experiments.Meanwhile, the decoloration duration and resin dosage were also determined. Macroporous resinadsorption method was better than the traditional activated carbon adsorption method. The resultsalso suggested that the polar and ionogenic properties significantly affected the decoloration rate. The001×7-201×7 type resin which are strongly polar resin offered the better decolorizing effect. Most ofpigment impurities were successfully removed from inulin solutions with 1:10 resin dosage and 40min decoloration process. Moreover, the decoloration rate and inulin loss rate were 82.29% and 12.67%respectively. This study would provide a potential approach for large-scale production of inulin forits wide applications in dietary supplements.

Development of heterogeneous preparation with inulinase for tubular reactor systems

We developed highly stable heterogeneous preparations of inulinase immobilized on the ion-exchange matrixes and show that such preparations effectively split the chemically pure inulin and the inulin contained in plant extracts.The optimal conditions of hydrolysis are created for the migration of inulin solution from top to bottom (the downsteam flow) through the column filled by immobilized compounds extracted from Kluyveromyces marxianus and Helianthus tuberosus with the flow rate of 3mL/min. For the bottom-up migration of the inulin solution (i.e. the upstream flow) through the column the flow rate of 5mL/min was found to be the most optimal for the hydrolysis.When the extract of H. tuberosus was allowed to pass through the column filled by the immobilized plant inulinase from top to bottom with the flow rate of 5–10mL/min, the conditions for hydrolysis appear to be the most optimal. The conditions for hydrolysis were also found to be favourable for the bottom-up moving of the H. tuberosus extract through the column for the flow rate of 3–5mL/min.For the yeasts inulinase immobilized on VION KN-1 the most optimal flow rates of the H. tuberosus extract in the reactor were found to be similar for the following rates of inulin flow, viz. 3mL/min for the downstream flow and 5mL/min for the upstream flow.A theoretical description of the process of the inulin hydrolysis has been proposed and experimentally verified, which allows predicting the time of the full hydrolysis at different operating conditions with an error not exceeding 20%. It could be applied for the design of continuous reactors.

English

The optimization of growth conditions for the production of inulinase by Penicillium funiculosum cells were studied as well as the continuous production of the enzyme using immobilized cells. The highest amount of enzyme (163.5U/mL) was obtained when the producing cells were incubated for 96 hours at 27 o C and 200 rpm in a fermentation medium containing both inulin and peptone as sole carbon and nitrogen sources respectively. However, when the cells of the tested microorganism were adsorbed on different carriers, especially linen fibers, their production ability was also successfully maintained, to different extends, for seven successive batches. Moreover, commercially pure inulin is very expensive in only small quantities, this fermentation medium was later substituted by a crude inulin solution obtained from Jerusalem artichoke tubers ( Helianthus tuberosus) . The crude inulin juice was able to sustain inulinase production during the second batch cultivation of the P. funiculosum , immobilized by their adsorption on linen fibers, in a satisfactory level of about 122U/mL. Moreover, the use of the previously mentioned crude inulin preparation was also compared to the use of either complete or minimal media, composed solely of 1% pure inulin. The method, adopted in this study for inulinase production, is simple, economic, time saving, non-toxic to the microorganism and the loaded linen pads are reusable.

Rheological characteristics of inulin solution at low concentrations: Effect of temperature and solid content.

The rheological properties of inulin solution was investigated at different solid content (Xs) ranging from 1 to 12% at wide range of temperatures ranging from 10 to 85°C. The rheological parameter shear stress was measured upto a shear rate of 300s(-1) using concentric cylinders attachment by controlled stress rheometer. The investigation showed that the inulin solution behaved like Newtonian liquid and viscosity (η) was in the range 2.0998 to 3.2439mPas depending upon the concentration and temperature studied. The temperature dependency of Newtonian viscosity of inulin solution was described by Arrhenius equation (r > 0.88, p < 0.05) and activation energy (Ea) for viscous flow was in the range 2.111 to 3.013kJ/mol depending upon the solid content studied. The flow activation energy (Ea) of inulin solution was significantly (p < 0.05) affected by solid content and described by exponential type equation (r = 0.9646, rmse% = 1.07, p < 0.001). Effect of solid content on Newtonian viscosity was described by linear as well as power law models depending upon the temperature studied. The combined effect of temperature and solid content on Newtonian viscosity of inulin solution was described by power law type equation and represented as η = 0.8835* (Xs)(0.0731) *Exp(296.410/T), (r = 0.9538, p < 0.001, rmse% = 0.15) Where η is Newtonian viscosity in mPa s, Xs is solid content in % and T is temperature in Kelvin (K).

