Binding of gossypol under conditions of complete rupture of the pigment glands

Summary The “free” gossypol of cooked cottonseed meats is composed of gossypol and of “gossypol-like pigments,” which are soluble in 70% aqueous acetone. The “gossypol-like pigments” may account for 30 to 100% of the “free” gossypol as determined by the A.O.C.S. method. Thorough comminution, followed by prolonged cooking, results in reduction of all the pigments in cotton-seed meats. “Free” gossypol is not completely eliminated, but the gossypol level, as determined by the benzene transfer method, may be reduced to zero. “Gossypol-like pigments” are converted into gossypol by the action of hot aqueous hydrochloric acid. Good agreement is observed between the data for “total” gossypol, as determined through the use of the A.O.C.S. oxalic acid method and through the use of hot aniline. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

A simple and precise method for the routine determination of platelet-activating factor in blood and urine

A simple and precise method is described for the measurement of platelet-activating factor (PAF) in blood and urine. The method involves the isolation of PAF from blood samples by two successive steps. In the first step, blood proteins are precipitated with ethanol and the “free” PAF, i.e. the PAF which is extractable with ethanol, is recovered. In the second step, “bound” PAF, i.e., PAF not extractable with ethanol, is extracted from the protein precipitate with chloroform/methanol/water. The extraction of PAF from urine samples requires only the ethanol extraction step. “Free” and “bound” PAF are then each fractionated by silicic acid column chromatography, and the methanol/water eluent containing PAF is then further fractionated by high-performance liquid chromatography using an isocratic solvent system of acetonitrile/methanol/water. PAF is then quantitated by measuring its ability to induce platelet aggregation in an aggregometer. Application of the method to blood and urine samples from twenty-three healthy volunteers revealed PAF levels in blood of 140–480 pg/mL (630–254.4 pg “free” PAF/mL and 64–225.6 pg “bound” PAF/mL), and of 1.2–4.0 pg PAF/mL in urine. The method overcomes various technical problems and was shown to be very precise. It should prove useful for monitoring PAF levels in various disease conditions.     

Field evaluation of extraction performance

This paper presents 5 methods to evaluate the performance of percolation-type extractors during actual operation by determining the sources of residual oil left in the extracted meal. To determine residual oil left due to poor “flake extractability,” the operator may use either or both the “shaker” and “stain and soak” methods. The “shaker” method first determines the maximum oil that can be removed from the flake and compares this result with the actual amount extracted. The “stain and soak” method involves the microscopic examination of the flakes before extraction. Three methods are described to determine the residual oil due to poor drainage in the extractor. The first involves removing the undrained oil in the laboratory by washing with additional hexane and then comparing the residual oil in the meal with a sample that has not been washed. The second is a colorimetric determination of the final-stage miscella and comparison against known standards, and, finally, a method is presented using a comparison between the design conditions of the extractor and the actual operating conditions to infer the residual oil left due to poor drainage. A combination of any or all of these methods provides a useful means for a field evaluation of the performance of a percolation-type extractor.     

Towards paired and coupled electrode reactions for clean organic microreactor electrosyntheses

Electrosynthesis offers a powerful tool for the formation of anion and cation radical intermediates and for driving clean synthetic reactions without the need for additional chemical reagents. Recent advances in microfluidic reactor technologies triggered an opportunity for new microflow electrolysis reactions to be developed for novel and clean electrosynthetic processes. Naturally, two electrodes, anode and cathode, are required in all electrochemical processes and combining the two electrode processes into one “paired” reaction allows waste to be minimised. By decreasing the inter-electrode gap “paired” reactions may be further “coupled” by overlapping diffusion layers. The concept of “coupling” electrode processes is new and in some cases coupled processes in micro-flow cells are possible even in the absence of intentionally added electrolyte. The charged intermediates in the inter-electrode gap act as electrolyte and processes become “self-supported”. Hardly any examples of “coupled” paired electrochemical processes are known to date and both “paired” and “coupled” processes are reviewed here. Coupled electrode processes remain a challenge. In future “pairing” and “coupling” electrode processes into more complex reaction sequences will be the key to novel and clean flow-through microreactor processes and to novel chemistry.     

