Early Maillard Reaction Products Research Articles

Preliminary Assessment of Non-Enzymatic Browning and Antioxidant Activity in Sea Cucumber Derived Gelatin-Sugar Models

Four models were developed to assess the development of non-enzymatic browning and antioxidant activity in mixtures of sea cucumber derived gelatin (control), gelatin-glucose, gelatin-fructose and gelatin-glucosamine. All gelatin-sugar models were prepared in mixtures consisted of 5% w/v gelatin and 1.25% w/v sugar and compared against a control (5% w/v gelatin). The mixtures were incubated at 37 °C and 70 °C respectively for up to 24 h. The progress of non-enzymatic browning was monitored via changes in absorption at 280 nm, 320 nm and 420 nm. The gelatin-glucosamine model showed greater development in early Maillard reaction products (280 nm) and pre-melanoidins (320 nm) when incubated at 70 °C after 16 h of incubation. Meanwhile lower incubation temperature (37 °C) promoted browning development (420 nm) in all the models. The gelatin-glucosamine mixture incubated at 70 °C showed high potency in antioxidant activity (p<0.05), this is in accordance to the greater reactivity of glucosamine in the formation of Maillard reaction products at the early and intermediate stages. The results suggested the gelatin-glucosamine model can be further optimized to achieve high potency in antioxidant activity and a desired browning intensity to cater specific applications such as in food and biomaterials.

Milk-Derived Amadori Products in Feces of Formula-Fed Infants

Food processing of infant formula alters chemical structures, including the formation of Maillard reaction products between proteins and sugars. We detected early Maillard reaction products, so-called Amadori products, in stool samples of formula-fed infants. In total, four Amadori products (N-deoxylactulosyllysine, N-deoxyfructosyllysine, N-deoxylactulosylleucylisoleucine, N-deoxyfructosylleucylisoleucine) were identified by a combination of complementary nontargeted and targeted metabolomics approaches. Chemical structures were confirmed by preparation and isolation of reference compounds, LC-MS/MS, and NMR. The leucylisoleucine Amadori compounds, which most likely originate from β-lactoglobulin, were excreted throughout the first year of life in feces of formula-fed infants but were absent in feces of breastfed infants. Despite high inter- and intraindividual differences of Amadori products in the infants' stool, solid food introduction resulted in a continuous decrease, proving infant formula as the major source of the excreted Amadori products.

Angiotensin I-Converting Enzyme Inhibitory Effect of Chinese Soypaste Along Fermentation and Ripening: Contribution of Early Soybean Protein Borne Peptides and Late Maillard Reaction Products

Angiotensin I-converting enzyme inhibitory effect of Chinese soypaste was investigated during 4-month fermentation and ripening. This effect increased significantly at early stage and reached a plateau until the end of ripening, with an IC50 value of 0.436 mg/mL for the final product. Peptide and reducing sugar contents increased drastically during early fermentation and declined afterward. Maillard reaction took place continuously as indicated by consistent accumulation of precursor, intermediate, and final Maillard reaction products monitored by fluorescence, ultraviolet-absorbance and absorbance at 420 nm, respectively. During early fermentation, peptides were principal compounds responsible for the angiotensin I-converting enzyme inhibitory effect. During late ripening, angiotensin I-converting enzyme inhibition by Maillard reaction products could compensate for the loss of the effect caused by the utilization of peptides, and enable the total effect to remain at a good and steady level, suggesting an indispensable contribution of Maillard reaction products to angiotensin I-converting enzyme inhibitory effect of soypaste, particularly in products with prolonged maturation.