Towards the continuous production of fructose syrups from inulin using inulinase entrapped in PVA-based particles

The use of fructose in food and pharmaceutical formulations has gained some relevance because of its sweetening properties. The enzymatic hydrolysis of inulin has been studied as an alternative to conventional approaches for fructose production. The present work focuses on the improvement and characterization of a polyvinyl alcohol (PVA)-based method for inulinase immobilization, and in establishing the feasibility of its application in a continuous process. Results show an enhancement of thermal, operational and storage stabilities resulting from the use of glutaraldehyde during the immobilization procedure, with the penalty of a slight increase in diffusion limitations. The continuous production of fructose from a 5% (w/v) inulin solution was performed for 20 days, with an initial volumetric productivity of 146.4 g/L/h and a product yield of 100%. After that period the production yield was still of 75%, suggesting the potential of the studied approach to be used in a large-scale process.

Inulin potential for encapsulation and controlled delivery of Oregano essential oil

The ability of inulin, a prebiotic material, as encapsulation matrix was explored. Microcapsules of Raftiline were produced by spray drying inulin solutions at different solids content (5, 15 and 25%) at 120, 155 and 190 °C, according to a Central Composite Rotatable design. Produced capsules were analysed for morphology and size by SEM and physiochemical characterized by DSC, IR and RAMAN. Oregano essential oil was incorporated in the inulin solutions at 15% solids basis and the emulsions dried at the same conditions. The above mentioned methodologies were applied to evaluate the encapsulation ability and the changes induced by the presence of the EO in capsules morphology and structure. Furthermore the kinetics and amount of release was assessed by a spectrophotometric method. Results showed that it was possible to produce regular spherical inulin microcapsules (3–4.5 μm) for all the tested experimental conditions. According to IR and Raman results mainly drying temperature affected the structure of the capsules, three groups being clearly formed. These groups could be related to the morphology of inulin crystals. The EO was successfully encapsulated in the system as demonstrated by IR and Raman analysis. The differences found in the EO releasing amount, make clear that different degrees of core material retention is achieved, what should be related to structural changes in the matrix wall, denoting in some processing conditions interactions phenomena among inulin and EO. Those different releasing profiles patterns may be quite useful in finding different potential uses for the encapsulates.

Elaboration of a probiotic oblea from whey fermented using Lactobacillus acidophilus or Bifidobacterium infantis

A novel probiotic product was developed, which was formulated as an oblea (wafer-type dehydrated traditional Mexican dessert) using goat sweet whey fermented with Bifidobacterium infantis or Lactobacillus acidophilus. To obtain the probiotic oblea, the fermented whey was formulated with prebiotic carbohydrates (inulin and resistant starch) and gelatin, and the preparation was poured onto a polytetrafluoroethylene-coated nonstick baking pan, dried in a convection oven, and finally dehydrated at a low relative humidity and room temperature (23±2°C). The amounts of prebiotic carbohydrates and gelatin to be used in the formulation were determined by a factorial experimental design. An untrained sensory panel evaluated 3 quality characteristics (film formation, homogeneity, and smoothness) in the final product. Three different drying temperatures were tested, namely, 40, 55, and 70°C. Bacterial survival at each temperature was determined by viable plate-counting. The best formulation, based on the quality characteristics tested, consisted of 58.33% (vol/vol) of fermented whey, 8.33% (vol/vol) of 6% (wt/vol) resistant starch dispersion, 16.66% (vol/vol) of 15% (wt/vol) inulin solution, and 16.66% (vol/vol) of a 10% (wt/vol) gelatin solution. Drying at 55±2°C for 2.66±0.22h allowed for concentrations of probiotic bacteria above 9 log10 cfu/g, which is above the minimum concentration required in a probiotic product.

