During ultrafiltration in a hollow fiber device 105 liters of lipase frort Pseudomonas fluorescens was concentrated to 4 liters with a yield of 56% of total initial activity. The concentrated lipase solution was lyophilized and purified on a DEAE-cellulose anion exchanger column. The partly purified lipase was found to probably contain carbohydrates. © 1980 Kluwer Academic Publishers.

A strain of Lactobacillus plantarum was examined for production of an extracellular antagonistic compound. Cellfree preparations, dialyzed to remove organic acids, were used in inhibition studies which revealed that Gram-positive bacteria were sensitive. Among these, Staphylococcus aureus was chosen for further characterization of the agent. The antagonistic compound was susceptible to breakdown by proteolytic enzymes and its effect was completely lost after heat treatment at 121°C for 15 min. Ultrafiltration studies indicated that the agent had a molecular weight of over 100, 000, suggesting a complex protein-containing aggregate. The antagonistic effect was found to be highest at low pH values and S. aureus was shown to be able to adapt to the agent. Most Gram-negative bacteria were resistant to the compound. However, after their transformation to spheroplasts, which removed most of the cell envelopes, these bacteria were sensitized. The conclusion is that the antagonistic mechanism probably includes agent influence on the cell surface. © 1986.

An HPLC technique is described for the analysis of organic acids in lactic acid fermented vegetables. An Aminex HPX-87 column with 0.013 M-H 2SO 4 as mobile phase was used. Separation data are presented for oxalic, citric, tartaric, malic, succinic, lactic, formic, acetic, propionic, and butyric acids. Interference problems from sugars are also reported. © 1983 J. F. Bergmann Verlag.

The influence of independent processing parameters on the product properties of extruded mixtures of wheat flour and water has been investigated. Physical, chemical, and sensory measurements are reported and correlated with underlying processing parameters. Such correlation could be used to automate and control the extrusion process. © 1991.