6. AOACSPIFANMethods-2018Awards

236

518 F eng et al .: J ournal of AOAC I nternational V ol . 100, N o . 2, 2017

Figure 10. E-gram of infant formula 1 with sweet whey ingredient (60% whey claim).

Figure 11. E-gram of infant formula 2 with sweet whey ingredient (60% whey claim).

property of proteins and depends on the proteins’ amino acid sequence and molecular structure status. Unfortunately, no literature is currently available regarding whey protein and casein ratios under SDS-CGE conditions, nor for proteins after infant formula processing. In contrast, the mass ratio of whey proteins to caseins is well established (4, 5; Table 8) and can be calculated as 26.9% (whey proteins versus caseins) in bovine milk and SMP.

To correct for the difference between the mass-to-area ratios of whey proteins and caseins, 13 SMP samples from different batches and suppliers were analyzed by SDS-CGE with 50 measurements. The two whey protein areas and the one casein area were integrated, and the area percentage ratio of whey proteins to caseins was established at 20.8% (Table 9). The mass-to-area CF for whey proteins relative to caseins was obtained by comparing the whey-to-casein mass percentage

Figure 12. E-gram of infant formula 3 with α-Lac-enriched whey ingredient (65% whey claim).