6. AOACSPIFANMethods-2018Awards

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Figure 13. E-gram of infant formula 4 with CGMP-reduced sweet whey ingredient (70% whey claim).

Figure 14. E-gram of infant formula 5 with sweet whey ingredient (40% whey claim).

Table 8. Protein profile of bovine milk and calculated whey protein as the mass percentage of casein (4, 5)

ratio from the literature with the area percentage ratio obtained with the SDS-CGE method. Based on the literature mass percentage ratio (26.9%) and the experimental area percentage ratio (20.8%), a CF of 1.29 should be applied to the integrated signal of whey proteins. To evaluate the impact of the infant formula manufacturing process on the area CF of whey proteins to caseins, a whey protein-dominant infant formula was manufactured. Two samples were taken; one before processing and one after. The test results are listed in Table 10 and indicate that processing further increased this ratio 1.11-fold. Therefore, a final CF of 1.4 for whey protein-to-casein area for infant formulas was chosen (Table 9). Forty-three infant formulas manufactured by both Chinese and international manufacturers with different whey ingredients, including regular sweet whey, α-Lac-enriched whey, LF-added whey, and casein glycomacropeptide (CGMP)-reduced whey, were analyzed and compared with manufacturers’ claims (Table 11). The results show that among the 41 samples with manufacturers’ claims, measured whey content was in close agreement with declared value: within 5% of the declared value for 31 (76%) samples and within 10% for 37 (90%) samples. Two infant formulas did not contain added whey protein; hence, a factor of 1.29, not 1.4, should be used. Taking this into account, 39 (95%) samples were within 10% of the declared value.

Whole milk content g/L (5) %

Protein

MW, kDa

23.69 25.31 23.97 21.30 20.59 14.19 67.41 12.43 17.89 78.06 160.00

10.0

30.3

a S1-casein a S2-casein

2.6 9.3 3.3 0.8 1.2 0.4 0.8 0.5 0.3 0.1 0.4

7.9

28.2 10.0

b -Casein k -Casein g -Casein

2.4 3.6 1.2 2.4 1.5 0.9 0.3 1.2

a -Lac

BSA

Immunoglobulin

Peptone 5 Peptone 3

LF

Milk fat globule membrane

18.27

3.3

10.0

b -Lg

CGMP  Sum

9.15

33.0 26.0

100.0

 Casein  Whey

78.8 21.2 26.9

7.0

 Whey as percentage of casein

26.9