Acrylamide formation in traditional Czech leavened wheat-rye breads and wheat rolls

The main aim of our study was to collect the data on the acrylamide content in typical Czech leavened wheat-rye breads and wheat rolls, and to demonstrate the influence of various technological factors on its contents. We analysed several sets of industrially and laboratory baked breads to better understand the acrylamide formation. Following factors were tested: (i) the content of rye in respective bread formulae and (ii) the character of leavening procedure. We were, as well, monitoring for ten days the variability of acrylamide levels in bread baked by one bakery and, afterwards, we analysed the same type of bread baked in 12 bakeries. In the case of rolls, the influence of yeasts and vital gluten content in the dough were subjects of an assessment. The levels of acrylamide in a common type of the Czech bread baked in various bakeries were relatively low, ranging from 7 to 22 μg kg⁻¹. The content of acrylamide was rather higher in breads prepared using a commercial starter (Lactobacilli) and yeasts than in bread prepared using natural rye sourdough only. A varying content of rye flour did not seem to have any impact on acrylamide levels. The ‘size dilution effect’ was observed when comparing the same type of bread with different weight. Since acrylamide is exclusively located in the bread crust, smaller loaves contained higher acrylamide content per kg. The contents of acrylamide in standard wheat bakery goods were very low, bellow 10 μg kg⁻¹. No influence of varying content of added yeast or vital gluten was observed.     

Fate of deoxynivalenol and deoxynivalenol-3-glucoside during wheat milling and Chinese steamed bread processing

To investigate the fate of deoxynivalenol (DON) and deoxynivalenol-3-glucoside (D3G) during wheat milling and Chinese steamed bread (CSB) processing, Fusarium-contaminated wheat samples containing DON and D3G at five different levels were milled and processed to CSB. Mycotoxin levels in milling fractions, doughs and CSB were determined with UPLC-MS/MS. Concentrations of DON and D3G were 1.2–2.2 times and 2.9–4.4 times higher in bran than that in wheat grain and they were slightly lower in shorts compared to bran. Reductions of 79–90% for DON and 23–39% for D3G in flour were observed, respectively, compared to wheat grain. With respect to wheat grain, the distribution of DON was 35% in bran, 27% in shorts, and 9% in flour, and the distribution of D3G was 77% in bran, 58% in shorts, and 37% in flour. Milling decreased the total amount of DON but increased the amount of D3G, which may result from the binding of DON to starch during the milling process. DON levels approximately doubled when the mixed and fermented dough was processed into CSB. D3G concentrations in mixed and fermented doughs and in CSB did not differ significantly, but were almost 50% lower than in flour. Dough making decreased the amount of D3G and steaming increased the amount of DON. CSB processing may thus release bound DON in flour.     

Fate of ochratoxin A during wheat milling and some Chinese breakfast processing

To estimate the dietary intake of ochratoxin A (OTA), information on the fate during wheat processing is needed. The wheat contaminated with OTA at both levels (93.22 and 248.93 μg/kg) was artificially inoculated by Aspergillus ochraceus. Concentrations of OTA were 1.43–1.66 times higher in bran than whole wheat and 1.27–1.50 times higher in shorts than bran. A concentration reduction of 43.29–55.16% for OTA in flour was observed, with the final concentrations of 41.80 and 138.33 μg/kg in flour respectively. Whereas, OTA was not transferred or decomposed during milling, as the total amount of OTA in all milling fractions didn't decreased. The further losses of OTA were various depending on different processes. The concentration of OTA increased by 11–16% when the flour was processed into Chinese steamed bread (CBS), with the OTA concentrations of 49.2 and 161.35 μg/kg in CBS. It revealed fermentation and steaming increased the OTA levels in CBS. The loss of OTA was small in the Chinese fried bread sticks (CFBS) (38.84 and 129.02 μg/kg), being of 6.73–9.63%. A higher reduction of 23.27–23.92% for OTA was detected in the noodles processing, with the final concentration of 32.98 and 108.24 μg/kg in noodles respectively. The result revealed that the temperature, pH values and strains involved the processes exerted different effects. High temperature (180 °C) and alkaline condition (pH > 7) facilitated to the removal of OTA, while fermentation (with dry yeast) increased the OTA levels in products.     

