Investigating the correlation between acrylamide content and browning ratio of model cookies

Morphological changes and color development during cookie baking-Kinetic, heat, and mass transfer considerations

Color and shape are important quality attributes in baked goods, particularly cookies. Composition and processing conditions determine and influence color development and morphological changes in these baked goods. The objective of this study was to systematically evaluate the evolution of color and shape during baking to determine useful correlations that can be implemented during the assessment and modeling of the baking process. Cookies (AACC-I standard protocol 10-53.01) were baked at 185, 205, and 225°C. Moisture content, water activity, surface temperature, characteristic dimensions (radius and thickness), and color indexes (lightness, redness, blueness, and browning index [BI]) were monitored at different locations on the cookie surface and baking times. Relationships among the tested conditions were explored using correlation analysis. The cookies' dimensions and color indexes were strongly correlated with changes in moisture content over time, and those relationships were characterized using empirical models. The temperature dependence of the kinetic parameters of the changes in lightness and BI was also described and deemed independent of the location on the cookie surface. This study provides insights into the influence of heat and mass transfer on the physical and physicochemical changes of cookies during baking. The kinetic and secondary models developed in this study can serve as important components for establishing a comprehensive approach for coupling heat transfer, mass transfer, and reaction kinetics to estimate and optimize cookie-baking processes. PRACTICAL APPLICATION: The findings from this study provide valuable information for better understanding the morphological changes and color developments during the cookie-baking process. The quantitative data and models generated in this study will allow identifying baking conditions for better quality development.

Unravelling caramelization and Maillard reactions in glucose and glucose + leucine model cakes: Formation and degradation kinetics of volatile markers extracted during baking

A large number of volatile compounds are formed during the baking of foods by reactions such as caramelization and Maillard reactions. Elucidating the reaction mechanisms may be useful to predict and control food quality. Ten reaction volatile markers were extracted during baking of solid model cakes implemented with known amounts of precursors (glucose with or without leucine) and then quantified by Thermal desorption-Gas chromatography-Mass spectrometry. The kinetic data showed that the level of air convection in the oven had no significant influence on the reaction rates. In contrast, increasing baking temperatures had a nonlinear accelerating impact on the generation of newly formed volatile compounds with a bell-shaped kinetic curve found for most of the markers at 200 °C. The presence of leucine triggered the activation of the Maillard and Strecker routes with a specific and very rapid formation of 3-Methylbutanal and pyrazines. A dynamic model was developed, combining evaporation flow rate and kinetic formation and consumption of reaction markers. It can be used to describe, for two furanic compounds of different volatilities, the vapor concentrations in the oven from the concentrations measured in the model cakes.

Identifying temporal sensory drivers of liking of biscuit supplemented with brewer's spent grain for young consumers

Brewer's spent grain (BSG), a by-product of the brewing industry, has great potential as food additive. BSG is particularly rich in protein and fibre content which makes it an ideal nutritional fortifier for biscuits. However, adding BSG to biscuits can lead to changes in sensory perception and consumer acceptance. This study explored the temporal sensory profiles and drivers/inhibitors of liking in BSG-fortified biscuits. Six biscuit formulations were obtained from a design with factors oat flake particle size (three levels: 0.5 mm, small commercial flakes, large commercial flakes) and baking powder (two levels: with, without). Consumers (n = 104) tasted the samples, described their dynamic sensory perception using the Temporal Check-All-That-Apply (TCATA) method, and rated their liking on a 7-point categorical scale. The Clustering around Latent Variables (CLV) approach was used to group consumers into two clusters based on their preferences. The temporal sensory profiles and drivers/inhibitors of liking were investigated within each cluster. Foamy and Easy-to-swallow were sensory drivers of liking for both groups of consumers. However, inhibitors of liking were different in the two clusters: Dense and Hard-to-swallow for one cluster and Chewy, Hard-to-swallow and Hard for the other cluster. These findings give evidence that manipulating oat particle size and presence/absence of baking powder changes BSG-fortified biscuits' sensory profiles and consumer preferences. A complementary analysis of the area-under-curve of the TCATA data and inspection of individual temporal curves showed the dynamics of perception and showed how oat particle size and presence/absence of baking powder affected consumer perception and acceptance of BSG-fortified biscuits. The methods proposed in this paper can be further applied to understand how enriching products with ingredients that would otherwise go to waste affects acceptance in different consumer segments.

