FOOD SCIENCE ›› 2012, Vol. 33 ›› Issue (15): 262-265.

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Effect of Ultra High Pressure Treatment on Polyphenol Oxidase Activity in Purple Sweet Potato

  

  • Received:2011-10-23 Revised:2012-07-11 Online:2012-08-15 Published:2012-09-07

Abstract: Purple sweet potato Jishu 18 was used to investigate the effect of combined ultra high pressure (UHP, 100—600 MPa) and heat (20—60 ℃) treatment on polyphenol oxidase (PPO) activity in purple sweet potato. The results showed that in the investigated range of pressure, UHP treatment at 500 MPa and 30 ℃ for 10 min resulted in maximum PPO activity in Jishu 18, exceeding the pre-treatment activity level. When the UHP pressure was 600 MPa, PPO activity in Jishu 18 indicated an upward trend with increasing temperature up to 30 ℃, followed by a decline at higher temperature. Moreover, a decreasing trend was found with prolonged pressure holding time. PPO activity decreased gradually during the first 20 min of UHP treatment at 300 MPa, but increased during the subsequent 30 min. Consequently, PPO activity is tolerant to high pressure. The results of orthogonal array design experiments revealed that treatment at 600 MPa and 65 ℃ for 35 min had the best inhibitory effect on PPO activity in purple sweet potato.

Key words: ultra-high pressure, purple sweet potato, polyphenol oxidase

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