Isoelectric Point of Glycinin.

Hartman, R. J.; Cheng, Liu

doi:10.1021/j150373a004

Cited by 9 publications

(5 citation statements)

References 2 publications

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“…Recently experimental data appeared relating to the Joule-Thomson coefficient of methane (6) which are in good agreement with existing pressure-volume-temperature data (9). The isobaric heat capacity of methane at infinite dilution was calculated from spectroscopic data by Void (Iff).…”

Section: Nosupporting

confidence: 66%

“…This is a serious drawback in their industrial utilization, especially in the fields of plastics and paper coatings. If the protein is dried by the use of alcohol and ether (9,20) or over sulfuric acid in a refrigerator under vacuum, a much lighter colored product (light gray) is obtained; but it is a false whiteness, probably caused by the physical state of subdivision, and the yellow-brown color returns when the protein is again dispersed in alkali or pressed into a plastic mixture. The production of a white or nearly white soybean protein appears to be a difficult problem, but if solved it will add greatly to the industrial usefulness of this protein.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

“…By this method a white protein product was isolated but in rather low yields. Later Hartman and Cheng (9) modified the Osborne procedure and studied the physical chemistry of glycinin. Since recent publications from this laboratory (18,23) have shown that water is a better extracting agent than salt solutions for removing the protein from the meal, there can be little commercial interest in the Osborne method.…”

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confidence: 99%

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SOYBEAN PROTEIN Precipitation from Water and Alkaline Dispersions by Acids and by Electrodialysis

Smith¹,

Circle²

1939

Ind. Eng. Chem.

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Oil-free soybean meal was extracted with water and alkaline solutions.The proteins precipitated from these dispersions by various acids and electrodialysis are compared in respect to yield and ease of manipulation and preparation. The data presented indicate that electrodialysis through parchment paper offers no advantages over acid precipitation. Tannic acid may be used to recover protein not precipitated by sulfuric acid.ON THE basis of potential supply, chemical and physical properties, comparatively simple methods of refining, and possible extension of uses through scientific investigation, soybean protein promises to occupy a substantial place in the industrial picture (1, 3).The domestic supply of soybeans rose from less than 5,000,000 bushels in 1925 to more than 40,000,000 in 1937 (7). The North Central States are the chief producers at present, Illinois accounting for more than half of the yield with 23,000,-000 bushels in 1937. Illinois leads in both acreage planted and average yield per acre.

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Section: Nosupporting

confidence: 66%

Section: Discussion Of Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

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SOYBEAN PROTEIN Precipitation from Water and Alkaline Dispersions by Acids and by Electrodialysis

Smith¹,

Circle²

1939

Ind. Eng. Chem.

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“…The usual concentration of formaldehyde in the protein solutions was 10 per cent by volume. In addition, the effect of concentration of formaldehyde was determined by treating the gelatin with 5 per cent and 20 per cent formaldehyde, the aqueous soybean meal extract with 5 per cent formaldehyde, and the acid-precipitated soybean protein with 1 per cent, 5 per cent, and 20 per cent formaldehyde. The mobility determinations were carried out within 2 to 4 hr.…”

Section: Methodsmentioning

confidence: 99%

“…It is difficult to explain why salt-extracted soybean protein prepared by the Hartman-Cheng procedure (5) should have an isoelectric pH so much higher than that for any other soybean protein preparation. It was noted that the buffered salt-extracted protein solutions had a pronounced odor of hydrogen sulfide, which indicates that extraction of the meal with 10 per cent sodium chloride and the subsequent treatment has altered the protein in some manner.…”

Section: Soybean Protein Preparationsmentioning

confidence: 99%

The Effect of Formaldehyde on the Isoelectric Points of Some Proteins, Determined by Microelectrophoresis.

Circle¹,

Smith²

1941

J. Phys. Chem.

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The action of formaldehyde on proteins is of practical as well as theoretical interest. Formaldehyde has long been used industrially to increase the water resistance of proteins, especially casein, in the fields of plastics and coatings. Formaldehyde is also extensively employed as a preservative and fixative for biological specimens and to block off the amino groups in the titration of the acid groups of proteins and amino acids.An appreciable literature has accumulated concerning the nature of the reaction of formaldehyde with proteins and amino acids. Since reviews on this subject are available (7, 10, 23), it will not be discussed in detail. All the theories possess in common the postulate that the formaldehyde reacts with the free basic (amino, guanidino, or imino) groups of the protein or amino acid, but they differ in the complexities of the structures proposed for the product.According to the postulated reactions, the free basic groups on the micelle or molecule are rendered relatively inactive by the action of the formaldehyde. This should lessen the positive charge on the micelle and result in a shift of the isoelectric point to a lower pH value, since at any given pH the protein is less basic than before.It has been demonstrated by Smith, Max, and Handler (21) that the points of minimum solubility of casein and soybean protein are shifted to lower pH values by the action of formaldehyde. Gerngross and Bach (4) found that in gelatin solutions containing 10 per cent formaldehyde the isoelectric point of one gelatin sample shifted from a pH of 5.05 to 4.6 and of another from 4.75 to 4.3, as determined by an electrophoretic transference technique. Also, Swyngedauw ( 22), from a study of electroosmosis in gelatin gels before and after formaldehyde treatment, claims that formaldehyde does not combine with gelatin on the acid side of the isoelectric point but does on the basic side. Mudd and Joffe (15) studied the modification of antibodies by formaldehyde and showed a shift to

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