Effects of lotus seedpod oligomeric procyanidins on the inhibition of AGEs formation and sensory quality of tough biscuits

The advanced glycation end products (AGEs) are formed in baked products through the Maillard reaction (MR), which are thought to be a contributing factor to chronic diseases such as heart diseases and diabetes. Lotus seedpod oligomeric procyanidins (LSOPC) are natural antioxidants that have been added to tough biscuit to create functional foods that may lower the risk of chronic diseases. The effect of LSOPC on AGEs formation and the sensory quality of tough biscuit were examined in this study. With the addition of LSOPC, the AGEs scavenging rate and antioxidant capacity of LSOPC-added tough biscuits were dramatically improved. The chromatic aberration (ΔE) value of tough biscuits containing LSOPC increased significantly. Higher addition of LSOPC, on the other hand, could effectively substantially reduced the moisture content, water activity, and pH of LSOPC toughen biscuits. These findings imply that using LSOPC as additive not only lowers the generation of AGEs, but also improves sensory quality of tough biscuit.

The Effect of Microwave Baking Conditions on the Quality of Biscuits and the Control of Thermal Processing Hazards in the Maillard Reaction

To reduce thermal processing hazards (TPHs), microwave baking has been extensively used in food thermal processing. In this study, the influence of microwave power and microwave time on the formation of TPHs and their precursors was explored in microwave-baked biscuits. The results indicated that the content of acrylamide, 5-hydroxymethylfurfural, methylglyoxal, and 3-deoxyglucosone increased linearly with the extension of microwave time (2, 2.5, and 3 min) and microwave power (440, 480, and 520 W). There was a significant correlation between the four TPHs. 3-Deoxyglucosone may directly or indirectly participate in the formation of the other three TPHs. The relationship between TPH levels with some heat-induced sensory characteristics was analyzed. The correlation between the sensory characteristics and the content of TPHs is L* > a* > hardness > Water activity (AW). The correlation coefficients between L* value and the four TPHs are −0.950, −0.891, −0.803, and −0.985. Furthermore, the content of TPHs produced by traditional baking and microwave baking under the same texture level was compared. Compared with traditional baking (190°C, 7 min), microwave baking at 440 W for 3 min successfully decrease methylglyoxal, 3-Deoxyglucosone, acrylamide, and 5-hydroxymethylfurfural content by 60.75, 30.19, 30.87, and 61.28%, respectively. Traditionally baked biscuits, which had a more obvious color, as characterized by lower L* value, larger a* and b* values, are more susceptible to the formation of TPHs. Therefore, microwave baking can reduce the generation of TPHs.

5-Hydroxymethylfurfural Formation in Bread as a Function of Heat Treatment Intensity: Correlations with Browning Indices

5-hydroxymethylfurfural (HMF) is formed during bread baking as a Maillard reaction product (MRP); it can exert toxicity and it is regarded as a potential health risk because of its high consumption levels in western diets. The aim of this study was to evaluate HMF formation in bread as a function of heat treatment intensity (HTI) and to investigate correlations between HMF and easily detectable browning indices. White breads were baked at 200 °C and 225 °C for different baking times for a total of 24 baking trials. Browning development was evaluated by reflectance colorimetric and computer vision colour analysis; MRP were quantified spectrophotometrically at 280, 360 and 420 nm and HMF was determined by HPLC. HMF concentrations varied from 4 to 300 mg/kg dw. Colour indices (100-L*) and Intensity mean resulted significantly correlated between each other (r = -0.961) and with MRP (r ≥ 0.819). The effects of the different HTI were visualized by principal component analysis and the data were used to evaluate the best fitting regression models between HMF concentration and other browning indices, obtaining models with high correlation coefficients (r > 0.90).

