Milk-clotting activity of berries extracts from nine Solanum plants

Nine Solanum species (Solanum aculeastrum, Solanum aethiopicum, Solanum anomalum, Solanum cerasiferum, Solanum dasyphyllum, Solanum indicum, Solanum nigrum, Solanum nodiflorum and Solanum terminale) berries were studied in order to find a new source of milk-clotting enzymes for artisanal use by Cameroonian farmers. The results showed that milk-clotting activity was obtained by soaking fresh and dried berries in either distilled water or 5% NaCl solution. Maximum milk-clotting activity was obtained by soaking dried berries in 5% NaCl solution at optimum time of extraction for each species. Dried berries released active enzymes more easily than fresh ones, and addition of salt facilitated the extraction process. Extract from S. aethiopicum berries had the highest milk-clotting activity. All extracts had proteolytic activity. High milk-clotting and proteolytic activities were found in extract from S. cerasiferum obtained after 24 h of soaking dried berries in 5% NaCl solution. High milkclotting and low proteolytic activities were found in extract from S. aethiopicum obtained under same condition

Milk-clotting potential of fruit extracts from Solanum esculentum, Solanum macrocarpon L. and Solanum melongena

Fruit extracts from Solanum esculentum, Solanum macrocarpon L. and Solanum melongena were tested for their milk-clotting potential. The release of substances associated with milk-clotting was highly dependent upon quantity of berries, extraction duration and sodium chloride concentration. The highest milk-clotting activity was obtained after 8 h (for S. esculentum and S. melongena), and 12 h (for S. macrocarpon) of soaking 20 g of fruit in 6% NaCl 4°C. In these conditions, there was a non linear relationship between the milk-clotting time and the amount of fruit extracts from each species. The loss of milk-clotting activity was dramatic after wet-heating of extracts from S. esculentum and S. macrocarpon at 80°C for 10 min and after dry-heating of fruits at 100°C for 24 h. Heat treatment did not significantly affect the clotting activity of extract from S. melongena. Fruit extracts from S. esculentum had the greatest milk-clotting activity followed by extracts from S. macrocarpon and S. melongena. Extracts from S. esculentum and S. macrocarpon exhibited a proteolytic activity on the casein