Micro extrusion of innovative alumina pastes based on aqueous solvent and eco-friendly binder

The aim of this work is to develop the micro-extrusion process with an innovative approach linked to respect for the principles of green chemistry. Alumina pastes are prepared in an aqueous medium with psyllium as a natural binder, which is not derived from the petrochemical industry. The challenge is to obtain a concentrated system which is suitable for the micro-extrusion process and which ensures satisfactory structural and mechanical properties of the final parts.The manufacturing of alumina networks is achieved by using the micro-extrusion shaping process consisting of an XYZ displacement platform and a homemade extrusion head. The nozzle diameter is equal to 400?μm. The rheological behavior of the paste is studied as well as its capability to be extruded. The green parts are consolidated by heat treatment at 1600?°C. Their microstructural characteristics have been studied. Final density equal to 98% has been obtained.     

The impact of concentration,temperature and pH on dynamic rheology of psyllium gels

Structural aspects of the psyllium gum prepared from the seed husk of the plant of Plantago ovata Forsk was characterized by dynamic rheology and microscopy. Dynamic rheological properties of psyllium gel in the linear viscoelastic region, as a function of concentration (2, 2.5 and 3% w/w), temperature (5–95 °C) and pH (2.5–10) were investigated. Mechanical spectra of the psyllium gels were obtained by frequency sweep measurement classified into that of weak gels because G′ was larger than G″ throughout the tested frequency range and the separation of the two moduli (tan δ) was greater than 0.1. The phase angle increased with temperature and a peak associated with gel melting appeared at about 40 °C. All gels at different pH presented a typical weak gel spectrum. Scanning electron microscopy showed porous structures with different pore-size distribution for psyllium gels under different conditions in terms of concentration, pH and temperature.     

Modification of psyllium polysaccharides for use in oral insulin delivery

There is no doubt that fibers, in particular viscous dietary fibers, have positive effects on human health, both in the prevention and in treatment of chronic diseases. Psyllium, a medicinally important serum glucose reducing natural polysaccharide, if suitably tailored to prepare the hydrogels for controlled release of insulin; it can act as double potential candidate for cure of diabetes mellitus. Keeping in view the therapeutic importance of psyllium and its gel-forming nature we have prepared psyllium and methacrylamide based hydrogels by using N,N′-methylenebisacrylamide as crosslinker. The present paper discusses the effect of pH on swelling kinetics of the hydrogels and release dynamics of insulin from drug-loaded hydrogels, for the evaluation of the swelling mechanism and drug release mechanism from the hydrogels. Non-Fickian diffusion mechanism has been observed for the release of insulin in pH 2.2 buffer and pH 7.4 buffer.     

Does a mix of plant-based dietary fibre affect milk protein true digestibility? An in-vivo study

Milk protein is easily digestible. However, some plant-based dietary fibres (DF) could impact protein bioavailability. The effect of DF fortification on the true protein digestibility (TPD) of milk was evaluated following the rat balance method. Four groups of rats were fed four different diets. Three diets comprised milk protein as a source of protein along with either DF Blend I (a mix of psyllium husk, oat fibre, microcrystalline cellulose and inulin) or Blend II (psyllium husk, oat bran, wheat fibre and inulin) or cellulose (as control). The fourth group was nitrogen-free with cellulose (5%). The TPD of milk remained statistically unaffected (ANOVA, P > 0.05), indicating that DF blends are suitable for milk fortification.     

Microstructure and rheological properties of psyllium polysaccharide gel

The strong gelling property of psyllium polysaccharides is closely related to its health benefits and applications, such as use as a binding agent in the landscape industry. However, information about gelling properties of psyllium polysaccharides is very limited. To explore the gel properties of psyllium, the alkaline extracted gel fraction (AEG) of psyllium polysaccharides was studied in this investigation. The rheological and low-temperature electron microscopy methods including cryo-scanning electron microscopy (Cryo-SEM) and freeze-substitution for transmission electron microscopy (TEM) were used to investigate Ca²⁺ influence on the gel properties of AEG. AEG formed a weak gel with a fibrous appearance. AEG did not have a sharp melting point and exhibited no thermal hysteresis during heating and cooling procedure. The origin of this gelling behaviour was due to the fibrillar gel structure of psyllium polysaccharide. It was found that Ca²⁺ had a significant influence on the gel properties and microstructure. Elastic modulus G′ of gel increased as Ca²⁺ concentration increased. Critical strain S at first increased and then decreased as Ca²⁺ concentration increased. AEG gel became more resistant to temperature change on addition of Ca²⁺. Psyllium gel changed to aggregated gel with added Ca²⁺. The strands of gel appeared thicker and the density of the junction zone increased with increasing Ca²⁺ concentration as revealed by SEM and TEM. The changing bulk gelling properties of psyllium polysaccharide by adding Ca²⁺ was attributed to the change in gel structure.     

