Page Banner

United States Department of Agriculture

Agricultural Research Service

Research Project: DEVELOPMENT & MAINTENANCE OF FLAVOR & SHELF-LIFE IN PEANUTS THROUGH IMPROVED HANDLING, PROCESSING AND USE OF GENETIC RESOURCES

Location: Market Quality and Handling Research

2005 Annual Report


1.What major problem or issue is being resolved and how are you resolving it (summarize project aims and objectives)? How serious is the problem? What does it matter?
Since peanut flavor is the basis for marketing of peanuts, the issue being addressed is optimization of the vertically integrated system from peanut production to manufactured products that have consistent high flavor quality and shelf-life. The system is integrated because each successive process affects all that follow; however, process control passes from producer to handler to sheller to manufacturer to marketer. This system requires the definition, identification, and contribution of constituents and processes in related but separate activities that individually affect flavor and shelf-life of peanuts and peanut products. These issues are studied through examination of factors such as variety, maturity, farmers stock (in-shell) curing, moisture, blanching, storage, roasting, and the interactions within and among these parameters. Flavor and other quality characteristics of varieties and breeding lines is very limited until varieties are released and concerns in the industry dictate a needed change to conduct earlier flavor/quality evaluations. Very limited information is available on the nature or quantity of biochemical or bioactive compounds that may serve as markers for specific flavor defects, flavor intensity, or nutritional quality in peanuts. A need exists for identification of marker compounds so that rapid, inexpensive methods may be developed and utilized to define and predict flavor and nutritional quality of peanuts. Very little is known about the comparative quality of U.S. and other exporting country peanuts and development of this information should constitute valuable marketing information. A major concern of the peanut industry is to improve efficiency and reduce costs of handling associated with movement of peanuts from harvest through curing, a critical area of concern, and into storage. Microwave technology has the potential to be developed into a continuous flow system, dramatically reducing the time required to dry farmers' stock peanuts, improve handling efficiency, and reduce costs.


2.List the milestones (indicators of progress) from your Project Plan.
Year 1 (FY 2003) 1. – Roast and sort normal and off-flavor lots, complete initial sensory and other analyses, begin storage study. (objective 1, sub-objective 1a)

2. – Conduct initial evaluation. (objective 1, sub-objective 1c)

3. – U.S. Consumer study completed. Data analysis completed. (objective 1, sub-objective 1d)

4. – Breeding line sensory evaluations. (objective 1, sub-objective 1e)

5. – Osteoblast model system development. Crude extracts obtained and tested for activity. (objective 2, sub-objective 2a)

6. – Crude extracts from various plant parts examined for antioxidant activity. (objective 2, sub-objective 2b)

7. – Obtain high moisture peanuts. Generate different moisture control lots. Microwave samples and store roasted peanuts. (objective 3, sub-objective 3a)

8. – Obtain peanuts, examine internal and external temperature in microwave processed lots. (objective 3, sub-objective 3b)

9. – Design changes and upgrade. (objective 3, sub-objective 3c)

10. – Create off-flavor samples. Initial sensory and sniffer port analysis. (objective 3, sub-objective 3d)

Year 2 (FY 2004)

1. – Complete storage study complete analyses, compile data, present data. (objective 1, sub-objective 1a)

2. – Obtain and maturity sort peanuts, cure. Shell and roast. Store. (objective 1, sub-objective 1b)

3. – Windrow tests for year 1 completed and data analyzed. Variations in windrow configuration considered. (objective 1, sub-objective 1c)

4. – Consumer studies in UK, Germany, The Netherlands. (objective 1, sub-objective 1d) 5. – Seed increase. Prepare samples for sensory panel evaluation. Sensory evaluations. (objective 1, sub-objective 1e)

6. – Active fractions further fractionated by HPLC and tested. (objective 2, sub-objective 2a)

7. – Purified fractions examined. Data analysis. Presentation and publication. (objective 2, sub-objective 2b)

8. – Initial examination of various flavor samples by GC and GCO. (objective 2, sub-objective 2c)

9. – Lab analysis continues. Vary time, power, and airflow and repeat tests. (objective 3, sub-objective 3a)

10. – Conduct studies with combination of power, time, and airflow. Analyze samples. Store FS peanuts. (objective 3, sub-objective 3b)

11. – Initial tests and equipment modification. (objective 3, sub-objective 3c)

12. – Microwave time and power studies to identify parameters. Sensory analysis. (objective 3, sub-objective 3d)

Year 3 (FY 2005)

