Multiresponse Kinetic Modelling Research Articles

Multi-response kinetic modelling of the formation of five Strecker aldehydes during kilning of barley malt

Control of aroma formation during production of barley malt is critical to provide consistent and high-quality products for the brewing industry. Malt quality can be affected by the inherent variability of raw material and processing conditions, leading to inconsistent and/or undesirable profiles. Dried green malts were cured isothermally at 65, 78 and 90 °C for 8.4 h, and characteristic aroma compounds (Strecker aldehydes), precursors and intermediate compounds were analysed over time. By kinetic modelling of Strecker aldehydes, based on fundamental chemical pathways, we showed that degradation of Amadori rearrangement products and short-chain dicarbonyls was more sensitive to temperature change due to their higher activation energies compared to other kinetic steps. This study can help maltsters to manipulate formation of Strecker aldehydes, via raw material screening and process control, and hence optimise the organoleptic quality of malts and their products, such as non-alcoholic beers, where these aldehydes play a key role.

The kinetic study of 2-acetyl-1-pyrroline accumulation in the model system: An insight into enhancing rice flavor through the Maillard reaction

Controlling the Maillard reaction may affect the generation of 2-acetyl-1-pyrroline, the key aroma compound in rice. In this study, the kinetics of 2-acetyl-1-pyrroline accumulation in the glucose/proline model system was comprehensively investigated and extra methylglyoxal or glyoxal was added to enhance 2-acetyl-1-pyrroline concentrations during rice cooking. Using the multi-response kinetic modeling to derive kinetic parameters, the formation of glyoxal, as the reactive intermediate, was rate-determining for the overall generation rate of 2-acetyl-1-pyrroline. Besides, although 2-acetyl-1-pyrroline generation was easier to occur with lower activation energy, much higher depletion rates of 2-acetyl-1-pyrrroline at 120 °C and 140 °C led to maximal 2-acetyl-1-pyrroline accumulation at the lower temperature of 100 °C. Furthermore, the inclusion of 0.05 μmol/kg additional methylglyoxal in cooked rice significantly enhanced 2-acetyl-1-pyrroline generation. The work suggested that the development of rice products with superior flavor quality may be achieved by the slight accumulation of intermediates prior to thermal processing.

Multiresponse Kinetic Modeling of Acrylamide Formation in Low Moisture Food Systems Like Nuts and Seeds during Roasting

Multiresponse Kinetic Modeling of Acrylamide Formation in Low Moisture Food Systems Like Nuts and Seeds during Roasting

Kinetic modeling of Maillard and caramelization reactions in sucrose-rich and low moisture foods applied for roasted nuts and seeds

A kinetic model was proposed by using a multiresponse kinetic modeling approach for Maillard and caramelization reactions in low moisture foods at neutral pH containing a moderate amount of amino acid and sucrose but a restricted amount reducing sugar. The change in the amount of sucrose, protein-bound lysine, free amino acids, and certain products of Maillard reaction was monitored during roasting of sunflower seed, pumpkin seed, flaxseed, peanut, and almond at 160 and 180 °C. A slightly different model was proposed for pumpkin seed due to its difference in compositional and physicochemical characteristics as expressed by principal component analysis. Accordingly, 3-deoxyglucosone formation via sugar degradation; 5-hydroxymethylfurfural formation from 3-deoxyglucosone and only in pumpkin seeds the conversion of N-ε-fructoselysine to glyoxal and Heyns product to 1-deoxyglucosone were found to be quantitatively important. N-ε-carboxymethyllysine and N-ε-carboxyethyllysine mainly originated through oxidation of N-ε-fructoselysine and the reaction of methylglyoxal with lysine residue, respectively.

