Proximal composition and in vitro starch digestibility in flaxseed‐added corn tortilla

BACKGROUND: The effect of addition of flaxseed flour (10:90, 15:85 and 20:80, w/w) on the chemical composition and starch digestibility of corn tortilla was investigated. Tortillas were baked and frozen in liquid nitrogen, freeze‐dried, ground and analyzed for fat, protein, ash, total starch (TS), available starch (AS) and resistant starch (RS) contents as well as for starch hydrolysis rate and predicted glycemic index (pGI). Tortillas made from commercial nixtamalized corn flour were used as control sample. RESULTS: Flaxseed flour addition increased the fat and protein content of tortilla, whereas TS and AS decreased. TS was 15.25% lower in the 20% flaxseed‐containing tortilla as compared to the control sample. The AS content was 12.65% lower in the composite tortilla. RS content in the samples ranged between 1.92% for the control sample and 5.08% for the tortilla containing 20% flaxseed. The reduced enzymatic starch hydrolysis rate and pGI recorded for the flaxseed‐added tortilla, indicated slow digestion features. CONCLUSIONS: Flaxseed‐added tortilla might be used to increase the consumption of α‐linolenic acid in the daily diet and modulate starch digestibility of corn tortilla. This kind of product may be used by people with special diet reqirements. Copyright © 2008 Society of Chemical Industry     

Optical properties of randomly distributed soot: improved polarimetric and intensity scattering functions

Reference scattering curves for polarization and intensity produced by aggregates and agglomerates of ethylene and kerosene soot are obtained for scattering angles in the 10-170 degrees range. The polarization measurements were obtained with the Propriétés Optiques des Grains Astronomiques et Atmosphériques instrument for particles that levitate in microgravity during parabolic flights and on the ground by an air draught technique. The intensity measurements were obtained also on the ground with a Laboratoire de Metéorologie Physique nephelometer. The maximum polarization is of the order of 80% at a scattering angle of 80 degrees at lambda = 632.8 nm and approximately 75% at an angle of 90 degrees at lambda = 543.5 nm. The polarization increases by approximately 10% when the size of the agglomerate increases from 10 microm to a few hundred micrometers. The intensity curve exhibits a strong increase at small scattering angles. These reference curves will be used in the near future for the detection of stratospheric soot by remote-sensing measurement techniques.     

Herstellung und Anwendungsmöglichkeiten von Eiweiß-Fettsäurekondensaten

Production and application of acylated protein hydrolysates Acylated protein hydrolysates are very mild surfactants based on protein as a renewable natural resource. Protein raw materials of animal or plant sources are hydrolyzed and acylated with fatty acid chlorides according to Schotten-Baumann. Compared to surfactants based on fats or carbohydrates, acylated protein hydrolysates are different in application due to their hydrophilic protein part. In the formulation of surfactants, addition of small amounts of acylated protein hydrolysates to the more strongly irritating bulk surfactants results in a more than proportional improvement in their compatibility with the skin.     

Object recognition by three-dimensional curve matching

Experimental results for the recognition of general curves in three-space using registered range and intensity images are presented. the matching algorithm uses fast Fourier transforms to determine the least-squares difference between sequences of points sampled at equal intervals along two piecewise linear approximations of curves in three-space and returns the rotation and translation required to bring one of the curves into closest juxtaposition with the other. Performance of the algorithm is demonstrated by matching curves in three-space which are the boundaries of regions of contrasting reflectivity on curved surfaces. the experiments use a recently developed range sensor which is able to generate a 512 × 460 × 12 bit range image (with registered intensity image) in 40 s.     

Korrosionsverhalten und Deckschichtbildung auf Kupfer und Kupferlegierungen

Corrosion Behaviour and Film Formation of Copper and Copper Alloys Film formation processes on Cu, CuZn, CuAl and CuNi materials in NH₃- and Cl^?-containing aqueous solutions are discussed in a summary article by way of corrosion systems, some typical and some of practical significance, and the protection offered by these films against general corrosion is described. Also considered are localized corrosion phenomena to which Cu-base alloys with oxide films are typically exposed. A comparison of the resistance of the various alloying systems illustrates the particular danger of stress corrosion cracking of mechanically stressed metals. Finally, the type and structure of oxide surface films are discussed with respect to their effect on crack initiation.     

Tracing atmospheric nitrate deposition in a complex semiarid ecosystem using delta17O

The isotopic composition of nitrate collected from aerosols, fog, and precipitation was measured and found to have a large 17O anomaly with delta17O values ranging from 20 percent per thousand to 30% percent per thousand (delta17O = delta17O - 0.52(delta18O)). This 17O anomaly was used to trace atmospheric deposition of nitrate to a semiarid ecosystem in southern California. We demonstrate that the delta17O signal is a conserved tracer of atmospheric nitrate deposition and is a more robust indicator of N deposition relative to standard delta18O techniques. The data indicate that a substantial portion of nitrate found in the local soil, stream, and groundwater is of atmospheric origin and does not undergo biologic processing before being exported from the system.