Production of conjugated linoleic acid by food‐grade bacteria: A review

Conjugated linoleic acid (CLA) is a group of isomers of linoleic acid (LA) with several potential health benefits which justifies the efforts to obtain foods with enhanced CLA contents. A possible way to obtain CLA‐enriched products is via fermentation as several micro‐organisms, many of which are employed in the manufacture of foods, are known to convert free LA into CLA. However, due to several constraints, the use of CLA‐producing bacteria still remains challenging and continuous efforts are required. This review summarises the current knowledge on microbial CLA production by food‐grade micro‐organisms, its technical issues and limitations, potential applications and bioactivities.     

PERCEPTION OF TEXTURE AND FLAVOR IN SOUPS BY ELDERLY AND YOUNG SUBJECTS

The perception of texture and flavor and their interaction effects in white cream soups were studied in 12 young subjects (18–29 years) and 15 elderly subjects (60–84 years). Eight soup samples (2 × 2 × 2 factorial design) were prepared with or without potato starch, with or without mushroom flavor and with water or with milk. The elderly were less sensitive to changes in the flavor profile of the soups than the young, and their perception of creaminess was reduced. Solvent by flavor interaction effects were independent of age, whereas texture by flavor interaction effects were age specific. Besides the intensities of flavor and texture attributes, pleasantness was also assessed. No indication was found that the contribution of texture and flavor to food appreciation was different for the young and for the elderly in the current study. This study supports the assumption that age‐related differences in product perception exist.     

DETERMINATION OF THE MIXING RATE OF A HIGH VELOCITY FEED STREAM IN AGITATED VESSELS

In semi-batch or continuously stirred reactors, often a feed containing one or more reactants has to be mixed with the contents of the vessel. For fast competitive or consecutive reactions the mixing rate of the feed stream with the vessel contents has a large influence on the product quality. The mixing rate is often controlled by the turbulent dispersion process. Therefore, it has been suggested in the literature to keep the turbulent dispersion time constant upon scale-up to obtain a constant product quality. In this study, based on a combination of a theoretical model, Planar Laser Induced Fluorescence experiments and Laser Doppler Velocimetry experiments, the turbulent dispersion coefficient is determined. This has been done for the case that a feed stream is mixed in a stirred vessel by a combination of feed stream and stirrer generated turbulence. The turbulent dispersion coefficient is used to derive an equation for the turbulent dispersion time as function of several design and process variables.     

Use of Landsat data for automatic classification and area estimation of sugar-cane plantation in Sao Paulo state,Brazil

Sugar-cane (saccharum spp.) plantations in São Paulo State were classified automatically using an lmage-100 system and Landsat digital data. Ten segments of size 10 × 20 km were aerially photographed and used as training areas for automatic classification. The study area was covered by four Landsat paths, 235, 236, 237 and 238. The percentages of overall correct classification for these paths range from 79·56 per cent for path 238 to 95·59 per cent for path 237.