Effect of milling on the content of deoxynivalenol,nivalenol, and zearalenone in Japanese wheat

The effect of milling on the content of zearalenone (ZEA), a Fusarium mycotoxin, in a semi-processed wheat product was investigated and compared with that of deoxynivalenol (DON) or nivalenol (NIV). Two grain samples of Japanese soft wheat varieties, norin 61 and chikugoizumi, were milled to obtain three breaking flours (1B, 2B, 3B), three middling flours (1M, 2M, 3M) and two outer-layer fractions (bran and shorts). Patent flour for human consumption was made from 1B, 1M, 2B and 2M flours, while low-grade flour for animal feed was made from 3B to 3M flours. The contents of ZEA in patent flour, low-grade flour, bran and shorts were analyzed by an in-house validated analytical method using solvent extraction, multifunctional cartridge cleanup, and HPLC-fluorescence detection. A greater than 50% reduction in ZEA was observed in the patent flour of both samples, while 4–74% reduction in DON and NIV in the patent flour of the same two samples was observed. The results of this study revealed that the transfer ratios of ZEA had different features from those of deoxynivalenol and nivalenol.     

Detection of adulterations with different grains in wheat products based on the hyperspectral image technique: The specific cases of flour and bread

The objective of this study was to test the capability of a SW-NIR hyperspectral image technique to detect adulterations in wheat flour and bread with cheap grains, such us sorghum, oats and corn, and to compare the hyperspectral information with the physicochemical alterations in the properties of products. Wheat flour was adulterated at four different degrees (2.5, 5, 7.5 and 10%) with sorghum, oat and corn flours. Flours were prepared and used to make bread. Flours and breads were characterized according to several physicochemical parameters (pasting properties, water activity, mass loss during the baking process and texture profile analysis). Crumbs were extracted from breads and conditioned. Hyperspectral image captures were taken of both flours and conditioned crumbs. The data analysis was based on multivariate statistical process control method (MSPC), where the differentiation of adulterated samples was observed in all cases for both flours and crumbs. Finally, in order to relate the image analysis results and the adulterated sample properties, a correlation significance map was created between the physicochemical properties of samples and the multivariate statistical parameters. The SW-NIR image technique was capable of detecting adulterations in each case and high correlation significances were observed (α = 0.01) between wavelengths from specific spectra zones and the physicochemical properties of samples.     

Effect of liquid fermented Chinese edible Ganoderma Lucidum fungus on wheat bread: A quality improver and staling inhibitor

People's pursuit to additive-free products inspired us to find natural functional compositions to improve bread quality. Ganoderma Lucidum is used as nutraceutical Chinese traditional edible fungus for thousands of years. In this study, Ganoderma Lucidum fermentation broth were prepared by liquid fermentation to obtain high-yield of functional components like polysaccharides that exhibited water holding ability to restrict water migration and inhibited starch retrogradation in bread crumb. The data demonstrated the fermentation broth added to dough, whether sterilized or not, could improve the bread quality, especially decrease crumb softness. Dose-response relationship was observed, however when the addition amount exceeded the critical concentration, there was no more improvement in bread quality. The detection of volatile organic components in bread indicated Ganoderma Lucidum fermentation broth promoted the generation of the aroma of bread and enriched the flavor. This research suggested Ganoderma Lucidum fermentation broth whether sterilized or not could both improve bread quality and offer a potential strategy of additive-free ameliorant for prolonging bread shelf-life in industrial process.     

Co-occurrence of aflatoxins and ochratoxin A in cereal flours commercialised in Turkey

In this study, we aim to determine co-occurrence of aflatoxins (AFs) and ochratoxin A (OTA) in cereal flours commercialised in Corum, Turkey. One hundred cereal flours were checked for target fungal metabolites between the years 2011 and 2013. The samples were analysed by high-performance liquid chromatography with fluorescence detection (HPLC-FLD) after immunoaffinity column (IAC) clean-up procedure. The method was successfully validated in accordance to European Union guidelines acceptance criteria for specificity, linearity, sensitivity, trueness and repeatability. All the results are well below the maximum limits specified in the EU legislation. AFs were detected neither wheat flour nor rice flour samples, while 66.7% of maize flours contained AFs with maximum concentration of 1.12 μg kg⁻¹. OTA was present in 26.7% of wheat flour, 41.7% of maize flour and 18.8% of rice flour samples, with mean levels of 0.247, 0.218 and 0.154 μg kg⁻¹, respectively. The co-occurence of AFs and OTA was found in 9 maize flour samples.     

