title: Glucose tolerance and antioxidant activity of spent brewer's yeast hydrolysate with a high content of Cyclo-His-Pro (CHP).
abstract: To elevate the Cyclo-His-Pro (CHP) content in yeast, the yeast hydrolysate that was obtained from enzymatic hydrolysis was subjected to various treatments. Flavourzyme-treated hydrolysate showed the highest CHP content (674.0 μg/g) among the various proteases treatments. Ultrafiltration was selected as the best method for concentrating CHP in yeast hydrolysate, based on the yields and CHP contents. In addition, we evaluated the radical scavenge and glucose tolerance of yeast hydrolysate with a high content of CHP. Yeast hydrolysate showed intense scavenging abilities of both 1, 1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals. The IC(50) values of yeast hydrolysate on DPPH and ABTS radicals were 1.9 and 0.9 mg/mL, respectively. There were significant differences in glucose level between the diabetes-control and yeast hydrolysate group at 30, 60, 90, and 120 min after injection in a type 1 diabetes model (P < 0.01). Also, there were significant differences in blood glucose levels between the 2 groups at 30, 60, and 100 min after injection in the type 2 diabetes group (P < 0.05). Therefore, it is possible to use the yeast hydrolysate with high levels of CHP as an antioxidative and/or antidiabetic material for the preparation of functional foods.
  
  
  CONCLUSIONS
  This study tried to develop a material containing a high content of CHP using yeast for possible applications of this cyclic dipeptide in the therapy of metabolic disorders. The yeast hydrolysate prepared with Flavourzyme showed a high level of CHP. The hydrolysate with a high content of CHP showed high levels of radical scavenging activities and oral glucose tolerance activity. Therefore, it is possible to use the yeast hydrolysate with high levels of CHP as an antioxidative and/or antidiabetic material for the preparation of functional foods.
authors.affiliation: Dept of Food and Nutrition, Korea Univ, Seoul 136-703, Republic of Korea.
authors.forename: Eun Young
authors.initials: EY
authors.lastname: Jung
authors.forename: Hyun-Sun
authors.initials: HS
authors.lastname: Lee
authors.forename: Jang Won
authors.initials: JW
authors.lastname: Choi
authors.forename: Kyung Soo
authors.initials: KS
authors.lastname: Ra
authors.forename: Mi-Ryung
authors.initials: MR
authors.lastname: Kim
authors.forename: Hyung Joo
authors.initials: HJ
authors.lastname: Suh
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism*; D052160:Benzothiazoles / Q000378:metabolism; D001713:Biphenyl Compounds / Q000378:metabolism; D001786:Blood Glucose / Q000032:analysis*; D055598:Chemical Phenomena; D003920:Diabetes Mellitus; D004151:Dipeptides / Q000032:analysis*; D010450:Endopeptidases / Q000032:analysis; D016166:Free Radical Scavengers / Q000378:metabolism; D005951:Glucose Tolerance Test; D006868:Hydrolysis; D007004:Hypoglycemic Agents / Q000378:metabolism; D007333:Insulin Resistance; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010456:Peptides, Cyclic / Q000032:analysis*; D010851:Picrates / Q000378:metabolism; D011492:Protein Hydrolysates / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D013451:Sulfonic Acids / Q000378:metabolism
chemical_list: D000975:Antioxidants; D052160:Benzothiazoles; D001713:Biphenyl Compounds; D001786:Blood Glucose; D004151:Dipeptides; D016166:Free Radical Scavengers; D007004:Hypoglycemic Agents; D010456:Peptides, Cyclic; D010851:Picrates; D011492:Protein Hydrolysates; D013451:Sulfonic Acids; C035699:histidylproline; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; C004931:1,1-diphenyl-2-picrylhydrazyl; D010450:Endopeptidases; C412470:flavourzyme