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United States Department of Agriculture

Agricultural Research Service


Location: Market Quality and Handling Research

2007 Annual Report

1a.Objectives (from AD-416)
Determine the effect of production location, maturity, curing, seed moisture, composition, processing and relevant interactions to improve flavor and flavor consistency in peanut varieties and breeding lines. Identify, isolate, and characterize biochemcial/bioactive components in peanuts that influence or indicate flavor, flavor potential, off-flavor, or nutritional quality. Evaluate microwave heating to cure and blanch peanuts.

1b.Approach (from AD-416)
Individual effects of maturity, composition, and moisture content of individual seed and how these factors interact during blanching and subseqent oil and dry roast processing will be examined in varieties and breeding lines of peanuts grown in the Uniform Peanut Performance Trials (UPPT) at several different locations. Peanut samples with high standard flavor profiles, unique flavor profiles, and peanuts subjected to various deviations in production, curing, and handling procedures will be evaluated for variations in components identifiable by GC, HPLC, and other chromatographic methods. Compunds associated with specific flavor characteristics unique in presence or magnitude will be isolated and identified by GC-MS or HPLC-MS. Newly developed microwave technology that provides uniform exposure to microwave energy will be utilized to study the effects of various time and power protocols on drying rate, flavor, and shelf-life of shelled and inshell peanuts.

3.Progress Report
Peanut Flavor and Influences:.
1)A sampling plan was derived for fruity fermented off flavor (FF) in peanuts. The roasted samples were evaluated by a trained sensory panel. Consumers were neutral or preferred FF at very low levels. No commonly occurring chem. compounds were determined by GC-MS between natural and artificially induced FF. Sensory evaluation showed these samples had different flavor profiles. .
2)Windrow studies in TX agreed with earlier yrs. work that sandwich windrows provided the greatest protection from temps. leading to FF. A study was initiated on the effect of growing loc. on the sugar-off-flavor dynamic in order to determine FF formation mechanism..
3)A trained sensory panel evaluated lines in the 2006 UPPT. The data was posted to aid breeders with selections and to study interactions between flavor and environ. .
4)Marketing info. was developed and delivered to audiences in MX and SP for foreign peanut product producers. The info. was applied domestically to educate the industry on foreign perception of US product attributes of peanut flavor. .
5)The MQHRU collaborated with the NPRL to address spots appearing after roasting. Our lab. performed all spot ids. and quantification. The source was found and possible remedies id. .
6)A study began to use advanced flavor chem. techniques to id. compounds. .
7)The MQHRU collaborated with Clemson Univ. to study the effect of burrowing bug damage on peanut qual. Peanut and Peanut Plant Compounds: Identity, Activity and Health Effects:.
1) Plant parts harvested over the last two growing seasons are being analyzed for bioactives and changes occurring due to growing yr. and loc. The MQRHU collaborated with the Food Sci. Unit to id. similar compounds in sweet potato plant parts. Methodology is being devel. to increase capacity to analyze for bioactives and nutrients. .
2)Samples representing most of the “Core of the Core” of the peanut germplasm collection were analyzed for nutritional components..
3)A study began eval. the antioxidant properties of hydrolyzed peanut proteins..
4) Peanuts, fat free meal, and oil were fed to hamsters bred to develop heart disease when fed high cholesterol diets. Preliminary data revealed pronounced effects on organs and blood chem. Peanut and peanut oil-containing diets were able to maintain cholesterol levels at low pre-study levels. Peanut Processing:.
1) Eval. of the planar microwave applicator for processing of farmers stock and shelled peanuts continued. Some compounds related to microwave induced off-flavor were id. A preliminary study determined that temps. sufficient to kill Salmonella can be achieved with almonds for pasteurization. .
2) Variation in oil crystallization behavior, as detected by rheological and differential scanning calorimetry measurements, was documented for commercial cultivars. Crystallization, viscosity, and density data were correlated to fatty acid profiles..
3) Rheological properties of model sys. prepared from peanut flours and peanut flours treated with transglutaminase were done..
4) The MQHRU collab. with the NPRL to evaluate chem. and sensory changes in peanuts stored under low O2 atmosphere.

Sampling plan for fruity fermented off-flavor in peanuts established. International consumer study showed foreign consumers possess similar preferences concerning peanut flavor as U.S. consumers and that some consumers actually prefer low levels of the fruity fermented off-flavor. This research addresses National Program 306 problem area 1c (Factors and Processes That Affect Quality).

