Ethanol washing does not attenuate the hypocholesterolemic potential of soy protein.
OBJECTIVE
A feeding study in rats investigated the principal active component for the hypocholesterolemic effect of soy protein isolate (SPI) by comparing the effect before and after ethanol washing.


METHODS
Five-week-old male Sprague-Dawley rats were fed cholesterol-enriched AIN-93G diets containing 20% casein (CAS), 20% SPI, 20% ethanol-washed SPI (EWS), 18.4% EWS plus 1.6% ethanol extract (EE), or 20% CAS plus 1.6% EE for 2 wk.


RESULTS
Plasma cholesterol concentrations in rats fed EWS and SPI were comparable and were significantly lower than those in rats fed CAS. The addition of EE to EWS and CAS did not influence plasma cholesterol level. Fecal steroid excretion of the three SPI groups was higher than that of the two CAS groups. The addition of EE to EWS and CAS showed a tendency to increase acidic steroid and decrease neutral steroid.


CONCLUSIONS
In this experiment which used identifiable protein preparations, a significant fraction of the cholesterol-lowering effect of SPI in rats was attributed to its protein component but not to the ethanol-extractable minor constituents including isoflavones.
Fukui
Kensuke
K
Food Science Research Institute, Fuji Oil Co., Ltd., Osaka, Japan. 910293@so.fujioil.co.jp
Tachibana
Nobuhiko
N
Fukuda
Youichi
Y
Takamatsu
Kiyoharu
K
Sugano
Michihiro
M
D000818:Animals; D000924:Anticholesteremic Agents / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D002784:Cholesterol / Q000097:blood*; D000431:Ethanol / Q000009:adverse effects*; D005243:Feces / Q000737:chemistry; D006937:Hypercholesterolemia / Q000188:drug therapy; D007529:Isoflavones / Q000032:analysis; D008297:Male; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D030262:Soybean Proteins / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D013256:Steroids / Q000032:analysis
D000924:Anticholesteremic Agents; D007529:Isoflavones; D030262:Soybean Proteins; D013256:Steroids; D000431:Ethanol; D002784:Cholesterol