Comparative variability of nutrients, minerals, phenolics and anthocyanins with antioxidant potentials during fruit development stages in five Mulberry (Morus) cultivars

Abstract

Abstract BACKGROUND: The versatility of mulberry from the Morus genus is growing among various suppliers and users globally. OBJECTIVES: To assess the variations in total sugar, acidity, minerals, phenolics and anthocyanins and antioxidant dynamics of three black mulberry (Morrus serrata, M. nigra and M. macroura black) and two white mulberry cultivars (M. alba and M. macroura white) during development stages. METHODS: Total sugars and titratable acidity were evaluated with AOAC methods and TPC was estimated with folin-ciocalteau method. The antioxidant activity was determined with DPPH assay, minerals were quantified with atomic absorption spectroscopy and anthocyanins were assessed with pH differential assay and identified with HPLC and LC-MS. RESULTS: Over all, M. alba (white cultivar) displayed maximum sugar (1.35%) at development stage 3 (FDS-3) followed by M. serrata (black cultivar) at FDS-5 (1.1%) and M. macroura white (white cultivar) at FDS-4 (0.9%). A decreasing trends in acidity in M. alba (0.8-0.09%), M. nigra (0.8-0.03%) and M. macroura white (0.6-0.04%) were observed during development. TPC was maximum (590 GAE/100g) in M. nigra at FDS-6 and M. serrata (450 GAE/100g) at FDS-7. Two black cultivars (M. serrata and M. nigra) showed significant increase in total anthocyanins (14.57-100.06 and 14.13-201.87 CGE/100g FW) from FDS-1 to FDS-7 while decrease in M. macroura black and M. macroura white (17.07-11.79 and 9.03-2.68) from FDS-1 to FDS-7. The DPPH inhibition of black mulberry cultivars was pointedly greater with elevated levels of Fe, Cu, Zn, Ca, Mg, Na, P and K than white cultivars during maturity. HPLC and MS procedures identified various anthocyanins in all mulberry cultivars including cyanidin, cyanidin rutinoside, mono glucosides of malvidin, pelargonidin and delphinidin. CONCLUSIONS: The selection of mulberries with improved nutrition, acceptable range of metals, bioactive compounds and higher antioxidant potentials could be a significant natural cure against health related complications such as diabetes and other metabolic syndromes.