A comparative study on the anisole methylation activity of lanthanum-promoted SnO2 catalyst and its sulfate-doped analogue

A comparative study on the anisole methylation with methanol over lanthanum-promoted SnO₂ catalyst and its sulfate-doped analogue is presented. A maximum 2,6-xylenol selectivity of 82% was achieved at 400°C under optimized conditions at an anisole conversion of 65% over lanthanum-promoted SnO₂ catalyst. The sulfate modification resulted in the dealkylation of anisole to phenol followed by several unselective side reactions due to the creation of strong acid sites. The activity of lanthanum-modified tin oxide catalysts in the selective formation of 2,6-xylenol is ascribed to the presence of weak Lewis acid sites and comparatively stronger basic sites.     

Comparison of the NHANES dietary screener questionnaire to the Automated Self-Administered 24-Hour Recall for Children in the Healthy Communities Study

Background

A dietary screener questionnaire (DSQ) was used to assess dietary outcomes among children in the Healthy Communities Study (HCS), a study of the relationships between programs and policies to prevent child obesity and child diet, physical activity and weight outcomes.

Methods

To compare dietary intake estimates derived from the DSQ against those from the Automated Self-Administered 24-Hour Recalls for Children (ASA24-Kids) among children, a measurement error model, using structural equation modelling, was utilized to estimate slopes, deattenuated correlation coefficients, and attenuation factors by age and sex, ethnicity, and BMI status.

Participants/setting

A randomly selected sub-sample of HCS participants aged 4–15 years in 130 communities throughout the U.S. who completed the DSQ and up to two ASA24-Kids recalls (n?=?656;13% of HCS participants).

Results

For most nutrient/foods examined, the DSQ yielded larger mean intake estimates than the ASA24-Kids, and agreement between the two measures varied by food/nutrient, age and sex, ethnicity, and BMI category. Deattenuated correlation coefficients of 0.4 or greater were observed for added sugars from SSBs (0.54), fruits and vegetables (0.40), and dairy foods (0.50). Lower deattenuated correlation coefficients were seen for total added sugars (0.37), whole grains (0.34), and fiber (0.34). Attenuation factors were most severe for total added sugars intake among overweight children, and for several other dietary outcomes among children aged 9–11 years.

Conclusions

The DSQ was found to be a tool with acceptable agreement with the ASA24-Kids for measuring multiple dietary outcomes of interest in the HCS, although there may be potential due to measurement error to underestimate results (bias towards the null). In future studies, measurement error modelling and regression calibration may be possible solutions to correct for bias due to measurement error in most food/nutrient intake estimates from the DSQ when used among children.

     

Effect of soya protein on the dialysability of exogenous iron and zinc

The investigation aimed at studying the influence of soya proteins on in vitro dialysability of exogenous iron and zinc. Soyabean was processed into various components like soya flour (SF), concentrate (SC) and isolate (SI) and two peptides (<30 kDa and >30 kDa). The protein contents of SF, SC and SI were 51, 62 and 78 g/100 g, respectively. Their iron contents ranged between 9.7 and 15.8 mg/100 g and zinc contents from 3.3 to 6.7 mg/100 g. Phytic acid contents (mg/100 g) of the soya components were SF 339, SC 226, SI 186 and peptides 18–20. In SF, percent dialysable iron and zinc were 12.6 and 50, respectively, this reduced to one-third and one-fifth in SC and SI. Dialysability of exogenously added minerals was found to be significantly lower in all soya protein components. However, the inhibitory effect was less pronounced in peptides. The protein component/matrix effect needs to be investigated to counteract the inhibitory effect of soya on iron dialysability.     