Formation of α-dicarbonyl compounds and glycation products in sesame (Sesamum indicum L.) seeds during roasting: a multiresponse kinetic modelling approach

Formation of α-dicarbonyl compounds and glycation products in sesame (Sesamum indicum L.) seeds during roasting: a multiresponse kinetic modelling approach

Modelling the effect of food composition on antimicrobial compound absorption and degradation in an active packaging

Abstract This study aims to comprehensively describe the rate of AITC release, absorption, and degradation in the packaging system by using multiresponse kinetic modelling. The effects of food composition and temperature on allyl isothiocyanates (AITC) partitioning in an antimicrobial packaging system were investigated. A higher protein content in the food caused a higher AITC concentration in the headspace, which can be explained by a lower mass transfer coefficient of AITC transfer from the headspace into the food matrix. A higher fat content in the food matrix caused a lower AITC concentration in the headspace, which can be explained by the fat stimulating AITC partitioning into the food matrix. At a lower temperature AITC is more stable in the headspace and food matrix. The results can be used to optimize the design of a packaging system with an AITC concentration tailored to the packed food product.

Multiresponse kinetic modelling of the formation, release, and degradation of allyl isothiocyanate from ground mustard seeds to improve active packaging

This study aims to describe allyl isothiocyanates (AITC) formation from enzymatic sinigrin hydrolysis in ground mustard seeds and its release and degradation in the headspace using multiresponse kinetics modelling. The mechanistic modelling of the steps involved in the packaging system consists of a set of ordinary differential equations established from bio (chemical) reaction models combined with mass transfer models. The estimated parameters consist of the accessible sinigrin fraction, rate constants of sinigrin hydrolysis, AITC degradation in the particles and headspace, and its mass transfer coefficient. The model provides a good fit to experimental results and confirms the proposed mechanism of the AITC formation, degradation, and release inside the packaging system. Fat content has significant effects on AITC formation and release rate constants, while particle sizes significantly affect accessible sinigrin in the particles. These results give an understanding of AITC's controlled release by manipulating the mustard properties to optimize antimicrobial packaging designs. • A multiresponse model can describe AITC formation, release, and degradation. • Fat content has significant effects on rate constants of AITC formation and release. • Particle sizes have significant effects on accessible sinigrin in the particles. • AITC release can be controlled by manipulating the mustard-seeds properties. • The developed model can be used to optimize the design of antimicrobial packaging.

Multiresponse kinetic modelling of 5-hydroxymethylfurfural and acrylamide formation in sesame (Sesamum indicum L.) seeds during roasting

This study aims to investigate the formation mechanism of 5-hydroxymethylfurfural and acrylamide in sesame seeds during roasting. Sesame seeds were roasted at 180, 200, and 220 °C for different time intervals, and changes in the concentration of sucrose, free amino acids, asparagine, 3-deoxyglucosone, 5-hydroxymethylfurfural, and acrylamide were monitored. Multiresponse kinetic modelling was used to develop a reaction model including possible ways of 5-hydroxymethylfurfural and acrylamide formation. According to this, sucrose degraded into glucose and fructofuranosyl cation under dry conditions and high temperatures during sesame roasting. The results of the kinetic model indicated that glucose mostly degraded to 3-deoxyglucosone formation and 5-hydroxymethylfurfural formation was mostly originated from fructofuranosyl cation. Additionally, acrylamide formation through the reaction of asparagine with 5-hydroxymethylfurfural was kinetically important than its reaction with glucose or 3-deoxyglucosone. Multiresponse kinetic modelling provided understanding the roles of intermediates giving rise to the formation of acrylamide and 5-hydroxymethylfurfural in roasted sesame seeds.

