Preparation and properties of probiotic cheese high in conjugated linoleic acid content

The development of probiotic Ras cheese rich in conjugated linoleic acid (CLA) was investigated using probiotic Lactobacillus casei and Lactobacillus acidophilus starters. The cheeses were assessed for composition, proteolysis, fatty acids and fat stability, and microbiology during 3 months of ripening. The cheese made with Lb. casei and Lb. acidophilus retained high counts of the probiotic strains (～log 8) throughout storage. Ripening changes followed the normal pattern of this type of cheese during ripening. Ras cheese made with Lb. casei and Lb. acidophilus contained the highest CLA content (0.84% after 3 months) as compared to control and cheese fat had acceptable oxidative stability.     

Screening of some potentially probiotic lactic acid bacteria for their ability to synthesis conjugated linoleic acid

Strains of potentially probiotic lactobacilli, propionibacteria, leuconostoc, lactococcus, enterococcus, and pediococcus, were tested for their ability to convert linoleic acid to conjugated linoleic acid (CLA). Growth and CLA production were followed during incubation for 48 h in reconstituted skim milk containing 0.2% lipolysed sesame oil. Lactococcus lactis subsp. lactis biovar diacetylactis and Leuconostoc mesenteroides subsp. mesenteroides gave the highest CLA production. Also, the effect of lipolysed oil concentration on the growth and CLA production of six strains were studied in medium containing 0.0–1% lipolysed oil. Leuconostoc mesenteroides subsp. mesenteroides and Lac. lactis subsp. lactis biovar diacetylactis gave maximum dienes in medium containing 0.6% and 0.8% lipolysed oil respectively.     

Inhibitory effect of amino acids on Al pitting corrosion in 0.1m NaCl

The effect of some -amino acids on the inhibition of pitting corrosion of Al in 0.1m NaCl solution was studied by the potentiodynamic technique. All inhibitors used shift the pitting potential (Ep) and the protection potential (Epp) towards more noble values. The order of effectiveness of the inhibitors was arginine>histidine>glutamine>asparagine>alanine>glycine. The adsorption of amino acids on platinum was investigated by cyclic voltammetry using a flow cell technique. The results confirm that the inhibition efficiency of the amino acids studied is due to their adsorption on the metal surface. Variation in inhibition efficiency with the structure of the compounds was interpreted in terms of the number of adsorption active centres in the molecule, the molecular size and the mode of adsorption.