Characterization of Turmeric and Curry Samples by Liquid Chromatography with Spectroscopic Detection Based on Polyphenolic and Curcuminoid Contents

Abstract

This paper deals with the characterization of turmeric and related products using the compositional fingerprints of curcuminoids (e.g., curcumin, demethoxycurcumin and bisdemethoxycurcumin) and other phenolic compounds (e.g., hydroxybenzoic and hydroxycinnamic acids and flavonoids) as the source of analytical information. Under this approach, the quantitative determination of analytes becomes unnecessary and even data from unknown components can be advantageously exploited for sample exploration and authentication. The methodology relied on sample extraction with hydro-organic solvents to recover the components of interest and further analysis of the corresponding extracts by liquid chromatography with diode array detection (HPLC-DAD). Extraction conditions were optimized focusing on the independent recovery of curcuminoids and polyphenols. Two different HPLC methods under reversed-phase mode were used to generate the chromatographic fingerprints at 420 and 280 nm for the specific monitoring of curcuminoids and polyphenols, respectively. Both extraction and separation steps were optimized under experimental design approaches to achieve the richest compositional fingerprints in terms of variety of components. The resulting data was subsequently treated chemometrically by principal component analysis (PCA) and related classification methods to achieve a better overall description of samples. Polyphenolic fingerprints were appropriate to discriminate among turmeric and mixed spices, while curcuminoid fingerprints could be useful to distinguish turmeric varieties.

Characterization, Classification and Authentication of Turmeric and Curry Samples by Targeted LC-HRMS Polyphenolic and Curcuminoid Profiling and Chemometrics

“…This work aims to evaluate the suitability of targeted LC-HRMS polyphenolic and curcuminoid profiles as sample chemical descriptors to address the characterization and classification of turmeric versus curry samples. For that purpose, a simple liquid–solid extraction procedure to recover polyphenolic and curcuminoid compounds with dimethyl sulfoxide (DMSO) as the extracting solvent was proposed [ 40 ].…”

“…Gas chromatography coupled to mass spectrometry (GC–MS) has also been used for the characterization of powdered turmeric [ 32 ] and turmeric oil [ 33 ] samples. Nevertheless, liquid chromatography (LC) with UV detection (LC-UV) [ 34 , 35 , 36 , 37 , 38 , 39 , 40 ] and coupled to mass spectrometry (LC–MS) [ 32 , 41 ] are currently the techniques of choice. Besides, the great chemical diversity among bioactive substances, including polyphenolic and curcuminoid compounds, and the wide range of concentrations in which these phytochemicals can be found in turmeric and related products make liquid chromatography coupled to high-resolution mass spectrometry (LC-HRMS) the most appropriate strategy for characterization, identification and authentication purposes [ 42 ].…”

“…Apart from quantitative methods, instrumental signals such as chromatographic peak areas of known selected compounds are a good alternative for food characterization and classification, also providing chemical information related to bioactive substances [ 22 , 23 , 24 ]. In this regard, polyphenolic and curcuminoid profiling by HPLC-UV has been reported for the characterization of turmeric and curry samples [ 39 , 40 ]. Finally, the use of DNA barcoding by polymerase chain reaction (PCR) amplification was also proposed for the detection of plant-based adulterants (cassava starch, wheat, barley and rye) in turmeric powder samples [ 52 ].…”

Non-Targeted Ultra-High Performance Liquid Chromatography-High-Resolution Mass Spectrometry (UHPLC-HRMS) Fingerprints for the Chemometric Characterization and Classification of Turmeric and Curry Samples

“…Samples were analysed in triplicate, thus obtaining 63 turmeric and 27 curry sample extracts. Sample extracts were obtained following previously described procedures with some modifications [24]. Turmeric or curry samples (10 mg) were suspended in 5 mL of DMSO and extracted by sonication (Branson 5510 bath, Branson Ultrasonics, Danbury, CT, USA) at room temperature during 15 min.…”

“…Few critical reviews addressing the characterization and determination of curcumin and curcumin derivatives in turmeric samples have been reported [1,2,13,14]. Analytical methodologies involved spectroscopy such as ultraviolet [15], fluorescence [16], infrared [17,18], and nuclear magnetic resonance (NMR) [19], as well as separation techniques such as capillary electrophoresis (CE) [20][21][22], liquid chromatography (LC) [23][24][25][26], and gas chromatography (GC) [27,28].…”