Sensory Evaluation of Alternative Turkey Genotypes

Final Report for OS07-036

Project Type: On-Farm Research
Funds awarded in 2007: $14,962.00
Projected End Date: 12/31/2009
Grant Recipient: Appalachian State University
Region: Southern
State: Arkansas
Principal Investigator:
Dr. Anne Fanatico
Appalachian State University
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Project Information

Abstract:

Consumer interest is growing in specialty poultry products including free-range production and alternative turkey products, such as “heritage.” Heritage turkeys are slow-growing, naturally-mating turkeys and are typically raised with outdoor access and without routine medications or animal by-products in the feed. There is interest in sensory attributes of the meat, as well as conservation of livestock breeds/varieties.
A trial was conducted to assess impact of genotype on yield, meat quality, and sensory attributes. A commercial fast-growing genotype (Fast) and a slow-growing genotype (Slow) (all females) were raised for 14 weeks and approximately 26 weeks, respectively. Placement dates were staggered in order to achieve a similar final body weight on day of processing. Forty turkeys of each genotype were raised on a small commercial farm in a naturally-ventilated house with access to outdoor yards and were provided the same diets. Turkeys were processed at a small facility and stored at 1 C. Sixteen turkeys of each genotype were deboned at 2 d postmortem for meat quality analyses. Descriptive analysis of fresh breast and thigh meat of Fast and Slow turkeys was conducted by a trained panel, while consumer analysis included an additional treatment, a retail turkey (injected with marinade at processing). In addition, a consumer focus group was held to gather data on consumer interest in specialty turkey, and community outreach allowed local participants to learn about specialty turkey and to sample it. In terms of results, carcasses of Fast turkeys were heavier than those of Slow (P < 0.05). Breast yield was higher (P < 0.05) for Fast compared to Slow, while leg yield was higher for Slow (P < 0.05). Breast meat of Slow had lower pH and was less pale and more red than Fast (P < 0.05). The descriptive panel found few differences in flavor of breast meat although Fast had more intense cooked meat flavor and Slow had more intense aftertaste of blood/metal (P < 0.05). The panel found more differences in texture; specifically, breast meat of Slow was more hard, cohesive, and fibrous than Fast (P < 0.05). However, in instrumental (MORS) analysis, Slow was more tender than Fast (P < 0.05). In most categories of consumer trials, Retail and Fast were preferred over Slow, including appearance and texture. For breast meat, the overall liking was higher for Retail than Fast and Slow (P < 0.05), and the liking of flavor was higher for Retail than Slow (P < 0.05). Reasons for buying or planning to buy a specialty turkey that were ranked highest were antibiotic/growth promotant concern, flavor/texture, use of pesticide concern, and nutrients. These data indicate differences in yield, meat quality and sensory attributes between the commercial fast-growing and specialty slow-growing turkeys as well as differences in reasons for purchase.

Introduction

Consumers are interested in specialty poultry products including naturally-raised, free-range, organic, and locally-produced. There is particular interest in “heritage” turkeys. Heritage turkeys are slow-growing, naturally-mating turkeys and are typically raised with outdoor access and without routine medications or animal by-products in the feed. The American Livestock Breeds Conservancy (www.albc-usa.org) uses a definition for heritage that includes naturally-mating standard varieties, slow growth rate where birds reach market weight in about 28 weeks, and the ability to withstand the environmental rigors of outdoor access.

In contrast, a fast-growing hybrid turkey is raised indoors in environmentally-controlled housing in conventional turkey production. Because it has been selected for a high breast yield, natural reproduction is difficult for fast-growing turkeys and therefore artificial insemination is used for breeding. Fast-growing turkey genetics are very similar and are called the Broad-Breasted White. At processing, conventional turkey carcasses are usually “pre-basted” or injected with water, salt, phosphates, and spices to help ensure that the breast will not become dry due to overcooking; however, specialty turkeys usually are not pre-basted.

Turkeys are a livestock species native to the Americas. The wild turkey was domesticated in the Americas and taken to Europe by explorers. Standardized varieties were used in commercial production in the past and therefore have a cultural heritage. They were the forerunners of the fast-growing Broad-breasted White. Many of these standard varieties have historical ties to regions of the country. The Bronze, Narragansett, White Holland, Black, and Slate were admitted to the American Poultry Association’s The American Standard of Perfection in 1874. The Bourbon Red was admitted in 1909 and the Beltsville Small White was admitted in 1951 (American Poultry Association, 1993).

