NOPR Collection:

The Effect of pH and Air Superficial Velocity on the Foam Fractionation of Okra (Hibiscus esculentus)

Fri, 01 Jun 2001 00:00:00 GMT

Title: The Effect of pH and Air Superficial Velocity on the Foam Fractionation of Okra (Hibiscus esculentus) Authors: Butler, Ernest E; Rajab, Fahd; Prokop, Ales; Tanner, Robert D Abstract: separation technique that utilizes the differences in surface activities of molecules in a bulk solution. Fresh frozen cut okra, a product of EI Salvador, Guatemala, or Mexico, was obtained from a local grocery store. Surface tension analysis indicated that a pH value of 7 yielded the best separation due to the increased surface-activity of the proteins in solution (minimization of surface tension). The optimum concentration to be used in foam fractionation for the initial bulk solution has also been determined via surface tension analysis. Laboratory experiments show that a 14-weight per cent solution (a 7-fold dilution has been used to pre-remove the cellulose by vacuum filtration) maximize the separation ratio during the foam fractionation experiments. The superficial air velocity, V_o, maximized the separation ratio of 110 cm/min in the range 70 ≤ V_o ≤ 150 sec/min. The effect of pH on the separation ratio has been examined for two okra samples. The results show that sample 1 hardly foamed over the entire pH range while sample 2 completely foamed over the same range. It is speculated that the presence of anti-foaming agents in the okra determines the extent of foaming and their presence could possibly be related to the location in which the sample is harvested. Actual harvest locations were not given on the okra package. The mean viscosity of the okra solution has been determined to be about 67% greater than that of water. The addition of an emulsifying agent (carboxymethyl cellulose, CMC) to the okra solution has been found to first enhance and then suppress the total foamate volume as the concentration of the CMC is increased. Page(s): 513-520

Dehydration of Ginger Slices

Fri, 01 Jun 2001 00:00:00 GMT

Title: Dehydration of Ginger Slices Authors: Singh, Kawaljit; Bawa, A.S.; Ahmed, Jasim Abstract: The results of kinetic study conducted on the dehydration of ginger slices using a tray drier at 55-60°C are reported. It is also revealed that the dehydration of ginger occurs in the falling rate period. The sorption isotherm and rehydration studies conducted on the dried product are also reported. The dried ginger has shown a water activity of 0.58 and the maximum rehydration is obtained after 60 min. The overall acceptability is found to be very good (up to 6 months) for the dehydrated ginger slices packed in 300 gauge HDPE and stored at ambient temperatures. Page(s): 510-512

Oligomerization of a C-olefinic By-product Stream Using Cationic and Ziegler-Natta Catalysts

Fri, 01 Jun 2001 00:00:00 GMT

Title: Oligomerization of a C-olefinic By-product Stream Using Cationic and Ziegler-Natta Catalysts Authors: Tembe, G L; Ganeshpure, P A Abstract: Mixed hexene stream, a by- product of ethylene dimerization process, on oligomerization with Ziegler type and cationic catalyst systems predominantly yields dimers (C₁₂), trimers (C₁₈), and tetramers (C₂₄) Ziegler type catalysts based on Ti(IV) or Cr(III) and ethylaluminum sesquichloride as the co-catalyst mainly produce dimers (C₁₂) with selectivity greater than 78 per cent. The conversion to trimers(C₁₈) and tetramers (C₂₄) with cationic catalysts was better compared to Ziegler system. The use of anhydrous AlCl₃ or an alkylaluminum halide in comhination with tert-alkyl halide produces an active catalyst which readily converts the C₆ olefins to higher oligomers at ambient temperatures. The physical properties of the products have been measured to evaluate their suitability as synthetic lubricants. Page(s): 504-509

Structure Elucidation of Bacterial Polysaccharides by NMR and Mass Spectrometry - A Review

Fri, 01 Jun 2001 00:00:00 GMT

Title: Structure Elucidation of Bacterial Polysaccharides by NMR and Mass Spectrometry - A Review Authors: Sanghi, Rashmi; Dhar, Durga Nath Abstract: The article highlights the use of NMR and Mass Spectrometry in the structural elucidation of bacterial polysaccharides. Page(s): 463-492