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

Abstract

BACKGROUND: Mulberry (Morus) from the Moraceae family is distributed widely in tropical to temperate regions of the world having economic and medicinal significance with exceptional nutritional characteristics. OBJECTIVES: Assessment of variations in sugars, acidity, minerals, total phenolics, anthocyanins and antioxidant potentials 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 acidity were evaluated with AOAC methods and total phenolic content was estimated with folin-ciocalteau method. Antioxidant activity was evaluated with DPPH assay, minerals were quantified with atomic absorption spectroscopy and anthocyanins were assessed and identified with high performance liquid chromatography and liquid chromatography-mass spectroscopy. RESULTS: Over all, M. alba (white cultivar) displayed maximum sugar (1.35%) at fruit development stage 3 (FDS-3) following M. serrata (black cultivar) at FDS-5 (1.1%) and M. macroura white (white cultivar) at FDS-4 (0.9%). Acidity decreased in M. alba (0.8–0.09%), M. nigra (0.8–0.03%) and M. macroura white (0.6–0.04%) during development. Total phenolic content was maximum (590 GAE/100 g) in M. nigra at FDS-6 and M. serrata (450 GAE/100 g) 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/100 g 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 mulberries was pointedly greater with significant levels of iron, copper, zinc, calcium, magnesium, sodium, phosphorus and potassium than white cultivars during maturity. HPLC and LC-MS procedures identified various anthocyanins in all cultivars including cyanidin, malvidin, pelargonidin and delphinidin. CONCLUSIONS: Mulberries with improved nutrition, acceptable range of metals, bioactive compounds and higher antioxidant potentials could be significant against various diseases like cancer, cardiovascular problems, neurodegenerative disorders, obesity, diabetes and other metabolic syndromes.