Little genetic selection of standard varieties of heritage turkeys has taken place in recent decades; however, Frank Reese in Lindsborg, KS (www.reeseturkeys.com) has continued the tradition of selecting heritage turkeys for meat production. His Bronze turkeys have pure bloodlines that can be traced back to 1917.

Consumers buy specialty poultry products for personal health reasons such as a concern about the use of growth promotants or antibiotics in meat production, or pesticides, as well as personal interest such as nutrient/sensory attributes. Consumers may also be interested in animal welfare, the environment, or endangered livestock breed conservation. Anecdotal tastings usually rank heritage turkey high for flavor (McManus, 2007). However, there are few scientific studies on this subject. Therefore, the objective of our study was to determine the impact of genetic type on meat quality and sensory attributes including flavor and texture, and to investigate consumer perceptions.

Project Objectives:
  • Determine impact of genotype on meat quality and sensory attributes of turkeys in specialty poultry production

    Investigate consumer perceptions about specialty turkey meat.

Cooperators

Click linked name(s) to expand
  • Jean-Francois Meullenet
  • Casey Owens
  • Frank Reese

Research

Materials and methods:

Two genotypes were raised for this study: conventional, fast-growing Broad Breasted White (Fast) and a slow-growing, “heritage” Standard Bronze (Slow). These birds were raised on a small commercial operation in Kansas. The fast-growing turkeys were obtained from a commercial source as day-old poults. The slow-growing turkeys were placed in May 2007 and the fast-growing turkeys in mid-July 2007. Forty turkeys of each genotype were raised for 14 and 24-28 wk, respectively, with the goal of raising the birds to a similar slaughter weight. The genotypes were raised in separate flocks and only females were used. The same feed was used for both genotypes. The turkeys were harvested in late October 2007. They were transported to a small processing plant one hour away. After processing, carcasses were transported under refrigeration to the University of Arkansas Pilot Poultry Processing plant where they were placed in storage at 33 F. All carcasses were stored in refrigeration until further analysis (described below).

At 2 d postmortem, 16 carcasses of each genotype were placed on cones and cut up for parts yield analysis and deboning of breast fillets. Breast and skin samples were taken for nutrient analysis and frozen until analysis. The remaining meat was repackaged and vacuum sealed for the consumer focus group and placed back in storage at 33 F. The pH was also measured at 2 d postmortem. The right breast fillet was weighed after deboning and the color of the meat was measured. Breast fillets were cooked on racks in pans to an internal temperature of 165 F. The cooked fillets were reweighed to determine cook loss, an indicator of water-holding capacity. The tenderness was measured by an instrumental method, Meullenet-Owens razor shear (MORS; Cavitt et al., 2004).

Descriptive analysis was conducted on breast and thigh meat at the University of Arkansas Department of Food Science sensory facility by a trained meat descriptive panel (15 members; Sensory Spectrum Inc., Chatham, NJ). Initial orientation was held to refine flavor and texture definitions. At 8 d postmortem, 4 turkeys of each type were cooked whole for flavor descriptive analysis. Carcasses were placed on a rack in a shallow pan and roasted at 325 F. After the breast was browned, a loose tent of aluminum foil was placed over the breast to prevent overcooking. The carcass was roasted until the thigh reached an internal temperature of 180 F. Carcasses were cooled for 30 m before cutting. Breast samples were taken of cooked meat for nutrient analysis. Meat was cut into 0.75-inch, bite-size cubes and was not seasoned or salted. The descriptive panel used 15 descriptive flavor terms to describe the white meat: sweet, salty, sour, bitter, cooked white meat, white meat fat, brothy, blood serum/metallic, organy, sulfury, sweet aromatic, other, astringent, and associated aftertastes. Dark meat flavor was described with similar flavor terms.

At 9 d postmortem, 4 Fast and 4 Slow turkeys were cooked for texture analysis. The trained panel used descriptive textural attributes to evaluate tenderness characteristics of breast meat. Initial hardness, cohesiveness, moisture release were evaluated in the first bite stage, while hardness of mass, cohesiveness of mass, fibrousness, and number of chews to swallow were evaluated in the chewdown stage. All intensities were expressed to one significant digit on 15-point numerical scales, with higher scores indicating higher attribute intensities.