Effect of Microwave Heating on the Acrylamide Formation in Foods

Acrylamide (AA) is a neurotoxic and carcinogenic substance that has recently been discovered in food. One of the factors affecting its formation is the heat treatment method. This review discusses the microwave heating as one of the methods of thermal food processing and the influence of microwave radiation on the acrylamide formation in food. In addition, conventional and microwave heating were compared, especially the way they affect the AA formation in food. Available studies demonstrate differences in the mechanisms of microwave and conventional heating. These differences may be beneficial or detrimental depending on different processes. The published studies showed that microwave heating at a high power level can cause greater AA formation in products than conventional food heat treatment. The higher content of acrylamide in microwave-heated foods may be due to differences in its formation during microwave heating and conventional methods. At the same time, short exposure to microwaves (during blanching and thawing) at low power may even limit the formation of acrylamide during the final heat treatment. Considering the possible harmful effects of microwave heating on food quality (e.g., intensive formation of acrylamide), further research in this direction should be carried out.

Influence of different baking powders on physico-chemical, sensory and volatile compounds in biscuits and their impact on textural modifications during soaking

The aim of this study was to investigate the effects of different type of leavening agents (ammonium bicarbonate-A, cream of tartar-B, grape-based leavening agent-C, baking powder-D) on the structural (also after soaking), physico-chemical and other quality characteristics of biscuits made with the same formulation. The major changes observed between samples were related to their textural properties, volatile profile and sensory characteristics. The presence of ammonium bicarbonate in sample A, gave arise to a biscuit with the most homogeneous surface appearance, the less hard structure and highest fracturability and spread, that promoted their greater milk uptake during soaking. The B and C biscuits, made with baking powder having tartaric acid, were characterized by a crisper texture and lower sensory overall acceptability. The presence in formulation of baking powders made with cream of tartar (B) and ammonium bicarbonate (A) mostly influenced the biscuit volatile profiles. Biscuit sample obtained with the most common baking powder (diphosphates powder) showed in general intermediate characteristics between A and B-C samples. Results obtained in this study demonstrate that a lot of final properties of biscuits can be strongly influenced by the type of leavening agents used in formulation.

Acrylamide and Thermal-Processing Indexes in Market-Purchased Food

Determining acrylamide (AA) content in foods using chromatographic methods is expensive and time-consuming. Therefore, there is a need to develop a simple, economical method for monitoring the content of acrylamide in foods. This study analysed whether there is a relationship between acrylamide levels with some heat-induced parameters, such as 5-hydroxymethylfurfural (HMF) and browning, in order to assess their usefulness in predicting the potential acrylamide levels in market-purchased food. Sixty plant-based food products were tested. The correlation coefficients for AA levels with L*, a* and b* values and HMF content were significant (p < 0.05) for French fries and potato chips. There was no statistically significant correlation between thermal-processing indexes (HMF and colour parameters) and acrylamide levels in commercial bread, breakfast cereals and biscuits. The results indicate that these classical thermal-processing indexes are not directly related to the acrylamide content in commercial cereal-based food and they cannot be indicators of AA level. Thus, the correlation between HMF and colour parameters with acrylamide content depends on the type of food and it is difficult to estimate the amount of AA based on these classical thermal-processing indexes of market-purchased food.

Preparation, characterization and application of haemoglobin nanoparticles for detection of acrylamide in processed foods

The nanoparticles of haemoglobin (HbNPs) were prepared by desolvation method and characterized by transmission electron microscopy (TEM),UV-vis spectroscopy, Fourier transformation infra red (FTIR) spectroscopy and X-ray diffraction (XRD) and atomic force microscopy (AFM). Protein profile of HbNPs was also studied by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). An amperometric acrylamide biosensor was constructed by immobilizing covalently HbNPs onto polycrystalline Au electrode. The Au electrode was characterized by scanning electron microscopy (SEM) and electrochemical impedance spectra (EIS) before and after immobilization of HbNPs. The biosensor showed optimum current response within 2s at 0.26V, pH 5.0 at room temperature (20°C). The biosensor measured the acrylamide concentration in processed foods. The working range of biosensor was 0.1nm-100mM with a limit of detection (LOD) as low as 0.1nM. The biosensor measured acrylamide concentration in various processed foods such as biscuits, bread, potato crisps, "kurkure", nuts and fried cereals. The analytical recovery of added acrylamide in aqueous extract of food at 5 and 10mM was 99% and 98% respectively. Within-and between-batch, co-efficient of variations were 3.85% and 4.67% respectively. The structural analogs of acrylamide such as acrylic acid and propionic acid had practically no interference on the biosensor.

