QUANTIFYING ADULTERATION IN ROAST COFFEE POWDERS BY DIGITAL IMAGE PROCESSING

Abstract A new method based on digital image processing used to quantify adulteration in roast and ground coffee beans is presented in this study. Pure arabica coffee and mixtures of coffee husks and straw, maize, brown sugar and soybean were produced in our laboratory as investigation materials. Red/Green/Blue (RGB) color composites, magnified twelve times, were generated using a Charge Coupled Device (CCD) camera connected to a stereo microscope and a personal computer with an image processing software package. The percent areas of the contaminants in each image were calculated by the Maximum Likelihood supervised classification technique. Best-fit equations relating weight percentage (g.kg^-1) and the percent areas were obtained for each coffee contaminant. To test the method, 247 coffee samples of different amounts and types of adulterants were analyzed in the laboratory. The results showed that the new method developed can analyze precisely and quickly a large number of ground coffee powders.     

ISOLATION AND CHARACTERIZATION OF AMARANTIN, THE 11S AMARANTH SEED GLOBULIN

The 11S globulin of seed storage protein of Amaranthus hypochondriacus, termed amarantin, was isolated. This fraction was evaluated for its purity by chromatographic techniques and ultracentrifugation. The 11S globulin was analyzed by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE) without and with prior reduction of disulfide bonds, and by nondenaturing-PAGE. It exhibited an electrophoretic behavior similar to that of 11S-like proteins in other materials. Its apparent relative molecular weight was estimated to be 389 kDa by gel filtration chromatography at low ionic strength. Ultracentrifugation of the freeze-dried extract gave a sedimentation coefficient of 11S.     

Protein extraction from lupin seeds: a mathematical model

The effect of particle size and microstructural modification on protein extraction from defatted lupin was studied. Particles of different sizes (128–1425 μm) from untreated (control), flaked and exploded samples were extracted at pH 8.0–8.5 and different temperatures. A three-parameter kinetic model as well as a diffusional model were fitted to data. The yield of protein from the surface of particles, and the total extracted protein yield increased as particle size decreased, while the first order rate constant increased slightly or remained constant. Diffusion coefficients varied between 0.5 and 4.5x10⁻¹² m² s⁻¹ and were higher in exploded and flaked material than in the control. The energy of activation for diffusion was 43 kJ mol⁻¹. Differences in microstructure were studied by scanning electron microscopy.     

New models of adipogenic differentiation highlight a cell-autonomous response to temperature

Temperature is a key regulator of brown adipose tissue (BAT) function, acting through central sensory inputs to influence metabolism and energy storage. Although animal models have produced a wealth of information on the pathways, effectors and responses mediating the physiological response of adipose tissue to temperature in vivo, the use of cell culture models now offers evidence of an additional cell-autonomous response to temperature changes, in the absence of neural input. In particular, stem cell models provide new insight into the regulation of adipogenic differentiation and the induction of browning features in vitro. Here the basis for adipogenic responsiveness to low temperature is discussed, together with different human cell models available to outline the benefits of cell-based approaches for future BAT research.     

Inhibitory effect of jasmonic acid and ethylene on epicotyl growth and bud induction in the maritime pine, <i>Pinus pinaster</i> Soland. in Ait

Two independent parameters, epicotyl height (cm) and number of induced buds were studied on Pinus pinaster explants to analyse the effects of three phytohormones (6-benzylaminopurine, jasmonic acid, ethylene) which were combined or not in 11 different treatments. Epicotyle length diminished significantly in relation to the control medium (medium without exogen phytohormones) in presence of jasmonic acid, 6-benzylaminopurine or Ethephon (which is converted to ethylene in plants) in any of treatments. Concentrations of 100 μM of jasmonic acid and Ethephon had a greater inhibitory effect than the treatments with 10 μM. In addition to that, jasmonic acid was a stronger inhibitor than Ethephon in any of the tried combinations. There were no significant differences between the control treatment and the treatments with only 10 μM of jasmonic acid or Ethephon. However, 10 μM 6-benzylaminopurine induced bud formation. The different combinations of 6-benzylaminopurine with jasmonic acid and Ethephon showed that concentrations of 10 to 100 μM did not affect the number of induced buds. Jasmonic acid had an inhibitory effect which Ethephon only showed when combined with 100 μM of jasmonic acid and 10 μM of 6-benzylaminopurine. Three response groups were defined by cluster analysis: group 1 produced the greatest mean number of buds (4 to 5) and a mean epicotyl growth of 1 to 1.5 cm; group 2 produced 2 to 4 buds and a mean growth of 0.5 to 1.2 cm; group 3 produced only one bud and a mean epicotyl length of 1.2 to 2 cm.