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United States Department of Agriculture

Agricultural Research Service

2011 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
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. A study was 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.

Peanuts shipped to Europe from the U.S., China, and Argentina were examined for oil quality and both descriptive sensory and consumer analysis of flavor to clearly demonstrated the superior quality of U.S. peanuts. Consumer studies in Europe demonstrated a preference for U.S. peanuts.

European consumer response to peanuts of different origins provided data which demonstrated that European 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. 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. Volatile compounds corresponding to artificially-created fruity fermented off-flavor and naturally occurring off-flavor proved to be different.

For oils from 9 commercially available peanut cultivars, significant 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.

Samples representing most of the “Core of the Core” of the peanut germplasm collection from a three crop years were analyzed for nutritional components. Fatty acids, amino acids, tocopherols and total folates were determined.

Research was completed to determine the niacin and folate derivative concentrations in several core of the core and UPPT samples. Peanuts skins have extremely high antioxidant capacity and identification of compounds responsible has been initiated. Volatile compound analysis related to roasted peanutty flavor was conducted on peanuts of different maturity classes. Model systems prepared from high aroma active compounds were similar to roasted peanut aroma.

Last Modified: 5/23/2015
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