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United States Department of Agriculture

Agricultural Research Service

Title: Interference of Amino Acids in Pulsed Amperometric Detection of Peanut Sugars

Authors
item Singleton, John
item Grimm, Daniel - SOUTHERN TESTING & RES
item Sanders, Timothy

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: April 10, 1996
Publication Date: N/A

Interpretive Summary: Free amino acids and sugars are precursors for the nitrogenous compounds responsible for the "nutty aroma" perceived when peanuts are roasted. Monitoring sugars in food products has commercial application in quality control to determine adulteration of fruit juice, monitoring the fermentation process in the production of alcoholic beverages, and in the analysis of sweeteners. Sugars have been analyzed by several different methods which require many preparation steps and potential interferences from other compounds. Detection methods have been refined, and we have optimized a separation and detection method for peanut sugars which eliminates other interfering substances. This method can be applied to processed peanut products for determining sugar content in the finished product, and this is especially important since the total sugar content must be stated on all food labels.

Technical Abstract: High performance anion exchange chromatography and pulsed amperometry were used to separate and quantify peanut sugars extracted with methanol: chloroform:water (60:25:15, V/V/V), a highly polar solvent which solubilizes other seed components including amino acids. Free sugars were separated on an anion exchange column using a sodium hydroxide gradient and ddetected with a pulsed amperometric detector equipped with a gold electrode. Free amino acids in the seed extract interfered with sugar analysis by causing peak shifting and co-elution of some amino acids with sugars. Free arginine co-eluted with inositol resulting in a peak area which was 42% less than the actual total area for both compounds. Proline co-eluted with fructose. Serine eluted on the leading edge of sucrose. Peak areas of these interfering amino acids were either "additive" or "subtractive" to sugar peaks. Altering the gradient elution or using cation nsyringe filters to remove contaminant amino acids, permitted the accurate identification and quantification of peanut seed sugars. Results from this study suggest applications that can be applied in other biological systems containing free amino acids and sugars.

Last Modified: 4/20/2014
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