Location: Food Science and Market Quality and Handling Research Unit
2016 Annual Report
Objectives
Objective 1. Determine the relationship between maturity, moisture, handling, and processing interactions with the fatty acid contents of peanuts that will potentially affect nutritional composition, flavor, shelf-life and texture characteristics of whole peanuts.
Objective 2. Enable improved peanut flavor, flavor consistency and nutritional composition through integration of novel peanut genetic/genomic resources.
Sub-objective 2.A. Evaluate the flavor and quality characteristics of specific peanut varieties or breeding lines in cooperation with U.S. peanut breeders.
Sub-objective 2.B. Evaluate the flavor and quality characteristics of accessions in the peanut germplasm collection.
Objective 3. Identify the bioactives and characterize their functional food attributes from raw/roasted peanuts and peanut skins.
Approach
The four market types, runners, virginias, spanish and valencias, will be examined for the development of high oleic to linoleic (O/L) after sorting lots at harvest into maturity classes to determine the relationship of O/L ratio to market type and maturity.
Late generation peanut breeding lines and varietal checks included in the Uniform Peanut Performance Tests (UPPT) and from the USDA NPGS and grown out by the collaborators over three crop years will be examined for physical, chemical, and where possible sensory quality using constantly updated analytical equipment.
Peanuts will be obtained from a commercial shelling operation for Identification and quantification, where possible, of the secondary metabolites.
Progress Report
Samples were received from the National Peanut Laboratory as part of the Uniform Peanut Performance Trials. Samples were characterized for total fat, moisture, fatty acids profiles, tocopherols, and sugars using established analytical methods. Sensory characteristics were determined using the ARS descriptive sensory panel. Results were reported to the program website.
Samples from the “core of the core” of the peanut germplasm collection were received from a cooperator at Auburn University. Samples were characterized for sugars and tocopherols and sensory profiles. Results were reported at a national meeting of the funding organization.
Spanish peanuts with a low oleic acid level control were submitted by an ARS peanut breeder. Single seed fatty acid profiles were performed to add information to a manuscript being prepared on all peanut market types.
Jumbo runner peanuts were roasted using three different techniques to three different roast colors. The sensory characteristics and effects on shelf life were evaluated. The study report was written and submitted to a peer review journal.
Non target analysis of the metabolites present raw runner and virginia peanuts was performed. The results were statistically evaluated and reported at a national and an international meeting. This is the first report of the metabolic profile of the peanut.
Accomplishments
1. Peanut oil blends with different levels of oleic acid content demonstrated differences in shelf life and oxidative stability are associated with the ratio of oleic acid to linoleic acid in the lipid of peanuts. High oleic peanuts (oleic acid to linoleic acid ratios above 9) are prized for their longer shelf life in food products containing peanuts. Scientist with the ARS in Raleigh, North Carolina, in cooperation with a industrial cooperator used oil was expressed from peanuts and blended to create models contain ratios from 1 to 38 and tested them for the onset of rancidity, off flavors, changes in density and viscosity after storage under accelerated conditions. While viscosity was greatest for high oleic samples when comparing fresh oils, after storage under abusive conditions oil viscosity increased exponentially with decreasing O/L ratio due to oxidation/polymerization reactions. This information was published in a peer reviewed journal. Peanut processor can use this information to evaluate the suitability of peanut cultivars for their applications.
2. A functional food ingredient created from extracts of peanut skins after spray drying and encapsulation with maltodextrin was used to increase the antioxidant activity in chocolate without negative flavor impact. Peanut skins are removed during the blanching operation for most peanuts. Peanut processing plants produce thousands of tons of peanut skins which represent a waste management problem. The skins have proven to have high levels of phenolic compounds with bioactivity but also have bitter flavors. ARS scientists in Raleigh, North Carolina, in cooperation with North Carolina State University created a powdered ingredient from the peanut skins that was incorporated into milk chocolate. This resulted in a milk chocolate product with levels of bioactivity higher than that of conventional dark chocolate. Extensive sensory testing proved that the flavor of the product was not changed at levels objectionable to consumers. A manuscript was submitted to a peer reviewed journal and an invention disclosure was filed.