Stability of DON and OTA during the breadmaking process and determination of process and performance criteria

The fate of deoxynivalenol (DON) and ochratoxin A (OTA) during the breadmaking process was studied. In particular, toxin content was analysed in mixed baking ingredients before kneading, after fermentation and proofing, and finally after baking. Fermentation and proofing were carried out at 30 °C for 1 h, while baking was performed at different temperature levels (from 170 to 210 °C) and baking times from 45 to 135 min, in a full factorial design. DON increased from unkneaded mix to fermented dough, and decreased due to baking; this trend depended on the initial concentration of DON in the flour. The level in the bread was significantly lower than in the initial mix of ingredients. In contrast, deoxynivalenol-3-glucoside (DON-3-G) content increased both during kneading and fermentation, and also during baking. Moreover, the results confirmed the high stability of OTA as no significant change in its content could be observed as a result of the breadmaking process. As conclusion, the design of bakery product processes may help to control DON in final products, because although quite stable, its levels can be reduced to some extent. However, high levels of DON-3-G were released during baking, and this point should be further investigated. Mycotoxins have been always considered as stable compounds; however, in depth knowledge of the processing steps that may lead to some reduction (although limited) and those which can stimulate their release from conjugated forms, will definitely help in their control in finished foodstuffs.     

黄土区废弃钻井液对苜蓿产量和品质的影响

以长庆油田废弃钻井液回填法处理后井场生长的苜蓿为研究对象，研究了废弃钻井液对苜蓿的产量、重金属含量、品质和氨基酸的影响。结果表明，废弃钻井液处理场生长的苜蓿Pb、Cd、Cr、As、Hg和Cu等重金属含量均在GB13078-2017安全范围内，重金属未超标；废弃钻井液对苜蓿有明显的增产作用，苜蓿产量增加了730.20 kg/hm2，增长了21.6%。苜蓿品质也得到明显提升，其中粗蛋白总量增加24.87 kg/hm2，粗脂肪总量增加3.34 kg/hm2，淀粉总量增加9.61kg/hm2，还原性糖总量增加45.92 kg/hm2，粗纤维含量有所降低。氨基酸总量增加3.6%，必需氨基酸和非必需氨基酸含量分别增长了1.2%和2.3%。      

2D-fluorescence and multivariate data analysis for monitoring of sourdough fermentation process

Sourdough is used for the manufacture of bakery products, especially rye bread and vital for the development of its typical flavor. Although the process of sourdough fermentation is known thousands of years, still it is not understood in detail. Despite, in modern bread fabrication quality requirements are very high and demand a consequent control not only for the final baking process, but also for the production of intermediates. Characteristic process variables like pH-value and the degree of acidity are typically measured off-line to receive information about the state of the fermentation process. A new approach for monitoring the actual process state is the employment of 2D-fluorescence spectroscopy. As a non-invasive, optical method it is widely used for monitoring various types of bioprocesses, e.g. yeast or bacterial cultivations. In this contribution the application of partial least squares (PLS) regression and principal component regression (PCR) models for prediction of process variables of rye sourdough fermentations are compared to an evaluation where principal component analysis (PCA) is combined with artificial neural networks (ANN) for prediction of pH-value and acidity. For the pH-value PLS regression proved as good as PCR models and the combination of PCA and ANN. The average percentage root mean square error of prediction (pRMSEP) was between 2.5 and 5.1%. For the prediction of the acidity level, the best results were obtained using PLS regression models (pRMSEP: 6.0–8.1%). Smoothing the noisy 2D-fluorescence spectra slightly decreased the errors about 0.6%. Predictions with data sets of varying dough yield and constant temperature led to about 2% better results than data sets with different temperatures and constant dough yield. These results indicate a higher sensitivity of the prediction quality with respect to varying temperature compared to varying dough yield.     