Characteristics of Early Maillard Reaction Products by Electrospray Ionization Mass Spectrometry

Characteristics of Early Maillard Reaction Products by Electrospray Ionization Mass Spectrometry

The Maillard reaction and pet food processing: effects on nutritive value and pet health

The Maillard reaction, which can occur during heat processing of pet foods or ingredients, is known to reduce the bioavailability of essential amino acids such as lysine due to the formation of early and advanced Maillard reaction products (MRP) that are unavailable for utilisation by the body. Determination of the difference between total and reactive lysine by chemical methods provides an indication of the amount of early MRP present in foods, feeds and ingredients. Previous research reported that the difference between total and reactive lysine in pet foods can be up to 61.8%, and foods for growing dogs may be at risk of supplying less lysine than the animal may require. The endogenous analogues of advanced MRP, advanced glycation endproducts, have been associated with age-related diseases in humans, such as diabetes and impaired renal function. It is unknown to what extent advanced MRP are present in pet foods, and if dietary MRP can be associated with the development of diseases such as diabetes and impaired renal function in pet animals. Avoidance of ingredients with high levels of MRP and processing conditions known to favour the Maillard reaction may be useful strategies to prevent the formation of MRP in manufactured pet food. Future work should further focus on understanding the effects of ingredient choice and processing conditions on the formation of early and advanced MRP, and possible effects on animal health.

Stability and bioactivity of a Bowman–Birk inhibitor in orange juice during processing and storage

The present research aimed to evaluate the feasibility of a soybean Bowman-Birk inhibitor (BBI) as a natural functional food ingredient. The influence of food processing, storage and digestion on the structure and bioactivity of BBI added to a food matrix was evaluated. The cytotoxic effect of the digested samples was also tested with the aim to provide information regarding the safe use of BBI as a functional food ingredient. Samples of freshly squeezed orange juice (OJ) and two orange juice model systems (OJ-ms) supplemented and non-supplemented with BBI were prepared and processed mimicking pasteurization and sterilization industrial conditions. Moreover, pasteurized samples were stored at 4 °C for two months. The samples were digested in vitro under oral-gastrointestinal physiological conditions. Results seem to indicate that the activity of BBI supplemented to the food matrix sufficiently survives thermal processing, storage and digestion processes. Changes in BBI bioactivity may be ascribed among others to the Maillard reaction. Formation of early Maillard reaction products also called Amadori products has been detected in the food sample. No cytotoxic effect was observed for the samples under study. In conclusion, our findings support that BBI has significant potential as a natural functional food ingredient in pasteurized orange juice stored at 4 °C.

Testing isotopic labeling with [13C6]glucose as a method of advanced glycation sites identification

The Maillard reaction occurring between reducing sugars and reactive amino groups of biomolecules leads to the formation of a heterogeneous mixture of compounds: early, intermediate, and advanced glycation end products (AGEs). These compounds could be markers of certain diseases and of the premature aging process. Detection of Amadori products can be performed by various methods, including MS/MS techniques and affinity chromatography on immobilized boronic acid. However, the diversity of the structures of AGEs makes detection of these compounds more difficult. The aim of this study was to test a new method of AGE identification based on isotope 13C labeling. The model protein (hen egg lysozyme) was modified with an equimolar mixture of [12C6]glucose and [13C6]glucose and then subjected to reduction of the disulfide bridges followed by tryptic hydrolysis. The digest obtained was analyzed by LC–MS. The glycation products were identified on the basis of characteristic isotopic patterns resulting from the use of isotopically labeled glucose. This method allowed identification of 38 early Maillard reaction products and five different structures of the end glycation products. This isotopic labeling technique combined with LC–MS is a sensitive method for identification of advanced glycation end products even if their chemical structure is unknown.

Control of the Maillard reaction by ferulic acid

This study investigated how ferulic acid (FA) affects the formation of certain Maillard reaction products (MRPs), i.e., early MRPs, fluorescent and non-fluorescent advanced glycation end products (AGEs), and melanoidins in model systems. Glycation mixtures were prepared containing soy glycinin or bovine serum albumin (final concentration 10mg/ml) and fructose (222mM) in 0.2% KOH in the presence or absence of FA (12.95mM) and incubated at 60°C for 60min. The extent of the MR was estimated by analysis of free amino groups, the incorporation of sugar into the protein backbone as well as the formation of Nϵ-(carboxymethyl)lysine (CML), fluorescent AGEs (λexc=337nm, λem=350–550nm) and melanoidins (absorbance at 420nm). Formation of CML and fluorescent AGEs was reduced by nearly 90% by the addition of FA while early MRPs and melanoidins were inhibited to a lesser extent (∼10% and 28%, respectively) compared to AGE formation. A controlled formation of early MRPs was achieved by use of FA, and it is a new finding. To the best of our knowledge, for the first time the use of FA as a reliable means of obtaining novel glycoprotein preparations containing low amounts of AGEs, with the potential to be used as functional food ingredients, is proposed.

