Correlation of colour, antioxidant capacity and phytochemical diversity of imported saffron by principal components analysis

Abstract

PurposeThe aim of the present study is to gain correlation between saffron colours, their antioxidant capacity and the constituents of the secondary metabolites of three different saffron samples commonly available in the Malaysian market.Design/methodology/approachIn this study, saffron samples imported from Iran, Spain and Kashmir were extracted using methanol and the total antioxidant capacity were analysed using 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical-scavenging assay. Ultra-high performance liquid chromatography (UHPLC) and electrospray ionization coupled with mass spectrometry (ESI-MS/MS) were then used to identify secondary metabolites present in the saffron crude extracts. The colour variation of the saffron extract was expressed by the CIELAB colorimeter in terms of lightness (L*), greenness (a*), yellowness (b*), chroma (C) and hue angle (H°). Principle component analysis (PCA) was carried out to analyse the similarities and correlation between variables.FindingsThis study reveals that antioxidant has a positive correlation with flavanols, especially quercetin and kaempferol. In addition, colour appearance is not necessarily an indicator for the antioxidant level.Research limitations/implicationsThe major classes of polyphenolics identified in saffron methanolic crude extract are flavonoids and phenolic acids. Further improvements in the extraction and identification methods may find other compounds that could attribute to the visual factors and antioxidant capacity as a complement for this preliminary study.Practical implicationsThis analysis provides comparison basis and valuable information for saffron consumers in Malaysia depending on the consumers’ purpose of whether to have a certain desired colour or health benefits.Originality/valueA comparative study about saffron product available in Malaysian market is original. To the best of the authors’ knowledge, this is the first attempt of evaluation on a saffron product that has been carried out in Malaysia.