A new variety of low-linolenic rapeseed oil; Characteristics and room-odor tests

Two Canadian rapeseed oils, “Westar” and “low-linolenic”, supplied by the Canola Council were studied and compared with a French rapeseed. The linolenic acid content of the low-linolenic variety is about 3%. This drop in the C18∶3 is completely compensated for by an increase in the C18∶2. Seventy-two percent of the triglycerides with at least one linolenic chain disappeared. A strong increase in the OOL and OLL was observed. The room-odor tests showed that the “low-linolenic” had a significantly higher odor score than the French rapeseed and the “Westar”, both of these being very similar. A fruity odor dominated in the “low-linolenic”, and the fishy painty odors were particularly reduced.     

Isolation and characterization of two nonaflatoxigenic classes of morphological variants ofaspergillus parasiticus

Serial transfer of mycelial macerates of aflatoxigenic strains ofAspergillus parasiticus produced 2 morphological variants. The “fan” variant type showed flat growth, a gradient of sporulation density, absence of mycelial pigmentation and deep furrows on the back of the colony. The “fluff” variants displayed abundant aerial mycelium, sparse sporulation, absence of mycelial pigmentation and furrows on the reverse of the colony. Neither “fan” nor “fluff” produced detectable aflatoxin. In a marked mutant strain, the appearance of “fan” and “fluff” and their concomitant loss of aflatoxin production occurred whereas spore color and auxotrophic markers were retained. A parasexual diploid synthesized from the mutant strain with the “fan” phenotype produced high levels of aflatoxin whereas a parasexual diploid containing the “fluff” pheno-type produced low levels of aflatoxin. The unusual mode of isolation, the differential retention of aflatoxin and other genetic markers in a mutant strain, and the different levels of aflatoxin production in parasexual diploids with “fan” and “fluff” imply an unusual genetic mechanism for the control of the aflatoxin pathway.     

Insights into surface reactivity: formic acid oxidation on Cu(110) studied using STM and a molecular beam reactor

Using a combination of STM and molecular beam reactor data we summarise some important features of a model reaction (formic acid oxidation on Cu(110)) which is of general significance to surface reactivity and to catalysis. Three such features are highlighted here. The first concerns the role of weakly held species (possibly physisorbed) in surface reactions. These species, although of very short lifetime on the surface, can, nevertheless, diffuse over long distances to “find” a sparse distribution of active sites. Thus a very low coverage of oxygen on the surface of Cu(110) increases the sticking probability of all the formic acid molecules which strike the surface to high value (0.82), even though the clean surface is relatively unreactive. The important concept here is the “diffusion circle” or “collection zone” which represents the area of surface visited by the molecule in its short sojourn in the weakly held state. The second theme concerns the concept of the “flexible surface”. We show that the involvement of surface atoms in reactions directs the structure and reactivity for a particular reaction. For formic acid oxidation the liberation of Cu atoms during the removal of oxygen as water leads to gross restructuring of the surface and can lead to “compression” of one reactant (the oxygen in this case) into a lower area, higher local coverage, unreactive state (the c(6×2) oxygen structure). Thirdly, and finally, it is proposed that, for many surface reactions, the surface acts in an analogous way to a solvent, supporting a “dissolved” (highly mobile and fluxional) phase of intermediates at low coverage, which crystallise out above a critical coverage (the 2D “solubility limit”). This revised version was published online in July 2006 with corrections to the Cover Date.     

Extraction and methanolysis of oil from whole or crushed rapeseed for fatty acid analysis

Three methods are described for extraction of oil from rapeseed for routine determinations of fatty acid composition. In the “whole-seed method,” ca. 50% of the total seed oil is extracted, without prior crushing of the seeds, by soaking the dried seeds in petroleum ether and benzene at room temperature for 2 days. For certain types of rapeseed with a “less permeable seed coat,” a presoaking in water is required to rupture the seed coat. The extracted oil has practically the same fatty acid composition as the total seed oil, and can therefore be used as a representative sample for determination of the fatty acid composition of the total seed oil. In the “crushing method,” the seeds are lightly crushed before the oil is extracted. In the “half-seed method,” the outer cotyledon of a single seed is dissected from the embryo; the oil is extracted from this cotyledon for fatty acid analysis, while the remaining part of the embryo can be germinated and planted to produce the progeny of the seed. In all three methods the extracted oil is converted to fatty acid methyl esters by a rapid reaction with sodium in methanol at room temperature. Presented in part at the Joint Conference of the Chemical Institute of Canada and the American Chemical Society, Toronto, May 1970. Contribution No. 329, Department of Plant Science, University of Manitoba.     

