Mechanism of anti-obesity and anti-diabetic activities of chicken egg white protein

2021 Fiscal Year Final Research Report

• Project/Area Number: 20K22567
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0601:Agricultural chemistry and related fields
• Research Institution: Miyagi University
• Principal Investigator: Akazawa Takashi 宮城大学, 食産業学群, 助教 (00882276)
• Project Period (FY): 2020-09-11 – 2022-03-31
• Keywords: 鶏卵白 / ペプチド / 抗肥満 / 抗糖尿病

Outline of Final Research Achievements

Egg white hydrolysate prepared with pepsin (EWP) is known to reduce intra-abdominal fat accumulation and improve glucose tolerance. However, the active compound in EWP has not been determined. In this study, EWP was fractionated into a peptide fraction and a protein fraction. The effect of these fractions on glucose and lipid metabolisms was investigated in mice fed a high-fat and high-sucrose diet. Consuming the peptide fraction reduced the weight of the epididymal adipose tissue, liver cholesterol content, and plasma glucose level. Meanwhile, consumption of the protein fraction did not suppress fat accumulation, but it improved glucose tolerance as deduced from an oral glucose tolerance test. These findings suggest that EWP exerts its activity through the peptide fraction to inhibit fat accumulation and the protein fraction to improve glucose tolerance, respectively.

Free Research Field

食品科学

Academic Significance and Societal Importance of the Research Achievements

EWPの脂肪蓄積抑制作用に中心的に関与している成分は卵白タンパク質オボアルブミンであると考えられており，オボアルブミンが消化管において胆汁酸によるミセル形成を阻害し，脂質の吸収を阻害することで脂肪蓄積を抑制していると考えられている。一方，本研究ではタンパク質画分ではなく，低分子ペプチド画分から脂肪蓄積の抑制作用が認められた。また，ペプチド画分は食餌脂質の吸収を阻害しなかった。よって，オボアルブミンとは異なる作用メカニズムで抗肥満作用を示す卵白活性ペプチドの存在を明らかにすることができた。EWPのペプチド画分は，肥満や脂質代謝を改善する機能性食品素材となることが期待できる。