Biological activity of proteins from pulps of tropical fruits

Proteins present in fruit pulps were extracted and concentrated to 90% saturation point with ammonium sulfate. The total protein content (mg/g) from each fruit pulp was: Assai (0.20), Suriname Cherry (0.10), Mangaba (0.62), Yellow Mombim (0.15), Acerola (0.17), Cupuassu (0.54), Melon (0.24) and Passion fruit (0.80). Inhibitory activity against digestive enzymes, bovine trypsin, human salivary α-amylase and porcine pancreatic α-amylase, were assessed. Results show that inhibitory activity against pancreatic α-amylase was greater in yellow mombim and cupuassu pulps with 0.0345 and 0.0335 mg inhibitor/g pulp, respectively. Melon and assai pulps had the greatest inhibitory activity towards salivary α-amylase with 0.042 and 0.142 mg inhibitor/g pulp, respectively. Antitryptic activity was detected in Assai, mangaba, yellow mombim, suriname cherry, acerola and cupuassu. The levels of inhibitory activity were low for most fruits and those with highest activities were assaı́ (0.054 mg/g), mangaba (0.0395 mg/g) and cajá (0.0328 mg/g).