Unravelling the effect of flavonoids on the kinetic profiles of acrylamide in the Maillard reaction

Flavonoids play a positive role in the fructose-participating Maillard reaction and significantly reduce the formation of acrylamide during the advanced reaction stage but not affect its elimination process.

Computer vision-based analysis of foods: a non-destructive colour measurement tool to monitor quality and safety

Computer vision-based image analysis has been widely used in food industry to monitor food quality. It allows low-cost and non-contact measurements of colour to be performed. In this paper, two computer vision-based image analysis approaches are discussed to extract mean colour or featured colour information from the digital images of foods. These types of information may be of particular importance as colour indicates certain chemical changes or physical properties in foods. As exemplified here, the mean CIE a* value or browning ratio determined by means of computer vision-based image analysis algorithms can be correlated with acrylamide content of potato chips or cookies. Or, porosity index as an important physical property of breadcrumb can be calculated easily. In this respect, computer vision-based image analysis provides a useful tool for automatic inspection of food products in a manufacturing line, and it can be actively involved in the decision-making process where rapid quality/safety evaluation is needed.

Effects of extrusion, infrared and microwave processing on Maillard reaction products and phenolic compounds in soybean

BACKGROUND

The Maillard reaction indicators furosine, hydroxymethylfurfural (HMF), acrylamide and color were determined to evaluate heat effects induced during extrusion, infrared and microwave heating of soybean. In addition, the present paper aimed to study changes in the phenolic compounds, as well as in the overall antioxidant properties of different soybean products in relation to heating at 45-140 °C during the processes.

RESULTS

Soybean proteins were highly sensible to Maillard reaction and furosine was rapidly formed under slight heating conditions during extrusion and infrared heating. Microwave heating at lower temperatures for a longer time yielded lower acrylamide levels in the final soybean products, as a result of its partial degradation. However, during infrared heating, acrylamide formation greatly increased with decreasing moisture content. After a short time of extrusion and infrared heating at 140 °C and microwave heating at 135 °C for 5 min, concentrations of HMF increased to 11.34, 26.21 and 34.97 µg g(-1), respectively.

CONCLUSION

The heating conditions caused formation of acrylamide, HMF and furosine in high concentration. The results indicate that the complex structure of soybeans provides protection of phenolic compounds from thermal degradation, and that Maillard reaction products improved the antioxidant properties of heat-treated soybean.

Dietary plant materials reduce acrylamide formation in cookie and starch-based model systems

BACKGROUND

Dietary plant materials have attracted much attention because of their health benefits to humans. Acrylamide is found in various heated carbohydrate-rich foods. Our previous results showed that crude aqueous extracts from diverse dietary plants and some phenolic compounds could mitigate acrylamide formation in an asparagine-glucose model system. Based on our previous study, several plant materials were selected to further investigate their inhibitory effects on acrylamide formation in cookies and starch-based model systems.

RESULTS

Addition of raw powders from selected dietary plants and their crude aqueous extracts could considerably reduce acrylamide formation in both cookie and potato starch-based models. Aqueous extracts of clove at 4% caused the largest reduction (50.9%) of acrylamide in cookies, whereas addition of 2% proanthocyanidins from grape seeds gave the greatest acrylamide reduction (62.2%) in a starch-based model system.

CONCLUSION

It may be feasible to use some of the tested dietary plant materials to reduce acrylamide formation in cookies and other starchy foods.

