Hydrolysate preparation with high content of 5-hydroxytryptophan from liquid egg protein and its sleep-potentiating activity

Jung Il Kwon, Yooheon Park, Sung Hee Han, Hyung Joo Suh

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)


Alcalase hydrolysis of liquid egg white was used to produce 5-hydroxytryptophan (HTP) under various conditions and investigate the sleep-potentiating activity of liquid egg white hydrolysate (LEH) on pentobarbital-induced sleep. Alcalase hydrolysis yielded the highest content of 5-HTP (13.50 μg/mL), while neutrase hydrolysis showed the lowest 5-HTP content (5.23 μg/mL). The liquid egg white to water ratio (1:1) was optimal for the production of 5-HTP with high amino-nitrogen (A-N) content and degree of hydrolysis. The 5-HTP, aminonitrogen, and degree of hydrolysis increased until 24 h of hydrolysis and slightly increased thereafter during hydrolysis with 2% and 5% enzyme addition. 5-HTP administration at doses of 6 and 9 mg/kg significantly increased sleep duration and decreased sleep latency time compared to that in the control (p<0.05). LEH (150 mg/mouse), which was equivalent to 5-HTP at 6 mg/kg, significantly decreased sleep latency time and increased sleep duration time compared to that in the control (p<0.05). Oral administration of LEH showed sleep-potentiating effects because of 5-HTP. The sleep-potentiating activity of LEH may have occurred through 5-HTP in our pentobarbital-induced sleep model. LEH may be a valuable alternative to sleep enhancement and may be used as a sleep-potentiating agent.

Original languageEnglish
Pages (from-to)646-653
Number of pages8
JournalKorean Journal for Food Science of Animal Resources
Issue number5
Publication statusPublished - 2017 Oct

Bibliographical note

Funding Information:
This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF), funded by the Ministry of Science, ICT, and Future Planning (2014R1A2A1A11052187).

Publisher Copyright:
Copyright © Korean Society for Food Science of Animal Resources.


  • 5-hydroxytryptophan
  • Alcalase
  • Hydrolysate
  • Liquid egg white
  • Sleep-potentiating activity

ASJC Scopus subject areas

  • Food Science
  • Animal Science and Zoology


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