Panelists for the descriptive tests were randomly presented samples from all treatment groups in duplicate utilizing a randomized complete block design. Panelists were randomly presented samples from all treatment groups in duplicate. Between each sample, panelists were instructed to cleanse their palate with distilled water and unsalted crackers. A 15-minute break period was allocated to the panelists halfway through the session.

At 10 d postmortem, a consumer test (40 panelists) was conducted on the breast and thigh meat from the Slow and Fast turkeys, with the addition of a third treatment, frozen retail turkey (Retail). The Retail turkey was purchased at a local grocery store and thawed at 33 F. It was cut up at the University of Arkansas processing plant like the other treatments. The Retail turkey contained additional ingredients (water, salt, phosphates, and spices) from injection as is common in retail turkeys in the US. These turkeys are fast-growing birds from indoor production systems and the inclusion of this treatment helped elaborate differences between specialty and conventional turkey products. Four turkeys of each type, Retail, Fast, and Slow (12 total), were cooked for consumer analysis. At 11 d postmortem, the procedure was repeated with an additional 40 panelists (80 panelists total). Whole turkeys were roasted as described above, and breast and thigh meat cut into bite-size cubes.

The consumer panelists were recruited via a panelist database housed at the University of Arkansas Food Science Department, and selection of panelists was based on consumption patterns of white and dark poultry meat and on the consumption of natural and/or organic poultry products. Institutional Review Board protocol was followed. Consumer panelists were each served samples from the different treatments one at a time and were instructed to cleanse their palates between samples. They were asked to evaluate their overall liking of the product, liking of appearance, texture, and flavor, and appropriateness of color, tenderness, juiciness, and flavor. They were also asked to indicate the likelihood that they would buy the product and if they would pay more for the product than for their usual poultry product. Nine-point hedonic scales were used to assess overall liking and liking of appearance, texture, and of flavor (1 = dislike extremely, 5 = neither like nor dislike, 9 = like extremely). Just-About-Right (JAR) scales were used to assess the appropriateness of color (1 = much too light, 2 = too light, 3 = just about right, 4 = too dark, 5 = much too dark), the appropriateness of tenderness (1 = much too tough, 5 = much too tender), the appropriateness of juiciness (1 = much too dry; 5 = much too juicy), and the appropriateness of flavor (1 = much too weak, 5 = much too strong). Samples were randomized by product type and then by meat type (breast meat or thigh meat). The use of Just-About-Right (JAR) scales are useful for diagnostics, because hedonic scales do not allow determination of the appropriateness of intensity of the attribute (Meilgaard et al., 1999). These questions were based on the differences determined earlier by the descriptive panel.

For the consumer focus group and community outreach, a nonprofit organization that focuses on local food, Ozark Slow Food, organized a “turkey tasting” event at a local restaurant in which these same 3 turkey treatments were sampled. Consumers with an interest in natural and local food were targeted and were contacted in various ways. Specifically, Ozark Slow Food developed a series of three informational pieces for the public on specialty poultry production with outdoor access, endangered farm breeds and their cultural contest as “heritage” breeds, and the “turkey tasting” consumer event. These informational pieces were posted over a period of 3 weeks to the OzarkSlowFood email listserver with a distribution of 120 recipients. The turkey-tasting event was announced on public calendars and the local public radio station. The public radio station also interviewed UA researchers about the project, as well as a local heritage turkey producer, and the interview was broadcasted in a show called Ozarks at Large on November 2, 2007 the day before the event. The turkey tasting event was also announced throughout Northwest Arkansas with posters at natural food stores and announcements by Ozark Slow Food at local events and at farmers markets. The community outreach and announcements of the event was done in the weeks before Thanksgiving.

The turkey tasting event was held at a local upscale restaurant, Basil’s Restaurant in Rogers, AR, on November 3, 2007, which was 5 d postmortem to the slaughter of the turkeys. Meat was cut up and prepared according to recipes selected by the restaurant chefs but all meat was cooked to 165 F.