Multiresponse kinetic modelling of α-dicarbonyl compounds formation in fruit juices during storage

This study aims to investigate the formation of α-dicarbonyl compounds in fruit juices and nectars during storage using multi-response kinetic modeling approach. Changes in the concentrations of sugars, amino acids, α-dicarbonyl compounds (glucosone, 3-deoxyglucosone, threosone, methylglyoxal, glyoxal) and 5-hydroxymethylfurfural in apple juice, orange juice and peach nectar were monitored during storage. The concentrations of free amino acids showed no statistically significant change during storage. This suggested that sugar degradation reactions were found responsible for α-dicarbonyl compound formation. In apple and orange juices, the reaction rate constant of glucosone formation was found higher than that of 3-deoxyglucosone formation. Contrary, in peach nectar, 3-deoxyglucosone formation was the dominant. The contribution of fructose dehydration through fructofuranosyl cation on the formation of 5-hydroxymethylfurfural was significantly higher (p < 0.05) than 3-deoxyglucosone dehydration. The use of multi-response kinetic modeling provided better understanding the most possible pathway of sugar degradation reactions in fruit juices.

5-Hydroxymethylfurfural accumulation plays a critical role on acrylamide formation in coffee during roasting as confirmed by multiresponse kinetic modelling

This study aims to investigate in depth the mechanism of acrylamide formation in coffee during roasting. For this purpose, a comprehensive kinetic model including the elementary steps for acrylamide formation was proposed. The changes in sucrose, reducing sugars, free amino acids, asparagine, acrylamide, 3-deoxyglucosone, methylglyoxal, glyoxal, and 5-hydroxymethylfurfural were monitored in coffee during roasting at 200, 220 and 240 °C. Dominant pathways of complex reactions leading to acrylamide were unravelled by means of multiresponse kinetic modelling approach. The results of the model indicated that sucrose degrades into glucose and a reactive fructofuranosyl cation. Interestingly, glucose takes part mostly in the formation of intermediates, glyoxal and especially 3-deoxyglucosone rather than acrylamide formation. On the other hand, fructofuranosyl cation contributed mostly to the formation of 5-hydroxymethylfurfural which was found to be the most important intermediate precursor of acrylamide formed in coffee during roasting.

Multiresponse Kinetic Modeling of Heat-Induced Equilibrium of β-Carotene cis-trans Isomerization in Medium-Chain Triglyceride Oil.

The kinetics and mechanism of the stepwise cis-trans isomerization reactions of all-trans-β-carotene dissolved in MCT (medium-chain triglyceride) oil at temperatures in the range of 80-160 °C have been analyzed using multiresponse modeling. Quantitation of the cis-isomers was performed using HPLC-DAD and quantitation at the reaction isosbestic point at 421 nm. Multiresponse kinetic modeling using the Bayesian criterion was initially performed at 120 °C to determine the best model. Subsequently, the reparametrized Arrhenius equation was used to calculate the activation energies of all reactions. The equilibrium constants for the individual isomerization reactions were determined from the rate constants and the final product distributions. The enthalpies and entropies of the isomerization reactions were determined from the temperature dependence of the equilibrium constants. The 13-cis and 13,13'-di-cis isomers were found to be the fastest formed isomers followed by the 9-cis, 9,13-di-cis, and 13,15-di-cis isomers, where the latter was found to be formed from 13-cis and not the 15-cis isomer. The relative free energies of the β-carotene isomers were determined as all-trans < 13-cis < 9-cis < 13,13'-di-cis < 9,13-di-cis ≈ 15-cis < 13,15-di-cis. The entropic contribution of each reaction was found to play an important role in the ordering. It is concluded that the β-carotene system is quite labile at temperatures ranging from 80 to 160 °C and resulting in equilibrium distributions of the cis-trans isomers.

Kinetic evaluation of the formation of tryptophan derivatives in the kynurenine pathway during wort fermentation using Saccharomyces pastorianus and Saccharomyces cerevisiae

This study aimed to evaluate the formation of tryptophan derivatives in the kynurenine pathway during wort fermentation using a multi-response kinetic model and an empirical modified logistic model. Saccharomyces cerevisiae NCYC 88 (ale yeast) and S. pastorianus NCYC 203 (lager yeast) were used to understand the effect of fermentation type on tryptophan derivatives. According to the modified logistic model, tryptophan concentration was critical for the maximum production rate of kynurenic acid, a neuroprotective compound. The results indicated that utilization of tryptophan and kynurenic acid formation were faster in wort fermented with S. cerevisiae than with S. pastorianus. The reaction rate constants implied that the kynurenic acid formation stage was minor compared to other enzymatic reactions leading to NAD+ synthesis. Multi-response kinetic modeling of kynurenine pathway provided insights into tryptophan derivative formation, which can facilitate improved beer fermentation processing.

