Postmortem Biochemical and Physical Changes in the Red Musculature of Korean Native Beef Cattle Stored at $15^{\circ}C$

사후 저장온도 $15^{\circ}C$에서 한우적색근육의 생화학, 물리적 변화에 관한 연구

The influence of the storage temperature at $15^{\circ}C$ on the biochemical and structural changes in the red muscles (M. sternomandibularis) of korean native cattle postmortem were studied. The results obtained were summarized as follows; 1.5 to 2 hours postmortem the pH-value had dropped to $6.7{\sim}6.8$, after 18 or 20 hours at $15^{\circ}C$ it had reached its final pH-value (5.5). The irreversible loss of extensibility, i.e. the onset of rigor mortis, arose at $15^{\circ}C$ between 9 and 10 hours postmortem at pH 6.1 to 6.0 and R-value between 1.05/1.10. The complete loss of extensibility postmortem was reached after 18 to 20 hours at pH 5.5/5.6. Muscle and sarcomere length of korean native cattle were contracted about 20% and 15%, respectively at $15^{\circ}C$. Meat of korean native cattle had the highest shear force (4.7 kg) on 1 day after slaughter. The tenderness was increased with the ripening period prolonged and was highest at the end of the 9 day ripening period.

본 연구는 사후 저장온도 $15^{\circ}C$가 한우근육(M. sternomandibularis)의 생화학, 물리학적 변화에 미치는 영향을 조사하였다. 도살 1.5시간 후의 pH는 6.7/6.8이었으며, 저장온도 $15^{\circ}C$에서 $18{\sim}20$시간 후 최종 pH인 5.5에 도달했다. 한우육의 불가역적인 신전성의 상실 즉, 사후강직은 $15^{\circ}C$에서 도살 $9{\sim}10$시간 후 pH 6.1{\sim}6.0$, R-value $1.05{\sim}1.10$에서 시작하여 도살 $18{\sim}20$시간, pH 5.9에서 강직이 완료되어 신전성을 완전히 상실하였다. 저장온도 $15^{\circ}C$에서 한우근육은 약 20%, 근절은 15% 정도 수축하였다. 한우육은 도살 약 1일 후 전단력이 4.7 kg으로 가장 높았으며, 9일 숙성 후 3.0 kg으로 숙성기간이 경과함에 따라 연도가 증가하였다.