Quantification of Nε-(2-Furoylmethyl)-L-lysine (furosine), Nε-(Carboxymethyl)-L-lysine (CML), Nε-(Carboxyethyl)-L-lysine (CEL) and total lysine through stable isotope dilution assay and tandem mass spectrometry

The control of Maillard reaction (MR) is a key point to ensure processed foods quality. Due to the presence of a primary amino group on its side chain, lysine is particularly prone to chemical modifications with the formation of Amadori products (AP), Nε-(Carboxymethyl)-L-lysine (CML), Nε-(Carboxyethyl)-L-lysine (CEL). A new analytical strategy was proposed which allowed to simultaneously quantify lysine, CML, CEL and the Nε-(2-Furoylmethyl)-L-lysine (furosine), the indirect marker of AP. The procedure is based on stable isotope dilution assay followed by, liquid chromatography tandem mass spectrometry. It showed high sensitivity and good reproducibility and repeatability in different foods. The limit of detection and the RSD% were lower than 5 ppb and below 8%, respectively. Results obtained with the new procedure not only improved the knowledge about the reliability of thermal treatment markers, but also defined new insights in the relationship between Maillard reaction products and their precursors

Impact of rapeseed press-cake on Maillard reaction in a cookie model system

Rapeseed press-cake (RPC) is a byproduct of rapeseed oil production, rich in proteins and fiber. The aim of this study was to investigate the impact of cold pressed RPC, RPC fiber isolate and RPC alkaline extract on the formation of acrylamide and 5-hydroxymethylfufural (HMF) in cookies. Both compounds were influenced by the ingredients: the addition of RPC led to a significant dose-dependent increase of HMF in the cookies and to an increase of acrylamide up to 66.9%. On the contrary, acrylamide concentration was reduced down to 39.6% in presence of the alkaline extract and down to 4.4% in the presence of the fiber extract. The Michael addition of free amino acids to acrylamide was further investigated by high-resolution mass spectrometry (HRMS) revealing that cysteine was the preferred nucleophile for acrylamide elimination

Effects of formulation and baking process on acrylamide formation in Kolompeh, a traditional cookie in Iran

Thermal treatments and recipes are two critical aspects for the formation of acrylamide at ordinary household cooking conditions and industrial level. Kolompeh is a traditional Iranian cookie, and the aim of this study was to monitor acrylamide formation in four different recipes: traditional sugary Kolompeh (TSK), traditional simple Kolompeh (TSIK), industrial sugary Kolompeh (ISK), and industrial simple Kolompeh (ISIK). Along with the measurement of reducing sugars, moisture, and pH, acrylamide was quantified by gas chromatography mass spectrometry (GC-MS). Results indicated that acrylamide content was 1758, 1048, 888, and 560 μg/kg for TSK, TSIK, ISK, and ISIK, respectively, revealing that the kind of thermal treatment in combination with higher concentrations of reducing sugars were the major driver for acrylamide formation. In particular, acrylamide concentration in TSIK direct heating was 1.87 times higher than industrial indirect heating treatment, highlighting that domestic preparation of Kolompeh required a specific attention as a source of potential toxic molecule formation

Evolution of protein bound Maillard reaction end-products and free Amadori compounds in low lactose milk in presence of fructosamine oxidase I

Thermal treatments and storage influence milk quality, particularly in low lactose milk as the higher concentration of reducing sugars can lead to the increased formation of the Maillard reaction products (MRPs). The control of the Amadori products (APs) formation is the key step to mitigate the Maillard reaction (MR) in milk. The use of fructosamine oxidases, (Faox) provided promising results. In this paper, the effects of Faox I were evaluated by monitoring the concentration of free and bound MRPs in low lactose milk during shelf life. Results showed that the enzyme reduced the formation of protein-bound MRPs down to 79% after six days at 37 °C. Faox I lowered the glycation of almost all the free amino acids resulting effective on basic and polar amino acids. Data here reported corroborate previous findings on the potentiality of Faox enzymes in controlling the early stage of the MR in foods

Analytical strategies for the monitoring of food quality through the Maillard reaction

The Maillard reaction (MR) supervises the final quality of foods and the study of the underneath reaction mechanisms provides a detailed overview of the thermal impact. The monitoring of Maillard reaction products formation (MRPs) is one of the most challenging procedures in Analytical Chemistry since their detection is highly influenced by the polarity of the compounds, the high reactivity, the complexity of the matrix, and the continuous changes in the reaction mixture. The accurate setup of the analytical methods for the MRPs quantification defines several opportunities for the monitoring of food quality. The MR can be divided into three stages: activation stage, intermediate stage and advanced stage; each of them contributes to the final quality of foods. The analysis of free amino acids and free Amadori compounds by high resolution mass spectrometry provides useful information on the initial stages and the final direction of the reaction can be depicted by monitoring the ratio between free Amadori compounds and free amino acids. Beside the monitoring of the first stages of the MR, the analysis of bound MRPs, furosine, CML, CEL and total lysine by stable isotope dilution assay tandem mass spectrometry offers a snapshot of the glycation on proteins and the loss in the nutritional values of foods. According to the advanced staged, the quantification of acrylamide by high resolution mass spectrometry highlights two novel insights: on one hand the use of some contaminants for the continuous recalibration of the instrument as a tool to reduce the mass error up to 1 ppm also with small amides; on the other hand the possibility to rule out the solid phase extraction for acrylamide detection. Finally, the “FancyTiles” approach reveals the possibility to combine the signals of different MRPs in order to obtain a colorimetric scale typical for a defined process and thermal treatment. These preliminary findings highlights the possibility to create a direct link between MR, chemometric and food quality

