Gelatin pigskin

Proteins. Crystalline lysozyme, bovine serum albumin, ribonucle-ase,and pepsin were obtained from the Armour Laboratories and crystalline /3-lactoglobulin was prepared from skimmed milk. a-Lactalbu-min was obtained from W. G. Gordon of this laboratory. Crystalline ovalbumin and human serum albumin were obtained from Nutritional Biochemical Corp. and purified pigskin gelatin from the Eastman Kodak Co. 

Different types of gelatine cannot be mixed as they have different isoelectric points and these different types are referred to by their origin and the agent used for hydrolysis, e.g. acid pigskin gelatine. Limed ossein gelatine is normally produced from cattle bones. 

Figure 4. Isoelectric point of deionized pigskin gelatin in KNO3 solution at...

Sobral, P.J.A. and Habitante, A.M.Q.B. Phase transitions of pigskin gelatin. Food... 

The enzyme-membranes were placed in a well-agitated 1-2 wt % pigskin gelatin (pi — 8.5 where pi is the pH of the isoelectic point of the gelatin) solution at 25°C and also at 37°C. After varying periods of time the reduced viscosity of the solution was measured with a Cannon-Ubbelohde No. 1 capillary viscometer. The decrease in viscosity of the gelatin solutions containing enzyme-membranes was compared to the viscosity decrease of control solutions and solutions to which a known amount of soluble enzyme was added. 

Gelatines are produced by the partial hydrolysis of collagen. In Europe, gelatine is mainly produced from fresh bones, from which yields of up to 12% are obtained. For this, the bones are first demineralized to osseine with hydrochloric acid. Pigskin provides the main source of gelatine in the United States. 

The osseine, or defatted pigskins, is first treated with acids or alkali in order to remove undesirable components. The acid process leads to A-gelatine, which is mostly used in the food industry. Alkali yields the B-gelatine used in photographic film. 

Essentially the same procedure is reported for encapsulation by gelatin-polyphosphate complex coacervation at pH 4-5 Compared with gum arabic, however, maximum coacervation is achieved at only 1 part of commercially available sodium hexametaphosphates to 10-20 parts of acid-extracted pigskin gelatin. This is due to the lower apparent (ionic) equivalent weight of polyphosphates." The gelatin-... 

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