3. A lexicon for the evaluation of cashew flavor and texture was created. There was no sensory lexicon for cashews in the scientific literature before the one developed by the Market Quality and Handling Research Unit. Sensory parameter were created and formalized. A descriptive sensory panel maintained by the unit validated the lexicon using commercial and experimental cashew products. The new lexicon was submitted to a peer reviewed sensory journal for publication.
4. A new type of cashew product was evaluated for nutrient and sensory profiles. Skin-on cashews have not been available in the past due to contamination with a caustic liquid that naturally occurs in the shells. A new process was developed by a private corporation that eliminates the contamination. ARS scientists in Raleigh, North Carolina, completed a characterization of the nutrients and other chemical components in this new type of cashew product provided by the industrial processor in comparison with conventionally blanched cashew products currently available at the retail level. Sensory characteristics were also evaluated using a lexicon for the descriptive sensory parameters was created.
5. Peanut roasting by three different commercial methods were compared to determine how quality parameters are affected by the methodology. The color of roasted peanuts is used as the major determinant for the optimum finished product. The main methods of roasting are dry roasting, oil roasting and blister frying. Each method requires different time and temperature combinations to achieve equivalent final colors. ARS scientists in Raleigh, North Carolina, subjected jumbo runner market type peanuts to the three different roasting operations at the time and temperature combinations to achieve equivalent light, medium and dark final roasted colors. Chemical and descriptive sensory evaluations before and after accelerated storage showed that each technique produced a product with significantly different textures and flavors and that the shelf life was affect by the type of roasting as well as the final roasted color. A manuscript describing the study and the findings was submitted to a peer reviewed journal.
6. Hamsters used as model for the study of diet effects on cardiovascular disease onset indicators are not affected by standard reference diets. Syrian Golden hamsters are often used to determine the effects of dietary ingredients including peanuts on the development of cardiovascular disease. These results have close relationships with the probability of the risk factor on humans. This study was performed by ARS scientists in Raleigh, North Carolina to prove that these animals are an effect model by showing the reference diets used as the controls in these studies has no effect on atherosclerotic disease factors as the animal age by monitoring the changes in related metabolites over the course of thirty one weeks. By proving the suitability of this animal model, their use for the diet effects of peanuts and peanut products is validated. This study was published in a peer reviewed manuscript.
7. Peanut cultivars from the 2015 Uniform Peanut Performance Trials (UPPT) were evaluated for chemical and sensory characteristics. Samples from seven USA peanut breeders were submitted to the ARS Market Quality and Handling Research Unit after processing at the National Peanut Laboratory. The breeders are cooperators from Universities and other ARS units. Samples were analyzed for moisture, total lipid, fatty acids profiles, sugars, and tocopherols using established methods. The flavor characteristics of the samples after dry roasting were evaluated by the descriptive sensory panel maintained by the Unit. The results were reported on the website of the program so the information can be used by the cooperators and others in the peanut industry for the suitability of new cultivars for growing areas and food processing.
8. Accessions from the U.S. Peanut Germplasm Collection were evaluated for chemical and sensory characteristics. As part of an ongoing cooperation with Auburn University with funding by the Peanut Foundation, samples of the “core of the core” of the U.S. Peanut Germplasm Collection were submitted to the ARS Market Quality and Handling Research Unit. The core samples are selected from the much larger germplasm collection as representative of the most important morphological traits. The samples were analyzed for sugars and tocopherols using established methods. The flavor characteristics of the samples after dry roasting were evaluated by the descriptive sensory panel maintained by the Unit. This is the first study of the flavor characteristics of samples of from the collection. Results were reported to the cooperator to be used as part of a larger study for the suitability of including the selected germplasm accessions for conventional peanut plant breeding for crop improvement.
None.
Review Publications
Davis, J.P., Price, K.M., Dean, L.L., Sweigart, D.S., Cottonaro, J.M., Sanders, T.H. 2016. Peanut oil stability and physical properties across a range of industrially relevant O/L ratios. Peanut Science. 43:(1)1-11.
Stephens, A.M., Sanders, T.H. 2015. blood lipid distribution, aortic cholesterol concentrations, and selected inflammatory and bile metabolism markers in syrian hamsters fed a standard breeding diet. Journal of the American Association for Laboratory Animal Science. Vol. 54 (4).
