Comparison of Subjective and Objective Methods of Evaluating Cooked Normal and Woody Breast Meat

Lab 1

Sensory Evaluation and Evaluation of Protein Functionality

Amanda Barkley

January 15th, 2020

Comparison of Subjective and Objective Methods of Evaluating Cooked Normal and Woody Breast Meat in Chickens.

Introduction:

Background Information: In the poultry industry, there have been issues in the quality of chicken breast meat because of genetic selection and changes in nutrition in the past 50 years. Consumers have noticed that the fast growth rate and large yielding birds that are being used tend to have less palatable texture and, therefore, are not as desired. The phenomenon that the consumers are mostly noticing is called woody breast. Woody breast meat is characterized by collagenous breast muscles in birds that make the muscle harder and less tender than normal breast meat (Huang, X., and D. U. Ahn, 2018). It has been believed to be caused specifically by the tissues outgrowing the structure and metabolism of the muscle (Petracci, M., and C. Cavani, 2011). It is estimated that 90% of the broilers in the industry are affected by some sort of abnormality that decreases the quality of breast meat (Huang, X., and D. U. Ahn, 2018). Not only is this phenomenon not desired by consumers, but it is also costly to producers because it downgrades the quality of the protein they are producing. Woody breast was estimated to cost the industry 200 million dollars in 2017 (Jenkins, M. 2018).

This myopathy in breast muscle can be identified using data collected from a variety of experiments that determine its quality.

Objectives: To compare the effects of cooked normal and woody breast meat by subjective and objective methods of evaluation.

Materials and Methods:

Breast Meat Fillets – Freshly deboned and obtained from a local poultry producer categorized by normal and wood breasted fillets by plant personnel.

A. Sample Preparation for Sensory Analysis

Purpose: To prepare woody and normal chicken breast for sampling on a consumer panel.

Two types of breast fillets were cooked with no added seasoning. One breast fillet being normal breast meat and the other being woody breast meat. The samples were then cut into specific, bite-size pieces. The pieces were cut to only use the most tender part of the breast meat that was not affected by elements of cooking that could affect the texture of the sample. After the samples had been cut, they were placed in containers with non-sequential ID numbers to not form panel bias. The samples in the containers were placed on trays that also contained two crackers and a cup of water for the panelists to cleanse their pallets. Panelists were also given a sheet for that evaluation.

a. These steps were performed twice with two different evaluation sheets. The first sheet was to evaluate texture differences between the two samples. This sheet had panelists rate the Hardness, Crunchiness, Fibrousness, and Chewiness of the sample. The second sheet provided with the second round of samples had panelists rate the Appearance, Texture, Juiciness, Flavor, and overall Consumer Acceptance.

B. Sensory Analysis

Purpose: To get consumer feedback by specific subjective analysis with cooked normal and woody breast meat.

Two groups were formed. The first group prepared samples of products for the other group to taste test in a blind sensory evaluation. The groups switched places when the evaluation was concluded. Panelists were instructed to perform certain steps to cleanse their pallets before sampling the cooked breast meat. These steps were performed for both the texture evaluation and overall consumer acceptance evaluation.

a) Drink some of the non-ionized water provided.

b) Take a bite of one of the non-salted crackers

c) Drink more of the non-ionized water provided

d) Eat the first sample and record your evaluation using the ID number for the sample provided.

e) Repeat steps a, b, and c before evaluation the second sample.

C. Hand-Palpation

Purpose: To evaluate breast muscle in broiler chickens using the hands to palpate the breast to diagnose the quality of breast muscle myopathies.

Using the hands, press firmly on boneless-skinless breast fillets to feel textural differences in the muscle. Wood Breast will feel harder and dense. Normal Breast Fillets will feel softer and supple.

D. Cook-Loss

Purpose: Water retention in meat affects texture. Ideally, chicken breast meat should have a low cook loss to maintain quality.

Cook Loss is calculated by weighing the breast fillets before and after cooking. High cook loss indicated poorer meat quality, while low cook loss indicates higher meat quality. See below for the equation for calculating cook loss.

Cook Loss (%) = (Weight Before Cooking – Weight After Cooking)

Weight Before Cooking

E. Texture Analysis

Purpose: To collect objective data by using two different machine analyses by comparing shear and peak force.

