Abstract: The effects of four cooking methods, namely boiling, steaming, stir-frying and microwaving, on the texture, structure and pasting properties of Chinese yam tubers were investigated. The results showed that the hardness of Chinese yam tubers was decreased significantly after cooking (P < 0.05). Microwave cooking resulted in significantly high chewiness (P < 0.05), whereas the chewiness was significantly lowered by boiling and steaming (P < 0.05). After cooking, starch in yam tubers showed varying degrees of gelatinization, the crystal structure was damaged to varying degrees. Among the cooking methods, microwaving led to the lowest gelatinization degree, while steaming resulted in the lowest orderliness and crystallinity of starch granules. Different cooking methods had a significant effect on the pasting properties of yam tubers. The pasting temperature was significantly increased by microwaving (P < 0.05), but was significantly decreased by the other cooking methods (P < 0.05). In conclusion, different cooking treatments have different effects on the structure and gelatinization properties of Chinese yam tubers , which can provide a theoretical basis for Chinese yam scientific cooking.

Key words: Chinese yam; cooking methods; structure; pasting properties