Dependent light scattering in white paint films: clarification and application of the theoretical concepts

Among the numerous publications analyzing the causes and consequences of titanium dioxide crowding on the optical properties of white paint films, one notes some inconsistencies. First, a significant number of studies are inclined to describe “dependent” and “multiple” scattering of light as distinct phenomena. Second, the transition from independent to dependent light-scattering is often associated with an ill-defined “threshold” concentration. The aim of this study is to clarify the intricate connections between these two scattering regimes and in particular to show that for white paint films loaded with rutile titanium dioxide pigments, “dependent” light scattering is merely a particular manifestation of multiple scattering processes. We also clarify that the transition from independent to dependent scattering is a continuous process that cannot be formally related to a specific threshold in the pigment volume concentration. Finally, we propose a simple method based on the dependent scattering amplitude to assist paint formulators facing the task of improving the hiding power of a white paint either by increasing the quantity of pigments or by improving their spatial state of dispersion.     

Intraspecific Variation in Plant Defense Alters Effects of Root Herbivores on Leaf Chemistry and Aboveground Herbivore Damage

Root herbivores can indirectly affect aboveground herbivores by altering the food quality of the plant. However, it is largely unknown whether plant genotypes differ in their response to root herbivores, leading to variable defensive phenotypes. In this study, we investigated whether root-feeding insect larvae (Agriotes sp. larvae, wireworms) induce different responses in Plantago lanceolata plants from lines selected for low and high levels of iridoid glycosides (IG). In the absence of wireworms, plants of the “high-IG line” contained approximately twofold higher levels of total IG and threefold higher levels of catalpol (one of the IG) in leaves than plants from the “low-IG line,” whereas both lines had similar levels of IG in roots. In response to wireworms, roots of plants from both lines showed increased concentrations of catalpol. Leaves of “low-IG line” plants increased catalpol concentrations in response to wireworms, whereas catalpol concentrations of leaves of “high-IG line” plants decreased. In contrast, glucose concentrations in roots of “low-IG” plants decreased, while they increased in “high-IG” plants after feeding by wireworms. The leaf volatile profile differed between the lines, but was not affected by root herbivores. In the field, leaf damage by herbivores was higher in wireworm-induced compared to noninduced “low-IG” plants and lower in wireworm-induced compared to noninduced “high-IG” plants, despite induction of catalpol in leaves of the “low-IG” plants and reduction in “high-IG” plants. This pattern might arise if damage is caused mainly by specialist herbivores for which catalpol may act as feeding stimulant rather than as deterrent. The present study documents for the first time that intraspecific variation in plant defense affects the outcome of plant-mediated interactions between root and shoot herbivores.     

Czonolysis as a method for establishing the position of olefinic linkages

Summary Ozonolysis and chromatographic procedures as a method for determining the position of double bonds in olefinic acids are not entirely satisfactory. Ozonolysis is seriously limited because of the secondary reactions undergone by the ozonide. Chromatographic resolution of the decomposed ozonides of oleic acid yields the expected pelargonic and azelaic acids but also yields fractions that indicate double bonds which do not exist. Fractions corresponding to pimelic, sebacic, caprylic, suberic, and capric acids appeared. The “pimelic acid” fraction resulted from the reaction of ozone with an oxidizable or hydrolyzable solvent such as acetone, methanol, or tetrachloromethane. The “sebacic” and “caprylic acid” fractions were incompletely decomposed ozonide. The suberic and capric acid fractions however were real and are believed to have resulted from 8-octadecenoic acid present in the oleic acid in amounts too small to be detected by the methods used to establish its purity.     

