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Food Science and Biotechnology
→ Food Science and Biotechnology 2018 ; 27(1): 27-36
Comparison of structural features and in vitro digestibility of purple yam (Dioscorea alata L.) resistant starches by autoclaving and multi-enzyme hydrolysis
Tao Li1, Fengping An1, Hui Teng1, Qun Huang1, Feng Zeng1, Hongbo Song1,2
1College of Food Science, Fujian Agriculture and Forestry University, Fuzhou 350002, Fujian Province, China, 2Fujian Provincial Key Laboratory of Quality Science and Processing Technology in Special Starch, Fuzhou 350002, Fujian Province, China
ABSTRACT
Resistant starches (RS) were prepared from purple yam by dual autoclaving-retrogradation (DAS), and pullulanase debranching treatment (PDS). DAS and PDS were then hydrolyzed by α-amylase and amyloglucosidase to obtain DAS.H and PDS.H. Differences in structural characteristics and in vitro digestibility among the four samples were investigated. The results showed that granules of RS had a rough surface and irregular shape. DAS had the lowest amylose content (29.52%), whereas PDS.H had the highest amylose content (41.96%). The order of crystallinity of the RS was: PDS.H (31.23%)>DAS.H (30.16%)>PDS (21.23%)>DAS (15.30%). Analysis by in vitro digestibility indicated a decreased hydrolysis index and glycemic index due to lower swelling power and water-binding capacity, and a well-ordered double helix structure and more crystallization in PDS.H than in the other RS samples. These results suggest that pullulanase debranching combined with α-amylase and amyloglucosidase hydrolysis may produce better RS with improved crystalline structure and higher digestion resistibility.
KEYWORD
Purple yam, Resistant starch, Hydrolysis, Structure, Digestibility
Food Science and Biotechnology 2018 ; 27(1): 27-36
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