Maillard reaction and caramelization during hazelnut roasting: A multiresponse kinetic study.

A comprehensive kinetic model indicating the elementary steps of Maillard reaction and caramelization during hazelnut roasting was proposed based on a multi-response kinetic modeling approach. Changes in the concentrations of sucrose, fructose, glucose, amino acids, 3-deoxyglucosone, 1-deoxyglucosone, 3,4-dideoxyglucosone, glyoxal, methylglyoxal, dimethylglyoxal, and 5-hydroxymethylfurfural were examined in hazelnuts during roasting at 150, 160 and 170°C for 15, 30, 60, 90, and 120min. The results suggested that 1,2-enolization was important in the interconversion of glucose and fructose, 5-hydroxymethylfurfural formation mainly proceeded via fructofuranosyl cation dehydration rather than 3-deoxglucosone, glucose contributed more than fructose and fructofuranosyl cation to the early stage of the Maillard reaction. Methylglyoxal and dimethylglyoxal were mainly formed from 1-deoxyglucosone with high reaction rate constants while glyoxal formed through glucose degradation. α-Dicarbonyl compounds could have a role in the formation of melanoidins. The temperature dependence of the reactions was complicated and could not be explained by the Arrhenius equation.

Effect of Sodium Chloride on α-Dicarbonyl Compound and 5-Hydroxymethyl-2-furfural Formations from Glucose under Caramelization Conditions: A Multiresponse Kinetic Modeling Approach.

This study aimed to investigate the kinetics of α-dicarbonyl compound formation in glucose and glucose-sodium chloride mixture during heating under caramelization conditions. Changes in the concentrations of glucose, fructose, glucosone, 1-deoxyglucosone, 3-deoxyglucosone, 3,4-dideoxyglucosone, 5-hydroxymethyl-2-furfural (HMF), glyoxal, methylglyoxal, and diacetyl were determined. A comprehensive reaction network was built, and the multiresponse model was compared to the experimentally observed data. Interconversion between glucose and fructose became 2.5 times faster in the presence of NaCl at 180 and 200 °C. The effect of NaCl on the rate constants of α-dicarbonyl compound formation varied across the precursor and the compound itself and temperature. A decrease in rate constants of 3-deoxyglucosone and 1-deoxyglucosone formations by the presence of NaCl was observed. HMF formation was revealed to be mainly via isomerization to fructose and dehydration over cyclic intermediates, and the rate constants increase 4-fold in the presence of NaCl.

Multiresponse kinetic modelling of Maillard reaction and caramelisation in a heated glucose/wheat flour system

The study describes the kinetics of the formation and degradation of α-dicarbonyl compounds in glucose/wheat flour system heated under low moisture conditions. Changes in the concentrations of glucose, fructose, individual free amino acids, lysine and arginine residues, glucosone, 1-deoxyglucosone, 3-deoxyglucosone, 3,4-dideoxyglucosone, 5-hydroxymethyl-2-furfural, glyoxal, methylglyoxal and diacetyl concentrations were determined to form a multiresponse kinetic model for isomerisation and degradation reactions of glucose. Degradation of Amadori product mainly produced 1-deoxyglucosone. Formation of 3-deoxyglucosone proceeded directly from glucose and also Amadori product degradation. Glyoxal formation was predominant from glucosone while methylglyoxal and diacetyl originated from 1-deoxyglucosone. Formation of 5-hydroxymethyl-2-furfural from fructose was found to be a key step. Multi-response kinetic modelling of Maillard reaction and caramelisation simultaneously indicated quantitatively predominant parallel and consecutive pathways and rate limiting steps by estimating the reaction rate constants.

