Application of the Indicator Amino Acid Oxidation Technique to Determine the Protein Quality of Indian Wheat by Studying the Metabolic Availability of Lysine in Healthy Young Adult Men

The protein quality (PQ) of wheat, limiting in Lysine (Lys), is understudied in humans. Wheat and pulse mixed diet (MD) improves PQ but data on combination ratio (CR) is lacking. We aimed to 1)determine the PQ of wheat (bread) by assessing the metabolic availability (MA) of Lys and 2)determine the effect of bread and lentil stew as a MD on PQ by using the indicator amino acid oxidation method repeated measures design in 5 healthy adult males. Based on the slope-ratio principles, L-[1-13C] phenylalanine oxidation (Pheox) to 13CO2 in response to graded Lys intakes fed as crystalline amino acid (reference protein), wheat (test protein), and wheat complemented with lentil (MD) provided the MA and MD effectiveness. Despite being of limiting concentration, the MA of Lys in yeast-leavened bread is 90%. Complementation with lentils reduced Pheox i.e. augmented MD Lys content. We recommend a CR of 2:1 bread to lentil protein.M.Sc