Variability in soy flour composition

  • Michael A. Porter
  • Alison M. Jones


Soy flour is commonly used as a protein source in industrial fermentations. As an essentially natural product, the composition of soy flour can vary from year to year as a result of changes in growing conditions. The composition of soy flour from a single manufacturing plant was determined over an 8-yr period. Protein concentration varied from 51.2% in the 1997 crop to 53.2% in the 1998 crop, but overal amino acid composition was relatively constant. The concentrations of valine, isoleucine, tyrosine, and alanine showed significant variation between years. Crude fat levels were steady, but the fat by acid hydrolysis (FAH) levels varied, suggesting changes in the level of phospholipids. The difference between the crude fat and FAH analyses (a proxy for phospholipids) had a strong positive correlation (P<0.001) with the total phosphorus concentration, consistent with this interpretation. FA distribution varied year to year with linoleic acid providing the most dramatic effect. Fe and P concentrations showed significant variation, but Al, Ca, Cu, K, Mg, Mn, Mo, Ni, and Zn did not vary significantly. Although P concentration had a significant correlation with proxy phospholipid levels, there was not a significant correlation between P concentration and phytic acid concentrations

Key words

Amino acid composition consistency lipid m minerals protein soy flour 


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Copyright information

© AOCS Press 2003

Authors and Affiliations

  1. 1.Cargill Soy Protein SolutionsMinneapolis
  2. 2.Cargill Sweetners North AmericaWayzata

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