0000000000018047
AUTHOR
Lourdes Bosch
Simultaneous analysis of lysine, Nɛ-carboxymethyllysine and lysinoalanine from proteins
Protein quality was assayed by simultaneous measurement of lysine (Lys), carboxymethyllysine (CML) and lysinoalanine (LAL). GC-FID analysis of N-tert-butyl dimethylsilyl (tBDMSi) derivatives of these amino acids was undertaken. tBDMSi derivates were separated on a CP-SIL 5CB commercially fused silica capillary column (25 m × 0.25 mm i.d., 0.25 μm film thickness) employing a thermal gradient programmed from 200 to 300 °C. The identity of tBDMSi derivatives of Lys, CML and LAL was established by GC–MS while FID detection was employed for quantification. Analytical parameters such as linearity (lysine 350–4200 μM, LAL 3–81 μM, CML 16–172 μM), precision (1–13% variation coefficients), accuracy …
Effect of storage conditions on furosine formation in milk-cereal based baby foods
[EN] The effect of storage during 9 months at 25, 30 and 37 degrees C on furosine formation in three milk-cereal based baby foods was studied to evaluate development of the Maillard reaction. Furosine was measured by HPLC-UV. Immediately after the manufacturing process, furosine contents were 310-340 mg/100 g protein and at the 9th storage month were 426-603 mg/100 g protein. Storage time and temperature have a significant increase (p < 0.05) of furosine content during storage. Furosine contents were higher in sample containing honey than in those without honey. Interactions (p < 0.05) between storage time and temperature or type of sample were found. A predictive model equation of the evol…
Amino acid contents of infant foods.
The protein quality of three milk-cereal-based infant foods (paps) was evaluated by determining their amino acid contents and calculating the amino acid score. Proteins were subjected to acid hydrolysis, prior to which cysteine and methionine were oxidized with performic acid. Amino acids were determined by reverse-phase high-performance liquid chromatography with fluorescence detection with a prior derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate. Tryptophan was determined by reverse-phase high-performance liquid chromatography with ultraviolet detection after basic hydrolysis. Glutamic acid, proline and leucine were the most abundant amino acids, whereas tryptophan and …
Application of the 6-aminoquinolyl-N-hydroxysccinimidyl carbamate (AQC) reagent to the RP-HPLC determination of amino acids in infant foods.
The validation of a pre-column derivatization procedure with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) to the determination of the amino acid content by RP-HPLC with fluorescence detection (lambda excitation 250 nm, lambda emission 395 nm) in milk-cereal based infant foods was carried out. The analytical parameters: linearity (0.0025-0.2mM), precision of the method (0.2-3.5% variation coefficients), accuracy (derivatization: 86-106% average recovery and method: 88.3-118.2% average recovery) and the limits of detection (0.016-0.367 microM) and quantification (0.044-1.073 microM) were determined. Glutamic acid, proline and leucine were the most abundant amino acid whereas the lowe…
Effect of processing on the bioaccessibility of bioactive compounds – A review focusing on carotenoids, minerals, ascorbic acid, tocopherols and polyphenols
Health benefits of bioactive compounds depend not only on the intake levels but also on their bioavailability (BAv). In vitro methods to simulate gastro-intestinal digestion allow to determine the bioaccessibility (BAcs) of these compounds, as a first step of BAv, and can be used to evaluate the effect of processing on them to design functional foods with increased health-promoting effects. The impact of traditional processing technologies such as thermal treatment and novel emerging non-thermal technologies such as high pressure processing, high-intensity pulsed electric fields and ultrasound on BAcs of bioactive compounds as carotenoids, minerals, ascorbic acid, tocopherols, polyphenols a…
Fluorescence and color as markers for the Maillard reaction in milk–cereal based infant foods during storage
Abstract Free and total fluorescence compounds and color formation were measured in three different milk–cereal based infant foods stored at 25, 30 and 37 °C for 9 months to evaluate the advanced and final stages of the Maillard reaction. Milk–cereal infant foods containing honey (B) or fruits (C) had fluorescent values higher than sample (A) without them. This difference could be ascribed to the higher monosaccharide (fructose and/or glucose) content of (B) and (C), which could increase susceptibility to the Maillard reaction. However, for color increase (ΔE), no significant differences (p