An introductory session was held first to provide basic information and definitions on specialty turkeys. A presentation on Slow Food was also provided by visiting professor Dr. Paulo Sambo from the University of Padova. Following the presentation, participants completed a survey, sampled and ranked the three turkey products, conventional (marinated), fast-growing free-range turkey, and slow-growing heritage free-range turkey, in a blind test. The roasted breast and thigh meat samples were offered as appetizers with bread. After completing the survey and ranking, a full holiday meal made from locally-raised, seasonal ingredients was served. The participants had the opportunity to further sample the turkey products as part of their meal.

Statistical analysis:

The meat quality data were analyzed as a t-test. The descriptive panel sensory data were analyzed as a randomized complete block design with 2 experimental units per treatment in each block. Genotype was treated as a fixed effect and panelist as a random effect. The consumer panel sensory data were subjected to analysis of variance. The JAR scores were compared using a chi-square test for equality of distributions except in those cases where small expected counts may have substantially affected the approximate p-value from the chi-square. In those cases, Fisher’s exact test was used (Fleiss, 2003).

In regard to the consumer survey and ranking, for the binomial distributions from the yes/no questions, a 95% Confidence Interval of the proportion of successes or positive answers was calculated. For multiple category questions, respondents who checked more than one answer were removed. We used a chi-square test for equality of distributions except in those cases where small expected counts may have substantially affected the approximate p-value from the chi-square where Fisher’s exact test was used. If there was a significant difference among categories, we calculated confidence intervals for the difference between each possible pair of proportions based on the properties of a multinomial distribution. The variance estimate of the difference included a correlation because all questions were answered by same people. If 0 was not in the Confidence Interval, the proportions were different.

For ranking data regarding the reason for buying and of product preference, we used the Friedman test which is a nonparametric two-way analysis of variance of ranks and used the Person as the blocking variable. To separate the ranks, we used the average of the ranks (Least Squares Means) rather than the means because not all individuals answered all questions. P-values smaller than 5% were considered to be statistically significant. All statistical analyses were carried out using SAS version 9 (SAS Institute, Inc., Cary, NC).

Research results and discussion:

Although the Slow turkeys were older than the Fast, the carcasses of the Fast turkeys were larger than those of the Slow (P < 0.05). The breast yield was higher for the Fast compared to the Slow, while the leg yield was higher for the Slow (P < 0.05). These data reflect the fact that the Fast were selected for fast growth and high yield of breast meat.

The breast meat of the Fast was higher in protein and lower in fat, and the skin of the Fast was also lower in fat (P < 0.05). The Slow turkeys were older than the Fast and had an opportunity to deposit more fat in the skin as well as the meat. However, there was no difference in fat content of the cooked breast meat when roasted as a whole carcass with the skin on. The vitamin A content of the breast meat from the Slow was higher than Fast (P < 0.05). It is possible that the Slow turkeys were more active than the Fast and forage on plants that contribute to vitamin A content. The breast meat of the Slow had lower pH and was less pale and more red than Fast (P < 0.05). The breast meat of the Slow had a high cook loss (P < 0.05), which indicates a lower water-holding capacity than Fast.

The descriptive panel found few differences in the flavor of breast meat, although the Fast had more intense cooked meat flavor and the Slow had more intense aftertaste of blood/metal (P < 0.05). The panel found more differences in texture. The breast meat of the Slow had higher intensities for initial hardness, cohesiveness, and fibrousness than the Fast (P < 0.05). However, in the instrumental study, the Slow was more tender than the Fast (P < 0.05). This may be due to multidimensional qualities of meat texture or possibly differences in rigor development, although deboning did not take place until 48 h postmortem. In contrast, Fernandez et al. (2001) found the breast meat of slow-growing turkeys to be tougher than fast-growing.

In most categories of the consumer trials, the Retail and Fast were preferred over the Slow, including appearance and texture. For the breast meat, the overall liking was higher for Retail than Fast and Slow, and the liking of flavor was higher for Retail than the Slow (P < 0.05). These preferences are likely related to pre-basting with water, salt, phosphates, and spices. Furthermore, ten percent of consumer panel indicated they would definitely pay more for the breast meat from the Retail product, while 2.5% would definitely pay more for the Fast and 0% for the Slow.

