|Van Laack, Henriette|
Submitted to: International Congress of Meat Science and Technology Proceedings
Publication Type: Proceedings
Publication Acceptance Date: August 8, 1995
Publication Date: N/A
Interpretive Summary: Fresh pork should be reddish-pink in color. A light pale color is associated with a quality defect known as PSE (pale, soft, exudative). The occurrence of the pale color and the high drip losses has led to the idea that color and waterholding capacity (WHC) are related. However, the existence of RSE (red, soft, exudative) pork suggests that color and WHC may vary independently. It was hypothesized that denaturation of myosin determines WHC and denaturation of sarcoplasmic proteins determines color. The assumption was that pre-rigor temperature (15 vs. 40 deg C) would affect myosin denaturation and pre- and post-rigor temperature (5, 20 and 30 deg C) would affect sarcoplasmic protein denaturation. Within 45 min after slaughter, loins were taken from pig carcasses and incubated at the indicated pre-rigor (3 hrs) and post-rigor (18 hrs) temperatures. Protein denaturation, color (lightness, L-value) and WHC (drip loss) were assessed. .Pre-rigor treatment did not influence drip loss and there was no correlation between drip loss and protein denaturation. Color (lightness) was affected by pre- and post-rigor treatment. There was a significant correlation between lightness and protein denaturation. Results indicate that it was not possible to influence myosin and sarcoplasmic protein independently. Thus, the contribution of the various protein fractions to pork color and WHC could not be determined.
Technical Abstract: Pork color is often used as an indicator of waterholding capacity (WHC). However, there are indications that color and WHC may vary independently. Knowledge of the relationship between the two characteristics is essential in the development of methods to predict and select a specific quality of meat. The purpose of this study was to determine the contribution of denaturation of various protein fractions to color and WHC. Loins from 7 pig carcasses were excised within 45 min after slaughter. Each loin was divided into 3 sections - three were incubated at 40 deg C, three at 15 deg C (3 hr = pre-rigor). After 3 h, one cut of each pre-rigor treatment was chilled at 5 deg C, one at 20 deg C and one at 30 deg C (= post-rigor). After 18 h, all cuts were chilled to 5 deg C, and drip loss, color (L-value), and solubility of sarcoplasmic protein, myosin and total protein was assessed. Pre-rigor treatment did not influence drip loss. Only when samples were kept at 15 deg C pre-rigor, did an increase in post-rigor temperature result in increased drip loss. There was no significant correlation between drip loss and protein denaturation. L-value was affected by pre- and post-rigor treatment and correlated with protein denaturation. The assumption was that both pre- and post-rigor treatment would affect sarcoplasmic proteins, whereas pre-rigor treatment would affect myosin denaturation. However, it was not possible to influence myosin and sarcoplasmic protein denaturation independently. Thus, it was not possible to determine the contribution of various protein fractions to color and WHC.