Effect of Dry Heat on Proteins

Mecham, Dale K.; Olcott, Henry Steel

doi:10.1021/ie50452a021

Cited by 61 publications

(16 citation statements)

References 10 publications

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“…In agreement with the work of others [34,62], it is found (Tables I, I and III) that the rate of degradation of cystyl residues in wool is much greater in the presence of water than in its absence ' or near-absence. Zahn and Osterloh [67] detected the formation in wool of a small proportion of lanthionyl and S-monoxylanthionyl residues, during treatment of wool at 160-200° for 2 hr, in the absence of water.…”

Section: Discussionsupporting

confidence: 92%

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The Hydrothermal Degrádation of Wool Keratin

Sweetman

1967

Textile Research Journal

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The nature of degradation of cystyl residues in wool by purified water at ca. pH 6 and at temperatures of 50-100° is studied. Cystyl residues in wool are slowly converted by water to lanthionyl residues, even at 60°, and the rate of this conversion increases with increasing temperature. At 100°, lanthionyl residues cannot form in solutions having pH values below ca. 4.5-5.0. Evidence suggests that, under these conditions, certain reactive sulfur-containing residues are also formed from cystyl residues. The other major action of water on wool at 100° appears to be in the hydrolysis of certain peptide bonds. Limited modification of residues in wool, such as the lysyl and tyrosyl, also apparently occurs during treatment of wool with water at 100°.Comparison of the amino-acid contents of the water extracts obtained at 100° and those of the treated wool samples reveals that some residues are either more or less easily extracted from wool than others. AbstractThe most marked chemical reaction occurring during the treatment of wool keratin with water or steam at high temperatures is the conversion of cystyl residues to lanthionyl residues and also, apparently, to alanyl residues. The degradation of some lysyl and aspartyl residues also occurs during treatments at 150°, together with at WESTERN OREGON UNIVERSITY on May 27, 2015 trj.sagepub.com Downloaded from

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Section: Discussionsupporting

confidence: 92%

“…. It is apparently not possible to dry wool completely in air at temperatures where decomposition of the wool does not occur [15,34,63]. Decomposition of wool occurs, at a given temperature, much faster in the presence of water than its absence or near-absence [33,41,53,62].…”

Section: Introductionmentioning

confidence: 99%

The Hydrothermal Degrádation of Wool Keratin

Sweetman

1967

Textile Research Journal

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“…On the other hand, Zahn [63] found no degradation of dried horsehair below 150"C, and Mecham and Olcott [64] heated dried hoof keratin above 153°C before general degradation took place. Vacuum-dried wool samples displayed a steady decrease in weight up to 140°C; the loss of weight amounted to 0.4% of the original weight of wool at 20°C but less water was removed if air was present [57].…”

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confidence: 99%

Sorption of Water Vapor by Keratin

Watt

1980

Journal of Macromolecular Science, Part C

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“…30 Earlier studies have been made of the damage resulting from heating casein alone, and it has been the general conclusion that the availability of lysine is reduced to a very much greater extent than that of the other amino-a~ids.~l-33 However, these were made with ' commercial ' or ' edible ' grades which are likely to have contained appreciable amounts of lactose.…”

Section: Comparison Of the $Resent Laboratory Tests With Othersmentioning

confidence: 99%

The nutritionally available lysine and methionine of heated casein‐glucose mixtures

et al. 1963

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A mixture of buffalo casein and glucose of high moisture content was given different heat treatments which greatly reduced the value of the materials as a protein source for young rats. Their value as a source of lysine fell much more than their value as a source of methionine or 'methionine + cystine'. These feeding results confirmed the results of two laboratory prediction tests-reactivity with fluorodinitrobenzene for ' available ' lysine, and a microbiological assay for ' available ' methionine with Strep. zymogenes NCDO 592 on mild papain digests.

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Effect of Dry Heat on Proteins

Cited by 61 publications

References 10 publications

The Hydrothermal Degrádation of Wool Keratin

The Hydrothermal Degrádation of Wool Keratin

Sorption of Water Vapor by Keratin

The nutritionally available lysine and methionine of heated casein‐glucose mixtures

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