1. – Publication completed. (objective 1, sub-objective 1a)

2. – Storage analysis complete. (objective 1, sub-objective 1b)

3. – Tests for year 2 completed and data analyzed. Presentation. (objective 1, sub-objective 1c)

4. – International studies complete and all data analyzed for publication. (objective 1, sub-objective 1d)

5. – Complete evaluations and prepare publications. (objective 1, sub-objective 1e)

6. – Active compound identification by HPLC/MS. Presentations and publications initiated. (objective 2, sub-objective 2a)

7. – As warranted, active compounds isolated and identified. (objective 2, sub-objective 2b)

8. – Specific flavor issues selected and isolation of compounds. (objective 2, sub-objective 2c)

9. – Publication and presentation preparation. Additional tests and analyses as indicated by previous work. (objective 3, sub-objective 3a)

10. – Storage study data analysis. (objective 3, sub-objective 3b)

11. -- FS and blanching tests. Sample storage and analysis. Presentation and publication. (objective 3, sub-objective 3c)

12. – Snifferport analysis followed by GC/MS of causative compounds. (objective 3, sub-objective 3d)

Year 4 (FY 2006)

1. – Lab analyses complete and analyzed. Presentation of data. (objective 1, sub-objective 1b)

2. – Additional tests as needed or application of test results in large commercial fields. Presentation and publication. (objective 1, sub-objective 1c)

3. – Publication. (objective 1, sub-objective 1d)

4. – Compound Quantization continues. Presentation and publications completed. (objective 2, sub-objective 2a)

5. – Continued isolation and identification. (objective 2, sub-objective 2b)

6. – Identification of compounds continues. Presentation and publication. (objective 2, sub-objective 2c)

7. – Publication and presentation. (objective 3, sub-objective 3a)

8. – Modified studies to optimize process. Presentations. (objective 3, sub-objective 3b)

9. – Completion of economic analysis on optimized procedures. (objective 3, sub-objective 3c)

10. –Final identification of compounds. Presentation and publication. (objective 3, sub-objective 3d)

Year 5 (FY 2007)

11. – Investigations on secondary activity compounds. (objective 2, sub-objective 2a)

12. – Presentation and publication. (objective 2, sub-objective 2b)

13. – Continue work as indicated by results. (objective 2, sub-objective 2c)

14. – Publication and presentation preparation. (objective 3, sub-objective 3b)

15. – Presentation and Publication. (objective 3, sub-objective 3c)

16. -- Presentation and Publication. (objective 3, sub-objective 3d)


4a.What was the single most significant accomplishment this past year?
Sandwich windrow construction (plants placed in windrows with one up and one down providing shade for the peanuts) was demonstrated as the most effective and cost efficient method to decrease intensity of fruity fermented off flavor. Fruity fermented off flavor is a significant economic problem in areas where peanuts are exposed to high temperature during initial curing. Because these studies were conducted in one of the worst years for the off flavor (CY 2003) and one of the best years (CY 2004), this information has already been instrumental in changes by producers toward use of sandwich diggers as standard practice.


4b.List other significant accomplishments, if any.
Removal of fruity fermented peanuts by color sorting of roasted peanuts was highly successful.

Sensory evaluation of 20 lots of fruity fermented peanuts provided data for development of a sampling plan for fruity fermented peanuts.

European consumer response to peanuts of different origins provided data which demonstrated that Europeans consumers have the same concept of what constitutes acceptable/good flavor as do consumers in the U.S. A greater percentage of peanut lots from China and Argentina have off flavors than do peanuts from the U.S. Because European consumers recognize the same off flavors as U.S. consumers there is a greater probability of consumer complaints with peanuts from China and Argentina. These data constitute positive marketing data for U.S. peanuts.


4c.List any significant activities that support special target populations.
None


4d.Progress report.
None


5.Describe the major accomplishments over the life of the project, including their predicted or actual impact.
Some discoveries over the life of this and the previous project were:.
1)moisture at roasting is important to shelf-life of roasted peanuts,.
2)quality of Virginia-type in-shell peanuts is highly correlated to maturity of peanuts at harvest,.
3)resveratrol is present in very low concentrations in edible peanuts,.
4)commercial peanut butter has nondetectable levels of trans fatty acids,.
5)various bioactive compounds are present in peanuts,6) internal and external pod temperature are highly correlated in microwave drying, and.
7)pod color is not a quality factor difference in comparison of inshell peanuts from different origins.

