Non-enzymatic Browning Development Research Articles

Inhibition of Browning in Apples Using Betacyclodextrin-Assisted Extracts of Green Rooibos (Aspalathus linearis).

Green rooibos' bioactive compounds contribute greatly towards its antioxidant activity. The anti-browning activity of aqueous (GRE) and beta-cyclodextrin (β-GRE)-assisted extracts of green rooibos was investigated in canned apples. Freeze-dried extracts (GRE and β-GRE) obtained at 40 °C for 60 min were added in canned apples at 0.25 and 0.5% prior to heat processing and stored at 23 and 37 °C for 24 weeks. Lightness (L*), colour difference (DE*), furfural and hydroxymethyl furfural (HMF) were determined to establish the effect of extracts against non-enzymatic browning (NEB) development. The L* value decreased, whereas DE*, HMF and furfural increased with increased storage time and temperature. A higher inhibition was observed for samples stored at 23 °C, and storage at 37 °C reduced (p < 0.05) the inhibitory capacity of extracts. Greater inhibition against NEB development was reported for β-GRE 0.25 and 0.5 via the L* value (40.93-46.67%), β-GRE 0.25 for DE* (46.67%) and β-GRE 0.25 and 0.5 for HMF (59.55-67.33%). No differences (p > 0.05) were observed in furfural inhibition between all extracts, although inhibition was reported at 62.69-72.29%. Browning inhibition correlated with the reaction rate constant (k0) and activation energy (Ea), exhibiting a correlation coefficient of 0.925, 0.964, 0.932 and 0.754 for L*, DE*, HMF and furfural, respectively.

Kinetics of L-ascorbic acid degradation and non-enzymatic browning development in hot-compressed water.

The effect of reaction conditions, which comprised the reaction temperature (150-190°C), processing time (0.50, 0.75, 1.00, 1.25, 1.50, 2.00, and 2.50 h), pH (5.0, 7.0, and 9.5), and concentration (0.03-0.07 mol/L) of L-ascorbic acid (ASA), on the degradation of ASA was investigated in hot-compressed water (HCW). The degradation kinetics of ASA and generation kinetics of browning products (BPs) were studied. The results showed that ASA degradation conformed to the pseudo-first-order kinetics, and the formation of BPs was closely related to the concentration of H3O+ in HCW. The acidic condition (pH = 5.0) and lower concentration of ASA (0.03 mol/L) were more favorable for ASA degradation. In HCW, the average apparent activation energy (Ea) of ASA was 15.77, 31.70, and 47.53 kJ/mol at pH 5.0, 7.0, and 9.5, respectively. The possible degradation mechanisms of ASA and the generation of BPs in HCW were proposed based on the experimental results.

Non-enzymatic browning of lotus root during boiling

Lotus root is the most consumed aquatic vegetable in China. Both the actual boiling of lotus root and the simulated boiling of its extract were performed at different conditions to explore the development of non-enzymatic browning and the loss of reducing sugars, free amino acids, total free phenols and ascorbic acid. The kinetic parameters of zero-order and first-order models indicated that both browning degree and nutrient loss had a positive correlation with boiling time, temperature and pH value. Moreover, nutrient contents and boiling conditions were adopted as independent variables to establish the multiple linear regression model of browning degree (P < 0.001), which confirmed that reducing sugars and total phenols principally contributed to the browning (P < 0.01), through caramelization and phenol oxidation. With the addition of baking soda (pH 8), 100 °C boiling decreased the DPPH radical scavenging capacity and ferric reducing antioxidant power of lotus root extract by 62.96% and 58.51%, respectively. Furthermore, 120 °C boiling probably induced the formation of browning products, which possessed cytotoxicity against HepG2 and L02 cells. A short boiling time, as well as an acidic condition induced by added vinegar, is recommended for cooking and processing of lotus root in consideration of nutrition and health.

