Amino Acid Composition of an Organic Brown Rice Protein
Concentrate and Isolate Compared to Soy and Whey
Concentrates and Isolates
Abstract: A protein concentrate (Oryzatein-80™) and a protein isolate (Oryzatein-90™)
from organic whole-grain brown rice were analyzed for their amino acid composition. Two
samples from different batches of Oryzatein-90™ and one sample of Oryzatein-80™ were
provided by Axiom Foods (Los Angeles, CA, USA). Preparation and analysis was carried
out by Covance Laboratories (Madison, WI, USA). After hydrolysis in 6-N hydrochloric
acid for 24 h at approximately 110 °C and further chemical stabilization, samples were
analyzed by HPLC after pre-injection derivitization. Total amino acid content of both the
isolate and the concentrate was approximately 78% by weight with 36% essential amino
acids and 18% branched-chain amino acids. These results are similar to the profiles of raw
and cooked brown rice except in the case of glutamic acid which was 3% lower in the
isolate and concentrate. The amino acid content and profile of the Oryzatein-90™ isolate
was similar to published values for soy protein isolate but the total, essential, and
branched-chain amino acid content of whey protein isolate was 20%, 39% and 33% greater,
respectively, than that of Oryzatein-90™. These results provide a valuable addition to the
nutrient database of protein isolates and concentrates from cereal grains.