Chemical,Functional and Pasting Properties of Defatted Starches from Cowpea and Soybean and Application in Stiff Porridge Preparation

The effects of defatting on the chemical, functional and pasting properties of starches from cowpea and soybean and their application in stiff porridge preparation were studied. Conventional cassava starch served as standard. Defatting of cowpea and soybean resulted in higher yield. Defatted starches also had higher amylose contents with low protein, fat and ash contents than full fat starches. In addition, defatted starches from cowpea and soybean had higher water absorption capacity, swelling power, blue value index and low bulk density, higher peak viscosity, trough, final viscosity, setback values than full fat cowpea and soybean starches while cassava starch had higher peak time and pasting temperature than the legume starches. The full fat starches from soybean and cowpea had high breakdown and low setback values than the defatted samples and control. The extensibility values of defatted starches were significantly (p ≤ 0.05) higher than full fat starches but lower than control. There was no significant (p ≥ 0.05) difference in texture and appearance of stiff porridges prepared from cowpea, soybean and cassava starches. Similarly, there was no significant (p ≥ 0.05) difference in mouldability, stickiness and overall acceptability between defatted starches and control but significantly different (p ≤ 0.05) with the full fat starches. It is therefore concluded that consumption of such stiff porridges could be beneficial to individuals requiring decreased and/or slow starch digestibility such as diabetic patients and long distance athletes since legume starches are known to have low starch digestibility.     

Physical,Chemical and Sensory Properties of Baked Products from Blends of Wheat and African Yam Bean (Sphenostylis stenocarpa) Water-Extractable Proteins

Blends of wheat flour (WF) and African yam bean water-extractable proteins (AYBWEP) were processed into bread and cookies in the following ratios: 100: 0; 95: 5; 90: 10; 85: 15; 80: 20. The proximate composition, physical, chemical properties and sensory properties of bread and cookies samples from the blends were determined. Breads and cookies produced from the resultant blends were significantly higher (p < 0.05) in protein (16.39% – 18.36%) than the control (11.80% – 12.58%). Carbohydrate content decreased from 60.74% with addition of AYBWEP to 52.81% following 20% substitution. The pH of bread samples prepared from whole wheat flour and blends of wheat flour and AYBWEP were significantly different (p < 0.05) while bulk density and specific volume were not significantly different (p > 0.05). The pH of bread samples and cookies decreased with increase in the proportion of the AYBWEP blend from 5% to 20%. The highest specific volume (3.70 ml/g) was observed in bread samples prepared from the control 100: 0 blends while the 80:20 blends had the lowest specific volume (3.10 ml/g). There was no significant difference (p > 0.05) in the bulk density and thickness of the cookies. The cookies prepared using 80: 20 blends had the higher diameter (22.53 cm) and spread factor (54.03 cm) compared to the control. Generally, acceptability of the bread and cookies decreased with higher ratios of AYBWEP inclusion. The sensory acceptability scores showed the best AYBWEP substitution level for making bread and cookies was 5% and 10% of the AYBWEP respectively. The results are discussed in the context of the growing importance of promoting the processing and utilization of lesser known local crops in baked products.enrichment.     

The influence of processing route on the structuring and properties of high‐density polyethylene (HDPE)/clay nanocomposites

The effect of different processing routes on structure and properties of high‐density polyethylene (HDPE)‐clay nanocomposites was assessed. Different compatibilizer/clay ratios (α) were also studied to determine if interactions exist between processing route and polymer‐clay compatibility. HDPE/HDPE‐g‐MA/clay with α values of 1 to 4 were melt compounded (twin screw extrusion), and then processed via three routes: compression moulding, compression moulding followed by biaxial stretching or blown film extrusion. The structure was examined using X‐ray diffraction (XRD) and transmission electron microscopy (TEM). Tensile and oxygen barrier properties were determined. It was found that biaxial extensional forming produced the best enhancement in properties. An interaction between processing route and polymer‐clay compatibility is evident. Halpin‐Tsai (H‐T) model was employed to predict relative modulus values. It showed good agreement with the experimental data. For biaxial extension at α = 4.0, the experimental relative modulus is greater than the predicted value. This may indicate the existence of a “nano” effect at the polymer‐clay interface. POLYM. ENG. SCI., 2012. © 2012 Society of Plastics Engineers     

Abrasiveness evaluation of selected river gravels of Pakistan using LCPC rock abrasivity test

Bulletin of Engineering Geology and the Environment - Abrasivity of rock and soil causes tool wear in excavation or drilling operations, and the presence of sandy gravels stratum also plays a...     