Influence of the frying process and potato cultivar on acrylamide formation in French fries

Acrylamide formation during the production of French fries is attributed to Maillard reactions from reducing sugars and asparagine and is dependent on the frying temperature. Low reducing sugars content in potatoes has been recommended to produce fried potato products. However, the influence of the complexity of the potato medium in the chemical reactions that promote the acrylamide formation during deep frying are not well understood. In this study, three potato cultivars (Kennebec, Red Pontiac and Agria) commonly used for fried potato products were evaluated to determine the relationships between the precursors of acrylamide in the fresh potato tubers and the properties of the fried potato strips with the acrylamide content after frying. Frying experiments were conducted at three conditions (time-temperature) to obtain French fries of similar visual colour. Acrylamide formation increased with frying temperature but different behaviour was observed between cultivars. For Red Pontiac, a remarkably increase in acrylamide content was found at 170 °C (∼40%) together with the increase in colour. However, lower oil uptake and higher moisture content was obtained as temperature increase. Significant positive correlations were observed between the acrylamide level and the reducing sugars and sucrose content on fresh potatoes (0.652, 0.699, p ≤ 0.01, respectively). The acrylamide content obtained in Agria cultivar may be obtained from the hydrolysis of sucrose during the frying process. In fried potato strips, positive significant correlation was found between the shear force and acrylamide (0.749, p ≤ 0.01). The significant correlations obtained between colour, and texture, colour and oil uptake and texture and acrylamide content indicate the intrinsic relationship between the properties of the fried potato strips and the acrylamide content.     

Detection of gluten-containing cereals in flours and “gluten-free” bakery products by polymerase chain reaction

A polymerase chain reaction-based method for the detection of gluten-containing cereals in flours and “gluten-free” bakery products was optimized and its intralaboratory validation was carried out. The optimized method involved DNA isolation by chaotropic solid-phase extraction and PCR with primers of Dahinden et al. [Dahinden I., von Büren M., Lüthy J., 2001. A quantitative competitive PCR system to detect contamination of wheat, barley and rye in gluten-free food for coeliac patients. European Food Research and Technology 212, 228–233]. Using purified DNA, intrinsic detection limit of 42 ± 12 pg was determined, which corresponds to 10° genome copies. By the analysis of a panel of 26 European wheat cultivars and flours from six non-gluten-containing plants, which are commonly used for the production of gluten-free bakery products, inclusivity of 100% and exclusivity of 100% were determined. By the analysis of model samples of soya flour and cakes, detection limit of 0.1% (w/w) of fine wheat flour was determined, which is suitable for the analysis of “gluten-free” food products, as it is approximately equivalent to the limit of 10 mg per 100 g for gluten stated by Codex Alimentarius. The method was successfully applied to four samples of flours and 13 brands of biscuits designated “gluten-free”, out of which two flours and one brand of biscuits were found positive for gluten-containing cereals. The method proved to be suitable for routine use, it was relatively straightforward and could be completed in one working day.     

Effects of extrusion variables and starch modification on the puffing characteristics of yam (Dioscorea alata) flour

The viability of extruding yam flour and the effects of extrusion temperature, feed moisture content, particle size and added amylose or amylopectin on the puffing characteristics of yam flour were investigated. Extrusion temperature < 100°C, feed moisture content >10% and any level of added amylose depressed product expansion. Product firmness and density decreased with increasing extrusion temperatures but increased with increasing feed moisture content above a critical limit of 9%. In general, feed particle size and addition of amylopectin did not affect the characteristics of yam flour extrudates. Yam flour can be successfully extruded with maximum expansion at a feed moisture range of 8–10% using extrusion temperatures of 100–115°C.     

Deoxynivalenol in the wheat milling process and wheat-based products and daily intake estimates for the Southern Brazilian population

