Effects of Processing on Liquid Infant Milk Formulas. I. Freshly Processed Products

Ready-to-feed milk-based infant formulas prepared with different types of nonfat milk solids were evaluated for effects of various processing conditions. Stage of processing, presence or absence of ultra high temperature short time heat treatment, and type of nonfat milk solids had no definitive effect on total or sedimentable calcium, phosphorus, or nitrogen. Electrophoretic characterization of the formulas prior to ultra high temperature short time heat treatment or sterilization steps revealed more heat damaged whey protein in the formulas prepared from commercial high-heat condensed skim milk and nonfat dry milk than in their lbw-heat counterparts. The effects of homogenization and standardization on electrophoretic patterns were minor. Sterilization of formulas with or without prior ultra high temperature short time heat treatment caused severe alteration of whey protein electrophoretic bands and a two to three fold increase in hydroxymethylfurfural content. An effect of ultra high temperature short time treatment on whey protein bands and hydroxymethylfurfural content was apparent, but the effect was less severe than that of final sterilization.