Predictor Of Tenderness Research Articles

Relationship Between Meat Quality, Carcass Characteristics, and Protein Abundance of HSPβ1, HSPA, and DJ1 in Beef Longissimus thoracis Pre-Rigor or After 14 Days’ Aging

This study evaluated associations of heat shock proteins (HSP) and an oxidative stress protein, protein deglycase (DJ1), with beef quality and tenderness. Samples from the longissimus thoracis (N = 99) were collected pre-rigor (day 0) and after 14-d aging. Warner-Bratzler shear force (WBSF), myofibrillar fragmentation index (MFI), and a trained sensory panel were used to determine meat quality. Protein abundance of DJ1 and 2 HSP—HSPβ1 and HSPA—were assessed. Regression analyses demonstrated that DJ1 abundance after 14 d of aging is a predictor of WBSF (P < 0.001), MFI (P = 0.02), and sensory panel tenderness (P < 0.001). Abundance of HSPβ1 after 14 d of aging is also a predictor of MFI (P = 0.03). Additionally, abundance of both HSPβ1 and DJ1 pre-rigor are predictors of juiciness (P < 0.05). Abundance of HSPβ1 pre-rigor was correlated with WBSF (R = 0.67), sensory panel tenderness (R = −0.44), juiciness (R = −0.30), and umami (R = −0.20). Abundance of DJ1 pre-rigor was also correlated with WBSF (R = 0.72), sensory panel tenderness (R = −0.44), juiciness (R = − 0.24), and umami (R = −0.31). After 14-d aging, HSP β 1 abundance was cor- related with WBSF (R = 0.66), sensory panel tenderness (R = −0.34), juiciness (R = −0.34), umami (R = −0.33), and brown/ roasted (R = −0.30). Abundance of DJ1 after 14-d aging was also correlated with WBSF (R = 0.68), sensory panel tenderness (R = −0.41), juiciness (R = −0.21), and umami (R = −0.28). These results demonstrate that abundance of HSPβ1 and DJ1 both pre-rigor and after 14 d of aging are correlated with meat tenderness and end-product quality as assessed by a trained sensory panel. Regression analyses further reveal that abundance of DJ1 and HSPβ1 after 14 d of aging is causative in development of beef tenderness and juiciness, respectively. Taken together, these results suggest that abundance of DJ1 is a predictor of tenderness, whereas abundance of HSPβ1 is related to meat quality but cannot be used to predict tenderness.

EVALUATION OF METHODS OF ASSESSING TENDERNESS ON RAW AND COOKED BEEF MUSCLE

Methods of estimating tenderness of beef muscle were evaluated on 282 steer and heifer carcasses. pH values (1 h and 2 h post-mortem) did not relate to shear values or panel tenderness scores on the cooked longissimus dorsi, evaluated after 6 days’ aging. Values obtained with the Armour tenderometer on the raw rib-eye were not useful predictors of tenderness of the cooked muscle (r2 < 6%). The Ottawa Texture Measuring System extrusion cell did not relate texture properties of the raw muscle to tenderness of the cooked meat. Marbling score explained 14% of the variance in panel tenderness scores. No satisfactory classification of carcasses into tenderness desirability groups was achieved with any of the methods examined.

POSTMORTEM pH CHANGE AS RELATED TO TENDERNESS AND WATER-HOLDING CAPACITY OF MUSCLE FROM STEER, BULL AND HEIFER CARCASSES

The patterns of postmortem pH change for four major bovine muscles, the semimembranosus, adductor, longissimus dorsi, and brachialis, were examined on carcasses from 130 bulls, 54 steers, and 40 heifers reared and slaughtered contemporaneously. Various muscle properties were related to rate and extent of pH change. Regression of pH on time for each of the four muscles was similar, although each of the four muscles differed (P < 0.05) at all pH recordings. Carcasses were designated fast-, medium-, and slow-glycolyzing on the basis of pH readings recorded within 2 h postmortem. Only 5 and 11% of the steers and heifers, respectively, were classed "slow" whereas approximately 30% of the bull carcasses fell into this category. This classification did not differentiate carcasses of any sex with respect to tenderness (shear values) or to water-holding capacity. Considerable sex heterogeneity of correlation coefficients was evident, with those from bulls generally being of greatest magnitude because of the tendency for bulls to be stressed by shipping and handling during the immediate pre-slaughter period. Where preslaughter stress effects were not important, postmortem pH measurements were not useful predictors of tenderness or water retention properties of muscle.

A Histological Study of Turkey Meat as Related to Sensory Characteristics

INTRODUCTIONDIFFERENCES in meat tenderness due to age, sex, breed, etc. have been attributed to differences in connective tissue. However, muscle fibers, which constitute the bulk of the muscle mass, must also be very important in meat quality.Sarcomere length, which measures the degree of muscle contraction, was first suggested by Locker (1960) as being associated with tenderness. Its usefulness as a predictor of tenderness is therefore of practical interest.Fiber diameter has been found to vary according to species, breed and age (Joubert, 1956). There have been many studies in red meats to correlate fiber diameter and meat quality, and an interrelationship has been found among fiber diameter, sarcomere length and tenderness. Herring et al. (1967) working with bovine muscle observed that tenderness was linearly related to fiber diameter and curvilinearly with sarcomere length.It has long been known that there are two types of skeletal muscle fiber; the…