The complex dependence of non-enzymatic browning development on processing conditions in maize snacks

The complex dependence of non-enzymatic browning development on processing conditions was analyzed in the production of maize snacks. The influence of the amount of water added to maize flour, toasting time, and toasting temperature on final water contents, HMF formation and CIELAB color parameters was evaluated by Response Surface Methodology. While L* values decreased continuously with increasing toasting temperature, the variables a* and b* showed maximum values at intermediate studied ranges of temperature and water contents, which is related to the complex interactions of the variables water content and temperature. The formation of HMF, as a marker of non-enzymatic browning reactions, was favored by low water contents and its concentration correlated with lower L* and b* but higher a* values. The optimum levels of toasting time, toasting temperature, and water addition for minimizing HMF concentration at which the snacks presented adequate color characteristics were determined. Finally, correlations between L*, b* and HMF were mathematically established to predict heat damage using these fast and non-destructive indicators to assure adequate processing and storage conditions.

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&lt;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.

Non-enzymatic browning kinetics in sucrose-glycine aqueous and dehydrated model systems in presence of MgCl2

The development of non-enzymatic browning in the presence of MgCl2 was evaluated in liquid and dehydrated sucrose-glycine model systems, in relation to interactions of the salt with water and/or with sucrose. In both systems, browning was accelerated by the presence of MgCl2 because of the increased sugar hydrolysis (ten times faster) and the reduction of water mobility (1H NMR T2 relaxation times) caused by this salt (between 6 and 14% lower), counteracting the inhibitory effect of water on the Maillard reaction. MgCl2 also provoked a 40% reduction on the fluorophores quantum yield, responsible also of the fluctuations observed in the fluorescence development as a function of time after 50 h at 70 °C. Molecular and supramolecular effects of the presence of MgCl2 have been observed on the Maillard reaction kinetics. These results are of high technological interest when strategies to control the Maillard reaction rate are required for a particular application.

Effect of formulation and baking conditions on the structure and development of non-enzymatic browning in biscuit models using images.

The aim of this research was to determine the effect of composition (dietary fiber=DF, fat=F, and gluten=G) and baking time on the target microstructural parameters that were observed using images of potato and wheat starch biscuits. Microstructures were studied Scanning Electron Microscope (SEM). Non-enzymatic browning (NEB) was assessed using color image analysis. Texture and moisture analysis was performed to have a better understanding of the baking process. Analysis of images revealed that the starch granules retained their native form at the end of baking, suggesting their in complete gelatinization. Granules size was similar at several different baking times, with an average equivalent diameter of 9 and 27µm for wheat and potato starch, respectively. However, samples with different levels of DF and G increased circularity during baking to more than 30%, and also increasing hardness. NEB developed during baking, with the maximum increase observed between 13 and 19min. This was reflected in decreased luminosity (L*) values due to a decrease in moisture levels. After 19min, luminosity did not vary significantly. The ingredients that are used, as well as their quantities, can affect sample L* values. Therefore, choosing the correct ingredients and quantities can lead to different microstructures in the biscuits, with varying amounts of NEB products.

Effect of parboiling on physical and chemical characteristics and non-enzymatic browning of emmer (Triticum dicoccon Schrank)

Parboiling is a popular technology applied to rice to increase its milling yield, nutritional value and resistance to spoilage by insects and mould. This process was applied to Triticum dicoccon Schrank to induce physical, chemical and organoleptic modifications in order to increase its use and product diversification.Hulled and dehulled emmer samples, subjected to different parboiling conditions, were characterized by analyzing the physical and chemical modifications and the non enzymatic browning.The results showed that although parboiled grains were darker than the untreated reference sample, due to the development of non-enzymatic browning and the diffusion of the pigments contained in the husk and bran, during hydrothermal treatment glumes have a protective action on the caryopsis integrity and against thermal damage.

Effects of conventional and multistage drying processing on non-enzymatic browning in tomato

The effect of different drying temperatures on the development of non-enzymatic browning in tomato was studied. In particular, the influence of product moisture and temperature on the colour change during drying at various temperatures in the range of 50–90 °С was investigated. The extent of browning was evaluated spectrophotometrically as tomato extracts absorbance at 420 nm. As a result of analysis of experimental data, a multistage drying process of tomato was developed. In this method, drying was realized at decreasing air temperature, arranged such, that the temperature inside the fruit did not exceed acceptable level of 55 °С. Higher product quality and shorter drying time in comparison with the conventional drying at constant air conditions were observed.

