Enzymatically assisted extraction of antioxidant and anti-mutagenic compounds from radish (Raphanus sativus)

In addition to being sources of carbohydrates, protein, and fiber, vegetables, and fruits also represent important sources of micro-nutrients, including antioxidants, and anti-mutagens in the form of carotenoids, and polyphenols, such as flavonoids. We describe the enhanced extraction of these bioactive compounds from radish (Raphanus sativus L.) by use of an enzymic pre-treatment to break up starch, and the complex mix of polysaccharides, cellulose, hemicellulose, and pectin, which constitute the plant cell wall. The enzymic cocktail included cellulases, pectinases, amylases, glucanases, and hemicellulases. Response surface methodology (RSM) was utilized to maximally explore the yield by estimating extraction conditions, enzyme concentration, incubation time, temperature, pH, and extraction solvents. Extracted antioxidant activity was assayed in terms of total phenolics content (TPC), free radical scavenging (DPPH and ABTS tests), inhibition of linolic peroxidation assay, Reducing potential, and Trolox equivalent antioxidant capacity (TEAC). Two different bacterial mutant strains (TA-98, TA-100, S. typhimurium) were used by applying Ames bacterial test. It was concluded that highest desirability was achieved at 3.53% (w/w) of enzyme formulation, at pH of 6.1, incubation time 66.08 min and 46.08 °C temperature produced 19.2 g/100 g FW of crude extract which contains 45.9 mg GAE/g FW total phenolics contents, 0.480 mg/mL Reducing Power, 85.9% LA inhibition and 271.7 mmole/g FW of TEAC in fresh radish root. We found that radish extract was an excellent source of antioxidants that might be further investigated for commercial exploitation.