Lysine,gossypol, and nitrogen solubility in chemically treated cottonseed meals

The effects of treatment of commercial prepress-solvent extracted and direct-solvent extracted cottonseed mares with several chemical agents and solvents were studied. The analytical results for “free” and “total” gossypol of the finished meals show that treatment with aliphatic amines, followed by extraction with a suitable solvent, removed large proportions of the “free” as well as “bound” gossypol. This reduction of “free” and “bound” gossypol was accompanied, in some experiments, by an increase in the nitrogen solubility and available lysine, as compared with the results obtained with the untreated air-dried marcs. The available lysine contents of the treated mares was significnatly correlated with the nitrogen solubility in 0.02N aqueous NaOH. One of the laboratories of the Southern Utilization Research and Development Division, Agricultural Research Service, U. S. Department of Agriculture.     

Note on acetone-soluble material in cottonseed meals

Summary In connection with a study of methods of eliminating traces of “free” gossypol from cottonseed meals a procedure for isolation of gossypol from the 70% acetone extracts of the meals by transfer to benzene solution has ben developed. A procedure is also given for quantitative determination of the isolated gossypol. Analysis of four samples of cooked cottonseed meats and meal by the method showed that in each instance substances other than gossypol are measured by the A.O.C.S. method for “free” gossypol in meals containing low concentrations of residual “free” gossypol. This procedure promises to provide another analytical tool for the study of residual material in processed cottonseed meal that causes egg discoloration when fed to laying hens. One of the laboratories of the Southern Utilization Research Branch, Agricultural Research Service, U. S. Department of Agriculture.     

Functional properties of low-fat soy flour produced by an extrusion-expelling system

Low-fat soy flour (LFSF) obtained by extrusion-expelling processing was investigated for functional properties. Flours with the following various levels of protein dispersibility indexes (PDI) and residual oil (RO) contents were investigated: “high” 67±4/10.4±1, “mid” 42±3/7.4±2, and “low” 14±5/6.5±0. The solubility of all three LFSF was minimal at pH 4.0 and increased at more alkaline and acidic pH levels. Water-holding capacity (WHC) increased with a decrease in PDI and RO content, whereas fat-binding capacity (FBC) decreased. Foaming stability increased as PDI and RO increased, with significant differences between all LFSF samples. Emulsification capacity (EC) was measured at three pH levels (5.5, 6.7, and 8.0). At each pH level, the “low” samples showed the least EC compared to the “mid” and “high” samples, with no significan difference between the “mid” and “high” samples at pH 6.7 and 8.0. Emulsification stability and activity decreased from low LFSF to high LFSF. This study showed that in general low LFSF was less functional than the other flours tested and there was no significant difference in the functionality of mid- and high-LFSF samples.     

A study of the kinetics of nucleation in a palm oil melt

Nucleation from a supercooled melt of palm oil was studied by optical microscopy and differential scanning calorimetry (DSC). Despite being a multicomponent system, palm oil exhibits a rather simple cooling thermogram with its high- and low-T exotherms exclusively related to the “hard” and “soft” components of the oil. As the “hard” components are being removed, the position of the high-T peak shifts down toward the low-T peak with diminishing peak intensity, while the position of the latter remains virtually unchanged. At 288°K, nucleation in a palm oil melt is instantaneous. Its induction time-temperature curve shows an abrupt discontinuity at 297°K, which demarcates the occurrence of one polymorph from another. Nucleation data fit very well into the Fisher-Turnbull equation. Its larger activation free energy of nucleation is accompanied by lowering of the melting point and an increase in the crystal/melt interfacial free energy as compared to palm stearin. The slow rate of nucleation in palm oil is attributed to intermolecular interaction between its “hard” and “soft” components. Partly presented at the 1989 PORIM International Palm Oil Development Conference, September 5–9, Kuala Lumpur, Malaysia.     

