scholarly journals Influence of ultrasound and proteolytic enzyme inhibitors on muscle degradation, tenderness, and cooking loss of hens during aging

2012 ◽  
Vol 30 (No. 3) ◽  
pp. 195-205 ◽  
Author(s):  
G.-Y. Xiong ◽  
L.-L. Zhang ◽  
W. Zhang ◽  
J. Wu
Keyword(s):  
Group Treatment ◽  
Proteolytic Enzyme ◽  
Shear Force ◽  
Enzyme Inhibitors ◽  
Proteolytic Enzymes ◽  
Treated Group ◽  
Cooking Loss ◽  
Potential Contribution ◽  
Meat Tenderness ◽  
Endogenous Proteases

The potential contribution of mechanical disruption by ultrasonics and endogenous proteolytic enzymes on the tenderisation of hen muscle were investigated. The importance of endogenous enzymes was evaluated using various specific inhibitors. Freshly obtained breast muscles of culled hens, from the 6 groups investigated were treated with different proteolytic enzyme inhibitors and/or ultrasonics, group was treated with different methods, and then stored at 4°C for 0, 1, 3, and 7 days. Shear force decreased by 1.19 kg, and shear force and cooking loss were reduced by 0.69 kg and 4.27%, respectively, in the incorporated group treatment. The calpastatin activity was affected by all treatments except in the Z-DEVD-fmk-treated group, caspase-3 activity decreased in Z-DEVD-fmk-treated group. Therefore, the results suggest that ultrasonics and endogenous proteases contributed to muscle degradation, thereby improving hen meat tenderness and decreasing the cooking loss. Thus muscle degradation, tenderness, and water-retaining properties of hens were improved by a combination of ultrasound and exogenous proteolytic enzyme inhibitors.  

scholarly journals Length of exposure to high post-rigor temperatures affects the tenderisation of the beef M. longissmus dorsi

2008 ◽  
Vol 48 (11) ◽  
pp. 1442 ◽  
Author(s):  
K. L. Thomson ◽  
G. E. Gardner ◽  
N. Simmons ◽  
J. M. Thompson
Keyword(s):  
Shear Force ◽  
Proteolytic Enzymes ◽  
Temperature Treatment ◽  
High Ionic Strength ◽  
Rapid Decline ◽  
Meat Tenderness ◽  
Post Mortem ◽  
Control Groups ◽  
Exposure Experiment ◽  
Initial Acceleration

This experiment examined the effect of length of exposure of bovine M. longissmus dorsi to high temperatures (37°C) on proteolytic activity during post-mortem aging and subsequent meat tenderness. To avoid confounding between pH decline and incubation treatments, the experiment was conducted on post-rigor meat (pH < 5.6), which had entered rigor at 15°C. This meat was first incubated at 15°C until rigor (pH < 5.6), whereupon samples were then reheated and maintained at 37°C for 0, 1 or 3 h. Following incubation, samples were aged at 1°C for 1–21 days. Control groups were incubated at either 15 or 37°C until pH < 5.6, followed by aging at 1°C. High rigor temperatures accelerated post-mortem proteolysis early in the post-mortem period, as indicated by a rapid decline in shear force (P < 0.01), but post-mortem aging ceased at about day 3 post-mortem and the high rigor temperature treatment was ultimately 30% tougher at day 21 post-mortem (P < 0.01). The process of reheating samples from 15 to 37°C had minimal effect on tenderness levels, but was associated with a slight increase in proteolysis, identified by myofibril length, and was associated with an increase in cook loss percentage (P < 0.05). Shear force in the length of exposure experiment was affected by an incubation time × post-mortem aging interaction (P < 0.01). This indicated an initial acceleration of post-mortem aging with increased length of exposure, but also a reduction in the ultimate tenderness of product after extended post-mortem aging. This was presumably due to the loss of proteolytic enzyme activity caused by the instability of proteolytic enzymes at high ionic strength conditions such as those present in post-mortem muscle.