In the consumer focus group, participants (n=25) completed a 10-question survey. Of the participants, 96% had heard of free-range or organic turkeys, but only 46% had heard of heritage; 36% had purchased a specialty turkey in the past. If they had not purchased, availability was the reason rather than cost or quality (P < 0.05). Their reasons for buying or planning to buy a specialty turkey were ranked. Antibiotic/growth promotant concern, flavor/texture, use of pesticide concern, and nutrients were ranked higher (P < 0.05) than environmental concern, animal welfare concern, local food, and breed conservation. Neufeld (2002) found Americans’ reasons for buying free-range or organic chicken are: no antibiotics or growth hormones (73%), like to eat healthy foods (69%), better taste and tenderness (54%), environmentally friendly (48%), locally grown (29%), 73% of free-range chicken purchasers said it had better taste than conventional.

Focus group participants also indicated they probably would (43.5%) or definitely would (26.1%) buy a specialty turkey in the future. A majority of the participants indicated they probably would (36.4%) or definitely would (45.5%) pay more for specialty turkey than conventional (P < 0.05). Most (71%) prefer whole turkey rather than parts or further processed. In a blind preference test, Retail turkey was ranked highest, followed by Fast, with Slow ranking lowest (P < 0.5).

It is interesting that focus group participants indicated a strong interest in specialty and heritage turkey; however, heritage turkey was least preferred in their blind test. These results agree with our consumer sensory analysis where consumer panelists did not prefer heritage turkey. Overall, data indicated differences in meat quality and sensory attributes, especially in terms of texture, with consumers preferring the conventional turkeys over the specialty. Most likely consumers are accustomed to conventional, marinated turkey products. Moreover, while consumer perception data indicates targeted consumers would pay more for heritage turkey, the consumer panel indicated they would not pay more for it. Therefore, consumer education and exposure is needed to market specialty turkey.

Citations

American Poultry Association. 1993. The American Standard of Perfection. Global Interprint, CA. 344 p.

Cavitt, L. C.*, G. W. Youm, J. F. Meullenet, C. M. Owens, and R. Xiong, 2004. Prediction of poultry meat tenderness using razor blade shear, Allo Kramer shear, and sarcomere length. J. Food Sci. 69:(1) SNQ11-15.

Fernandez, X., Sante, V., Baeza, E., Lebihan Duval, E., Berri, C., Remignon, H., Babile, R., Pottier, G le, Millet, N., Berge, P., and Astruc, T. 2001. Post mortem muscle metabolism and meat quality in three genetic types of turkey. British Poultry Science 42(4):462-469.

Fleiss, J. 2003. Statistical Methods for Rates and Proportions. J. Wiley, Hoboken, NJ.

McManus, L. 2007. Should you pay top dollar for turkey? Cook’s Illustrated. November and December. P. 26-27.

Meilgaard, M., G. V. Civille, and B. T. Carr. 1999. Sensory Evaluation Techniques. 3rd Edition. CRC Press, New York, NY. 387 p.

Neufeld, L. 2002. Consumer preferences for organic/free-range chickens. Kansas State University Master’s Thesis. Agricultural Marketing Resource Center. http://www.agmrc.org/media/cms/ksufreerangech_588C29A8ED362.pdf Accessed May 2010.

Participation Summary

Educational & Outreach Activities

Participation Summary

Education/outreach description:

Results of this project were shared at the annual meeting of the Poultry Science Association in July 2008 and July 2009 and the following abstracts were published in a peer-reviewed journal.
• Fanatico, A.C., J.F. Meullenet, J. L. Emmert, and C. M. Owens. 2008. Impact of genotype of carcass, meat quality, and sensory attributes for turkeys raised with outdoor access. Poultry Science 83 (Supplement 1). Abstr.
• Fanatico, A.C., H.L. Goodwin, C.M. Owens, and A.M. Donoghue. 2009. Consumer Perception of Specialty Turkeys: Free-range, Organic, and “Heritage.” Poultry Science 88 (Supplement 1). Abstr.
A poster that was part of these presentations has been uploaded.

See http://www.sustainablepoultry.ncat.org/slow_poultry.html for short videos of interviews with U.S. heritage turkey expert and breeder Frank Reese. Reese discusses the history of heritage turkeys and his bloodlines.

