Chemical composition, in vitro digestibility and antioxidant activity of solid wastes from the fruits of Silybum marianum

The chemical composition of solid wastes from Silybum marianum fruits (WSS) and the contents of total polyphenols, total flavonoids and antioxidant activity of the extracts from WSS with distilled water, ethanol (40%, 70% and 95%) and methanol was investigated. Chemical analysis indicated that WSS contained high amounts of crude protein (25.58%), calcium, potassium and magnesium. The content of plumbum, selenium and arsenium in WSS was below the maximum level established by the Commission of the European Communities. Essential amino acids in WSS favorably compared with the recommended level for pre-school children. Nitrogen release of WSS during sequential pepsin and trypsin digestion was 70.60%. The 70% ethanol extract exhibited the highest antioxidant activity. The nutritional compositions and bioactive compounds in WSS made it appropriate for applications in feedstuffs as supplemental sources in animal feeds and food additives.