Acrylamide in Foods: Chemistry and Analysis. A Review

Acrylamide is a potential cause of a wide spectrum of toxic effects and is classified as probably “carcinogenic in humans”. The discovery of acrylamide in human foods has given rise to extensive studies exploring its formation mechanisms and levels of exposure and has spurred search into suitable analytical procedures for its determination in foodstuffs. However, the exact chemical mechanisms governing acrylamide formation are not yet known and cheap, convenient, and rapid screening methods are still to be developed. Acrylamide in food is produced by heat-induced reactions between the amino group of asparagine and the carbonyl group of reducing sugars along with thermal treatment of early Maillard reaction products (N-glycosides). Similarly, the decarboxylated Schiff base and decarboxylated Amadori compounds of asparagine as well as the Strecker aldehyde have been proposed as direct precursors and intermediates of acrylamide. Corresponding chromatographic methods are used to determine various structural groups present in Maillard reaction model systems. Gas chromatography-mass spectrometry and liquid chromatography with tandem mass spectrometry analysis are both acknowledged as the main, useful, and authoritative methods for acrylamide determination. This review is an attempt to summarize the state-of-the-art knowledge of acrylamide chemistry, formation mechanisms, and analytical methods. Special attention is given to comparison of different chromatographic techniques, particularly the novel, simple, and low-cost methods of its determination.

Maillard reaction products profile and intake from Spanish typical dishes

The Mediterranean diet is proposed as one of the healthiest dietary models, but its contribution to Maillard reaction products (MRP) intake is unknown. Several Spanish dishes typical of the Mediterranean diet (paella, Spanish omelette, salmorejo or churros) were selected to evaluate MR extension and the presence of MRP. CIELab colour, browning at different wavelengths, furosine, hydroxymethylfurfural, furfural and acrylamide were determined, and content/serving was calculated. Development of MR was affected by ingredients: when protein levels were high and carbohydrates low, early MRP were formed, regardless of the culinary process. There was found a correlation between acrylamide and hydroxymethylfurfural. The possible underestimation of deterministic calculations of acrylamide dietary exposure is discussed. This study presents a first approximation to enable the MRP intake from the Mediterranean diet to be calculated, taking into account the moisture content and the serving size of dishes.

Kinetics of Maillard reactions in model infant formula during UHT treatment using a static batch ohmic heater

The impact of an ultrahigh temperature (UHT) treatment on amodel infant formula (IF) was examined by assessing the advancement of Maillard reactions during a thermal treatment by ohmic heating. The heating and holding steps of the heat treatment were carried out in a static batch ohmic heater equipped with a nitrogen counter-pressure system, allowing the reaching of five temperature levels from 100 to 140 °C. A heat treatment was characterised by monitoring a holding time at a given temperature. Samples were taken during heating and holding steps and analysed for early Maillard reaction products (MRPs), such as furosine, advanced MRPs, such as advanced glycated end products (AGEs) and carboxymethyllysine (CML), and final MRPs such as melanoidins. The results show that Maillard reactions in model IF are highly dependent from time-temperature treatment. In compliance with other classical heating techniques, the selected chemical markers followed a pseudo-zero order of reaction under isothermal conditions. However, the contribution of the heating step can be significant as MRPs could be detected from the first seconds of the UHT treatment.

The effect of heating and fermenting on antioxidant properties of white cabbage

It is widely believed that natural antioxidants found in food are significantly lost during processing. Nevertheless, it was recently demonstrated that processed fruits and vegetables may retain their antioxidant activity. In the present work, the changes in the overall antioxidant properties as a consequence of fermentation of cabbage and/or heat treatment of cabbage juices and extracts were studied. Fermentation processes as well as heat treatment increased the initial values of antioxidant activity. While a decrease in the antioxidant potential of sauerkraut juice was found for short heat treatments, a partial recovery of these properties was observed by prolonging heating periods. The TLC analysis showed that during fermentation and thermal processes, some substances with reactivity towards Folin–Ciocalteu reagent, hence with possible antioxidant activity, were released. We demonstrated that in contrast to common expectation, typical culinary processing of cabbage increases its antioxidant potency. The gain in antioxidant activity of heated samples coincided with the formation of both F–C reagent reactive compounds as well as brown early Maillard reaction products. This information may encourage the consumption of heat processed cabbage, especially that the release of antioxidants during heating may prevent oxidation of other food components, e.g. fats.

