Effect of Acid Treatment Process on the Physicochemical Properties of Gelatin Extracted from Pork Skin

산처리 공정에 따라 추출한 돈피 젤라틴의 이화학적 특성에 관한 연구

  • 염건웅 (알칸사스대학교 가금학부) ;
  • ;
  • 민상기 (건국대학교 동물자원연구센터)
  • Published : 2004.09.01

Abstract

The objective of this study was to investigate the physicochemical characteristics of gelatin extracted from pork skin under soaking in various acid solutions (lactic acid, acetic acid, and citric acid). Gelatin sol was extracted at 8$0^{\circ}C$, frozen at -2$0^{\circ}C$ and lyophilized it for 3 days to be completely dried in freeze drying unit. In the evaluation of gelatin quality, gelatin soaked in citric acid showed higher L- and a-values than those of any other gelatin (p<0.05). Gelatin treated by acetic acid showed the highest gel strength, cohesiveness, and brittleness. The content of hydroxyproline amino acid in gelatin treated by acetic acid was larger than one of gelatin treated in lactic and citric acid in order. From the experimental results, the highest quality of gelatin in all of period, which was soaked in acetic acid and lactic acid, has a more good quality than gelatin soaked in citric acid.

본 연구는 gelatin의 생산공정에서 각종 산 처리가 최종 gelatin의 품질에 어떤 영향을 주는지를 평가함으로써 양질의 gelatin을 생산하는데 기초를 제공하고자 하였다. Gelatin gel의 물성은 lactic acid로 처리한 gelatin이 높은 hardness, cohesiveness, brittleness를 나타내었고 다음으로는 citric acid, acetic acid 순으로 나타났다. Gelatin의 색도는 citric acid, 처리한 gelatin이 acetic acid나 lactic acid로 산침한 젤라틴 보다 높은 명도를 나타냈다. a-value는 acetic acid로 산침한 gelatin이 가장 높게 나타났으며 황색도를 나타내는 b-value는 lactic > acetic acid > citric acid 순으로 높게 나타났다. Gelatin의 점도를 측정한 결과 전단속도(shear rate)에 대한 전단응력(shear stress)의 관계는 모두 전단속도가 증가함에 따라 전단응력이 증가하는Newton성 유체로 판단되었다. 그 기울기는 acetic acid로 산침한 것이 가장 높게 나타났으며 lactic acid, citric acid 순으로 높게 나타났다. Gelatin내의 hydroxyproline 함량을 살펴보면 acetic acid(0.186 g/100 g sample)로 가장 높은 수치를 나타나며 다음으로 lactic acid, citric acid 순으로 나타났다. 그러나, sample중 crude protein 함량을 비교하면 acetic acid(68.74%), lactic acid(80.08%), citric acid(85.47%)로 나타났다. 이것은 gelatin의 열수 추출시 가장 작게 용출된 acetic acid가 가장 높은 collagenous connective tissue 함량(1.35 g/100g)을 나타내었다.

Keywords

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