Extractability and chemical and enzymic degradation of psyllium (Plantago ovata Forsk) seed husk arabinoxylans

To assess the potential of arabinoxylan (AX)-rich psyllium (Plantago ovata Forsk) seed husk (PSH) as a source for production of arabinoxylo-oligosaccharides (AXOS), the parameters determining PSH AX extraction yield and the chemical and enzymic hydrolysis of PSH AX were investigated. The seed husk material had a high content of AX (62.5%) with an arabinose to xylose ratio of 0.41. The water extractability of PSH AX was affected by suspension concentration rather than by temperature. Maximally, 27% of all AX could be extracted, even when using very dilute suspensions (0.1% w/v). When subjected to alkaline conditions, a pH of at least 12 was needed to significantly increase extractability (up to 77% of all AX). The extractability-increasing effect of alkali was, however, reversible, as extractability decreased again when lowering the pH. Acid hydrolysis at high temperature drastically increased AX extraction yields (up to 97% of all AX), released monomeric arabinose (up to 38%), and lowered the average degree of polymerisation (DP_avg) of the AX (down to 31). The presence of substituents (arabinose, xylose, rhamnose and galacturonic acid) on the xylan backbone was an important factor limiting degradation by xylanases. Enzyme preparations containing substituent-removing enzymes were far better for enhancing the extractability of a large portion of the AX population (up to 82%) and for degrading the extracted fragments (down to DP_avg 14) than preparations lacking such activities. The above results show that PSH is a good source for the production of AXOS, since both chemical and enzymic treatments significantly increase the extractability of PSH AX and convert PSH AX molecules into small fragments.     

The effects of psyllium supplementation on body weight,body mass index and waist circumference in adults: A systematic review and dose-response meta-analysis of randomized controlled trials

Abstract

Background: Previous studies reported inconsistent findings regarding the effects of psyllium supplementation on obesity measures. This systematic review and meta-analysis was performed to summarize data from available randomized clinical trials (RCTs) on the effect of psyllium supplementation on body weight, body mass index (BMI), and waist circumference (WC) in adults.

Methods: PubMed, SCOPUS, Cochrane Library, and Google Scholar were searched to identify relevant articles up to August 2018. The effect sizes were presented as weighted mean difference (WMD) and 95% confidence intervals (CI) by using random effects model. To detect dose-response relationships, we used fractional polynomial modeling.

Results: A total of 22 RCTs were included. Meta-analysis did not find any significant effect of psyllium supplementation on body weight (MD: ?0.28?kg, 95% CI: ?0.78, 0.21, p?=?0.268), BMI (MD: ?0.19?kg/m², 95% CI: ?0.55, 0.15, p?=?0.27) and WC (MD: ?1.2?cm, 95% CI: ?2.6, 0.2, p?=?0.09). Subgroup analysis showed that psyllium dosage, kind of psyllium administration, duration of trial, study design, sample size, and gender were potential sources of heterogeneity. Moreover, there was nonlinear association between duration of psyllium consumption, BMI and WC.

Conclusion: Psyllium supplementation does not reduce body weight, BMI, and WC significantly.     

Gamma‐radiation initiated synthesis of Psyllium and acrylic acid‐based polymeric networks for selective absorption of water from different oil–water emulsions

Removal of water from the crude petroleum during its extraction and refining process is one of the major problems faced by petroleum industries, so in this study a superabsorbent has been synthesized from Psyllium and acrylic acid based polymers under the influence of gamma radiations using hexamine as a crosslinker. After optimizing various reaction parameters, the optimized superabsorbent has been tested for its selective water absorption capacity from different oil–water emulsions as a function of time, temperature, pH, and NaCl concentration. The synthesized superabsorbent has been found to be highly selective toward water absorption with maximum percent swelling of 8560% in petrol–water emulsion. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Development and characterization of a novel biodegradable edible film obtained from psyllium seed (Plantago ovata Forsk)

In this study, the physical, thermal and mechanical properties of a novel edible film based on psyllium hydrocolloid (PH) were investigated. PH films were prepared by incorporation of three levels of glycerol (15%, 25%, and 35% w/w). As glycerol concentration increased, water vapor permeability (WVP), percent of elongation (E%) and water solubility of PH films increased whilst, tensile strength (TS), surface hydrophobicity and glass transition point (T_g) decreased significantly. At the level of 15% (W/W) of glycerol, PH films showed the lowest WVP values (1.16 × 10⁻¹⁰ g H₂O m⁻² s⁻¹ MPa⁻¹), E% (24.57%) and water solubility (47.69%) and the highest values for TS (14.31 MPa), water contact angle (84.47°) and T_g (175.2 °C). By increasing glycerol concentration, PH films became slightly greenish and yellowish in color but still transparent in appearance. This study revealed that the psyllium hydrocolloid had a good potential to be used in producing edible films with interesting specifications.