Study On Extraction Of Collagen From Goat Skin And Its Physical And Chemical Properties

The collagen from Sonid Sheep skin were extracted by citric acid and pepsin.And the properties of collagen were studied to provide a theoretical basis for its application.Extraction yield of collagen was regarded as an index to research on preparation of collagen from Sonid Sheep skin.The result showed that extraction yield of collagen all increased with increase of pepsin amount, extracting time and citric acid concentration.The effects of concentration, viscometer speed and temperature on viscosity were studied.The results showed that viscosity increased with growth of concentration and decreased with growth of viscometer speed .The viscosity was also affected by temperature and denaturation temperature of collagen was 33℃.Gel strength of collagen from goat skin increased with concentration. There was a rapid growth of gel strength in early gel form,with slight increase later.The gel strength was also affected by pH,reaching the maximum on pH5. The gel strength were decreased with addition of CaCl2 and MgSO4.The emulsifying activity(EA) of collagen were affected by concentrations, pH and NaCl. The changes of emulsion stability(ES) ,however,was complicated, with opposite trend sometimes in contrast with changes of EA.There were higher ES on some points with less EA, and vice versa.The EA of collagen ,reaching maximum under 300MPa,can be improved by ultra-high pressure (UHP) under certain conditions.Treating time had no positive effects on EA. The EA was also affected by pH ,reaching the minimum on isoelectric point pH=5 and the maximum on pH=8. The changes of ES,like changes in atmospheric pressure,were opposite trend sometimes in contrast with EAI changes.