Partitioning of Proteins and Anti-Nutrients in Cassava (Manihot esculenta Crantz) Leaf Processing Fractions after Mechanical Extraction and Ultrafiltration

Cassava plays a major role in improving food security and reducing malnutrition. The purpose of this study was to evaluate the influence of mechanical pressing coupled with ultrafiltration (UF) on the quality of different fractions of cassava leaves. Cassava leaves harvested from the greenhouse at the University of Hohenheim were passed through a mechanical screw press to extract the juice and separate the press cake. The juice was centrifuged and filtered to separate the sediment and clear supernatant. The clear supernatant was filtered using a 10 kDa UF system. The nutritional contents of the different fractions were analyzed at each processing step. The total phenolic content was significantly lower in the press cake that had a higher fiber and ash content. The juice and sediment fractions had higher crude protein and total phenolic content. Processing did not negatively affect the concentrations of essential amino acids except for tryptophan in the juice fraction. Non-protein nitrogen was mainly present in the UF permeate, illustrating the potential of UF for upgrading soluble protein fractions. The results indicated that the different fractions during processing could be a possible source of protein for food, feed (juice, sediment, and retentate), or fiber (press cake) for ruminant feed.

Emerging plant-based flocculation treatment of phosphate clay: case study from Metlaoui-Gafsa (southwest Tunisia)

The objective of this study was to investigate the ability of cactus Opuntia ficus-indica, used as a natural flocculant in the treatment of phosphate clay as an industrial wastewater. It is a new process that has proven very promising in the removal of high turbidity from industrial effluents. The volume of clear water recovered (supernatant) is one of the characteristic features which allow us to judge the effectiveness of this bioflocculant. The following of the settling velocity on the one hand and the analysis of supernatant and sludge on the other hand allow us to compare the cactus-based flocculant effectiveness with that of a chemical flocculant (CF) of anionic polyacrylamide nature. The optimum pH required for maximum settling velocity was found to be 12. Obtained results indicated that after 900 seconds of settling, the highest volume of clear supernatant was obtained with the natural flocculant (740 mL/L), against 666 mL/L obtained with CF. Several analyses on recovered clear water (pH, turbidity, Cu, Zn, Fe, Cd and Cr) and on dry sludge (P2O5, CaO, MgO, organic C, SiO2 and Cd) are highlighted.

A Novel Organic Electron Donor Derived from N-Methylisatin

We report the reactivity of an electron donor derived from N-methylisatin on reduction by sodium amalgam. Transfer of a clear supernatant solution to iodoarenes affords the products of two-electron reduction. Reductions of sulfones, activated arenesulfonamides, and Weinreb amides are also reported.

Rapid Determination of Ampicillin in Bovine Milk by Liquid Chromatography with Fluorescence Detection

A rapid and sensitive liquid chromatographic (LC) method was developed for the determination of am- picillin residues in raw bovine milk, processed skim milk, and pasteurized, homogenized whole milk with vitamin D. Milk samples were deprote- inized with trichloroacetic acid (TCA) and acetonitrile. After centrifugation, the clear supernatant was reacted with formaldehyde and TCA under heat. The major fluorescent derivative of ampicillin was then determined by reversed-phase LC with fluorescence detection. Average recoveries of ampicillin fortified at 5,10, and 20 ppb (ng/mL) were all >85% with coefficients of variation <10%. Limits of detection ranged from 0.31 to 0.51 ppb and limits of quantitation, from 0.66 to 1.2 ppb. After appropriate validation, this method should be suitable for rapid analysis of milk for ampicillin residues at the tolerance level of 10 ppb.

