Autolysate and enzymatic hydrolysates from yam (Dioscorea opposita Thunb.) tuber mucilage tororo have antioxidant and angiotensin I-converting enzyme inhibitory activities

Author: Takeshi Nagai ^1*, Nobutaka Suzuki ² and Toshio Nagashima ¹

Received 08 September 2006, accepted 27 November 2006.

Abstract

Autolysate and enzymatic hydrolysates from yam (Dioscorea opposita) tuber were prepared and the functional properties were demonstrated. The yields of lyophilized powders obtained were low, 0.75-2.0% on the basis of fresh tuber. Each lyophilized powder possessed high antioxidative and scavenging activities against superoxide anion and hydroxyl radicals. Particularly trypsin hydrolysate exhibited strongly these activities. Moreover, these samples showed angiotensin I-converting enzyme inhibitory activities similar to peptides derived from casein, fish muscle and other food proteins. The present study indicates that autolysate and enzymatic hydrolysates from yam tuber whose health benefits are supported by sufficient scientific substantiation have the potential to be an increasingly important component of a healthy lifestyle and to be beneficial to the public and the food industry.

Key words: Yam tuber, autolysate, enzymatic hydrolysate, antioxidant ability, free radical scavenging ability, ACE inhibitory capacity.