Spray-dried olive mill wastewater reduces Maillard reaction in cookies model system

The network of the Maillard reaction can be influenced by the presence of polyphenols. In this paper, we evaluated the ability of secoiridoids to interact with asparagine and lysine tuning the formation of dietary advanced glycation end-products (d-AGEs), dicarbonyls and acrylamide. Olive oil mill wastewater polyphenol powders (OMWP) were added to glucose and lysine or asparagine in silica model systems to mimic water activity present in cookies. Results revealed that acrylamide, Amadori compounds and N-ε-carboxyethyllysine (CEL) were reduced to 50%, after 13 min at 180°C; for the reduction of N-ε-carboxymethyllysine (CML), secoiridoids were effective only in model systems with the addition of acacia fiber and maltodextrin as coating agents. In cookies, OMWP at three different concentrations decreased the concentration of protein bound Amadori compounds, CML, CEL and dicarbonyls. Acrylamide and 5-hydroxymethylfurfural were reduced to 60% and 76% respectively, highlighting the ability of secoiridoids-based functional ingredients in controlling d-AGEs formation

Phytochemical-rich antioxidant extracts of <i>Vaccinium vitis-idaea L</i>. leaves inhibit the formation of toxic Maillard reaction products in food models

Thermal treatment of proteinaceous foods generates heat-induced Maillard reaction substances including toxic advanced glycation end products (AGEs) and heterocyclic amines (HAs). It is known that plant phenolic compounds may influence Maillard reaction. This study investigated the impact of lingonberry leaf extracts on the formation of Nε-(carboxymethyl)lysine (CML) and Nε-(2-furoylmethyl)-L-lysine (furosine) in milk model system and HAs in meat-protein and meat model systems. In addition, lingonberry leaf extracts obtained by different solvents were characterized by radical scavenging, Folin-Ciocalteu assays and ultra-high pressure liquid chromatography quadruple-time-of flight mass spectrometry (UPLC-qTOF-MS). Water extract (WE) stronger suppressed CML than furosine formation in milk model system: CML levels were reduced by nearly 40%. Moreover, quinic acid and catechin which were abundant in WE, were effective in inhibiting CML and furosine formation. WE and acetone extract (AE) at 10 mg/mL significantly inhibited HAs formation in both model systems. However, higher suppressing effect on HAs formation showed AE which had lower antioxidant capacity and total phenolic content values than WE. WE contained higher amounts of hydroxycinnamic acids, proanthocyanidins and flavonols, while AE was richer in flavan-3-ols and arbutin derivatives. It indicates that the composition of phenolics might be a major factor for explaining different effect of extracts from the same plant on HAs formation. In general, the results suggest that lingonberry leaves is a promising source of phytochemicals for inhibiting toxic Maillard reaction products and enriching foods with plant bioactive compounds

The quality of low lactose milk is affected by the side proteolytic activity of the lactase used in the production process

Lactose intolerance syndrome can be efficiently tackled consuming low lactose products. Lactase is the key tool to manufacture low lactose milk (LLM): its addition during milk processing can be done in batch, i.e. before thermal treatment, or directly in pack after sterilization. In this paper data on sensory properties, Maillard Reaction products (MRPs) and free amino acids formation were obtained on six commercial Italian LLMs over six months storage. They showed that the side proteolytic activity of lactase caused the release of amino acids with a significant higher MRPs and off-flavors formation in four out of five samples produced by adding the enzyme in the pack after thermal treatment. We concluded that the in pack addition of lactase after milk sterilization can have negative sensorial and nutritional consequences mainly related to the enzyme side proteolytic activity especially for prolonged storage time

α-Dicarbonyl compounds trapping ability and antiglycative effect of high-molecular-weight brewer's spent grain melanoidins

Polyphenols participate in the Maillard reaction pathways scavenging α-dicarbonyl compounds (DCs) and contributing to the mitigation of carbonyl burden through dietary exposure/routes. The current study demonstrated the effectiveness of high-molecular-weight brewer's spent grain melanoidins (HMW-BSGM) in reacting with DCs in an in vitro model system. HMW-BSGM (4 mg/mL) quenched more than 95% of glyoxal and methylglyoxal, and more than 80% of 2,3-butanedione after a 7-day incubation at 37 °C. Among tested polyphenols, sinapic acid showed the highest trapping capacity with inhibition rates of 33.1, 49.1 and 49.3% for glyoxal, methylglyoxal and 2,3-butanedione because of hydroxyalkylation reaction as revealed by liquid chromatography high-resolution tandem mass spectrometry experiments. The formation of free fluorescent AGEs was substantially hindered (79.3%) by HMW-BSGM (4 mg/mL). These findings corroborate the hypothesis that the accumulation of polyphenols in melanoidins skeleton can hinder undesired effects and potentially harmful reactions involving α-dicarbonyl compounds