Effects of dough formula and baking conditions on acrylamide and hydroxymethylfurfural formation in cookies

The effects of dough formula and baking conditions on the formations of acrylamide and hydroxymethylfurfural (HMF) were studied in a cookie model system. Increasing the sugar concentration in the dough formula increased acrylamide formation during baking at 205 °C for 11 min. The effect of sugar on acrylamide formation was more pronounced for glucose than for sucrose, expectedly. Addition of citric acid into dough formula comprising sucrose increased the susceptibility of acrylamide formation, while it decreased acrylamide formation in the dough formula comprising glucose. Decreasing the pH of dough formula increased the tendency to surface browning and the formation of hydroxymethylfurfural in cookies during baking. The results suggest that a cookie with acceptable texture and colour, but having less than 150 ng/g of acrylamide, can be manufactured by lowering the baking temperature and avoiding reducing sugars in the recipe.     

Effect of leavening agents and sugars on the formation of hydroxymethylfurfural in cookies during baking

The effects of recipe compositions in terms of leavening agent (ammonium and sodium bicarbonates) and sugars (sucrose and glucose), and baking conditions (temperature and time) on HMF formation in cookies were studied. Five recipes were prepared by varying the types of leavening agent and sugar. The cookies were baked at different temperatures (180, 200, 210 and 220 °C) for different time (10, 15, 20 and 25 min) to monitor physical and chemical changes in cookie composition in terms of water activity, pH, surface browning, sugar decomposition, and hydroxymethylfurfural (HMF) formation. Decreasing moisture to a level under a water activity of 0.4 appeared as the critical point in baking where the rate of HMF formation drastically increased after this point. After this stage, sucrose decomposed very rapidly if ammonium bicarbonate was used as the leavening agent at temperatures greater than 200 °C. Replacing ammonium bicarbonate with sodium bicarbonate maintained pH of cookies ranging between 9.0 and 10.0 during baking, which limited the decomposition of sucrose.     

Effect of crust temperature and water content on acrylamide formation during baking of white bread: Steam and falling temperature baking

The effect of crust temperature and water content on acrylamide formation was studied during the baking of white bread. To assess the effect of over-baking, we used a full factorial experimental design in which the baking time was increased by 5 and 10 min at each baking temperature. Additional experiments were performed with steam baking and falling temperature baking. Immediately after baking, the crust was divided into the outer and inner crust fractions, and the water content and acrylamide concentration of each fraction was measured. The outer crust had a significantly lower water content and higher acrylamide concentration than the inner crust did. Crust temperature in combination with water content had a significant effect on acrylamide formation, higher temperatures resulting in higher acrylamide concentrations. However, at very high temperatures and lower water contents, acrylamide concentration was observed to decrease, though the bread colour was then unacceptable for consumption. Steam and falling temperature baking, on the other hand, decreased the acrylamide content while producing bread crust with an acceptable colour. The lowest acrylamide values and an acceptable crust colour were produced by steam baking.     

Mitigating effect of amaranth (Amarantus hypochondriacus) protein on acrylamide formation in foods

The effect of addition of amaranth flour and amaranth protein isolate to both a glucose/asparagine model system and real foods (cookies, fried tortilla chips, and baked tortilla chips) was studied to analyse the acrylamide mitigating potential of this underexploited plant with attractive nutraceutical properties. Addition of amaranth flour, with a relatively low protein content (16.45%), did not mitigate acrylamide in either the model system or the studied foods. On the contrary, addition of amaranth protein isolate decreased acrylamide content by 35–40% in the model system, 89% in cookies, 51% in fried tortilla chips, and 62% in baked tortilla chips. This acrylamide reduction was obtained without change in the colour or the texture of the cookies. On the contrary, colour remained unchanged in tortilla chips, but the addition of amaranth protein isolate increased the hardness (16–36%) of the produced tortillas. Although a much more detailed sensory evaluation of cookies and tortilla chips prepared using amaranth protein isolate is needed, the above results suggest that the use of amaranth protein may be an interesting way to both mitigate acrylamide formation and improve nutritional properties of foods.     