Room temperature synthesis of high temperature stable lanthanum phosphate–yttria nano composite

A facile aqueous sol–gel route involving precipitation–peptization mechanism followed by electrostatic stabilization is used for synthesizing nanocrystalline composite containing lanthanum phosphate and yttria. Lanthanum phosphate (80 wt%)–yttria (20 wt%) nano composite (LaPO₄–20%Y₂O₃), has an average particle size of ～70 nm after heat treatment of precursor at 600 °C. TG–DTA analysis reveals that stable phase of the composite is formed on heating the precursor at 600 °C. The TEM images of the composite show rod shape morphology of LaPO₄ in which yttria is acquiring near spherical shape. Phase identification of the composite as well as the phase stability up to 1300 °C was carried out using X-ray diffraction technique. With the phases being stable at higher temperatures, the composite synthesized should be a potential material for high temperature applications like thermal barrier coatings and metal melting applications.     

Dispersed ZrO2 nanoparticles in MCM‐48 with high adsorption activity

A new two‐step synthesis of ZrO₂‐MCM nanocomposites using the gel combustion technique was accomplished; the resulting material had a high‐surface area and showed very high adsorption activity. The deposition of 2–5 nm ZrO₂ particles over MCM was achieved using gel combustion technique with glycine as a fuel, and the formation of nanocomposites was confirmed using transmission electron microscopy. The composites were also characterized by XRD, SEM, FTIR and N₂ adsorption‐desorption analysis. The nanocomposites were tested for the adsorption of cationic dyes. High rates of adsorption and large dye uptake were observed over the nanocomposites. The rate of adsorption over the nanocomposites was higher than that observed for physical ZrO₂‐MCM mixtures and commercial activated carbon. The nanocomposite with 10 wt % ZrO₂ showed the highest rate of adsorption owing to the synergistic effects of ZrO₂ surface groups, smaller particle size, fine dispersion and high‐surface area of the composite. © 2012 American Institute of Chemical Engineers AIChE J, 58: 2987–2996, 2012     

Effect of Ingredients on Rheological, Nutritional and Quality Characteristics of High Protein, High Fibre and Low Carbohydrate Bread

Effect of replacement of wheat flour with a combination of soy protein isolate, oat bran and chickpea flour (SPOBCP) at the levels of 20%, 40% and 60% and addition of combination of additives such as fungal ??-amylase, dry gluten powder, sodium stearoyl-2-lactylate, hydroxypropylmethylcellulose (CA) on the rheological and nutritional characteristics of bread was studied. Use of SPOBCP decreased farinograph dough stability, increased pasting temperature, decreased cold paste viscosity and overall quality score of bread. Scanning electron microscopy images showed higher degree of disruption of protein matrix in bread dough with 60% SPOBCP than 20% and 40% SPOBCP. Addition of 60% SPOBCP resulted in flat, uneven shaped bread with an overall quality score of 38 when compared with 54, 81 and 91 for breads with 40%, 20% and 0% SPOBCP, respectively. However, use of CA increased the strength of the dough and improved the overall quality of bread with 40% SPOBCP. Nutritional profile of bread with 40% SPOBCP?+?CA showed higher protein, in vitro protein digestibility, total dietary fibre, resistant starch, ??-glucan and lower starch hydrolysis index than control bread.     

Evaluation of nutritional and physico-mechanical characteristics of dietary fiber-enriched sweet potato pasta

The objective of the present study was to enhance the utilization of sweet potato (Ipomoea batatas Lam.) as a slowly digestible food by developing dietary fiber-fortified pasta from it. Swelling index as well as cooking loss (%) was more for the pasta made from the pale cream-fleshed variety, Sree Arun (V1) than that from the orange-fleshed variety, Sree Kanaka (V2), and least values were obtained in the pasta fortified with rice bran. Fortification with oat bran, wheat bran, and rice bran elevated the crude protein content to 5–10% in the pasta. Total and insoluble dietary fiber fractions were more in the pasta from Sree Arun (6–17 and 5–14%, respectively) than those from Sree Kanaka (5.25–15 and 3.7–11%, respectively) with the highest values in the wheat bran-fortified pastas. All the fiber-fortified pastas (10 and 20% level of fortification) had slow and progressive starch digestibility over 2 h compared to the control pastas. While approximately 70% of the total starch was rapidly digestible for the control pastas from both the varieties, this was drastically reduced to 45–54% in the test pasta from V1 and 37–50% in V2. Accordingly, the retention of resistant starch (RS; undigested starch after 2 h) in the control pastas was only 14–17%, while it was 38–49% in the test pastas from V1 and 39–55% from V2, with higher RS in the 20% fortified pastas. Texture profile analysis showed that the firmness (N) and toughness (Ns) increased with increase in the fortification level of fiber sources. The progressive starch digestibility coupled with high-resistant starch after 2 h indicated the potential of fiber-fortified sweet potato pasta as an ideal food for the diabetic and obese people.     