Investigation and kinetic evaluation of furan formation in tomato paste and pulp during heating

Due to its high ascorbic acid content and acidic environment, tomato is susceptible for furan formation during heat treatment. In this study, kinetics of furan formation was analyzed in order to have an understanding of the reactions taking place in tomato pulp during heating. Also several tomato paste samples were investigated in terms of their furan and hydroxymethylfurfural (HMF) concentrations, and the possible furan precursors. Paste samples were found to contain 3.3–13ng/g furan and 0.9–39.4μg/g HMF (dry weight basis). Freshly prepared tomato pulps were heated at 70, 80, and 90°C for different times, and analyzed for ascorbic acid, dehydroascorbic acid, and furan concentrations. The formation rates of furan in the very first 5min of heating at 70, 80, and 90°C were 0.0071, 0.0130, and 0.0168nmol/g·min, respectively. Rate constants related to reactions taking place during furan formation were estimated by multi-response kinetic modeling. The results revealed that ascorbic acid oxidation is the critical step in furan formation reaction mechanism during heating of tomato pulp, and prevention of oxidation during processing might help to limit furan formation.

Use of Multi-response Modelling to Investigate Mechanisms of β-Carotene Degradation in Dried Orange-Fleshed Sweet Potato During Storage: from Carotenoids to Aroma Compounds

In order to give insight into β-carotene degradation mechanism during the storage of dried orange-fleshed sweet potato, and particularly into the role of isomers and norisoprenoids formation, multi-response kinetic modelling was applied. Determination of degradation compounds were carried out by HPLD-DAD and SPME-GC-MS as a function of time between 10 and 40 °C and at four water activities from 0.13 to 0.76. Kinetic modelling was developed assuming first-order reactions and by using mass balance. Eight compounds, namely, two isomers (9-cis- and 13-cis-β-carotene), two β-carotene epoxides (β-carotene 5,6 and 5,8 epoxide) and four volatile compounds (β-cyclocitral, β-ionone, 5,6-epoxy-β-ionone and dihydroactinidiolide), were integrated into two theoretical reaction schemes. The different models were discriminated according to goodness of fit to experimental data. This work showed that: (1) the formation of cis-isomers from β-carotene preceded oxidation, (2) β-cyclocitral arose directly from β-carotene scission while the other norisoprenoids resulted from β-carotene epoxide degradation, (3) cis-isomers were high reactive compounds. Temperature had a major influence on reaction rates k while water activities only impacted k at values under 0.51. Therefore, multi-response modelling is not only a tool to predict β-carotene degradation but a interesting way to select the appropriate degradation scheme based on the different options presented in literature.

The release of dipicolinic acid — The rate-limiting step of Bacillus endospore inactivation during the high pressure thermal sterilization process

