Separation and Determination of Protein Sulfur, Sulfide Sulfur, and Other Sulfur in Sodium Sulfide Dispersions of Keratins

Potter, E. Vernon; Jones, Chase Breese

doi:10.1021/i560113a007

Cited by 3 publications

(1 citation statement)

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“…Tests using several well-known protein precipitants pointed to basic aluminum acetate as the most suitable. It has been successfully used by Potter and Jones (1943) in separating protein sulfur and sulfide sulfur. It gives a yellow color to extracts of yellow onions, but this does not interfere, the clear filtrate exhibiting at 670 mp an optical density of zero when compared with distilled water.…”

Section: Fig 2 Relation Between Optical Density and Varying Weightsmentioning

confidence: 99%

PHOTOMETRIC ESTIMATION OF VOLATILE SULFUR IN ONIONS AS A CRITERION OF PUNGENCY¹

Currier

1945

Journal of Food Science

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There has been an evident need f o r a rapid chemical method whereby pungency of onions may be determined. Although knowledge of the essential-oil complex of this plant is not complete, it has been established by Semmler (1892) that sulfur-containing volatile oils are the principal components, and it is permissible to assume that pungency is proportional to volatile sulfur content. This assumption was made by Platenius (1935), who has contributed the only known method designed especially for onions. It involves acid hydrolysis, distillation into saturated bromine water, and determination of volatile sulfur as barium sulfate. Since a period of three days is required to complete an analysis, it is not applicable to routine and control tests, although valuable studies in relation to pungency of onions have been made by its use-Arasimovich and Ivanova (1939) and Platenius and Knott (1934. Eaton (1942) employed it in measuring the volatile sulfur content of black mustard plants. It has been the experience of Platenius and of this laboratory that whenever differences in pungency between onion samples were great enough to be detected by taste tests, these differences were shown by the distillationbromine method.Methods for determining volatile sulfur in other plants, particularly mustard and rape, have been described. Peterson (1914) heated the tissue at 100°C.(212"F.) in a U-tube, the volatile sulfur being drawn through and absorbed by copper oxide filings. The copper sulfate formed was dissolved in water and the sulfur determined as barium sulfate. Distillation of volatile sulfur compounds into standard ammoniacal silver nitrate solution to form silver sulfide, with back-titration of residual silver with potassium thiocyanate, has been employed in, several modifications to determine the volatile sulfur content of plants- Gros and Pichon (1934), and Schuphan (1937). An official A.O.A.C. (1940) method for determining volatile oil in mustard seed is based upon this reaction. These procedures, although more rapid than that involving oxidation with bromine, are inapplicable to onions, since substances other than sulfides which react with the silver distill over.Information as to the nature of the essential oil of onion derives for the most part from the work of Semmler (1892), who found the principal constituent of the crude oil to be a substance having the formula C,H,,S,, which suggested allyl-propyl-disulfide. He found in addition a higher snlfide with the same radical, and a small amount of a substance seemingly 'The writer wishes to thank Mrs. Martha Miller for valuable criticism and cooperation, Mrs. Jessie Jennings for laboratory assistance, Miss Georgiana Flour for analyses of thiamin, and the Basic Vegetable Products Company for permission to publish.

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Section: Fig 2 Relation Between Optical Density and Varying Weightsmentioning

confidence: 99%