Fusarium head blight of wheat is caused by the Fusarium species that produces mycotoxins, such as deoxynivalenol (DON). The distribution of DON in wheat products can lead to high economic and health impacts. The objective of this study was to evaluate the natural distribution of DON in the wheat milling process and wheat-based products, as well as the daily intake estimates for the Southern Brazilian population. The fractions of wheat grains (milled wheat, finished flour and bran) were produced in a mill. Additionally, wheat-derived products, such as pasta, bread and crackers were analyzed. The bran fraction had the highest mean concentration of DON (2278 μg kg⁻¹), followed by milled wheat and finished flour (1895 μg kg⁻¹ and 1305 μg kg⁻¹). The distribution factor in the finished flour (69%) fraction demonstrates that DON was reduced when compared to milled wheat, by contrast of bran fraction that presents higher DON levels (120%). A percentage of 35% bran, 35% finished flour and 30% milled wheat samples would not be in compliance with future Brazilian regulations for DON levels. From the wheat-based products analyzed, 17% of whole bread and 10% of salted cracker products were contaminated with DON, with a median of 437 μg kg⁻¹ and 624 μg kg⁻¹, respectively. The finished flour was the fraction that most contributes to the daily intake of DON in Southern Brazil, representing 89.6% of the provisional maximum tolerable daily intake.     

Microbial composition of turbid rice wine (Makgeolli) at different stages of production in a real processing line

The aim of this study was to examine for changes in microbial populations during the production of turbid rice wine (also known as Makgeolli) at different production plants and to identify critical points for the control of microbial quality. Samples from raw ingredients (water, rice and wheat flour), materials from different production stages (steamed ingredients, the base of fermentation, primary and secondary fermentation stages at different time points), and the final rice wine products (non–sterilized and sterilized) were analyzed. The microbiological content of samples was assessed by quantitative (aerobic plate counts, lactic acid bacteria, fungi, acetic acid bacteria, coliforms and Bacillus cereus) and qualitative (Escherichia coli and eight foodborne pathogens) analyses. Aerobic plate counts for rice and wheat flour were relatively low (3.1 and 1.9 log CFU/g, respectively), as were those for lactic acid bacteria (1.6 and 2.1 log CFU/g), and fungi counts (2.2 and 0.7 log CFU/g). All counts increased to 7.8–7.9 log CFU/ml in the base of fermentation after the addition of Nuruk and Koji, and these counts were maintained at 8–9 log CFU/ml during fermentation. Acetic acid bacteria were not detected in the ingredients, but were isolated from the base of fermentation (1.2–2.8 log CFU/ml). Heat sterilization reduced aerobic pate counts significantly from 8.4 to 2.1 log CFF/ml, and lactic acid bacteria, fungi and acetic acid bacteria were reduced to non-detectable or negligible levels. Isolated microorganisms were considered as autochthonous to the environment or were artificially introduced with the starter culture. B. cereus was widely distributed throughout the manufacturing process, and may have been introduced from the raw material (present in 100% rice and 41.7% wheat flour samples). B. cereus counts were not significantly affected by sterilization, suggesting that it may exist at low levels as spores in the final products. No coliforms and other pathogens were detected in any samples. The raw materials, the base of fermentation, and sterilization stage were identified as important points for the control of microbial quality during the fermentation process.     

Storage stability of maize-groundnut composite flours and an assessment of aflatoxin B1 and ochratoxin A contamination in flours and porridges

Defatting of groundnut flour used for composite development can not only improve nutritional quality of its products but also the storage stability. Maize, groundnut and their composite (full fat and defatted) flours were prepared and stored at room temperature over a period of 3 months. Storage stability of these products was assessed based on changes in water activity, peroxide value (PV), free fatty acids (FFA), thiobarbituric acid (TBA), microbiological profiling and levels of mycotoxins that included aflatoxin B₁ (AFB₁) and ochratoxin A (OTA). Overall results revealed that the rate of change of PV, FFA and TBA significantly (p ≤ 0.05) increased with increasing storage time, which was highest for full fat flours than in the defatted flours. For example, PV of the FFG and DFG were respectively, 0.88 and 0.40 mEq/kg, meanwhile TBA was 4.53 and 2.71 mg malonaldehyde/kg. There was a much higher rate of increase in FFA (%) with increasing storage time in full fat and composite flours when compared to that of their defatted counterparts. Generally, microbiological data demonstrated an increase in total microbial counts during storage in these foods possibly resulting in mycotoxins, AFB₁ (range: 9.08–38.48 μg/kg) and OTA (range: 0.33–19.50 μg/kg) in all samples with groundnut and maize having the highest contamination levels. A 127.8% increase in OTA level was noted when maize flour inclusion level in the full fat composite increased from 55 to 85%, but only a 24.7% increase in OTA level was noted in defatted composites during storage. Reducing the inclusion level of groundnut flour, the main source of AFB₁ as found, resulted in a drastic reduction in AFB₁ level in full fat and defatted composite flours by 54.1 and 76.4%, respectively, during storage. The findings highlight that shelf life stability of composites can be maintained upon defatting during the fortification process. It can therefore, be inferred that monitoring quality and safety of the raw materials as well as that of the final products during storage is crucial.     