The effect of base particle size in complementary feedingstuffs using early maillard reaction products on the performance of post weaning piglets

The animal feed industry produces various complementary feedstuffs with high levels of crude protein (CP) and synthetic amino acids designed to provide optimum nutrition to the post weaned pig. The use of synthetic amino acids has both advantages and disadvantages and other ways of delivering amino acids are of interest to the feed industry. One possible way of delivering amino acids is through the Maillard reaction; this is the chemical catalysis of the amine group of an amino acid to the carboxyl group of a sugar giving Maillard reaction products (MRP). These molecules occur during cooking, but have been shown to have a variety of other applications (Namiki, 1996) In this study, lysine (Lys), methionine (Met) and threonine (Thr) where chemically reacted with sugar molecules to give in vitro early Maillard Reaction Products (MRP). The aim of this study was to assess the effect of a solution of these MRPs with particle sizes of cereal base in a complementary feedingstuff (Matan XL, Devenish Nutrition) on overall diet performance.

The digestibility and performance of complementary feedingstuffs using maillard reaction products in the post weaning pig

The addition of ‘high quality’ complementary feedingstuffs to the diet of the post weaning pig can positively impact on growth and lean muscle deposition. The Maillard Reaction bonds amino acid and sugar molecules together, and is one of the major pathways in the chemical changes that occur in the cooking process. Cooking of feedingstuffs has been shown to improve the digestibility and nutritive value of a diet (Pickford et al, 1992). In this study, lysine (Lys), methionine (Met) and threonine (Thr) where chemically reacted with sugar molecules to give in vitro early Maillard Reaction Products (MRP). The aim of this study was to assess what effect the addition of a solution of these MRPs to a complementary feedingstuff (Matan XL) would have on overall diet digestibility and subsequent piglet performance.

Role of sugar–amino acid interaction products (MRPs) as antioxidants in a methyl linoleate model system

Effects of early Maillard reaction products (MRPs) as antioxidants in methyl linoleate model system, during refrigerated storage at 5 °C for 6 days, have been evaluated. MRPs were prepared by reacting glucose with five different amino acids – glycine, methionine, tryptophan, aspartic acid and lysine – using two different concentrations and time intervals (30 mM/1 h, 30 mM/2 h, 60 mM/1 h and 60 mM/2 h). The preformed MRPs were incorporated, after studying pH and optical density profile, in a model system comprised of methyl linoleate and microcrystalline cellulose. Antioxidative characteristics were evaluated by estimating the thiobarbituric acid-reactive substance value (TBARS) and peroxide value (PV) and monitoring the gas chromatographic degradation pattern of methyl linoleate immediately after heating, as well as after storage at 5 °C for 2, 4 and 6 days. Analysis of variance revealed highly significant differences among TBARS, PV and the % of methyl linoleate degradation ( p < 0.01) values, both initially and during storage in glucose + lysine and glucose + glycine with respect to control. Other treatments, such as glucose + methionine and glucose + tryptophan exhibited moderately significant differences ( p < 0.05). But glucose + aspartic acid was not significantly different ( p > 0.05) Significant differences were observed between 60 mM/2 h and 30 mM/1 h of MRPs with glucose + lysine and glucose + glycine ( p < 0.01). Out of the five combinations tried, glucose + lysine and glucose + glycine exhibited good antioxidative potential at 60 mM/2 h. The % of antioxidant activity was in the order 60 mM/2 h > 60 mM/1 h > 30 mM/2 h > 30 mM/1 h for the treatments glucose + lysine > glucose + glycine > glucose + tryptophan > glucose + methionine > glucose + aspartic acid, respectively.

