Comparative analysis of the structure and content of N-glycans from different commercial whey protein materials

Infant formulas are constantly being updated and upgraded, and N-glycans are functional glycans that have not been fully exploited to date. Commercial whey protein materials are often used as basic ingredients in infant formulas. Therefore, it is important to study N-glycans in commercial whey protein materials. We used matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS) and ion chromatography to analyze N-glycans in bovine lactoferrin (Lf), whey protein isolate (WPI), whey protein concentrate 70 (WPC 70), goat whey protein powder 50, demineralized whey powder 90 (D90), and desalted goat whey powder. The results showed that 30, 6, 28, 16, 8, and 9 N-glycans were found in Lf, D90, desalted goat whey powder, WPI, WPC 70, and goat whey protein powder 50, respectively. A total of four structures of N-glycans were detected in this study. Only bovine Lf and WPC 70 contained fucosylated and sialylated binding (SFN-type) glycan structures. Regarding content, WPC 70 showed the highest yield of 14.5 mg/g, and the degree of sialylation was higher than fucosylation. This study provides a potential basis for the future use of commercial whey protein materials in dairy products such as infant formula.