A nutritional writer interviewed researchers about the project and published the following article.
• Moores, S. 2010. Hot for heritage: Saving endangered farm animals, supporting local agriculture, protecting the food supply, and preserving a legacy. ADA Times: A Publication for Members of the American Dietetic Association. Vol 7, Issue 3. p. 11-17.

Community outreach about specialty turkey was far-reaching. About 5,000 people visit the Fayetteville farmers market each Saturday where Ozark Slow Food had a booth and advertised the turkey-tasting event.

In preparation for the November 3, 2007 turkey tasting event at Basil’s Cafe, Ozark Slow Food (www.ozarkslowfood) published 3 “Turkey Talks” on its listserver, OzarkSlowFood, which has over 120 participants. These have been uploaded as a word document.

The public radio station KUAF interviewed University of Arkansas researchers about the project, as well as a local heritage turkey producer, and the interview was broadcasted in a show called Ozarks at Large on November 2, 2007 the day before the tasting event.

The University of Arkansas released a press release entitled Sample Turkey Meat Similar to that Grown by Pilgrims at Upcoming Tasting Event.

Additional materials have been uploaded including photographs of the research (turkeys in the field, processing, Consumer and descriptive sensory analysis, tasting event).

Project Outcomes

Project outcomes:

In order for U.S. consumers to learn more about specialty turkey products, educational programs are needed. U.S. consumers are accustomed to conventional turkey products and have little experience with specialty products. If they have more experience with heritage turkeys, they may develop a preference for the meat.

Because the difference in texture may be as important or more important than flavor, producers of heritage turkeys may want to focus on differences in texture of breast meat in their marketing. Producers also need to focus on the image to sell the meat. Many consumers are interested in buying heritage turkey because of perceived images. Producers may also want to position dark meat as a premium product because slow-growing turkeys are not bred for a high breast meat yield.

Economic Analysis

It is more costly to raise specialty turkey products, including “raised without added antibiotics,” free-range, slow-growing, and heritage turkeys compared to conventional turkey production. Raising turkeys without routine medications such as antibiotics may require a lower stocking density. Providing outdoor access requires “popholes” or bird doorways, additional land, outdoor equipment, and fencing or other methods to protect the birds from predators. Labor costs increase due to the need to open popholes and manage outdoor area. The temperature of the house may be relatively cold due to open popholes that provide outdoor access. When temperatures are cold, birds eat more feed to stay warm which is an increased cost.

If turkeys with a slow growth rate are used, more feed is required due to the long-growing period. If organic feed is used, feed costs are at least twice the cost of conventional. Standard-bred poults can be expensive, around $5.00 per poult. Although slow-growing meat birds with low breast yield are less efficient than fast-growing meat birds with high breast yield, mortality may be lower.

Because the cost of production is high, prices for specialty turkey products must be high in order to generate a profit for producers. At the present time, a 13-lb ready-to-cook heritage turkey costs $100 with shipping from Heritage Foods USA. Although the cost of the product is high, many consumers may buy such a product for specialty occasions such as holidays.

ATTRA the National Sustainable Agriculture Information Service has a publication called Meat Chicken Breeds for Pastured Production that has a budget at the end that is useful for slow-growing meat birds http://attra.ncat.org/attra-pub/PDF/meatchicken.pdf.

Farmer Adoption

Farmers are increasingly raising heritage breeds of turkey. However, American Livestock Breeds Conservancy still lists all the varieties on Critical, Threatened, and Watch lists; see http://www.albc-usa.org/cpl/wtchlist.html#turkeys.

Slow Food USA lists 8 varieties of heritage turkey on the U.S. Ark of Taste. To qualify for the US Ark of Taste, food products must be outstanding in terms of taste, linked historically linked to a specific region, locality, ethnicity or traditional production practice. It should also be produced only in limited quantities, by farms or by small-scale processing companies using sustainable practices.

Recommendations:

Areas needing additional study

The fatty acid profile of heritage turkeys should be investigated to determine if the meat is higher in healthy omega-3 fatty acids than conventional turkey.

Evaluation of cooking methods are important for specialty turkey products. Because the breast muscle is smaller in heritage turkeys, it is important not to overcook it.

More precise marketing terms in the future would help consumers make decisions. For example, when consumers purchase a “free-range” product, it would be helpful for them to know more about how the animal was raised.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.