Abstract

Type A gelatine was made from the skin of less than 6-month-old calves by an acid process. Type B gelatine was made from a 10-month-old calf skin as well as from the hides of mature bovines of 58 and 144 months of age, by an alkaline process. On electrophoretic separation the Type A calf skin gelatine closely resembled pigskin gelatine with a large number of bands below 100 kD while Type B calfskin gelatine contained unusually large amounts of intact collagen a- and /3- and y-chains. From the older animals, the best (first extraction) Type B gelatines contained large amounts of intact collagen chains the amounts of which appeared to decrease somewhat with increasing animal age.

Type B gelatines were also observed to contain a peptide with a molecular mass of 82 kD. The quantity of intact collagen chains in Type B gelatine decreased markedly at higher extraction temperatures. Gelatine colour was observed to become darker with animal age, however there was no strict relationship between gelatine colour and molecular composition. The implications of these observations on the molecular mechanisms of collagen conversion and gelatine colour are discussed.