Two texture analyses were performed. The first being an Allo-Krammer Shear Test. Allo-Krammer uses 10 blunt blades to slice through a piece of meat. Samples of cooked woody and normal breast meat were cut to the Allo-Krammer template. Samples were then weighted and inputted in data tables. The sample was then placed perpendicular to the blades on the Allo-Krammer machine. The machine was run for each sample and data was recorded. Shear Force was then calculated using the formula below:

Shear Force (Kg/g) = Force (Kg) / Sample Weight (g)

The second texture analysis test that was performed was a Blunt Mullenet Owens Shear Test (BMORS). Fillets were placed under the blade as to which the fibers of the muscle ran perpendicular to the blade. When the test is begun, the blade runs 2cm in the muscle. The fillet is then moved to different parts of the muscle to accurately read the entire fillet. This method uses a blunt blade simulating a tooth biting the meat. This machine calculates shear energy: the total energy required to cut 2cm through different regions of a piece of meat. This test provides more details than Allo-Krammer.

F. Statistical Analysis

Purpose: To analyze breast meat in an objective method by measuring color and electrical differences in normal and woody breast meat.

Color is an important factor in determining meat quality. The color and visual appearance of meat are crucial to consumer acceptance. Visual qualities are the first judgments consumers make when purchasing products. Color to ones’ eye is very subjective, that is why a Minola Colorimeter is used to determine the color for this experiment. A Minolta Colorimeter uses a Lightness, Red to Green, and Blue to Yellow scale, therefore providing three numbers to determine the color of the meat.

The method of Hand Palpation that was discussed earlier is also a subjective form of determining meat quality. An objective method to determine woody breast can be found by using a Bioelectrical Impedance Analysis. This product determines electrical differences in muscle and can help identify woody breasts.

Results and Discussions:

Table 1: Average and Standard Deviation of Texture Differences in Normal and Woody Cooked Breast Fillets

Table 2: Average and Standard Deviation of Customer Acceptance in Normal and Woody Cooked Breast Fillets

Table 3: Summary of Average and Standard Deviation for data collected and observations observed.

Sensory evaluations can be used to evaluate the quality of breast meat; however, this information is very subjective. From studies conducted and background information provided, we know that the cooked woody breast meat should be the lowest quality sample and be less favorable (Huang, X. and D. U. Ahn, 2018). Looking at the data collected in Table 1, panelists rated both normal and woody breast meats similar to each other when determining Hardness with an average of 6.17 for normal breast and 6.25 for woody breast. This reading was similar to the Hardness of an Olive. In this same study, however, panelists rated normal cook breast meat with an average of 1.67 for crunchiness; less than the crunchiness of a green grape. Woody breast meat received a 3.17 for crunchiness, in-between a rice crispy treat and a green grape. This informs us that panelists were able to more easily differentiate crunchiness better than hardness.

When evaluating the appearance of the breast meat, the data collected in Table 2 shows that the consumer panel was not drastically able to differentiate between woody and normal breast meat, however, normal breast meat scores slightly more acceptable in all categories except flavor. On a scale of 1 to 8, consumers rated overall acceptance for normal woody breast meat as an average of 5.58 and woody breast meat as an average of 5.42.

Cook-loss data observed that woody breast meat loses more water than normal breast meat. This is an issue because it significantly downgrades the quality of meat. The amount of water muscle can hold depends on the composition and other various processing factors. Water is a major contributor to the texture of the product. Reduced water in meat products leads to tough, dry, meat that is not favorable to consumers and causes companies to lose money.

When conducting the bioelectrical impedance analysis, it was observed that woody breast muscle conducted less Resistance (Ohm) and Reactance (Ohm). This is valuable data because it can be used as a more objective method to determine woody and normal breast muscle in the industry.

Texture analysis testing using the BMORS and Allo-Krammer tests showed results that woody breast meat required more shear energy to cut through than normal breast meat. Woody breast meat also had a higher peak count implicating that there were more sections of the meat that were harder to cut through. The Allo-Krammer test results showed higher shear force in woody breast meat. This consistent data correlates to the increased connective tissue in the woody breast meat. In conclusion to this data, it seems breast meat with woody myopathy display higher peak and shear force.

Literature Cited:

Huang, X., and D. U. Ahn. 2018. The Incidence of Muscle Abnormalities in Broiler Breast Meat – A Review. Korean Journal for food science of animal resources 38:835–850.

Jenkins, M. 2018. Woody breast explained. Poultry Worlds:1–1.

Petracci, M., and C. Cavani. 2011. Muscle Growth and Poultry Meat Quality Issues. Nutrients 4:1–12.

Petracci, M., S. Mudalal, F. Soglia, and C. Cavani. 2015. Meat quality in fast-growing broiler chickens. World’s Poultry Science Journal. 71:363-374.

Soglia, F., S. Mudalal, E. Babini, M. D. Nunzio, M. Mazzoni, F. Sirri, C. Cavani, and M. Petracci. 2016. Histology, composition, and quality traits of chicken Pectoralis major muscle affected by wooden breast abnormality. Poultry Science 95:651–659.