A collaborative study was undertaken in which five international laboratories participated to determine amino acid fingerprints in 39 authentic nonfat dry milk (NFDM)/skim milk powder (SMP) samples. A rapid method of amino acid analysis involving microwave-assisted hydrolysis followed by ultra-high performance liquid chromatography-ultraviolet detection (UHPLC-UV) was used for quantitation of amino acids and to calculate their distribution. The performance of this rapid method of analysis was evaluated and was used to determine the amino acid fingerprint of authentic milk powders. The distribution of different amino acids and their predictable upper and lower tolerance limits in authentic NFDM/SMP samples were established as a reference. Amino acid fingerprints of NFDM/SMP were compared with selected proteins and nitrogen rich compounds (proteins from pea, soy, rice, wheat, whey, and fish gelatin) which can be potential economically motivated adulterants (EMA). The amino acid fingerprints of NFDM/SMP were found to be affected by spiking with pea, soy, rice, whey, fish gelatin and arginine among the investigated adulterants but not by wheat protein and melamine. The study results establish an amino acid fingerprint of authentic NFDM/SMP and demonstrate the utility of this method as a tool in verifying the authenticity of milk powders and detecting their adulteration.

Single- and multilaboratory testing data have provided systematic scientific evidence that a simple, selective, accurate, and precise method can be used as a potential candidate reference method for dispute resolution in determining total biotin in all forms of infant, adult, and/or pediatric formula. Using LC coupled with immunoaffinity column cleanup extraction, the method fully meets the intended purpose and applicability statement in AOAC Standard Method Performance Requirement 2014.005. The method was applied to a cross-section of infant formula and adult nutritional matrixes, and acceptable precision and accuracy were established. The analytical platform is inexpensive, and the method can be used in almost any laboratory worldwide with basic facilities. The immunoaffinity column cleanup extraction is the key step to successful analysis.

Sunflower lecithin is commonly used as a food processing agent. In this study, residues of sunflower lecithin phospholipids in drum-dried fruits and vegetables were investigated. The contents of phosphatidylcholine and phosphatidylethanolamine were of interest due to their natural levels in fresh fruits and vegetables as well as their residues after the drum drying process. Identification of these compounds in freeze-dried and drum-dried fruits and vegetables was conducted by normal-phase and reverse-phase ultra-high-performance liquid chromatography (UPLC) coupled with Q Exactive Orbitrap electrospray mass spectrometry. Quantification of phosphatidylcholine in various fruits and vegetables was performed using normal-phase high-performance liquid chromatography with evaporative light scattering detector (ELSD). The quantification results from these various products demonstrate that use of de-oiled sunflower lecithin as a processing agent in the drum drying production process does not affect the quality of final drum-dried products.