Volume 7, Issue 4, August Issue - 2019, Pages:403-410
Authors: Anumol Jose, Sajna Nizar, Vishnu MR, Anil Kumar M
Abstract: The present study aims to evaluate and compare the phenolics, pigment content and antioxidant potential of the four landraces of Dioscorea alata prevalent in Kerala. Dioscorea alata (greater yam) is an underutilized, food security crop that exhibits wide variability in morphological, biochemical and agronomical traits. One of the distinct morphological features that varied among landraces of D. alata is tuber flesh colour which ranged from white, yellow, pink and purple. CIELAB coordinates of each tuber colour were estimated using reflectance spectroscopy and represented in L*a* b* values. Quantification of total phenolic compounds and pigments were done spectroscopically using standard protocols. Antioxidant activity of the tuber extracts were estimated using 1,1-Diphenyl-2-picryl hydrazyl (DPPH) quenching assay and ferric reducing antioxidant power (FRAP) assay. Total phenol and flavonoid content in yellow and purple-fleshed D. alata were significantly higher than white and pink fleshed landraces. Spectrophotometric assays revealed the differential expression of anthocyanins and carotenoids in tubers, which corresponds to the colour difference among different landraces. Antioxidant activity based DPPH and FRAP assay were significantly different among the four landraces. Yellow and purple-fleshed landraces shared high antioxidant activity and was positively correlated with the phenolic and pigment contents. The study also listed certain morphological features that aid in identifying the landraces of D. alata.