Antioxidant activity of cookies and its relationship with heat-processing contaminants: a risk/benefit approach

Formation of both health promoting and potential harmful substances (acrylamide and hydroxymethylfurfural) has been associated to the extent of the Maillard reaction. The effects of recipe compositions in terms of leavening agent (ammonium and sodium bicarbonates) and sugars (sucrose and glucose), and baking conditions (temperature and time) on the antioxidant activity (AOA) in cookies were studied. The cookies were baked at different temperatures (180–220 °C) for different times (10–25 min). AOA was measured by the ferric reducing power (FRAP), 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), 2,2,-diphenyl-1-picrylhydrazyl (DPPH) coloured radicals, and oxygen radical absorbance capacity (ORAC-fluorescein) in automated plate-reader assays. Net AOA varied regarding the assay applied, whereas higher AOA was always obtained for the ABTS assay and lower for DPPH assay, and ranging from 2 to 200 μmol Trolox/g sample. At higher temperature and baking times, higher AOA in cookies regardless of the formulation was recorded. Glucose enhances formation of compounds with higher AOA compounds as compared with sucrose recipes. Ammonium bicarbonate clearly promotes the formation of AOA for sucrose recipes but this effect is not observed in glucose recipes and varied with the AOA procedure applied. A risk/benefit index, based on the concomitant formation of neo-formed contaminants and substances with AOA (potentially health-promoting substances) is presented, and its application for recipe comparison is discussed. Risk/benefit index rapidly increased with increased temperature and time of baking.     

A methodology for evaluating the formation and human exposure to acrylamide through fried potato crisps

Potato crisps are a popular snack food which have been implicated as a potential source of acrylamide. This study develops a farm-to-fork human exposure assessment model for acrylamide in fried potato crisps for Irish consumers. The model used Monte Carlo simulation techniques to model the various stages from on farm production of potatoes, storage, processing, crisp production and final human consumption of potato crisps. A baseline model is created and a number of scenarios are subsequently created to look at the impact of different model assumptions and input parameters. The baseline model found that the mean level of acrylamide in potato crisps in Ireland was 720 μg/kg. Irish consumer exposure to acrylamide in potato crisps was estimated to be 0.052 and 0.064 μg/kg bw/day for males and females, respectively. A sensitivity analysis revealed the important parameters influencing the model predictions. The initial level of reducing sugars was found to be the most important parameter (correlation coefficient 0.58 and 0.57 for glucose and fructose, respectively), highlighting the importance of selecting cultivars with low reducing sugar levels for crisp production. The cooking regime had a significant impact on model predictions, highlighting the need for further research into the impact of different time and temperature combinations. Blanching and soaking of potatoes were also identified as important risk reduction processes.     

Kinetic modelling: A tool to predict the formation of acrylamide in potato crisps

Three empirical models were used to fit the formation of acrylamide in crisps of three different cold-sweetened potato genotypes, fried under the same experimental conditions. Statistical methods were used to compare the performance of the models, with the “Logistic-Exponential” model performing the best. The obtained model parameters for the formation of acrylamide showed improvement in precision compared to an earlier study, the precision of the parameter estimates for the degradation of acrylamide was still problematic. Nevertheless, the predictive capacity of the “Logistic-Exponential” model was tested, as this model showed a strong correlation between parameter a and the reducing sugar content of the raw potato. The predictions from this model for the formation of acrylamide in potato crisps were close to earlier reported experimental values. Therefore, the use of the “Logistic-Exponential” model as a tool to predict acrylamide in potato crisps seems promising and should be developed further.     

Potential for acrylamide formation in potatoes: data from the 2003 harvest

Reducing sugars, free amino acids, and the potential for acrylamide formation were determined in more than 50 potato samples from the 2003 harvest in Switzerland. The reducing sugar content strongly correlated with acrylamide, whereas no correlation was found between acrylamide and free asparagine or the pool of free amino acids. The reducing sugar contents and the acrylamide potentials were higher in most of the cultivars tested than in the samples from 2002. This was probably due to the hot and dry summer of 2003. Monitoring sugars and amino acids during heating at 120 °C and 180 °C showed that glucose and fructose reacted much faster than sucrose and the amino acids. Glutamine was consumed to a larger extent than any of the other amino acids. During prolonged storage, the reducing sugars decreased considerably while only moderate changes in the free amino acids were observed. Altogether, glucose and fructose remain the critical factors for acrylamide formation in potatoes and represent the most feasible way of reducing the formation of acrylamide in potato products.     

Study of acrylamide in coffee using an improved liquid chromatography mass spectrometry method: Investigation of colour changes and acrylamide formation in coffee during roasting

An improved analytical method for the determination of acrylamide in coffee is described using liquid chromatography coupled to mass spectrometric detection (LC-MS). A variety of instant, ground and laboratory roasted coffee samples were analysed using this method. The sample preparation entails extraction of acrylamide with methanol, purification with Carrez I and II solutions, evaporation and solvent change to water, and clean-up with an Oasis HLB solid-phase extraction (SPE) cartridge. The chromatographic conditions allowed separation of acrylamide and the remaining matrix co-extractives with accurate and precise quantification of acrylamide during MS detection in SIM mode. Recoveries for the spiking levels of 50, 100, 250 and 500 µg/kg ranged between 99 and 100% with relative standard deviations of less than 2%. The effects of roasting on the formation of acrylamide and colour development were also investigated at 150, 200 and 225°C. Change in the CIE (Commission Internationale de l'Eclairage) a* colour value was found to show a good correlation with the change in acrylamide. CIE a* and acrylamide data was fitted to a non-linear logarithmic function for the estimation of acrylamide level in coffee. Measured acrylamide levels in commercial roasted coffees compared well with the predicted acrylamide levels from the CIE a* values.     

