Evolution of available lysine and furosine contents in milk‐based infant formulas throughout the shelf‐life storage period

Abstract

The evolution of the Maillard reaction (MR) by measuring the available lysine and furosine (FUR) contents in adapted and follow-up powdered milk-based infant formulas over the shelf-life storage period, at 20 and 37 • C, was studied. Available lysine and FUR contents were determined by fluorimetry and high-performance liquid chromatography respectively. Statistically significant differences were found between adapted and follow-up infant formulas with respect to the available lysine and FUR contents. Available lysine contents decreased significantly throughout the storage time, and the contents at 37 • C were lower than at 20 • C. A statistically significant increase in FUR contents was observed during the storage period, with the contents being high at 37 • C than at 20 • C. A simple regression analysis between the available lysine and FUR contents during (a) the first year (b) the second year and (c) the two storage years was applied. The best correlations were obtained during the first year of storage. The results obtained show a clear MR evolution during the storage of infant formulas.

Effect of storage conditions on furosine formation in milk–cereal based baby foods

“…Furosine content provides an estimation of blocked and therefore non-reactive lysine, and it is considered to be the most specific earliest indicator of MR (Guerra-Hernández, Corzo  -Villanova, 1999;Ferrer, Alegría, Farré, Abellán, Romero  Clemente, 2003).…”

Effect of protein glycation in the presence or absence of wheat proteins on detection of soybean proteins by commercial ELISA

“…The loss of reactive lysine residues was monitored using derivatization with ortho-134 phthaldialdehyde (OPA) in the presence of 2-mercaptoethanol which yields a fluorescent product with a maximum excitation wavelength of 340 nm and emission of 450 nm using a 136 Spectramax Gemini XPS fluorimeter from Molecular Devices (Brussels, Belgium) (Ferrer et al 2003). A standard of β-casein was used to prepare a calibration curve and samples were 138 pre-treated and analyzed using a fluorimeter as previously described (Morales et al 1996).…”

ELISA detection of hazelnut proteins: effect of protein glycation in the presence or absence of wheat proteins

“…The loss of reactive lysine residues was monitored using derivatization with orthophthaldialdehyde (OPA) in the presence of 2-mercaptoethanol yielding a fluorescent product 142 with a maximum excitation wavelength of 340 nm and emission of 450 nm (Ferrer et al, 2003) and measured by a Spectramax Gemini XPS fluorimeter from Molecular Devices 144 (Brussels, Belgium). A standard of β-casein was used to prepare a calibration curve and samples were pre-treated and analyzed using a fluorimeter as described previously (Morales 146 et al, 1996).…”