Available lysine and digestible amino acid contents of proteinaceous foods of India

• Published in: British journal of nutrition 2012-08, Vol.108 (S2), p.S59-S68
• Main Authors: Rutherfurd, Shane M., Bains, Kiran, Moughan, Paul J.
• Format: Article
• Language: English
• Subjects: Amino acids; Amino Acids - analysis; Amino Acids - deficiency; Amino Acids - metabolism; Analytical chemistry; Animals; Cellulose; Cereals; Constraining; Developing countries; Diet; Dietary Proteins - analysis; Digestibility; Digestion; Edible Grain - chemistry; Energy intake; Fabaceae - chemistry; Flour; Food; Food Handling; Food quality; Humans; Ileum - metabolism; India; Ingredients; LDCs; Legumes; Lysine; Lysine - analysis; Lysine - deficiency; Lysine - metabolism; Maillard Reaction; Male; Nitrogen; Nutrition research; Oryza; Prepared foods; Proprietary; Proteins; Quality assessment; Rats; Rats, Sprague-Dawley; Rice; Salt; Section One: Protein and amino acid requirements, amino acid scoring patterns and the assessment of dietary protein and amino acid adequacy in developing countries; Small intestine; Sulfur - analysis; Titanium; Titanium - metabolism; Titanium dioxide; Wheat
• ISSN: 0007-1145; 1475-2662
• DOI: 10.1017/S0007114512002280

Cereals and legumes are staple foods in India and are limiting in lysine and sulphur amino acids, respectively. Available lysine loss, due to Maillard-type reactions that may occur during food preparation, exacerbates the problem of lysine deficiency particularly in cereals. Consequently, determining the contents of digestible essential amino acids, particularly lysine, is important. True ileal digestibilities of most amino acids (including total and reactive lysine) were determined for ten food ingredients and eleven foods commonly consumed in India. Semi-synthetic diets each containing either an ingredient or the prepared food as the sole protein source were formulated to contain 100 g kg− 1 protein (75 g kg− 1 for rice-based diets) and fed to growing rats. Titanium dioxide was included as an indigestible marker. Digesta were collected and the amino acid content (including reactive lysine) of diets and ileal digesta determined. Available (digestible reactive) lysine content ranged from 1·9–15·4 g kg− 1 and 1·8–12·7 g kg− 1 across the ingredients and prepared foods respectively. True ileal amino acid digestibility varied widely both across ingredients and prepared foods for each amino acid (on average 60–92 %) and across amino acids within each ingredient and prepared food (overall digestibility 31–96 %). Amino acid digestibility was low for many of the ingredients and prepared foods and consequently digestibility must be considered when assessing the protein quality of poorer quality foods. Given commonly encountered daily energy intakes for members of the Indian population, it is estimated that lysine is limiting for adults in many Indian diets.