Intra-amniotic administration and dietary inulin affect the iron status and intestinal functionality of iron-deficient broiler chickens

Inulin, a linear β-fructan, is present in a variety of plants, with relatively high levels of up to 20% in chicory root. It exhibits prebiotic properties and was shown to enhance mineral absorption. Our objectives were to assess the effect of intra-amniotic administration of inulin at 17 d of incubation on the iron status of broiler chicks (at hatch, 21 d) and to continue to monitor iron status with and without dietary inulin on these hatchlings for 42 d. The study included 3 prehatch treatment groups (n = 30): 1) inulin, inulin solution (4% inulin/0.85% saline); 2) control 1, untreated eggs; and 3) control 2, saline solution (0.85% saline). Solutions were injected into the naturally consumed amniotic fluid of 17-d-old chicken embryos (groups 1, 3). Upon hatch (93% hatchability), and from each group, 10 chicks were killed and their small intestine, liver, and cecum were removed for mRNA abundance of intestinal iron-related transporters, liver ferritin amounts, and bacterial analysis of cecal content, respectively. From the remaining chicks of each group, chicks were allocated to a standard corn-based diet (± 4% inulin, n = 10). During the trial, hemoglobin concentrations and body hemoglobin-Fe values were higher in the inulin group versus controls (P < 0.05). On d 42, birds were anesthetized and their duodenal loops were exposed. A nonocclusive catheter was inserted into the duodenal vein for blood sampling. A solution containing ⁵⁸Fe (0.1 mg of Fe/10 mM ascorbic acid) added to the digested diet sample was injected into the loop. Blood samples were collected every 5 min and for 90 min postinjection and analyzed by inductively coupled argon-plasma mass spectrometry for ⁵⁸Fe concentrations. At the end of the procedure, animals were killed and cecum contents and sections of the duodenum and liver were removed. Results showed that ⁵⁸Fe absorption rates were at times higher in the inulin group versus the other groups. Also, mRNA abundance of DMT1 (an Fe transporter) and ferroportin in addition to liver ferritin amounts were higher (P < 0.05) in the inulin group versus controls. Results indicate that intra-amniotic administration and dietary inulin improved the iron status of iron-deficient broilers.

Surface activity and aggregation of pristine and hydrophobically modified inulin

In search of more effective and lower impact surfactants, hydrophobic modification of polymers has emerged as a promising strategy for the substitution of low molecular weight surfactants. Inulin, a polysaccharide obtained from chicory roots, has links with the sustainable chemistry model. Furthermore, hydrophobically modified inulins (HMI) can be synthesized in aqueous media. This article reports on the surface activity and aggregation of several compounds with differences in hydrophobic alkyl length and backbone linkage. HMI significantly reduces (down to 30 mN m−1) water surface tension while inulin does not. Both inulins and HMI are shown to aggregate hierarchically at three levels, namely aggregates (<20 nm), flocks (<100 nm) and precipitates (>500 nm). The smaller aggregates, which in the case of inulins can be classified as monomers and in the case of HMI as micelles, have dimensions below 15 nm. The second level of aggregation corresponds to loose flocks with dimensions up to 100 nm and the third level corresponds to the precipitate constituted by aggregation of the flocks. Temperature and basic conditions affect the flock formation and kinetics without a strong influence on the smaller aggregates structure and size. Long term standing of both HMI and inulin solutions eventually precipitates. This precipitate may occupy a large volume but corresponds to a small amount of the solute. In the case of inulins, the precipitate has been found to have a degree of crystallinity that diminishes with increasing temperature.