Temperature of peanuts during curing is critical to flavor and shelling quality characteristics. Studies were conducted in cooperation with NC State University in the laboratories of the Market Quality and Handling Research Unit to examine the relationship between internal pod temperature detected by fiber optic probes and external pod temperature detected by infrared thermometry for use in development of a microwave control system based on easily measured external pod temperature. The internal and external temperatures were highly correlated and indicated that external pod temperatures can be used in algorithms and models developed for control of microwave power application so that internal temperatures are controlled. These data add to the already strong possibility for development of a continuous flow microwave drying system for peanuts.

Georgia Green is the dominant runner market-type in the United States because of its superior disease resistance, however, the peanut industry has expressed continued concerns about the roasted flavor quality of Georgia Green. The roasted peanut flavor qualities of Georgia Green were compared to the roasted peanut flavor quality standard Florunner and parent selection effects on progeny roasted peanut flavor quality were examined using Georgia Green=s parents, Southern Runner and Sunbelt Runner, by the Market Quality and Handling Research Unit located at NC State University in cooperation with T.G. Isleib, D. W. Gorbet, K.M. Moore, Y. Lopez, M.R. Baring, and C.E. Simpson. Georgia Green was not significantly different from the industry standard cultivar, Florunner, in the sensory attributes roasted peanut, bitter and astringent, but was significantly sweeter than Florunner and the breeding value for roasted peanut and sweet attributes of Georgia Green were among the highest of any peanut lines examined. This accomplishment provided the peanut industry with a definitive answer on the flavor of the Georgia Green variety and, based on these findings, widespread use of Georgia Green as a parent should contribute to flavor improvement in runner market-type breeding programs.

In-shell peanuts roasted to dark color are not as acceptable to consumers as are lighter roasted in-shell colors, and manufacturers are concerned about this marketing issue. Studies were conducted in the laboratories of the Market Quality and Handling Research Unit in the Department of Food Science, NC State University in cooperation with Northampton Peanut Company to evaluate quality differences of in-shell peanuts roasted to different degrees of roast. The study indicated that lighter roasted in-shell peanuts contained more residual water, and thus, had shorter shelf-life than darker roasted peanuts, and although the aesthetic appearance might be more acceptable to consumers, the flavor loss and off-flavor development would be more objectionable. These data support continuation of current roasting practices of in-shell peanuts in the U.S. and provide manufacturers with marketing information on in-shell peanut quality.

Markets for U.S. in-shell peanuts in Canada and the U.K. were thought to be negatively impacted by differences in pod color with Chinese produced peanuts. In cooperation with the Virginia-Carolina Peanut Association, manufacturers in Canada and the U.K., and the American Peanut Council, studies were conducted in the laboratories of the Market Quality and Handling Research Unit located in the Department of Food Science, NC State University to evaluate pod color, oil quality and sensory characteristics of in-shell peanuts produced in the U.S. and China. The data demonstrated that pod colors were actually similar from the two origins, but oil and sensory quality were superior in the U.S.-produced peanuts. These data will contribute to market development and provide information on which improvements in pod aesthetics can be accomplished.

As the peanut marketing system continues to change, a method to rapidly cure farmers’ stock peanuts in a continuous flow system is needed because of the tremendous volume of peanuts requiring drying for 18-24 hours. Studies were conducted which demonstrated the high potential to rapidly dry farmers’ stock peanuts with microwave technology. Data from the studies indicated no decrease in flavor potential or shelf-life of peanuts. These data potentially indicate commercial feasibility of microwave drying of farmers’ stock peanuts and provide impetus to develop handling systems that function in connection with this type of drying.

Tomato spotted wilt virus (TSWV) is the most important disease of peanut in the southeastern U.S. and there are concerns that this disease has a negative impact on roasted peanut flavor quality. We conducted sensory analysis of three TSWV resistant genotypes and one susceptible genotype using three market grade sizes. The sensory panel was able to taste a difference between infected and non-infected roasted peanuts, but differences were not related to any specific flavor attribute such as sweet, bitter, or roasted peanut. These data suggest to peanut product manufacturers that subtle differences in TSWV-infected and non-infected peanut flavor may or may not be detectable by consumers.

Flavor of peanut breeding lines being developed for commercial release as new varieties is highly important to manufacturers of peanut products. For the second year a trained panel evaluated the flavor of all 12 peanut breeding lines from 8 locations in the Uniform Peanut Performance Tests (UPPT). The evaluations again indicated some differences in flavor among the lines but indicated that all lines were of acceptable flavor quality. These data indicate to breeders working with these lines that continuation of development is warranted, and indicate to peanut shellers and manufacturers that forthcoming lines will have acceptable flavor characteristics.

