Effect of home and industrial processing on protein quality of baby foods and breakfast cereals

The effect of home and industrial processing on the protein quality of baby foods and breakfast cereals, commonly consumed in Pakistan, was studied. The nutritive value of baby foods and breakfast cereals was determined chemically (including amino acid analyses) and biologically in N‐balance experiments with growing rats. Lysine and threonine were found to be the limiting amino acids in home and industrially produced baby foods whereas lysine was the limiting amino acid in all the breakfast cereals. The lysine contents of home‐prepared baby foods were damaged to a great extent at 150–160°C compared with 100–110°C. The levels of lysine (35–76%) and arginine (10–41%) were in all the breakfast cereals reduced by the industrial processing. The net protein utilisation (NPU) of home‐prepared baby foods ranged from 51–81% as compared to 57–60% for industrially produced baby foods. The net dietary protein calorie per cent (NDp cal%) of home and industrially produced baby foods varied between 2.6 and 7.3% and between 7.0 and 7.1% respectively. The industrial processing reduced significantly the true digestibility (4–20%), biological value (13–34%) and net protein utilisation (17–41%) of all the breakfast cereals.