scholarly journals Approximate determination of the cell-wall complex of vegetables by enzymatic digestion

1967 ◽  
Vol 39 (1) ◽  
pp. 38-43
Author(s):  
Maija-Liisa Salo ◽  
Kaija Kotilainen

The paper describes the results of experiments in which 12 different vegetables were treated with pepsin, trypsin or trypsin + diastase in buffer solutions. The effects of certain variations in the methods on the final results are also discussed. The purpose of the study was to find out whether it would be possible to develop a simple procedure that would yield a residue roughly corresponding to the cell-wall complex in readily soluble plant materials such as vegetables. However, such great differences were found in the solubility of hemicellulose and protein among the different materials that good results cannot be achieved by a uniform method, at least not without many correction determinations.

1967 ◽  
Vol 50 (4) ◽  
pp. 911-917
Author(s):  
Stanley E Katz

Abstract Linuron and its known and/or suspected metabolites are extracted from crops with acetone. The acetone is evaporated, and the aqueous residue containing precipitated plant materials and linuron and metabolites is extracted several times with hexane to remove linuron and any 3,4-dichloroaniline, a metabolite. The 3,4-dichloroaniline is separated from the linuron by HC1 extraction. Other possible metabolites, 3-(3,4- dichlorophenyl)-l-methoxy urea, 3-(3,4-dichlorophenyl)- l-methyl urea, and 3-(3,4-dichlorophenyl) urea, remain in the aqueous phase which is made basic with ammonium hydroxide. These metabolites are extracted into hexane and identified by thin layer chromatography. Linuron and metabolites other than 3,4-dichloroaniline can be determined colorimetrically after acid hydrolysis to the aniline, followed by a diazotization reaction and coupling with iV-(l-naphthyl) ethylenediamine. Levels as low as 0.02 ppm linuron can be detected. Recoveries of 98.9% were found. Bound linuron can be determined by alkaline hydrolysis or by enzymatic digestion of crop material which frees the undegraded bound linuron


1965 ◽  
Vol 37 (4) ◽  
pp. 305-312
Author(s):  
L. Paloheimo ◽  
K. A. Vainio

The authors present a new method for the determination of the complex of vegetable cell wall substances. The sample is extracted with boiling 80 % ethanol, boiling absolute ethanol and cold water. The residue corrected for ash, protein, and, if necessary, for starch, gives the amount of cell wall substances. Determinations were made of the same samples of which Salo in this department, using quite a different principle, has determined the cell wall complex. She determined separately cellulose, neutral sugar hemicellulose, uronic acid hemicellulose, and lignin. Adding up these items Salo obtained the total of the cell wall substances. The results obtained with the new method are in most cases in agreement with the results of Salo (Table 1). The 80 % ethanol seems to be a very efficient solvent. In most cases more than 35 % of the dry matter of the sample was dissolved by it, while only about 0.3 % was dissolved in the succeeding extraction with absolute ethanol (Table 2). 1—12 % was dissolved by water. The new method is compared also with the earlier method of Paloheimo in which the sample is boiled in 0.05 N hydrochloric acid. It appeared that the results obtained with the latter procedure are considerably lower than those obtained with the new method. Evidently most plant materials contain cell wall substances which are extractable with a very weak acid treatment.


Author(s):  
Venkatasubramanian Sivakumar

Background: In the growing environmental concern use of natural products, efficient processes and devices are necessary. Solid-Liquid extraction of active Ingredients from Plant materials is one of the important unit operations in Chemical Engineering and need to be enhanced. Objectives: Since, these active ingredients are firmly bound to the plant cell wall membrane, which pose mass-transfer resistance and need to get detached through the use of suitable process intensification tools such as ultrasound and suitable devices. Therefore, detailed analysis and review is essential on development made in this area through Publications and Patents. Hence, the present paper illustrates the development of ultrasound assisted device for solid-liquid extraction are presented in this paper. Methods: Advantages such as % Yield, Reduction in extraction time, use of ambient conditions, better process control, avoidance or minimizing multi stage extraction could be achieved due to the use of ultrasound in extraction as compared to conventional processes. Conclusions: Use of ultrasound to provide significant improvements in the extraction of Vegetable tannins, Natural dyes for application in Leather processing has been demonstrated and reported earlier. These enhancement could be possible through various effects of ultrasound such as better flow of solvents through micro-jet formation, mass transfer enhancement due to rupture of plant cell wall membranes through acoustic cavitation, better leaching due to micro-mixing and acoustic streaming effects. This approach would minimize material wastage; thereby, leading to eco-conservation of plant materials, which is very much essential for better environment. Hence, various methods and design for application of ultrasound assisted solid-liquid extractor device are necessary.


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