Influence of composition of edible films based on gellan polymers on l-(+)-ascorbic acid stability

Edible films made with gellan (deacylated) gum to carry l-(+)-ascorbic acid (AA) were formulated either in mixture with gellan acylated form or by addition of calcium ion. AA-stability and the subsequent non-enzymatic browning (NEB) development were evaluated during storage at 33.3%, 57.7% or 75.2% relative humidity and 25 °C. Presence of acyl-side chains in the gellan backbone led to a less rigid macromolecular network of the polymer mixture, which allowed lowering glycerol content, obtaining higher AA retention and lower NEB development with adequate mechanical characteristics of films. Otherwise, additional calcium presence in deacylated gellan film slowed down the browning development at the highest relative humidity of storage (75.2%). In general, it was observed an accelerating effect of local moisture mainly on non enzymic browning reactions, as well as the compromise of the film water content in plasticization of the polymeric networks when stored at 33.3% or 57.7% relative humidity.

Interactions between aspartame, glucose and xylitol in aqueous systems containing potassium sorbate

The interaction between aspartame, glucose and xylitol in aqueous model systems of pH 3.00 and containing potassium sorbate was studied. Potassium sorbate degradation diminished with the increment of aspartame level from 0.050 to 0.500 g/100 g of system. Xylitol was the humectant that minimized aspartame degradation and non-enzymatic browning development. In general, as expected, presence of aspartame, xylitol or glucose and their mixtures increased the sweetness and they also diminished the sourness of the systems. The addition of 0.050 g of aspartame/100 g of system to the system containing xylitol produced a synergistic effect on sweetness intensity. Based on that trend, it could be concluded that the use of more than one sweetener might allow diminishing the amount of each one of them to assure a specific sweet level. These results stand out the advantage of the use of xylitol as well as the importance of an appropriate choice of the additives and food ingredients to use in the formulation of modified products with lower sugar content to optimize their quality.

Phospholipid oxidation, non-enzymatic browning development and volatile compounds generation in model systems containing liposomes from porcine Longissimus dorsi and selected amino acids

Lipid oxidation, non-enzymatic browning development and volatile compounds generation were studied in sterile meat-model systems containing selected amino acids and/or liposomes during 35 days at 25 °C under pro-oxidative conditions, in order to simulate the ripening conditions of dry-cured meat products. Liposomes were prepared with polar lipids (PL) from Longissimus dorsi muscle of outdoors pigs fed on grass and acorns (M) or indoors ones fed on concentrates (C). Thiobarbituric acid reactive substances (TBA-RS) in systems containing both amino acids and liposomes were higher than in those containing only liposomes. The higher susceptibility to lipid oxidation of liposomes from C animal was reflected in higher TBA-RS throughout the experiment. All model systems containing liposomes and/or amino acids showed non-enzymatic browning development, as measured by the yellowness index. Major volatile compounds were fatty acid oxidation products. Strecker-derived volatile compounds were predominantly detected in model systems containing both amino acids and liposomes. The chromatographic areas of Strecker-derived volatiles increased over time whereas those of lipid-derived volatiles decreased. The occurrence of lipid oxidation, non-enzymatic browning and Strecker-type degradation of amino acids were shown in sterile meat-model systems at low temperatures.

Water–solids interactions, matrix structural properties and the rate of non-enzymatic browning

The kinetics of non-enzymatic browning (NEB) was studied in freeze-dried model and food systems in a wide range of relative humidity (R.H.) values. PVP, lactose, lactose–starch solutions and food (milk, cabbage, apple, potato, and chicken meat) systems were freeze-dried, equilibrated at 11–85% of R.H. and incubated at 70 °C. Thermal transitions were determined by DSC. The kinetics of NEB development was analyzed. In PVP systems the maximum rate occurred at 33% R.H., at which T g was close to the storage temperature. Above 33% R.H. the samples presented a fluid aspect at 70 °C and the NEB rate decreased when increasing R.H. In tissues containing structuring water insoluble biopolymers and presenting an intermediate degree of collapse, the maximum rate of NEB occurred at relative humidities in a range of 50–80%, when the samples were well above T g at the storage temperature. In the lactose systems the maximum rate occurred at R.H. close to 40%, at conditions at which lactose was highly crystalline.