Inhibitory mechanism of naringenin against carcinogenic acrylamide formation and nonenzymatic browning in Maillard model reactions

Chemical model reactions were carried out to investigate the effect of a citrus flavonoid, naringenin, on the formation of acrylamide under mild heating conditions. Results showed that naringenin significantly and dose dependently inhibited the formation of acrylamide (20-50% relative to the control), although not in a linear manner. Moreover, the presence of naringenin in acrylamide-producing models effectively reduced the extent of browning. Careful comparison of the HPLC chromatograms of samples from the chemical model reactions revealed that naringenin likely reacted with Maillard intermediates, giving rise to new derivatives. Subsequent LC-MS analyses suggested that the proposed derivatives have a predicted molecular mass of 341 Da. Eventually, two derivatives were purified and characterized with LC-MS/MS and NMR spectroscopy as 8-C-(E-propenamide)naringenin and 6-C-(E-propenamide)naringenin, respectively. In other words, naringenin, a rather weak antioxidant, strongly inhibited acrylamide formation probably by directly reacting with acrylamide precursors, thus diverting them from the pathways that lead to acrylamide formation.

Effect of pyridoxamine on acrylamide formation in a glucose/asparagine model system

The effect of pyridoxamine (PM) on the reduction of acrylamide (AA) formation in a low-moisture equimolar glucose/asparagine model system was investigated. Formation/elimination kinetics of acrylamide was carried out at temperatures between 120 and 180 degrees C. Time courses of glucose, asparagine, pyridoxamine, 3-aminopropionamide (3-APA), acrylamide, and browning were measured to get more insight on the mechanism of action of PM. PM exhibited an inhibitory effect on AA formation at all temperatures studied, but became more relevant at 160 and 180 degrees C (up to 51% reduction). Degradation rates of glucose and asparagine were not significantly affected by PM, but PM was rapidly consumed in the glucose/asparagine system. Browning was significantly suppressed by addition of PM in the system, and formation of 3-APA was increased as compared to control. In comparison with pyridoxal, pyridoxine, and ascorbic acid, PM exerted the highest inhibition activity against AA formation, and a clear dose-response was observed. The nucleophilic aminomethyl group of PM was crucial for the exertion of an inhibition effect more than double those other B6 vitamers. The action mechanism of PM was attributable to its structural features that have the capacity to scavenge intermediary dicarbonyls formed during sugar degradation and advanced stages of the Maillard reaction. These findings open new possibilities for strategies in acrylamide mitigation where formation of reactive dicarbonyls should be carefully considered.

Review of methods for the reduction of dietary content and toxicity of acrylamide

Potentially toxic acrylamide is largely derived from heat-induced reactions between the amino group of the free amino acid asparagine and carbonyl groups of glucose and fructose in cereals, potatoes, and other plant-derived foods. This overview surveys and consolidates the following dietary aspects of acrylamide: distribution in food originating from different sources; consumption by diverse populations; reduction of the acrylamide content in the diet; and suppression of adverse effects in vivo. Methods to reduce adverse effects of dietary acrylamide include (a) selecting potato, cereal, and other plant varieties for dietary use that contain low levels of the acrylamide precursors, namely, asparagine and glucose; (b) removing precursors before processing; (c) using the enzyme asparaginase to hydrolyze asparagine to aspartic acid; (d) selecting processing conditions (pH, temperature, time, processing and storage atmosphere) that minimize acrylamide formation; (e) adding food ingredients (acidulants, amino acids, antioxidants, nonreducing carbohydrates, chitosan, garlic compounds, protein hydrolysates, proteins, metal salts) that have been reported to prevent acrylamide formation; (f) removing/trapping acrylamide after it is formed with the aid of chromatography, evaporation, polymerization, or reaction with other food ingredients; and (g) reducing in vivo toxicity. Research needs are suggested that may further facilitate reducing the acrylamide burden of the diet. Researchers are challenged to (a) apply the available methods and to minimize the acrylamide content of the diet without adversely affecting the nutritional quality, safety, and sensory attributes, including color and flavor, while maintaining consumer acceptance; and (b) educate commercial and home food processors and the public about available approaches to mitigating undesirable effects of dietary acrylamide.