Liquid Infant Formulas : technological tools for limiting heat damage

In a study considering 15 commercial samples of liquid milk-based infant formulas (MBF) from different manufacturers, the levels of selected molecules, that is, furosine (FUR), galactosyl-β-pyranone (GAP), lactulose (LCT), and lysinoalanine (LAL), have been measured to provide estimation of the heat damage in these products. The ranges of the studied markers were as follows: FUR = 153-600 mg 100 g-1 of protein, GAP = 0.5-4.3 mg L-1, LCT = 226-1511 mg L-1, and LAL = 1.0-16.1 mg 100 g-1 of protein. The highest levels were found in MBF intended for the youngest babies. Experimental samples were produced in an industrial plant to evaluate the relative contribution of individual technological aspects to the final heat damage. About 90% of both GAP and LCT contents was due to the ultrahigh-temperature sterilization process itself. This effect was more than halved when the pH of the ingredient mixture was adjusted from 7.2 to 6.9 before sterilization or when the product recirculated in the plant was discarded. Up to 60 and 20%, respectively, of the FUR and LAL levels in the finished product were already present in protein ingredients (whey powder, whey protein concentrate). Accurate optimization of processing conditions and scrupulous selection of raw materials proved to be effective means to minimize heat damage in such special food products.