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A study was carried out to investigate the effects of ionic strength and temperature on the interaction between fish myoglobin and myofibriliar proteins in a model system. Binding of myoglobin to natural actomyosin (NAM) was observed and it increased when ionic strength was increased at concentrations of 0.6 M KCL and with increases in temperature from 4 to 25 degree Celsius.

Research investigating the amount of aldehyde lipids found in beef and in vitro is presented. Particular attention is given to analyses of processes of lipid oxidation and proteins found in ground beef, as well as to detecting concentrations of tocopherol.

Research describing the formation of yellow pigment in thiobarbituric acid analysis of freeze dried meat is presented. The effects of fluorescence and different antioxidants are also evaluated.

There is an antioxidant effect of canthaxanthin (CX) in phosphatidylcholine liposomes in minced flesh from rainbow trout, according to research seeking to identify an effects of CX as a potential antioxidant in a liposome model system and in the flesh of CX-supplemented rainbow trout. It was found that CX concentration of minced trout muscle declines during six days of refrigerated storage. If fish are received by a supermarket or consumer with some initial oxidation, then CX may act as an effective antioxidant.

Hereford-Angus crossbred heifers were fed a cottonseed meal-based diet containing gossypol (14 mg free gossypol[center dot]kg body [wt.sup.-1][center dot][d.sup.-1]; CSM), a soybean meal-based diet (SBM), or [Alpha]-tocopherol-supplemented diets (4,036 IU vitamin E[center dot][heifer.sup.-1][center dot][d.sup.-1] for 90 d; CSM+E and SBM+E). The effects of diet on color stability and aerobic metmyoglobin reducing ability of beef longissimus lumborum (LL) and psoas major (PM) were evaluated. The CSM containing gossypol did not affect [Alpha]-tocopherol concentration, [a.sup.*] value, or hue angle value of beef muscles obtained from control or vitamin E-supplemented cattle compared to their SBM counterparts. Vitamin E supplementation increased endogenous [Alpha]-tocopherol concentrations and color stability in LL and PM muscles compared with controls from either diet (P < .05). In the aerobic metmyoglobin reducing ability study, LL and PM muscles were stored in 1%[O.sub.2]:99%[N.sub.2] (a pigment-oxidizing atmosphere) for 48 h and subsequently stored aerobically for an additional 48 h. Within the LL, [Alpha]-tocopherol supplementation delayed metmyoglobin formation in LL exposed to 1%[O.sub.2] (P < .05). Within the PM, no differences in metmyoglobin formation were found between controls and vitamin E treatments in SBM or CSM diets. Relative aerobic metmyoglobin reduction was the same (P > .05) in LL and PM muscles within SBM or CSM diets for control and vitamin E treatments. [Alpha]-Tocopherol did not seem to affect metmyoglobin aerobic reducing ability in LL and PM muscles. Key Words: Tocopherols, Gossypol, Meat Characteristics

Dietary supplementation of livestock with vitamin E results in improved quality of meat subsequently obtained from these animals. The effect is especially noteworthy in cattle, in which the primary effects are delayed discoloration and lipid oxidation. A threshold level of [Alpha]-tocopherol in muscle ensures a detectable effect; dietary strategies for attaining this threshold must consider tocopherol status of cattle arriving at the feedyard and duration and level of supplementation. The [Alpha]-tocopherol concentration in muscle must be determined before proper interpretation of experimental results can be made. Muscles vary in their color stability, and this relative difference is not changed by vitamin E supplementation. Several in vitro models have been used to characterize the interaction between .tocopherol, lipid oxidation, and oxymyoglobin oxidation. [Alpha]-Tocopherol seems to exert its color-stabilizing effect by indirectly delaying oxymyoglobin oxidation via direct inhibition of lipid oxidation. However, recent results demonstrating a protective effect of [Alpha]-tocopherol toward oxymyoglobin in low-oxygen atmospheres indicate that additional mechanisms may exist. A better understanding of the fundamental bases for protection of water-soluble myoglobin by lipid-soluble [Alpha]-tocopherol is needed to optimize this beneficial effect. Key Words: Vitamin E, Tocopherols, Oxidation, Meat Quality

The shelf life of meat is reduced by the growth of spoilage bacteria and can cause manufacturers major economic losses. Determining the total bacterial load of meat by the standard plate count method takes 48 hours and a faster method is required. A new study investigates whether fluorescein diacetate hydrolysis and resazurin reduction can be used as rapid predictors of spoilage bacterial load on stored fresh and frozen meat. It is shown that such methods could be rapid alternatives to the plate count method.

Vitamin E supplementation seems to help beef color stability as sensory panelists gave vitamine E-supplemented beef steaks higher scores. Meat spoilage is not affected by such supplementation. No differences in bacterial load appeared during storage of the 3 vitamin E treated groups. Meat maintained at 25 degrees celsius for 24 hours has increased metmyoglobin formation. Vitamin E supplementation does seem to mitigate the adverse effect of such temperature abuse.

