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 journalArticle

1 Citation (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 1



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

ASJC Scopus subject areas

  • Food Science
  • Animal Science and Zoology

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