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The formation of the Amadori products (APs) is the first key step of Maillard reaction. Only few papers have dealt with simultaneous quantitation of amino acids and corresponding APs (1-amino-1-deoxy-2-ketose). Chromatographic separation of APs is affected by several drawbacks mainly related to their poor retention in conventional reversed phase separation. In this paper, a method for the simultaneous quantification of amino acids and their respective APs was developed combining high-resolution mass spectrometry with ion-pairing liquid chromatography. The limit of detection was 0.1 ng/mL for tryptophan, valine and arginine, while the limit of quantification ranged from 2 to 5 ng/mL according to the specific sensitivity of each analyte. The relative standard deviation % was lower than 10 % and the coefficient of correlation was higher than 0.99 for each calibration curve. The method was applied to milk, milk-based products, raw and processed tomato. Among the analyzed products, the most abundant amino acid was glutamic acid (16,646.89 ± 1,385.40 µg/g) and the most abundant AP was fructosyl-arginine in tomato puree (774.82 ± 10.01 µg/g). The easiness of sample preparation coupled to the analytical performances of the proposed method introduced the possibility to use the pattern of free amino acids and corresponding APs in the evaluation of the quality of raw food as well as the extent of thermal treatments in different food products.

Fructosamines, also known as Amadori products, are formed by the condensation of glucose with the amino group of amino acids or proteins. These compounds are precursors of advanced glycation end products (AGEs) that can be formed either endogenously during aging and diabetes, and exogenously in heat-processed food. The negative effects of dietary AGEs on human health as well as their negative impact on the quality of dairy products have been widely described, therefore specific tools able to prevent the formation of glycation products are needed. Two fructosamine oxidase enzymes isolated from Aspergillus sp. namely, Faox I and Faox II catalyze the oxidative deglycation of Amadori products representing a potential tool for inhibiting the Maillard reaction in dairy products. In this paper, the ability of recombinant Faox I and II in limiting the formation of carboxy-methyl lysine (CML) and protein-bound hydroxymethyl furfurol (b-HMF) in a commercial UHT low lactose milk and a beta-lactoglobulin (β-LG) glucose model system was investigated. Results show a consistent reduction of CML and b-HMF under all conditions. Faox effects were particularly evident on b-HMF formation in low lactose commercial milk. Peptide analysis of the β-LG glucose system identified some peptides, derived from cyanogen bromide hydrolysis, as suitable candidates to monitor Faox action in milk-based products. All in all data suggested that non-enzymatic reactions in dairy products might be strongly reduced by implementing Faox enzymes.

This work deals with the Dakin-West synthesis, starting from the nucleoamino acid 1-thyminyl acetic acid, as well the NMR, ESI MS, and X-ray characterization of a heteroaromatic compound denominated by us T(2)CO, comprising two thymine moieties anchored to a 2-propanonic unit, the spectroscopic properties of which were studied by UV as a function of temperature and ionic strength. Preliminary binding-studies with molecules of biomedical interest such as nucleic acids and proteins, performed on samples containing T(2)CO, suggested that this molecule is able to interact very weakly with double-stranded RNA, whereas it does not seem to bind other nucleic acids or proteins. Moreover, by studies with fresh human serum we found that T(2)CO is resistant to enzymatic degradation till 24 h, whereas UV metal binding-studies, performed using solutions of copper (II) chloride dihydrate and nickel (II) chloride hexahydrate, revealed a certain ability of T(2)CO to bind copper (II) cation. Finally, by CD spectroscopy we investigated the influence of T(2)CO on the already described supramolecular networks based on L-serine-containing nucleopeptides. More particularly, we found that T(2)CO is able to increase the level of structuration of the non-covalent supramolecular assembly of the chiral nucleopeptides, which is a feature of remarkable interest for the development of innovative drug delivery tools.