Proteolytic Enzymes, their Inhibitors and Lung Diseases

1983 ◽  
Vol 64 (2) ◽  
pp. 119-126 ◽  
Author(s):  
R. A. Stockley
Keyword(s):  
Proteolytic Enzyme ◽  
Lung Diseases ◽  
Enzyme Inhibitors ◽  
Proteolytic Enzymes ◽  
General Concept ◽  
Chronic Lung Diseases ◽  
High Incidence ◽  
Serum Inhibitor ◽  
Reparative Changes

The pathogenesis of many acute and chronic lung diseases remains a mystery. However, recent years have seen a rapidly increasing interest in the role of proteolytic enzymes and their inhibitors in modifying the inflammatory, destructive and reparative changes that occur in the lung. Much of this interest owes its existence to two observations in the early 1960s: firstly, the recognition that subjects with an inherited deficiency of α1-antitrypsin (α1-AT; the main serum inhibitor of proteolytic enzymes) had a high incidence of pulmonary emphysema [1], and secondly the demonstration by Gross et al. [2] that a proteolytic enzyme (papain) was capable of producing lesions similar to emphysema in experimental animals. These observations ultimately led to the proteinase—anti-proteinase theory of emphysema, which predicts that a state of balance occurs in the healthy lung in which the proteolytic enzyme inhibitors functionally equal or exceed the enzymes. Destructive lung disease occurs when the enzymes functionally exceed the inhibitors such that they remain active within the lung, resulting in digestion of connective tissue. This general concept of a disturbed proteinase—anti-proteinase balance within the lung has been recently applied to many other lung diseases, and some will be mentioned later. However, it is in the study of chronic bronchitis and emphysema that the concept has become most well established.

scholarly journals Pseudocoagulase activity of staphylococci

1979 ◽  
Vol 9 (1) ◽  
pp. 15-19
Author(s):  
Z Wegrzynowicz ◽  
P B Heczko ◽  
J Jeljaszewicz ◽  
M Neugebauer ◽  
G Pulverer
Keyword(s):  
Proteolytic Enzyme ◽  
Enzyme Inhibitors ◽  
Proteolytic Enzymes ◽  
Test System ◽  
Rabbit Plasma ◽  
Test Systems ◽  
Activity Test ◽  
Human Infections ◽  
Culture Supernatants ◽  
Positive Results

A total of 245 strains of staphylococci isolated from various pathological specimens derived from cases of human infections was tested for staphylocoagulase activity. Test systems employing normal citrated rabbit plasma and the same substrate supplemented with inhibitors of thrombin and proteolytic enzymes (but not influencing the staphylocoagulase activity) were used for testing suspensions of bacteria and cell-free culture supernatants. A total of 237 strains clotted normal rabbit plasma; however, addition of Trasylol and heparin resulted in positive results in 222 strains, whereas plasma supplemented with Trasylol and hirudin was coagulated definitely by only 173 strains. It is postulated that proteolytic enzymes of staphylococci interfere with staphylocoagulase-induced clotting and may simulate coagulase-positive activity of staphylococci. To avoid such false results, a test system for detection of staphylocoagulase should include proteolytic enzyme inhibitors. Possible mechanisms of these findings are discussed.

scholarly journals Relationship of breast fillet deboning time to shear force, pH, cooking loss and color in broilers stunned by high electrical current

1996 ◽  
Vol 5 (1) ◽  
pp. 49-55 ◽  
Author(s):  
Petri A. Papinaho ◽  
Daniel L. Fletcher
Keyword(s):  
Shear Force ◽  
Geographical Area ◽  
Electrical Current ◽  
Cooking Loss ◽  
Processing Plant ◽  
Meat Tenderness ◽  
Post Mortem ◽  
Breast Meat ◽  
Potential Market ◽  
Broiler Breast