High pressure combined with elevated temperatures can produce low acid, commercially sterile and shelf-stable foods. Depending on the temperature and pressure levels applied, bacterial endospores pass through different pathways, which can lead to a pressure-induced germination or inactivation. Regardless of the pathway, Bacillus endospores first release pyridine-2,6-dicarboxylic acid (DPA), which contributes to the low amount of free water in the spore core and is consequently responsible for the spore's high resistance against wet and dry heat. This is therefore the rate-limiting step in the high pressure sterilization process. To evaluate the impact of a broad pressure, temperature and time domain on the DPA release, Bacillus subtilis spores were pressure treated between 0.1 and 900MPa at between 30 and 80°C under isothermal isobaric conditions during dwell time. DPA quantification was assessed using HPLC, and samples were taken both immediately and 2h after the pressure treatment. To obtain a release kinetic for some pressure–temperature conditions, samples were collected between 1s and 60min after decompression. A multiresponse kinetic model was then used to derive a model covering all kinetic data.The isorate lines modeled for the DPA release in the chosen pressure–temperature landscape enabled the determination of three distinct zones. (I) For pressures <600MPa and temperatures >50°C, a 90% DPA release was achievable in less than 5min and no difference in the amount of DPA was found immediately 2h after pressurization. This may indicate irreversible damage to the inner spore membrane or membrane proteins. (II) Above 600MPa the synergism between pressure and temperature diminished, and the treatment temperature alone dominated DPA release.(III) Pressures <600MPa and temperatures <50°C resulted in a retarded release of DPA, with strong increased differences in the amount of DPA released after 2h, which implies a pressure-induced physiological like germination with cortex degradation, which continues after pressure release. Furthermore, at 600MPa and 40°C, a linear relationship was found for the DPA release rate constants ln(kDPA) between 1 and 30min.

Influence of Reducing Carbohydrates on (6S)-5-Methyltetrahydrofolic Acid Degradation during Thermal Treatments

The mechanism and kinetics of the degradation of (6S)5-methyl-5,6,7,8-tetrahydrofolic acid in an aqueous solution in the presence of reducing carbohydrates such as glucose and fructose were investigated for thermal treatments. Preliminary experiments indicated that the presence of reducing carbohydrates, especially fructose (1.6 mM-1.5 M), strongly enhanced folate degradation at moderate temperatures (50-90 degrees C, 0-60 min). Identification of the predominant folate degradation products by LC-MS and NMR pointed to the formation of N(2alpha)-[1-(carboxyethyl)]-5-methyl-5,6,7,8-tetrahydrofolic acid diastereomers besides other folate degradation products upon prolonged heating (24 h, 100 degrees C) of (6S)5-methyl-5,6,7,8-tetrahydrofolic acid in fructose or dihydroxyacetone solutions. Using a Bayesian multiresponse kinetic modeling approach, kinetic characterization and elucidation of the degradation mechanism in the presence of equimolar amounts of dihydroxyacetone, fructose, and glucose were achieved. On the basis of the established degradation mechanism for (6S)5-methyl-5,6,7,8-tetrahydrofolic acid oxidation in the literature, it was shown that nonenzymatic glycation occurred due to reaction of dihydroxyacetone with 5-methyl-7,8-dihydrofolic acid. During thermal treatments (85-110 degrees C, 0-60 min), the nonenzymatic glycation reaction was characterized by an activation energy of 61.3 +/- 9.3 and 77.6 +/- 7.8 kJ mol(-1) in the presence of, respectively, dihydroxyacetone and fructose. Addition of L-ascorbic acid (1.13 mM) to folate samples (0.04 mM) with equimolar amounts of fructose prior to heating (100 degrees C, 0-45 min) was shown to retard the formation of 5-methyl-7,8-dihydrofolic acid and hence prevented the formation of the carboxyethylated derivatives under the investigated conditions.

Unravelling the kinetics of the formation of acrylamide in the Maillard reaction of fructose and asparagine by multiresponse modelling

A kinetic model for the formation of acrylamide in a fructose–asparagine reaction system at initial pH 5.5 is proposed, based on an approach called multiresponse kinetic modelling. The formation of acetic acid and formic acid from the degradation of fructose and its isomer glucose was included in the proposed kinetic model. The kinetic model suggests that the effect of temperature on acrylamide formation with fructose is more due to the preceding steps with the formation of the Schiff base. The use of fructose and lower pH resulted in a higher yield of acrylamide (3%), suggesting that both can play an important role in acrylamide mitigation. Furthermore, these models have shown that, at high temperatures (120–200 °C), the Maillard reaction rapidly goes into the advanced stages, forming high amounts of organic acids and high molecular weight melanoidins. Overall, these mechanistic models provide more insight of the formation of acrylamide in a quantitative way.