Evaluation of acrylamide formation in potatoes during deep-frying: The effect of operation and configuration

It is nowadays well known that heating, which is carried out to improve the hygienic, sensory and nutritional properties of foods, can be also responsible for the development of acrylamide. Acrylamide levels between a few ppb and in excess of 1000 ppb have been found in many heated foods. As acrylamide is classified as a probable human carcinogen, the knowledge of critical processing variables leading to its formation is needed to ensure safety requirements.     

Accumulation of 5-hydroxymethyl-2-furfural in cookies during the backing process: Validation of an extraction method

During baking, complex chemical reactions take place in the cookies, such as the Maillard reaction (MR) and caramelisation (CR). Both reactions involve glucose and fructose, generated from starch and sucrose hydrolysis during baking. Among the many products formed, HMF a possible mutagen, seems particularly interesting because of a rapid accumulation during the process.     

Contribution of peptides and polyphenols from olive water to acrylamide formation in sterilized table olives

To confirm the role of peptides as principal precursors of acrylamide formation in sterilized table olives, peptides from olive water were fractionated. After their partial fractionation by solid phase extraction (SPE) and ultrafiltration (<10,000 Da), respectively, small peptides from olive water were isolated by size-exclusion chromatography (SEC). In the fractions collected, peptides and polyphenolic compounds were determined colorimetrically, and acrylamide was quantitated by LC–MS/MS after heating of the samples. Subsequently, peptides were characterized by matrix-assisted laser desorption/ionization-tandem time of flight mass spectrometry (MALDI-TOF/TOF-MS), and polyphenols were analyzed by LC–MS in the respective fractions. Finally, peptides containing fractions were purified on a polymeric resin (Amberlite XAD 16HP) to remove unbound phenolic compounds by adsorption. The results of the different experiments performed in complete absence of free asparagine and reducing sugars strongly support small peptides bound to polyphenols to be the principal precursors of acrylamide in sterilized table olives.     

Model studies on the role of 5-hydroxymethyl-2-furfural in acrylamide formation from asparagine

This study aimed to investigate the mechanism of acrylamide formation during heating asparagine (ASN) at elevated temperatures with glucose (GLC), and 5-hydroxymethyl-2-furfural (HMF). The results revealed that HMF rapidly reacted with ASN, leading to acrylamide formation. The ASN-HMF model system generated acrylamide more efficiently than the ASN-GLC model system during heating at 180 °C. A significantly higher amount of 3-aminopropionamide (3-APA) was formed in the ASN-HMF model system than in the ASN-GLC model system within 5 min at 180 °C. The amount of 3-APA decreased after 5 min of heating in both model systems while the amount of acrylamide continued to increase in the ASN-HMF model system. In-depth high resolution mass spectrometry analyses of reaction products formed in the model systems together with the kinetic data suggested that HMF is a potent carbonyl accelerating acrylamide formation during heating. 3-APA was found as one of the key intermediates leading to acrylamide formation.     

Impact of additives to lower the formation of acrylamide in a potato model system through pH reduction and other mechanisms

The impact on acrylamide formation of several additives was investigated as well as the mechanisms behind it. In a potato powder model system, sodium acid pyrophosphate, citric, acetic and l-lactic acid significantly reduced the final acrylamide content, merely due to the lowering of the pH. Free glycine, l-lysine and l-cysteine also lowered acrylamide, while keeping the pH at its original level. l-glutamine increased the formation of acrylamide. A synergistic acrylamide lowering effect was observed, adding citric acid and glycine or l-lysine to the model system. Yet, a combination of these amino acids with acetic acid appeared to induce a restricted antagonistic acrylamide lowering effect. Calcium and magnesium ions induced a supplementary acrylamide reduction in addition to a lower pH of the food matrix. No lowering effect was however observed upon NaCl addition to the model system.     