Studies on the synthesis and properties of hydroxypropyl derivatives of cassava (Manihot esculenta Crantz) starch

Cassava starch was subjected to hydroxypropylation in three different media, which included water, water in the presence of a phase transfer catalyst, and 2‐propanol, all at 30 ± 2 °C for 24 h. Propylene oxide was used in four different concentrations (50, 100, 150 and 200 g kg^?1 of starch dry weight). The products were characterized by determining their molar substitution (MS), structural and functional properties. The analyses were done in triplicate and the data were analyzed using the statistical package 8.01. The MS of the products ranged from 0.26 to 1.41. The MS of the hydroxypropyl derivatives were found to be higher when the reaction was carried out in the aqueous medium in the presence of tetrabutylammonium bromide, a phase transfer catalyst, when compared to the reaction in 2‐propanol, which was found to be not very effective at 30 ± 2 °C. The etherification altered the granular properties of starch, as could be seen from scanning electron micrographs. Hydroxypropylation resulted in starch pastes which were stable and with higher swelling volume, solubility, light transmittance and water binding capacity as compared to native starch. The hydroxypropyl starches showed significantly lower pasting temperatures and setback viscosities. The enzyme digestibility of the derivatives was seen to decrease with increase in MS and there was a significant reduction in the syneresis of the starch pastes of hydroxypropyl derivatives. Texture profile analysis showed that hydroxypropylated starch gels exhibited higher hardness, springiness (elasticity) and gumminess and lower cohesiveness than the native starch. Copyright © 2007 Society of Chemical Industry     

Synthesis of carbon-free Si3N4/SiC nanopowders using silica fume

We have investigated a possible method of synthesizing carbon-free, nano-silicon nitride-silicon carbide (Si₃N₄/SiC) powders from the waste silica fume for the first time, using the integrated mechanical and thermal activation (IMTA) process. This novel process results in the formation of nano-Si₃N₄/SiC powders at 1465 °C with crystallite sizes as small as 45 nm. In order to synthesize carbon-free nano-Si₃N₄/SiC powders, two different approaches, one using the H₂ gas and the other using air, have been studied for their effectiveness in removing the free carbon present. It is found that the H₂ treatment is not very effective although both Si₃N₄ and SiC are stable during the H₂ treatment. In contrast, removing the free carbon using air is effective, and the limited oxidation of nano-Si₃N₄ and SiC can be achieved if the air treatment is terminated soon after the free carbon is eliminated. This study has provided a clear pathway and understanding for effectively synthesizing carbon-free, nano-Si₃N₄/SiC powders from the silica fume.     

Corrosion inhibition of mildsteel in sulphuric acid by methanol extract of Luffa aegyptiaca leaves – electrochemical and statistical view

An electrochemical and statistical view of methanol extract of Luffa aegyptiaca leaves (MLA) on the corrosion inhibition of mild steel (MS) in 0.5 M H₂SO₄ medium were investigated by potentiodynamic polarisation and electrochemical impedance spectroscopy. Polarization studies showed that the MLA acts as mixed type inhibitor with predominant cathodic behaviour. The percentage inhibition efficiency was found to increase with MLA concentration and decreased with the temperature. Thermodynamic parameter such as free energy value was negative, that indicates spontaneous adsorption of inhibitor on MS surface. Adsorption of MLA was found to obey Langmuir isotherm. The analysis of variance studies showed that the inhibition efficiencies calculated from the different electrochemical parameters are statistically significant. Surface studies were performed by Fourier transform infrared spectroscopy and atomic force microscopy.