Effect of processing and storage on the chemical quality markers of spray-dried whole egg

Chromatographic techniques were used in order to determine the modifications induced in egg, by a spray-drying treatment, on the native constituents and on the formation of cholesterol oxidation products (COPs) and early Maillard reaction products. The same powdered egg was stored for 12 months at room temperature and at 4 °C, and sampled at 1, 3, 6 and 12 months, respectively. The spray-drying treatment did not affect tocopherol or retinol composition, but caused a severe Maillard reaction (furosine increased from 15 to 500 mg/100 g protein) and accelerated cholesterol oxidation (the sum of COPs increased from 24 to 55 μg/g fat). Only slight modifications were registered in powdered egg stored at 4 °C. During storage at room temperature, however, COPs increased significantly (up to 167 μg/g fat), tocopherols and retinols decreased, whereas furosine was not significantly modified. Thus, furosine can be considered as a suitable technology marker, whereas COPs are important markers of the storage conditions.

Solid-state glycation of beta-lactoglobulin monitored by electrospray ionisation mass spectrometry and gel electrophoresis techniques.

Glycation of beta-lactoglobulin (beta-Lg) with either lactose or galactose in a solid-state medium was monitored using gel electrophoresis techniques and liquid chromatography coupled to electrospray ionisation mass spectrometry (LC/ESI-MS). The kinetics of glycation monitored by SDS polyacrylamide gel electrophoresis showed a molecular weight increase over time of the beta-Lg bands for both sugars, but no significant amounts of aggregated proteins were observed. The isoelectric point of the protein, observed by isoelectric focusing gel electrophoresis, was dramatically affected by galactosylation. LC/MS measurements of beta-Lg variants A and B, over the whole glycation reaction time, showed a larger extent of glycation with galactose (from 4 up to 22 adducts) as compared with lactose (from 0 up to 14 adducts), and confirmed that early Maillard reaction products were the main species observed. Based on the relative abundances obtained from the deconvoluted mass spectra after a 8 h 15 min incubation time at 60 degrees C, the mean values of lactose and galactose molecules bound to the protein species were calculated to be 10.4 and 17.9, and 10.5 and 18.6, for variants A and B, respectively. Furthermore, the charge state distribution data obtained by ESI-MS was studied using different methanol percentages, and indicated that adduct formation with lactose, but more significantly galactose, tends to improve the stability properties of the native protein towards denaturation.

Acrylamide from Maillard reaction products.

The discovery of the adventitious formation of the potential cancer-causing agent acrylamide in a variety of foods during cooking has raised much concern, but the chemical mechanism(s) governing its production are unclear. Here we show that acrylamide can be released by the thermal treatment of certain amino acids (asparagine, for example), particularly in combination with reducing sugars, and of early Maillard reaction products (N-glycosides). Our findings indicate that the Maillard-driven generation of flavour and colour in thermally processed foods can -- under particular conditions -- be linked to the formation of acrylamide.

Antioxidant properties of tomato juice as affected by heating

The changes in the overall antioxidant properties of tomato juice samples and model solutions as a consequence of heat treatments were studied. The antioxidant properties were evaluated both through the measurement of the chain breaking and the oxygen scavenging activities. While a decrease in the antioxidant potential was found for short heat treatments, a recovery of these properties was measured by prolonging heating times. Results suggested that the initial reduction in the overall antioxidant activity can be attributed not only to the thermal degradation of naturally occurring antioxidants but also to the formation of early Maillard reaction products (MRP) with pro-oxidant properties. The gain in antioxidant activity coincided with the formation of brown MRP. © 1999 Society of Chemical Industry

Heating Milk: A Study on Mutagenicity

ABSTRACTThe mutagenicity of heated milk and model systems was investigated by the Ames mutagenicity assay. Heating varied from pasteurization to in‐bottle sterilization to ultra‐high‐temperature (UHT) heat‐treatment. No mutagenic response was found in heated milk or model systems. Early Maillard reaction products formed in heated milk or milk‐resembling model systems apparently did not show mutagenic activity in the Ames‐test. Milk that was burnt to the pan was also investigated. Chloroform and ethanol extracts of this milk showed mutagenic activity. Evidence showed this was due to Maillard reaction products. The antimutagenic activity of casein, reported in earlier studies, was confirmed.