Effect of formulation on the capacity of l-asparaginase to minimize acrylamide formation in short dough biscuits

The influence of the matrix composition and structure on the capacity of asparaginase to reduce acrylamide formation in biscuits was studied. In particular, formulations differing for water (10 to 20% on total weight) and fat (0 to 15% on total weight) content, fat type (margarine, palm oil) and lipid phase distribution were considered. In the latter case, palm oil was substituted with a monoglyceride–palm oil–water gel (hydrogel). The results showed that high water contents, by favoring precursor mobility, promoted acrylamide formation as well as the enzyme capability of reducing the toxic molecule levels in the final product. On the contrary, the presence of fat significantly reduced acrylamide development and enzyme activity as compared with the fat free formulation. It can be hypothesized that the presence of fat would hamper the interaction between the precursors in the aqueous phase, leading to lower amounts of acrylamide. By substituting fat with hydrogel, the biscuit behaved as a fat free system, where acrylamide formation as well as its reduction by means of asparaginase activity was higher than in the fat-containing biscuits. It is likely that the inclusion of palm oil in the dough through the hydrogel modified the system morphology, thus not hampering the encounter among reactants and consequently favoring acrylamide formation.     

Ageing and free radical formation. A biochemical approach to evaluate the efficacy of cosmetic preparations

A new method is described for studying the in vivo formation of oxygen reactive species (free radicals) in humans after exposure to UV radiation. The procedure is based on the quantitative determination in urine of (i) metabolic products of pentane, a hydrocarbon formed during lipid peroxidation, and (ii) thymine hydroxylated bases and deoxyribonucleosides as indices of DNA repair that has taken place. Creams containing UV filters protect the organism against free radical formation. Subjects using such cosmetic preparations during complete body tanning sessions do, in fact, have reduced urinary excretion of 2-pentanol and hydroxythmine derivatives.     

A new microbiological approach to the assessment of underarm deodorants

A general survey of odour generation in the axillae is given, with particular reference to the role of topically applied antimicrobial agents in odour suppression.
A new apparatus is described which will allow a rapid and reliable quantification of in vivo antimicrobial action and which may be usefully employed in optimization of individual systems to achieve effective deodorancy.
Findings are presented on the antimicrobial efficacy of deodorant compositions and correlated with practical olfactory studies.
Nouvelle approche microbiologique dans l'évaluation des déodorants axillaires     

A novel approach to evaluate the temperature during drying of food products with negligible external resistance to mass transfer

The paper deals with modeling the convective drying process. A relevant and reliable mathematical model that captures the history and distribution of temperature is presented. The attention is focused on the simultaneous heat and mass transfer occurring during drying where dry and hot air flows about the food. In the present study, external resistance to mass transfer is considered negligible. As a result, the drying curve is almost independent of the boundary conditions, which means that drying is diffusion-controlled. The main connotation of present study regards to undertake analytical procedure to establish the novel model for practical applications. The results show that the temperature evolution can be evaluated from an advanced analytical solution in a quick and efficient manner. The model is validated with the literature experimental data obtained for carrot and mango slabs. A good agreement is obtained between the model predictions and the available experimental results.     

CD2/CD21 index: A new marker to evaluate udder health in dairy cows

Lymphocytes play a significant role in the immunological processes of the bovine mammary gland and were found to be the dominant cell population in the milk of healthy udder quarters. The objective of this study was to investigate the quantitative relationship between CD2⁺ T and CD21⁺ B lymphocytes using flow cytometry. In a first study, quarter foremilk samples from apparently healthy udder quarters [somatic cell counts (SCC) ≤100,000 cells/mL; n = 65] were analyzed and compared with diseased quarters (SCC >100,000 cells/mL; n = 15). Percentages of CD2⁺ T cells were significantly higher in milk samples with SCC ≤100,000 cells/mL than in those with SCC >100,000 cells/mL, whereas percentages of CD21⁺ B cells developed in the opposite direction. As a result of this opposing trend, a new variable, the CD2/CD21 index—representing the percentages of CD2⁺ cells per CD21⁺ cells—was defined. Although diseased quarters with SCC >100,000 cells/mL and the detection of major pathogens revealed generally CD2/CD21 indices <10, values >10 were observed in apparently healthy quarters. Hence, a CD2/CD21 index cutoff value of 10 may be suitable to aid differentiation between unsuspicious and microbiologically suspicious or diseased udder quarters. To test whether CD2/CD21 indices <10 were primarily related to pathogens, quarters with SCC ≤100,000 cells/mL and >100,000 cells/mL with different bacteriological status (culture negative, or minor or major pathogens) were selectively examined in a second biphasic study. In the first trial, 63 udder quarters were analyzed and 55 of these quarters were able to be sampled again in the second trial carried out 14 d later. In both trials, results of the first study were confirmed. Indeed, CD2/CD21 indices <10 were also found in quarters showing SCC ≤100,000 cells/mL and containing minor or major pathogens at the time of the current or previous bacteriological analysis. The results of our examinations indicated a clear relationship between the CD2/CD21 index and the bacteriological status of the mammary gland. In combination with SCC, it offers a new marker for quick differentiation of unsuspicious and microbiologically suspicious or diseased udder quarters.