QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Thompson, D. B. Search for Related Content PubMed PubMed Citation Articles by Thompson, D. B.

Aqueous Ethanol Extraction of Dietary Soy Protein Isolate Improves ⁵⁹Fe Absorption by the Rat from a Casein-Based Test Meal

Department of Food Science, Penn State University, University Park, PA 16802

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°C for 30 min. Rats were fed their respective diets, each containing 25 mg Fe/kg, for 13d, and then all rats were fed a ⁵⁹Fe-radiolabeled 2.5-g casein test meal containing 64 µg 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 ± 3.6%) and the ethanol-extracted, SPI-based diet (80.2 ± 5.4%). Absorption was lower (P < 0.01) for groups fed each of the other SPI-based diets: SPI as such (68.3 ± 8.9%), neutralized SPI (69.8 ± 5.0%) and ethanol-exposed SPI (67.6 ± 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.

KEY WORDS: • iron • iron absorption • soy protein • ethanol extraction • radioactive isotopes • weanling male rats

Manuscript received 13 March 1989. Revision accepted 20 June 1989.