Percentage of lean, fat, and bone were determined in 18 bob veal (BV) and 28 special-fed veal (SFV) carcasses. Carcasses were subjected to a set of visual conformation scores and a variety of physical measurements. No significant differences were found regarding carcass percentage of lean, fat, and bone within the three BV weight groups (P [is greater than] .05). On average, SFV were 12% fatter than BV and did not have a greater percentage of lean (P [is greater than] .05), except for SFV carcasses weighing 88.2 to 97.7 kg. Bob veal had less fat (internal, external, and intermuscular) and a higher bone percentage than SFV (P [is less than] .05). The round and shoulder primals had the greatest proportion of lean in both the BV and SFV carcasses. Bob veal carcasses had an average conformation score of average Good and SFV carcasses had an average conformation score of average Choice. In addition, a parsimonious subset of variables was identified for predicting total percentage of lean (TPLEAN) for both BV and SFV separately, using 'stepwise' regression model building procedures. For BV, all four identified predictor variables were subjective conformation scores (i.e., muscling, appearance, leg thickness, loin-back plumpness) (R = .73, P [is less than] .03). For SFV, four predictor variables were also identified: kidney and pelvic fat, fat thickness, carcass length, and lateral thickness (R = .61, P [is less than] .03). Although both regression equations were significant predictors of TPLEAN, confidence limits for predicting future TPLEAN value were wide relative to the variation in the actual TPLEAN values. Thus, the practical utility of the regression equations is limited.

An oxymyoglobin (OxyMb)-liposome model facilitated the characterization of the antioxidant potential of alpha-tocopherol and pro- or antioxidant activities of ascorbate. These studies were aimed at identifying the correlation between oxidation of oxymyoglobin and phospholipid, and concentration of alpha-tocophorol and ascorbate. The two antioxidants prolonged the oxidation time of OxyMb and phospholipid concentrations of 14 micromoles for ascorbate optimized their antioxidant activities, thus rendering an optimal delay in the oxidation time.

The expression of heat shock protein with a molecular weight of 70 kDa (Hsp 70) in porcine tissue and its potential relationship to stress susceptibility was studied. Twelve pigs, four of each genotype (NN, Nn, and nn) for halothane sensitivity were slaughtered. At 45 min postmortem, several tissues (liver, kidney, spleen, skeletal and cardiac muscle, and adrenal gland) were sampled for Hsp 70 analysis. At 24 h postmortem, longissimus and semimembranosus muscle were sampled for assessment of meat quality. Water-holding and water-binding capacity, color, and protein denaturation of samples from halothane-positive animals indicated that these animals had been stressed. Homozygous nn pigs demonstrated a lower |pH.sub.45~ and higher L-value at 48 h than their NN and Nn counterparts (P |is less than~ .05). The longissimus, but not semimembranosus, muscle of nn pigs demonstrated lower water-holding capacity and greater protein denaturation than that of NN or Nn pigs (P |is less than~ .05). The water-binding capacity of both longissimus and semimembranosus was less in nn than in Nn or NN pork (P |is less than~ .05). Using one-dimensional PAGE and Western blotting, Hsp 70 was shown to be present in all tissues examined. With two-dimensional PAGE followed by blotting, the presence of the cognate and inducible form of Hsp 70 was investigated. There did not seem to be a relationship between stress (based on meat quality) and expression of either form of Hsp 70.

A comparative study of the nutritional content and storage-life of red and white veal is presented. Results indicate that both veal varieties are similar in many nutritional aspects, except that white veal has a lower iron content than the red veal variety which contained a lower cholesterol level but higher iron and zinc concentrations. However, red veal discolored faster than its white counterpart, indicative of its susceptibility to lipid oxidation.

An analysis of interactions between fish myoglobin (Mb) and myofibrillar proteins as a function of time in an Mb-natural actomyosin (NAM) model at refrigerated temperature (4 degree Celsius) is described. It is observed that the interaction between dish Mb and myofibrillar proteins were more prominent with greater storage time and formation of high-molecular-weight aggregates also became more with time and also that disulfide bonds were not involved in Mb-NAM interactions.

The relative proportions of myoglobin (Mb) redox forms in aqueous solution was estimated using modified Krzywicki's equations as the original one gave negative values for some redox forms. The new equations demonstrated improved performance in decreasing the occurrence and magnitude of negative values and in estimating total Mb, when compared with Krzywicki' original equations.

Myoglobin(MB) is the major oxygen storage and transport heme protein that gives meat its red color. MB is studied for several animal species and there are slight species differences in the molecular properties of this protein.

Research has been conducted on myoglobin. The covalent binding of 4-hydroxy-2-nonenal to bovine myoglobin and its role in redox stability have been investigated, and the results are reported.