The energy consumption in a batch stripper and a batch rectifier

The energy consumption in a batch rectifier and a batch stripper was investigated with a shortcut mathematical model. The minimum energy consumption of a batch stripper was compared to that of a batch rectifier under “general constant reflux” and “general constant distillate composition” with the ratio of minimum energy consumption E_S/E_R. When the feed contains a large amount of light component, the product purity specification is low and the relative volatility is small, the minimum energy consumption of a batch stripper is less than that of a batch rectifier under “general constant reflux” and “general constant distillate composition”. When the feed contains a small amount of light component, the product purity specification is very high and the relative volatility is low, a batch stripper can also consume less energy only in the “general constant distillate composition” operation mode. In other cases, a batch rectifier can consume less energy.     

Physicochemical aspects of texturization: Fiber formation from globular proteins

The modification of proteins to produce fibrous or “fiber-like” textured products is a subject of unique importance and interest. Unfortunately, very little is known about the physicochemical properties of texturized “fibers”, the mechanisms that produce them, or the forces that hold the protein molecules in a given structure. This paper deals with the following topics: (a) methods for characterizing the physico-chemical properties of textured protein products; (b) the structures of naturally occurring fibrous proteins and synthetic polypeptides as possible models for texturized “fibers”; (c) the current understanding of the mechanisms and the forces required to form and stabilize fibrous protein structures; and (d) a brief and generalized survey of the presently available “fiber” forming processes.     

Relationships between cholesterogenesis,microsomal sterols and HMG-CoA reductase in the perfused rat liver

The relationships between cholesterogenesis and the activity of HMG-CoA reductase of microsomes prepared with or without sodium fluoride, and between changes of cholesterogenesis and microsomal sterols were studied in the isolated rat liver perfused with or without oleic acid in the presence of AY-9944. AY-9944 inhibits the conversion of 7-dehydrocholesterol, measured colorimetrically as “fast-acting” sterols, to cholesterol, measured colorimetrically as “slow-acting” sterols. The level of “fast-acting” sterols is used to estimate cholesterogenesis and changes in microsomal sterols. It was observed that the activity of HMG-CoA reductase of microsomes prepared with or without fluoride reflects the relative changes in cholesterogenesis of the perfused livers. In addition, the amount of “fast-acting” and “slow-acting” sterols in microsomes correlates with increases in the activity of HMG-CoA reductase and cholesterogenesis.     

The mass spectra of the 4,4-dimethyloxazoline derivatives of the methoxymethyl olefins of malvalic and sterculic acids

A new approach to the gas chromatographymass spectrometry analysis of cyclopropenoid fatty acids is described. The method is based on the “on-site”-modification of the cyclopropenoid ring with AgNO₃-saturated methanol to the methoxymethyl olefin and a subsequent “remote-site”-derivatization of the carboxyl group to its 4,4-dimethyloxazoline. The mass spectra of the isomeric reaction products obtained from malvalic and sterculic acid were found to be useful for locating the original cyclopropenoid ring in the fatty acid chain.     

Heat resistance of alumina ceramics

A method for evaluating the heat resistance of structural ceramics according to which the thermally stressed state is created by blowing a directed air flow into the tip of a notch in a heated prismatic specimen is presented. For this purpose a special complexly shaped notch is formed in order to provide free inflow of the air to its tip. The radius of curvature of the notch in alumina ceramics is 5 Μm. In blowing, the heat is removed predominantly from a local volume at the tip of the notch, thus providing a “local” thermal shock. The heat resistance of alumina ceramics obtained by sintering and reaction bonding is studied. The mechanical properties of Al₂O₃ tend to improve after a local thermal shock. The tendency is proved by testing a statistically reliable sample of unnotched specimens by the conventional method for determining the heat resistance. This tendency can be explained by “curing” of some of the defects (commensurable with the elements of the substructure) in densely sintered ceramics under the effect of thermal stresses. This was established due to the low scattering of the values of the mechanical properties measured in testing a sample of specimens with a special notch. It cannot be detected in tests of unnotched specimens within the same sample. A heat cycle of “850‡C-water” worsens the mechanical properties of notched and unnotched specimens due to the initiated microfracture. Translated from Ogneupory i Tekhnicheskaya Keramika, Nos. 1–2, pp. 14–19, January–February, 1999.