Abstract:The proteinsamino acid composition, the total sugar, total phenol and the contents of water, salt, ethanol, tris(hydroxymethyl)aminomethane (Tris) and isoelectric point precipitation extracts of Zhangxi taro were determined. The antioxidant capacity, coagulating activity and trypsin inhibitory activities of the five extracts were analyzed, in order to obtain a taro protein extract with relatively high activity. The results from the experiment on antioxidant activity showed that all extracts had certain 2,2′-azino-bis (3-ethylbenzothiazoline- 6-sulfonic acid) (ABTS)?and hydroxyl radical scavenging capacities, and the Tris extract exhibited relatively strong scavenging capacities for both radicals. All taro extracts showed agglutinating activity against rabbit erythrocytes, but no coagulation activity against sheep erythrocytes. The specific hemagglutinating activities of the five extracts were as follows: salt extract (3.24 × 103 HU/mg) > Tris extract (2.88 × 103 HU/mg) > isoelectric point precipitation (1.86 × 103 HU/mg) > water extract (1.41×103 HU/mg) > ethanol extract (0.98×103 HU/mg). Among the five extracts, ethanol extract had no trypsin inhibitory activity. Salt extract, water extract, and Tris extract had higher trypsin inhibitory activities, and the corresponding values were 134 TIU/mg, 130.51 TIU/mg, and 113.30 mg/TIU, respectively. In conclusion, the Tris extract contained more proteins with high activity among the five extracts, as well as more protein bands than the others.