Coordinate Contribution of Lipid Oxidation and Maillard Reaction to the Nonenzymatic Food Browning

Lipid oxidation and the Maillard reaction are probably the two most important reactions in Food Science. Both include a whole network of different reactions in which an extraordinary complex mixture of compounds are obtained in very different amounts and produce important changes in food flavor, color, texture, and nutritional value, with positive and negative consequences. This article analyzes the interactions between both reactions, with special emphasis in nonenzymatic browning development, by discussing the influence of lipid oxidation products in the Maillard pathway and vice versa, as well as the existence of common intermediates and polymerization mechanisms in both reactions. The existing data suggest that both reactions are so interrelated that they should be considered simultaneously to understand the products of the Maillard reaction in the presence of lipids and vice versa, and should be included in one general pathway that can be initiated by both lipids and carbohydrates.

Phospholipid oxidation and nonenzymatic browning development in phosphatidylethanolamine/ribose/lysine model systems

Fatty acid losses, lipid oxidation, pyrrole formation, and browning and fluorescence development were determined in four mixtures of phosphatidylethanolamine (PE), ribose (RI), and/or lysine (lys) incubated at 37 °C to study the influence of lipid oxidation on the Maillard reaction and vice versa. Under the conditions assayed, the amino group of PE was preferentially damaged compared with the amino group of lys. In addition, oxidized lipid/amino acid reactions produced more pyrrolization, browning and fluorescence than carbohydrate/amino acid reactions, but both oxidized lipid/amino acid and sugar/amino acid reactions were produced in the PE/RI/lys system and both of them were inhibited by the presence of the other. Thus, fewer RI/lys reaction products were produced in the PE/RI/lys system than in an analogous system with no PE added. All these results confirm that there is an interaction between lipid oxidation and the Maillard reaction, and both of them should be considered simultaneously to understand their consequences on foods when lipids, carbohydrates, and amino acids or proteins are present.

Study on nonenzymatic browning in cookies, crackers and breakfast cereals by maltulose and furosine determination

Nonenzymatic browning development has been investigated in commercial cookies, crackers and breakfast cereals by determination of maltulose and furosine. In addition, maltose, lactose, lactulose, fructose, glucose and 2-furoylmethyl-GABA were also determined in the samples studied. Maltulose and furosine were present in all samples of cookies, crackers and breakfast cereals. Differences found among samples may be attributed to variations in composition and processing conditions. The maltose/maltulose ratio showed a wide range in the samples studied and could probably be attributed to differences in heating intensity during processing. Thus, maltose/maltulose ratio might serve as indicator of the heat load during manufacture. Furosine and 2-furoylmethyl-GABA may arise from Maillard reactions in some of the ingredients before manufacture of the cereal products: this appears to be a major drawback for the use of these compounds as suitable indicators to differentiate between commercial cereal products. However, in the cereal industry, where exact ingredient composition is known, measurement of the maltulose and furosine formed might be used as indicators to monitor processing conditions during the manufacture of cereal products.

Effect of irradiation and storage on patulin disappearance and some chemical constituents of apple juice concentrate.

The effect of irradiation on the patulin content and on the chemical composition of apple juice concentrate during storage at 4 degrees C over a period of several weeks was investigated. The radiation-induced disappearance of the mycotoxin in relation to the absorbed dose followed an exponential relationship. The radiation dose (D50), i.e., the dose which reduced the patulin content to 50% of its initial value was equal to 0.35 kGy. Storage of the irradiated concentrate had no effect on the patulin content; however, storage did lead to a slight increase in the titratable acidity and a decrease in the amounts of the carbonyl compounds and the ascorbic acid concentration. The development of non-enzymatic browning during storage of the irradiated samples followed the same kinetics as that of the non-irradiated samples.