대두 펩타이드의 표면소수도가 혈청 콜레스테롤의 농도에 미치는 영향을 조사하기 위하여, 대두 단백질(ISP), 카세인(CNP), 이들 단백질을 펩신으로 가수분해하여 pH에 따른 펩타이드 침전 획분들(SHT, SH8, SH6, SH4, CHT, CH6, CH5, CH4)을 흰쥐에 섭취시키고 혈청 콜레스테롤 농도 및 분변 스테로이드이 배설량을 측정하였다. 그리고 각 펩타이드의 표면소수도를 ANS 형광법 및 SDS 결합법으로 측정하여, 이들의 상관관계를 분석한 결과, 펩타이드의 ANS 표면소수도가 높아질수록 분변으로 배설된 스테로이드량은 증가하였으며(r=0.81), 혈청 콜레스테롤 농도는 낮아졌다.(r=-0.868). 그러나 SDS 표면소수도는 그들과 상관관계가 없었다. 또한 대두 단백질은 가수분해에 의하여 ANS 표면소수도가 증가하였다. 이상의 결과는 흰쥐의 담즙염이, 소화중 생성된 높은 표면소수도의 펩타이드와 결합하여 체외로 배출되므로서 대두단백질의 섭취에 의한 혈청 콜레스테롤 농도가 낮아짐을 시사하였다.
Effect of surface hydrophobicity of soybean peptides on serum cholesterol in rats was investigated. Soybean protein(ISP), casein(CNP), and their peptic hydrolyzates fractionated by acid precipitations (SHT, SH8, SH6, SH4, CHT, CH6, CH5, CH4) were fed to rats and the concentration of serum cholesterol and the fecal steroid excretion were measured. And surface hydrophobicities of the peptide fractions were measured by determining by the ANS flourescence intensity and SDS binding capacity. It was found that the higher the surface hydrophobicity of peptides was, the more the fecal steroids excreted(r=0.801) and the lower the concentration of serum cholesterol became(r=-0.868). However, there was no relationship between SDS surface hydrophobicity and fecal steroids or serum cholesterol. ANS surface hydrophobicity of soybean protein was increased by enzymatic hydrolysis. These results suggest that high surface hydrophobicity of peptides formed during digestion is responsible for the hypocholestrolemic effect of soybean protein through the hydrophobic interaction between the peptides and bile salts in rats.
