Assessment of the Protein Quality of Nine Northern Adapted Yellow and Brown Seed Coated Soybean Cultivars by Amino Acid Analysis

• Published in: Journal of agricultural and food chemistry Vol. 47; no. 12; pp. 5009 - 5018
• Main Authors: Zarkadas, Constantinos G, Voldeng, Harvey D, Yu, Zi Ran, Choi, Victor K
• Format: Journal Article
• Language: English
• Published: Washington, DC American Chemical Society 01-12-1999
• Subjects: Agronomy. Soil science and plant productions; Amino Acids - analysis; Biological and medical sciences; Food industries; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; Genetics and breeding of economic plants; Glycine max - classification; Humans; Nutritive Value; Seeds; Soybean Proteins - analysis; Varietal selection. Specialized plant breeding, plant breeding aims; Yield, quality, earliness, varia; Biochemical analysis; Nutritive value; Soybean; Experimental study; Glycine max; Protein; Grain legume; Leguminosae; Dicotyledones; Aminoacid; Quality; Angiospermae; Spermatophyta; Chemical composition; Comparative study; Protein content; Cultivar; Digestibility
• ISSN: 0021-8561; 1520-5118
• DOI: 10.1021/jf981381r

Accurate and detailed amino acid determinations were carried out on nine northern adapted soybean cultivars to ascertain whether their amino acid profiles could be used as potentially useful indices for assessing their protein quality. The cultivars were Maple Amber, Maple Donovan, Maple Glen, Maple Isle, Maple Presto, Maple Ridge, and three brown seed coat near-isogenic lines, Maple Presto Brown, Maple Ridge Brown, and Maple Arrow Brown. Their total protein and amino acid composition were compared with those of an established cultivar, Maple Arrow. Mean protein values for the new cultivars ranged from 30.1 to 33.1% compared to Maple Arrow, which was 33.2%. The total nitrogen content was also variable among these cultivars, ranging from 5.0 to 5.4%. All nine Maple series soybean cultivars were higher in their essential amino acid (EAA) content, that is, EAA9 = 45.2−46.5%, than the FAO/WHO reference protein pattern value of EAA9 = 33.9%, for a 2−5-year-old child. Each of the nine new soybean cultivars was limited only in methionine and to a lesser extent in valine and isoleucine and had a protein digestibility corrected amino acid score of 91% for all cultivars, compared to the value of egg protein (97%). These results suggest that the most accurate evaluation of protein quality in soybeans, and possibly other legumes and cereals, is by the protein digestibility-corrected amino acid score. Keywords: Soybeans [Glycine max (L.) Merr.]; assessment; protein quality; amino acids; composition; amino acid score