Contents of moisture, fat, protein, and eight minerals in commercial broiler breast and thigh meat were defined by analyzing ]5-bird lots in a factorial design of two sexes x two commercial strains x three widely separated regions of production. Small but statistically significant differences due to strain, sex, and region were found for many of the variables examined. Region significantly influenced all the element levels except phosphorus in both breast and thigh flesh. Calcium levels found were about half those previously reported. The differences are probably not nutritionally important under normal consumption patterns.

Chicken patties containing various levels of sodium tripolyphosphate (STPP) and NaCl were tested for moisture retention characteristics and instrumentally texture profiled. Both additives tended to increase moisture retention. Both additives also affected the textural quality of the patties. In the absence of NaCl, the STPP increased the product cohesiveness, springiness and chewiness at the highest phosphate level; but, in the presence of NaCI, the phosphate tended to increase these textural attributes, especially cohesiveness and chewiness, at lower phosphate levels. Improved meat quality might be achievable through a better understanding of relationships between NaCI, STPP, moisture retention and texture of poultry meat products.

Packing and handling treatmentsThe changes in nutrient composition of broiler breast meat subjected to the following handling methods were determined: 1) ice-packed whole birds (IW), 2) ice-packed breasts (IB) and 3) deepchilled, tray-packed breasts (DCB). All were chill-held for 14 days in ice or dry in 2°C storage. Significant losses of Mg, K, Na and P (20, 37, 12 and 36%, respectively) were found in 14 days IB samples. The loss ln IW was 11, 26 and 27% for Mg, K and P, re spectively. DCB meat retained more minerals than those packed in ice. The highest loss after 7-14 days of chill-holding of DCB was 18% for P and 15% for K. Significant increase of Ca content was found (68-144% gain) for all samples stored after 7 days suggesting migration of Ca from bone to tissue. Proximate data, thiamin and riboflavin content did not change.The ice-packed whole birds and whole breasts were obtained on the day of processing. They were transported to our laboratory within 1 hr. Upon arriving, 15 whole birds were randomly selected as the control birds and each was packed individually in a plastic poultry bag, sealed and frozen at -34°C. The remaining whole birds as well as all the whole breasts were packed in crushed ice in cardboard boxes and placed in a refrigera;ted room (2'C) for up to 14 days. Ice was added during this periT as needed. Boxes were placed on steel cart racks in a slightly tilted position to allow liquid to drain out.The deepchilled, tray-packed breast samples were the routinely processed birds cut into breast pieces in the plant. Four halves were packed per tray (tray size 17 x 22 x 2 cm), wrapped with plastic film, heat sealed and blast-frozen at -40°C for approximately 45 min until the outer shell of the meat was frozen, but the inner portion was still soft. These trays were then stored at -2.2'C (28OF) for 4 days. Then, they were placed in a large plastic bag, placed in insulated containers packed with ice, and transported to our laboratory. These trays were held at 2°C up to 10 additional days, Le., total 14 days from the day of processing.

The IGFs (-I and -II) are normally found in serum and other extracellular fluids complexed to specific binding proteins (IGFBPs). While several IGFBPs have been identified in vitreous and aqueous humors, the major serum carrier of IGF, IGFBP-3, is notably absent from these fluids. To determine if this paucity could be due to an IGFBP-3 proteinase (IGFBP-3ase), samples of bovine vitreous or aqueous humor were mixed with serum and incubated at 37 degrees C for 4 h followed by western ligand blotting. In these experiments, a distinct loss of the 46 kDa band representing IGFBP-3 was observed while other bands present at 35, 28 and 25 kDa were unaltered. The IGFBP-3ase activity is temperature sensitive, has a pH optimum of about 8.0 and is inhibited by EDTA. Acid treatment of serum to remove endogenously bound IGF does not affect the specificity or activity of the IGFBP-3 proteinase. Size exclusion chromatography of bovine aqueous indicates an approximate molecular weight of 260 kDa. Incubation of recombinant IGFBP-3 or serum with partially-purified IGFBP-3ase results in the appearance of low molecular weight fragments of approximately 30 kDa. These fragments are undetectable by western ligand blotting but are readily visualized using an IGFBP-3 specific antibody. Comparison of normal and diabetic vitreous humor reveals the presence of an increased amount of IGFBP-3 proteolytic fragments in the diabetic as compared to control. These findings indicate the presence of a IGFBP-3 proteinase in aqueous and vitreous humors that may be important in regulating ocular homeostasis.

No abstract

Muscle pyruvate kinase (PYK) activity was established as a biochemical indicator of temperature attained during cooking in both a model system and a commercial-type pullman-style canned cured pork product. Water extract (model system) or pressed-out meat juice (commercial-type pullman-style canned cured pork) was incubated (37°C up to 40 min) with reagent containing adenosine diphosphate, phosphoenolpyruvic acid and NADH. Lactate dehydrogenase (LDH) necessary for the reaction is provided by the muscle extract or meat juice. When muscle PYK activity is present, NADH is oxidized resulting in a loss of fluorescence (reaction mixture spots on filter paper viewed under long-wave ultraviolet light). Model system results showed high PYK activity (no fluorescence) remained in samples heated to 67.7°C. PYK activity progressively declined in samples heated to 68.3°C and 68.9°C. No PYK activity was detected in samples heated to 69.5°C or 70°C. Canned product attaining a core temperature of 62.9°C had high PYK activity. PYK activity progressively declined in product heated to 65.6°C and 68.6°C. Essentially no PYK activity was detected from product processed to 69.9°C.

No abstract

Breast and thigh meat samples from 40 individual broilers from a single commercial processing source were analyzed for calcium, copper, iron, phosphorus, magnesium, sodium, and zinc by atomic absorption spectrophotometry. Phosphorus was determined spectrophotometrically as the antimony-phosphate-molydbate complex. Assays of breast meat ranged from 25% higher than previously reported for potassium (3190 vs. 2550 ppm, wet weight basis) to 25% lower for sodium (485 vs. 650). Breast and thigh meat samples differed in the concentration of all elements checked. The differences were not due exclusively to dilution of sample by a higher fat level in thigh meat, since on a wet weight basis sodium, calcium, zinc, iron, and copper were higher in thigh than in breast meat.