Retention of deoxynivalenol and its derivatives during storage of wheat grain and flour

Fate of deoxynivalenol (DON) and its derivatives—deoxynivalenol-3-glucoside (D3G), 15-acetyldeoxynivalenol (15-AcDON) and 3-acetyldeoxynivalenol (3-AcDON) during six-month storage of wheat grain and flour was investigated. Wheat grain and flour polluted by DON, D3G, 15-AcDON and 3-AcDON were packaged in polyethylene bags, kraft paper bags and cloth bags, and stored at room temperature and 4–6 °C, and mycotoxin levels were analyzed by UPLC-MS/MS after storing for 30, 90 and 180 days. Levels of DON, 15-AcDON and 3-AcDON in wheat grain showed a generally decrease during the storage duration, and DON concentrations averagely decreased by 40–50%. An obviously increase of DON (more than 70%) and decrease of 15-AcDON and 3-AcDON were observed after storage in wheat flour. There were no significant differences of D3G levels in most of wheat grain and wheat flour samples after storage, but some increased dramatically with retention level up to 240%. The results suggested conversion of DON and its derivatives may occur during wheat grain and flour storage.     

淀粉与丙烯酰胺／丙烯磺酸钠接枝共聚物的研究

以硫酸高铈为引发剂,将淀粉与丙烯酰胺（AM）、丙烯磺酸钠（AS）进行接枝共聚,制备了淀粉与丙烯酰胺／丙烯磺酸钠接枝共聚物。用正交实验法确定了最佳聚合工艺条件,即聚合反应温度55℃,引发剂用量0．3g,AM与淀粉质量比4：1,AS用量0．2mL。考察了As用量对接枝共聚物产品性能的影响,包括粘度、溶解性、抗温性、抗盐性及降失水性。结果表明,随着AS用量的增加,共聚物粘度逐渐降低,溶解性逐渐增加,对抗温性影响不大,抗盐性好,水泥浆降失水性提高。     

Effect of the bread making process on wheat flour contaminated by deoxynivalenol and exposure estimate

The aim of this work was to identify the occurrence of deoxynivalenol (DON) and ochratoxin A (OTA) in flour; to estimate the reduction of contamination levels in French and Vienna bread manufactured with this flour, and the exposure to these toxins through the consumption of these products. OTA was not detected in the flour. The median reduction of DON between flour and products were, for French bread 33% and for Vienna bread 58.5%. A low exposure (the highest percentage of the Tolerable Daily Intake was 6.54% and the lowest 0.45%) was estimated due to the low contamination level: French bread median was 35.5 μg/kg and Vienna bread 22.0 μg/kg.     

Effect of deoxynivalenol detoxification by ozone treatment in wheat grains

Considering the wide existence of mycotoxin deoxynivalenol (DON) in wheat and derived products, finding ways to detoxify DON in wheat grains as original resources for food-chain contamination is very important to protect human health and reduce economic losses. This study aimed to evaluate the effectiveness of destroying DON in wheat via ozonation under different conditions, such as moisture content (MC), ozone concentration, exposure time, and form of raw-material. The achieved data showed that DON reduction significantly improved with increased ozone concentration and exposure time. The whole wheat flour (WWF) was easier to degrade than the wheat kernels. Higher MC decreased larger amounts of DON. The maximum reduction of DON was 20.10% for the MC group, compared with the 11.79% and 16.29% for the other MC groups. DON concentration decreased from 3.89 mg/kg to 0.83 mg/kg under the generally recognized Maximum Residue Limit (MRL) level of 1 mg/kg, when WWF was treated with 100 mg/L of ozone treatment for 60 min. The first-order kinetic model established in this work showed a good R-squared value (R² > 0.877) and was consistent with the results. Therefore, ozonation is an effective and rapid way to degrade DON in wheat, especially in whole wheat flour.