Modification of the dextran-Mg2+ high-density lipoprotein cholesterol precipitation method for use with previously frozen plasma

Although dextran-Mg2+ precipitation produces accurate and precise results for high-density lipoprotein (HDL) cholesterol in fresh plasma and serum, precipitation of frozen specimens with triglycerides > 2.26 mmol/L (> 200 mg/dL) is difficult. We developed a modification that dilutes thawed samples by 35% and increases dextran-Mg2+ reagent to 15% of sample volume. Standard precipitations were performed on 62 fresh EDTA-treated plasma specimens; supernatant solutions were analyzed fresh and after freezing. Standard and modified methods were also performed on thawed, paired plasmas. In specimens with triglycerides < or = 2.26 mmol/L, HDL cholesterol results for all methods were similar. For triglycerides > 2.26 mmol/L, however, bias and precision were significantly affected by freezing, and 38.5% of samples with standard precipitation required additional procedures to produce clear supernatant solutions. HDL cholesterol concentrations for thawed samples with standard precipitation were significantly greater than for fresh samples (P < 0.02), but those for the modified method were not different from fresh samples, and only one specimen required additional steps to produce a clear supernate.

Effect of Bentonites on Fluorometric Selenium Determination

Bentonites in feeds cause error in the analysis for Se by the AOAC (3.097-3.101) fluorometric method for Se in plants. The error apparently results from the binding of the piazselenol by insoluble residue from the bentonite. This effect is avoided by diluting digests to volume after reduction with HCl, centrifuging or allowing to stand, and analyzing a portion of the clear supernatant liquid. Insoluble residues present after digestion of plant materials do not appear to cause a similar error.

Infrared Spectrophotometry Method for Methazole Formulations: Collaborative Study

An infrared method was developed for the analysis of Probe 75% wettable powder formulation for methazole content. The procedure involves an extraction of the powder by agitation with acetone. The suspension is centrifuged, and the clear supernatant liquid is measured for absorbance at 755 cm−1. A collaborative study was conducted with 10 laboratories participating. One laboratory omitted the centrifugation, which resulted in a low assay. Statistical analysis of the data showed no significant variances. The coefficient of variation for 10 laboratories analyzing 2 samples in duplicate was 1.29%. The method has been adopted interim official first action.

CHARLES DICKENS ON THE MEDICAL USE OF TAR-WATER

Bishop George Berkeley (1685-1753), the Anglo-Irish philosopher and Bishop of Cloyne, a remote diocese in County Cork, published a remarkable book in 1744 on the panacean value of tar-water. Berkeley recommended that tar-water be prepared by pouring a gallon of water over a quart of tar, then stirring and mixing thoroughly for three or four minutes with a ladle or flat stick. After standing for 48 hours to allow the tar to settle, the clear supernatant layer was poured off and kept for use. Berkeley claimed that a pint of tar-water a day would cure almost every disease then known.1 Although the tar-water craze had abated by the end of the 18th century, it was apparently still in use in England as late as 1861, as is evident in this quotation from Dickens's Great Expectations.2

"High-pressure" liquid chromatography of sulfisoxazole and N4-acetylsulfisoxazole in body fluids.

We describe a simple, rapid chromatographic method for separating and quantitatively determining sulfisoxazole and its N4-acetyl metabolite in plasma and urine. A 100-micro L sample of plasma or urine is combined with 200 micro L of a solution containing 12 mg/L of the internal standard, N4-acetylsulfamethoxazole, in absolute methanol and centrifuged to obtain a clear supernatant solution. This solution is then eluted through a 10-micron microparticulate column with a mobile phase of 32/68 (by vol) methanol/sodium acetate buffer (0.01 mol/L, pH 4.7), at a flow rate of 1.2 mL/min. The eluted sompounds are detected by their absorption at 254 nm. We calculated concentration from the peak-height ratios of sulfisoxazole or N4-acetylsulfisoxazole to N4-acetylsulfamethoxazole. The peak-height ratio was linear with concentration in the range 0.05--200 mg/L for both drug and metabolite in plasma and urine. Because this assay can be completed within 30 min of obtaining a blood or urine sample, it should be a valuable tool in clinical drug monitoring and pharmacokinetic studies.