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Aqueous ethanol extraction of dietary soy protein isolate improves sup 59 Fe absorption by the rat from a casein-based test meal

Journal Article · · Journal of Nutrition; (USA)
OSTI ID:7168155
 [1]
  1. Penn State Univ., University Park (USA)

A commercial soy protein isolate (SPI) was further processed in an attempt to understand how a diet based on SPI can cause decreased iron retention by the rat from a separately administered casein-based test meal. Groups of eight rats were fed either a casein-based diet or a diet based on SPI. The acid-precipitated SPI was incorporated into diets as such, after neutralization, after 60% (v/v) ethanol extraction and neutralization, or after 60% ethanol exposure and neutralization. All dietary SPI was heat-treated by exposure to steam at 108 degrees C for 30 min. Rats were fed their respective diets, each containing 25 mg Fe/kg, for 13 d, and then all rats were fed a {sup 59}Fe-radiolabeled 2.5-g casein test meal containing 64 micrograms of iron. Ingested radioactivity was determined following the meal, and retained radioactivity over the subsequent 10-d period. Absorption was not distinguishable for groups fed the casein-based (78.3 {plus minus} 3.6%) and the ethanol-extracted, SPI-based diet (80.2 {plus minus} 5.4%). Absorption was lower (P less than 0.01) for groups fed each of the other SPI-based diets: SPI as such (68.3 {plus minus} 8.9%), neutralized SPI (69.8 {plus minus} 5.0%) and ethanol-exposed SPI (67.6 {plus minus} 4.8%). An ethanol-extractable component of SPI may be responsible for decreased iron absorption by animals fed SPI prior to a radiolabeled test meal.

OSTI ID:
7168155
Journal Information:
Journal of Nutrition; (USA), Journal Name: Journal of Nutrition; (USA) Vol. 119:11; ISSN 0022-3166; ISSN JONUA
Country of Publication:
United States
Language:
English