Composition and characteristics of Indian coffee bean,spent grounds and oil

The physical and chemical characteristics of raw and coffee bean (seed) and spent grounds (a byproduct of the instant coffee industry) and the corresponding oils of four varieties of Indian coffee beans were studied. The chemical characteristics of the oils were found to be similar to those of groundnut oil except for the unsaponifiable matter which is high in the case of coffee bean oil (6–12%). The colour of crude coffee bean oil varied from light green (from raw bean) to chocolate brown (from roasted and spent grounds). The oil is practically odourless. Practical aspects of drying and storage of sludge and solvent extraction of dried grounds are discussed.     

Ultrasonic pretreatment of corn gluten meal proteins and neutrase: Effect on protein conformation and preparation of ACE (angiotensin converting enzyme) inhibitory peptides

The impact of ultrasound pretreatment of corn gluten meal (CGM) protein and neutrase on the ACE (angiotensin converting enzyme) inhibitory activity of hydrolysate was studied. The UV–vis differential spectra and fluorescence spectra of the CGM protein and neutrase were determined. The neutrase activity and the ACE inhibitory activity of the CGM protein hydrolysates were analyzed. The highest ACE inhibitory activity was obtained at 10 min hydrolysis when the CGM protein was pretreated at 20 kHz for 10–30 min and at a power of 1000 W. The neutrase activity and ACE inhibitory activity were at their maxima at sonication of 250 W and sonication time of 15 min. The fluorescence and UV differential spectra of the proteins of CGM and neutrase reflected molecular unfolding due to sonication. Sonication of the protein substrate and the enzyme before hydrolysis may be an effective way to enhance the ACE inhibition attributes of the hydrolysate.     

Optimization of process parameters using D-optimal design for synthesis of ZnO nanoparticles via sol–gel technique

The experimental conditions for the synthesis of ZnO nanoparticles to produce minimal size were optimized using the D-optimal design. The influence of process parameters involves molar ratio of the starting materials, pH and the calcination temperature on the particle size were evaluated using the polynomial regression. The optimum conditions revealed by the model for obtaining a minimum particle size of ZnO were predicted to have a molar ratio of 1.76, pH of 1.50 and calcination at 402.2 °C. The obtainable particle size upon applying the model is 22.9 nm in compare to experimental result of 18 ± 2 nm was obtained.     

Fabrication of porous ZnO via electrochemical etching using 10 wt% potassium hydroxide solution

We described the fabrication of porous ZnO using the electrochemical etching method. ZnO thin films deposited by radiofrequency sputtering were etched electrochemically using 10 wt% KOH solution as an etching medium to obtain porous ZnO surface structure. A constant voltage of 15 V was applied to enhance the etching process. The etched samples were then characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence (PL) spectroscopy to examine their structural and optical properties. XRD spectra showed that by performing the electrochemical etching process, porous ZnO could be obtained without severely deteriorating the crystallinity of the samples. Moreover, SEM characterization revealed that hillock-type porous ZnO was fabricated successfully. In addition, the cross-sectional SEM images revealed that there were only minimal changes in the layer thickness after the ZnO had been etched for various lengths of time. This finding shows the dominance of the vertical etching process. Notably, the intensity of PL spectra increased and the PL excitation peak exhibited a red shift trend as the etching time increased. These observations are due to the increase of the surface to volume ratio of the ZnO surface and the strain relaxation along the dislocation and grain boundary.     

Development of novel potentiometric sensors for determination of tartrazine dye concentration in foodstuff products

Tartrazine dye Na₃TZ in foodstuff products was determined by a new modified carbon paste electrode, encoded sensor A, and a coated silver wire electrode, encoded sensor B, based on tartrazine TZ- cetryltrimethyl ammoniumbromide CTAB as a chemical modifier TZ-CTA. The electrodes exhibit the following characteristics listed respectively: a Nernstian slope of 17.9 ± 0.5 and 19.4 ± 0.2 mV/decade for tartrazine ion over a wide concentration range from 4.3 × 10⁻⁷ to 1.0 × 10⁻² and 1.1 × 10⁻⁷ to 1.0 × 10⁻² M. The lower detection limits: 3.2 × 10⁻⁷ and 5.5 × 10⁻⁸ M. Short response time (5–8 s) over the pH range 3.8–7.7 and 4.2–8.1. The proposed sensors display significantly high selectivity for TZ ion over a wide variety of sugars, some anions, common organic, inorganic compounds and additives. The developed electrodes were applied to the potentiometric determination of tartrazine ion in different kinds of foodstuffs: solid jelly (strawberry and custard) powder samples and soft drink (orange) samples with satisfactory results.