Flavor compounds corresponding to artificially-created fruity fermented off-flavor and naturally occurring off-flavor proved to be different. No compound was identified that could reliably act as a marker for the off-flavor. This research addresses National Program 306 problem area 1d (Preservation and/or Enhancement of Quality and Marketability).

Analytical work on the “Core of the Core” of the peanut germplasm collection was completed. The results were presented at a national meeting and a journal submission is being prepared. This research addresses National Program 306 problem area 1d (Preservation and/or Enhancement of Quality and Marketability).

Peanut plants were collected from the 2006 planting and analysis has begun for bioactive molecule identification and antioxidant activity. This research addresses National Program 306 problem area 2b (New Uses for Agricultural By-products). Analysis of peanuts and processed products for bioactive compounds and changes due to process effects was done. A presentation was made at a national meeting and a journal article submission on the analytical methodology is being prepared. This research addresses National Program 306 problem area 1c (Factors and Processes That Affect Quality).

Sugars analysis in a series of germinated seeds was performed in collaboration with the NCSU Department of Horticulture to evaluate stress tolerance. A journal article was published. This research addresses National Program 306 problem area 1c (Factors and Processes That Affect Quality).

Sugars analysis was performed in collaboration with the NCSU Materials Science Department to evaluate the feasibility of certain wood pulp materials for ethanol fermentation after plasma hydrolysis. A presentation at a regional meeting was made and a grant proposal was prepared. This research addresses National Program 306 problem area 2c (New and Improved Processes and Feedstocks).

For oils from 9 commercially available peanut cultivars, significant (p<0.001) variation in crystallization behavior, liquid viscosity, and liquid density were documented. Oils from high oleic varieties had the highest viscosities, lowest densities and were the last to crystallize upon equivalent cooling treatments. All data was well correlated to the fatty acid profiles of the various oils, meaning this information can be used to breed and/or process oils with specific physical properties, ultimately improving the marketability of peanuts and other oilseeds. This research addresses National Program 306 problem area 1b (Methods to Evaluate and Predict Quality).

Rheological properties of model systems prepared from a range of commercially available peanut flours suggest a variety of texture applications for these ingredients. This research addresses National Program 306 problem area 1b (Methods to Evaluate and Predict Quality).

The food grade enzyme, Transglutaminase, was demonstrated to modify rheological properties of peanut flours while minimally affecting the potential allergenic response of these ingredients. Potential applications for this work include various high-protein bars and beverages common to the food industry. This research addresses National Program 306 problem area 1b (Methods to Evaluate and Predict Quality).

6.Technology Transfer

Number of patent applications filed2
Number of web sites managed1
Number of non-peer reviewed presentations and proceedings12
Number of newspaper articles and other presentations for non-science audiences2

Review Publications
Chapin, J.W., Sanders, T.H., Dean, L.L., Hendrix, K., Thomas, J.S. 2006. Effect of Feeding by a Burrower Bug, Pangaeus bilineatus (Say) (Heteroptera: Cydnidae), on Peanut Flavor and Oil Quality. Journal of Entomological Science 41:33-39.

Krinsky, B., Drake, M., Civille, G., Dean, L.L., Hendrix, K., Sanders, T.H. 2006. The development of a lexicon for frozen vegetable soybeans. Journal of Sensory Studies 21:644-653.

Truong, V., McFeeters, R.F., Thompson, R.L., Dean, L.L., Shofran, B. 2007. Phenolic acid content and composition in leaves and roots of common commercial sweetpotato (Ipomea batatas L.) cultivars in the United States. Journal of Food Science. 72(6):C343-C349.

Schirack, A.V., Sanders, T.H., Sandeep, K.P. 2007. Effect of processing parameters on the temperature and moisture content of microwave-blanched peanuts. Journal of Food Process Engineering 30(2)225-240.

Schirack, A.V., Drake, M.A., Sanders, T.H., Sandeep, K.P. 2007. Characterization of Aroma-Active Compounds in Microwave Blanced Peanuts. Journal of Food Science 71(9) C513-C520.

Leatherwood, W.R., Pharr, D.M., Dean, L.L., Williamson, J.D. 2007. Carbonhydrate Content and Root Growth in Seeds Germinated Under Salt Stress: Implications for Seed Conditioning. Journal of the American Society for Horticultural Science v. 132 (6) 876-882.

Last Modified: 7/22/2014
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