Relationship Between Metmyoglobin Reductase Activity And Meat Color Stability

M. longissimus dorsi (LD) and M. psoas major (PM) of Landrace, Yorkshire, Wanbai II, Wanbai III, Shennong I, Yorkshire xShennong, Duroc×Shennong, Pietrain×Shennong, Pietrain×DurocxShennong pigs were chosen as meat samples in present study. Meat color parameters of LD chilled 24h in 4℃ refrigerator were evaluated using three different methods (color score, Colorphotography and chemistry method); changes in color parameters and metmyoglobin reductase activity of chilled LD muscle during 9 days storage, as well as the relationship between color stability and metmyoglobin reductase activity were studied; some characteristics of metmyoglobin reductase were also reseached in this paper. The results were summarized as follows:1 Comparision on color parameters of meat sample in crossbred pig & the changes in meat color during chilled storageGenerally speaking, redness (a* value) can reflect color score (r=0.61) and myoglobin content (r=0.38) of LD muscle. Compaired with Pork Color Standards Guide and chemistry method, Colorphotography can provide more color parameters and also convenient. PM muscle is redder than LD muscle for its instrumental color (a* value, b* value and C value) is higher. Using a* value as the measurement index, color attraction of LD muscle is: Wanbai II > Yorkshire xShennong > Shennong I > Wanbai III > DurocxShennong > PietrainxDurocxShennong > Landrace > Yorkshire> PietrainxShennong. In the condition of lack of O₂, dark and 4℃, L* value, a* value, b* value and C value increased sharply during the first three chilled storage, then color parameters changed in different ways. It suggested that the third day is the key point of chilled meat discoloration.2 Extraction and purification of metmyoglobin from porcine cardiac muscle tissueThe purpose of this experiment is to obtain the special substance for detection of metmyoglobin reductase activity. Metmyoglobin was extracted and purified from porcine cardiac muscle tissue. After extraction, centrifugation, precipitation, and separation by chromatography on DEAE-Sepharose Fast Flow and Sephacryl S-200HR, its purity was controlled by SDS-PAGE and scanning spectrophotometry. The Yield of metmyoglobin...