Analyzing Phenolic Composition of Lentil Flour

January 7/Salamanca, Spain/Food Business Week -- "The phenolic composition of lentil flour samples, processed with and without the addition of tannase during different times of incubation, 30, 60, 90, 120, 150 and 180 minutes, were analyzed by high-performance liquid chromatography-photodiode array detector-mass spectrometry (HPLC-PAD-MS). Quantitative and qualitative differences in the identified phenolic compounds were observed between the two studied processes, and with respect to the raw lentils," scientists in Salamanca, Spain, report.

"Processed lentils with and without tannase, contain gallic acid, gallic aldehyde and trans-resveratrol, compounds not detected in raw lentils. Quercetin 3-O-rutinoside and luteolin undergo an increase as a consequence of the processes. Analysis of principal components to examine the relationship between time of processing and concentration of phenolics in every lentil sample showed that incubation time is not the only factor that influences the modification of phenolic compounds, but also the activation of the endogenous enzyme together with the addition of commercial tannase, that can bring out synergic and/or antagonist effects depending on the structure of phenolic compound," wrote M. Duenas and colleagues, University of Salamanca.

The researchers concluded, "The application of commercial enzymes in the food industry has been recognized as a useful tool to improve the utilization of nutrients and the quality in raw materials. The success of the enzymatic treatment of legume flours depends on the biochemical reactions developed during the action of enzymes. The objective of this study was to know the modifications in the bioactive phenolic compounds of lentils, comparing the action of natural endogenous enzymes of the substrate with that of commercial tannase, in order to improve the functionality of the obtained lentils flours which could be used as supplement in some foods."

Duenas and colleagues published their study in the Journal of Food Processing and Preservation (Comparative Study of the Phenolic Composition in Lentils Processed with and without Addition of Commercial Tannase." Journal of Food Processing and Preservation, 2009;33(6):695-713).

For additional information, contact M. Duenas, University of Salamanca, Faculty Farm, Group Invest Polifenoles, Unidad Nutrition & Bromatol, Campus Miguel Unamuno, E-37007 Salamanca, Spain.

From the January 18, 2010, Prepared Foods E-dition