There is a lack of data to demonstrate the superior quality of U.S. peanuts which can be used in marketing strategies to increase export sales of U.S. peanuts. We examined peanuts that had been shipped to Europe from the U.S., China, and Argentina. Data on oil quality and both descriptive sensory and consumer analysis of flavor clearly demonstrated the superior quality of U.S. peanuts. The data have been presented in various international forums and used in development of marketing information for U.S. peanuts.

Determination of roasted peanut flavor intensity as an inherited trait is of major significance because the estimates of broad-sense heritability are sufficiently high enough to permit standard breeding techniques to be employed to improve roasted peanut flavor intensity. Broad-sense heritability estimates and genotype-by-environment interactions for roasted peanut, sweet, bitter and other sensory attributes in peanuts were determined. The genotype-by-environment findings have provided the information necessary to design the most efficient field experiments for the quality traits under investigation. Information from this project has been used in breeding line evaluations from the Florida and North Carolina programs and contributed to release of SunOleic95R, SunOleic97R, NC 12C, Gregory, Florida MDR98, Perry, C-99R, DP-1, Carver, Hull (HO), and Norden (HO).

Fruity fermented off flavor is reduced by sandwich windrows which shade peanuts from direct sunlight.

Fruity fermented peanuts can be removed by color sorting to remove darker colored (immature) peanuts.


6.What science and/or technologies have been transferred and to whom? When is the science and/or technology likely to become available to the end-user (industry, farmer, other scientists)? What are the constraints, if known, to the adoption and durability of the technology products?
Information on heritability of various quality traits has been transferred to peanut breeders and used in selecting the genotypic materials released as new varieties.

Information on quality of various peanut breeding lines soon to be released as varieties has been provided to peanut breeders and the peanut industry.

Information on the quality of dark and light roasted peanuts has been transferred to peanut processors.

Quality comparisons of U.S., Argentine, and Chinese peanuts have been presented to domestic and export industries and data are available for development of marketing strategies.

Technology towards development of a continuous flow microwave curing process has been provided to microwave equipment developers. Application of research data and more research are the present constraints in this area.

Information on trans fatty acids has been transferred to the peanut industry and consumers.

Data on quality comparisons of U.S., Argentine, and Chinese peanuts have been incorporated into a workshop on peanut sensory characteristics and have been presented at international meetings and at individual export industries.


7.List your most important publications in the popular press and presentations to organizations and articles written about your work. (NOTE: List your peer reviewed publications below).
Presentations:

Invited by Kasetsert University, Bangkok, Thailand to present a plenary lecture on Global Views on Peanut Quality. January 5-15, 2005.

Invited by the Texas Peanut Producers Board to present information on effect of soil temperature on peanut sugar content and effects of windrow construction on peanut flavor. January 25-26, 2005. Invited by the Starbucks, Inc to present information on nut quality. May 15-21, 2005.

Invited by the American Peanut Council to present peanut sensory workshops and lectures on the quality of peanuts from different origins at SnackEx and industry meetings in Europe. June 19-25, 2005.

Invited by the Kellogg’s Company and the Peanut Foundation to present a seminar on peanut Quality. August 118-19, 2005.


Review Publications
Sanders, T.H., Blankenship, P.D. 2004. Uniform peanut performance tests (uppt) 2003: chemical, sensory and shelf-life properties. Miscellaneous Publishing Information Bulletin.

Mozingo, R.W., O'Keefe, S.F., Sanders, T.H., and Hendrix, K.W. 2004. Improving shelf life of roasted and salted inshell peanuts using high oleic fatty acid chemistry. Peanut Science. 31:40-45.

Mehrotra, M., Sanders, T.H., Hendrix, K. 2004. Color sorting to remove fruity fermented off-flavor in roasted peanuts. American Peanut Research and Education Society Proceedings. Vol. 36, p. 41.

Sanders, T.H., Dean, L.L., Hendrix, K. 2004. Comparison of peanut flavor and shelf-life characteristics of peanuts from argentina, china and the united states. American Peanut Research and Education Society Proceedings. Vol. 36, p. 42.

Young, C.T., Pattee, H., Schadel, W.E., Sanders, T.H. 2003. Histochemical localization of amino acids and sugars in peanut cotyledons for light microscopy. Peanut Science. 30:104-107.

Last Modified: 8/22/2014
Footer Content Back to Top of Page