The Effect of Proteolytic Enzymes on Pork Loin. John Downey, F&N 453 Individual Project

Transcription

1 The Effect of Proteolytic Enzymes on Pork Loin John Downey, F&N 453 Individual Project Abstract The tenderizing of meat is achieved by breaking down the proteins that make up the muscle fibers as well as breaking the proteins the link the muscle fibers together. While enzymes are commonly used in the tenderizing of meat products for consumption, few studies have been conducted comparing the effectiveness of different enzymes. Despite recognizable differences from the control using a texture analyzer and shear press the data collected comparing the different source of enzymes showed that the differences were due to chance. Like wise there was not over all difference observed in the subjective analysis of the sample to one another or to the control. Further work needs to be done on how each enzyme acts in breaking down the proteins present in the meat. Introduction The tenderness of meat can be highly variable and to obtain a consistent high quality product for culinary use is difficult. With such variability in the tenderness multiple methods can be utilized to tenderize the muscles. A great deal of the problems of tenderness can be related to cold shortening of the sarcomeres and collagen cross linking. By degrading these proteins tenderness can be increased. Salts and weak organic acids have been shown to slightly enhance the tenderness of meat. But according to Kaya, M. Akta, N this produced undesired flavors. There for salt and acids do not make for great tenderizers. The Hydrodyne process has received much attention over the past few years. This is the process of exposing the meat to the high pressures of an explosion however in 1999 Wulf, D. Sundararajan, N. Ndife, M. Moeller, S. Meeker, D. found that while this method produced 17% more tender samples when using the shear press there was no significant difference in subjective evaluations of the sample. The use of enzymes to do this degradation is common; however 95% of the use enzymes to tenderize meat commercially are done with enzymes extracted from plants according to Enzyme Development Corporation. Most commonly the proteases from pineapple, papain and bromelain, are used; while enzymes extracted from microorganisms are rarely used. Methods Three pound sample of pork loin were inoculated with an enzyme solution of 50 ml. For each solution the enzyme were used at 0.005% of the weight of the pork loin. The solution was then injected into the sample at 10 locations in the pork loin injecting 5 ml into each spot. After inoculation of the enzymes the meat was placed individually in freezer bags and stored in a refrigerator for 48 hours prior to cooking. 1

2 was done in ovens heated to 177 C. The samples were individually placed into roasting pains and cover with foil. The internal temperature of the pork loin was monitored with meat thermometers and they were removed form the oven once the reached a temperature of 77 C. Objective test were conducted using the shear press and texture analyzer. For the shear press samples were cut from various areas of the pork loin and sized to 1 cm by 1 cm by 4 cm. They were then placed in the shear press and cut across the direction that the muscle fibers run. For the texture analyzer sample were again cut from various areas of the pork loin. The samples were sized to 1 cm thick. The knife probe was used while setting the pre test speed to 2 mm/s, the test speed to 3 mm/s and the post test speed to 5 mm/s. The distance was set to 5 mm with a force of 2000g and time of 5 s. The texture analyzer was run using a quick test run. Sensory evaluation was done by serving 5 g samples of each treatment identified by a three digit random number to the panelist. They were then asked to rate each samples tenderness, juiciness and flavor based on a 7 value category scale. For overall impression of the sample they were asked to rate in on a nine value hedonic scale. Results/Discussion Table 1 Objective Evaluation of the tenderizing Effect of enzymes on Pork (force in N) Sheer Press TA Pre Post Pre Post Control Papain Bacterial Fungal Table 1 shows the results observed when from the use of the shear press and texture analyzer before and after cooking of the samples. The shear press showed a difference of close to 3 N between the control and the papain before cooking and a difference of 3.3 N after. Like wise the sample treated with the fungal enzyme showed similar effect. The Bacterial enzyme however showed a greater effect of tenderization when the pre cooking and post cooking test were conducted. This treatment resulted in a difference of N before cooking and after. All three showed size able changes of tenderness. Using the texture analyzer smaller differences where observed in the samples to the control with the bacterial and fungal enzymes almost showing no difference between the two. From this, the most effective enzyme for tenderizing can not be determined. Table three shows that only between each treatment and the control was a difference observed that could not be attributed to chance. Table 2 Sensory Evaluation of the tenderizing Effect of enzymes on Pork Tenderness Juiciness Flavor Overall Control Papain Bacterial