Experiments were conducted to determine the relationships between deboning time and broiler breast meat quality, as determined by objective meat tenderness, pH, color and cooking loss. All birds were processed in a European commercial processing plant using a high current, constant voltage stunning system and air chilling. According to a modified Mitscherlich response equation, pH values reached their ultimate value by 5.77 h post-mortem, with an asymptotic 95 % confidence interval of 5.72 h-5.81 h post-mortem. The shear force data, which were analyzed using a logistic model, suggested that broiler breast fillets should be aged intact on the carcass for 10.58 h, 5.94 h or 2.28 h to guarantee that over 95 % of the fillets reach Allo-Kramer shear forces of 8.0, 9.0 or 11.0 kg/g, respectively. Since acceptable meat tenderness values vary with country, geographical area, or consumer groups, acceptable ranges should be determined according to potential market demands. No relationships between deboning time and fresh meat color or cooking loss was found.

scholarly journals Effects of stimulation on tenderness of lamb with a focus on protein degradation

2006 ◽  
Vol 46 (7) ◽  
pp. 891 ◽  
Author(s):  
K. M. Martin ◽  
D. L. Hopkins ◽  
G. E. Gardner ◽  
J. M. Thompson
Keyword(s):  
Electrical Stimulation ◽  
Protein Degradation ◽  
Proteolytic Enzyme ◽  
Shear Force ◽  
Meat Tenderness ◽  
Protein Breakdown ◽  
Structural Protein ◽  
Complete Understanding ◽  
Muscle Ph ◽  
Optimal Ph

Past studies have identified that electrical stimulation systems not only affect the pH–temperature decline of lamb carcasses, but also affect the tenderness of the product. It is unknown whether these differences are due to the effects of an optimal pH–temperature decline path by which the occurrence of shortening is decreased and proteolytic enzyme activity is increased, or by another mechanism, such as disruption of the muscle myofibres. This study attempted to elucidate this by placing control and mid-voltage electrically stimulated samples of the M. longissimus thoracis et lumborum in a water bath to prevent shortening by imposing an even pH–temperature decline on all samples. In order to obtain a complete understanding of the effects of stimulation on the muscle, samples were taken for indicators of tenderness, myofibre degradation and protein breakdown. No effect of stimulation was seen on tenderness and structural degradation measures aside from the expected rapid lowering of muscle pH. Interesting relationships were observed, however, between the different methods of meat tenderness assessment, with muscle structural protein degradation, shear force and muscle fibre and myofibre breakdown comparisons. These results suggest that the effects of electrical stimulation seen in mid-voltage systems as applied in this study are due only to the prevention of shortening conditions.

scholarly journals Influence of ageing time on yield and texture of marinated chicken breast cooked using a continuous process

2014 ◽  
Vol 17 (1) ◽  
pp. 2-7
Author(s):  
Tais Colpo Sartori ◽  
Nelcindo Nascimento Terra
Keyword(s):  
Experimental Design ◽  
Sensory Analysis ◽  
Shear Force ◽  
Ageing Time ◽  
Continuous Process ◽  
Sensory Attributes ◽  
Cooking Loss ◽  
Holding Time ◽  
Chicken Breast

The objective of this study was to evaluate the influence of different ageing times before deboning (deboning time) and ageing times after deboning (holding time) on the quality (sensory attributes and texture) and cooking loss of chicken breast marinated, cooked and frozen using a continuous process.The following3² experimental design was used (3 deboning times: zero, 6 and 12 hours; and 3 holding times: zero, 12 and 24 hours). Brine absorption, chicken breast pH and cooking loss were evaluated, a sensory analysis was carried out and the shear force was determined. The deboning and holding times did not significantly influence brine absorption and pH, but did significantly influence cooking loss, where the lowest value obtained was a mean of 19.72% for deboning times of 6 or 12 hours and a holding time of 24 hours. A deboning time of 6 hours was sufficient to improve tenderness as measured by a sensory analysis and shear force determination.

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