3 Fungal Table 2 shows the results complied from the sensory evaluation of the pork loin. While the sample treated with papain and the fungal enzyme wee rated better by the panels they this was most due to chance. As shown in table three with only the evaluation of the tenderness and juiciness showing a significant difference when compared to the control. The only other significant difference observed where in comparing the samples treated with papain to the ones treated with the bacterial enzyme and the samples treated with the fungal enzyme to the ones treated with the bacterial enzyme. There for overall the panelist were unable to detect any noticeable differences between the samples of pork loin. Table 3 Comparison of differnce between enzyme treatments through t-stat Shear press Pre Post Pre t-stat TA Post t-stat Significant Control/Papain 4.68 yes 6.02 yes 6.86 yes 4.51 yes Control/Bacterial 4.95 yes 7.41 yes 4.42 yes 3.34 yes Control/Fungal 5.23 yes 5.16 yes 4.97 yes 4.38 yes Papain/Bacterial 0.93 no 0.92 no 1.28 no 0.29 no Papain/Fungal 0.07 no 0.92 no 2.01 yes 0.88 no Bacterial/Fungal 1.06 no 1.37 no no 0.25 no Significant Subjective Tenderness Juiciness Flavor Over All Control/Papain 4.47 yes 3.84 yes 1.19 no 1.75 no Control/Bacterial 1.46 no 0.69 no 0.34 no 0.15 no Control/Fungal 3.05 yes 4.72 yes 1.94 no 1.40 no Papain/Bacterial 1.22 no 1.45 no 3.10 yes 1.31 no Papain/Fungal 0.24 no 1.00 no 0.22 no 0.00 no Bacterial/Fungal 0.71 no 1.94 no 2.67 yes 1.51 no The paired t-test calculations were done using the following method. The example. Mean Difference Standard Deviation Experimental t-value μ = ( difference)/n σ = ( difference 2 - (difference 2 /n))/(n-1) t = μ/(σ/ n) 3

4 A probability level of 99.5% was chosen for the t-test. This means that the significance level to read off the chart is α = References: Kaya, M. Akta, N The influence of marinating with weak organic acids and salts on the intramuscular connective tissue and sensory properties of beef. Eur Food Res Technol 213:88 94 Meat Tenderizing Enzymes Applications Enzyme Development Corporation. Sep. 19, Solomon, M. B The Callipyge Phenomenon: Tenderness Intervention Methods. Journal of Animal Sciences. 77: Szalata, M. Pospiech, E. Mikolajczak, B. Lyczynski, A. Grzes, B. Borzuta, K Muscle proteins and their changes in the process of meat tenderization. Animal Science Papers and Reports. 21 (supplement 1): Unruh, J. A. McFarlane, B J Effects of Blast Chilling and Postmortem Calcium Chloride Injection on Tenderness of Pork Longissimus Muscle. Journal of Animal Sciences. 74: Wulf, D. Sundararajan, N. Ndife, M. Moeller, S. Meeker, D Impact of the Hydrodyne Process on Tenderness, Microbial Load, and Sensory Characteristics of Pork Longissimus Muscle. Journal of Animal Sciences. 77 4

5 Pork Loin Name Date Sample nos. Rate each sample for each grouping listed. If no difference is observed between samples it is permissible for the sample to be given the same rating. Tenderness Juiciness Flavor Very Tender Very Juicy Intense Flavor Very Tough Very Dry No Flavor Judge each sample for tenderness and list how much you liked or disliked the sample. Indicate you impression of the sample by marking the statement that best reflects you attitude. Tenderness Sample Number Like Extremely Like Very Much Like Moderately Like Slightly Neither Like or Dislike Dislike Slightly Dislike Moderately Dislike Very Much Dislike Extremely 5