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Background: Consumers are more aware of the role of healthy diet in preventing food-related diseases (Cancer, cardiovascular diseases, diabetes, etc.). Consequently, they are looking for products with beneficial nutritional attributes that encourage the food industry to develop functional foods. Aims: In this study, we aimed at using a natural bioprocess to improve durum wheat “Triticum durum” nutritional properties for its further use as a functional ingredient. Materials and Methods: Six durum wheat cultivars were tested: four high yielding and two landrace ones. Seeds were germinated for 48 hours at 22°C. Nutritional properties were evaluated through proximate composition and bioactive compounds (carotenoids, total phenol, vitamin C and tocopherols) levels. Results: Biochemical characterization of sprouted seeds showed significant modifications with a decrease in ash, starch contents and an increase in reducing sugars, and in proteins. Improvements in bioactive compounds were also observed in sprouted seeds. Vitamin C, tocopherols, total phenols, carotenoid pigments as well as antioxidant activity significantly increased after sprouting. Interestingly, durum wheat landrace cultivars showed the best performances. Conclusions: Results provided by our study proved that sprouting is an interesting natural tool to use in the food industry for the development of cereal products with added nutritional value.

Sprouting is an old food engineering tool to improve edible seeds nutritional value. It can improve carbohydrate digestibility and enhance levels of bioactive compounds. These changes are strongly related to sprouting conditions: temperature, light, duration. The aim of this research was to evaluate the effect of sprouting temperature on sprouts bioactive molecules and proximate composition of Chili Tunisian durum wheat (Triticum durum) seeds. Hence, two temperatures were tested: 18°C and 25°C. Analysis of ashes, proteins, lipids, reducing sugars, carotenoids, vitamin C, vitamin E, and total phenols contents and DPPH radical scavenging activity were done. Our results indicated that temperature influenced significantly proximate composition of sprouts, as well as bioactive compounds. Vitamin C and tocopherols levels were higher at 25°C, than in raw seeds. In contrast, a temperature of 18°C led to highest amounts of carotenoids and total phenols. In addition, antioxidant properties of durum wheat seeds were improved by sprouting only at 18°C. In conclusion, evolution of nutritional properties and bioactive compounds in sprouts were strongly dependent on sprouting temperature used.

Mycotoxin contamination of cereals used for feed can cause intoxication, especially in farm animals; therefore, efficient analytical tools for the qualitative and quantitative analysis of toxic fungal metabolites in feed are required. Current trends in food/feed analysis are focusing on the application of biosensor technologies that offer fast and highly selective and sensitive detection with minimal sample treatment and reagents required. The article presents an overview of the recent progress of the development of biosensors for deoxynivalenol and zearalenone determination in cereals and feed. Novel biosensitive materials and highly sensitive detection methods applied for the sensors and the application of these sensors to food/feed products, the limit, and the time of detection are discussed.

Sprouting is a green tool that improves cereals nutritional properties. However, the increase in moisture content of sprouts may lead to a microbial proliferation, and consequently raises risks related to raw sprouts consumption. This research investigated the influence of sprouting temperature on sprouts hygienic quality and the potential use of zinc to improve it. Durum wheat seeds (Triticum durum) were sprouted at 18 and 25 °C for 48 h. In the second part, wheat seeds were soaked in zinc sulfate solution (400 mg. L−1) and then sprouted. Hygienic quality was assessed through enumeration of Total Mesophilic Aerobic Plate, Molds and Yeasts, and Coliforms. Results showed that sprouting increased bacterial growth significantly, regardless of the temperature. Soaking wheat seeds in zinc sulfate solution decreased microbial proliferation. Results suggested that seeds’ treatment with zinc could improve the sprouts’ microbiological properties for the safe use of raw sprouts.

Novel optical waveguide lightmode spectroscopy (OWLS)-based immunosensor formats were developed for label-free detection of Fusarium mycotoxin zearalenone (ZON). To achieve low limits of detection (LODs), both immobilised antibody-based (direct) and immobilised antigen-based (competitive) assay setups were applied. Immunoreagents were immobilised on epoxy-, amino-, and carboxyl-functionalised sensor surfaces, and by optimising the immobilisation methods, standard sigmoid curves were obtained in both sensor formats. An outstanding LOD of 0.002 pg/mL was obtained for ZON in the competitive immunosensor setup with a dynamic detection range between 0.01 and 1 pg/mL ZON concentrations, depending on the covalent immobilisation method applied. This corresponds to a five orders of magnitude improvement in detectability of ZON relative to the previously developed enzyme-linked immonosorbent assay (ELISA) method. The selectivity of the immunosensor for ZON was demonstrated with structural analogues (α-zearalenol, α-zearalanol, and β-zearalanol) and structurally unrelated mycotoxins. The method was found to be applicable in maize extract using acetonitrile as the organic solvent, upon a dilution rate of 1:10,000 in buffer. Thus, the OWLS immunosensor method developed appears to be suitable for the quantitative determination of ZON in aqueous medium. The new technique can widen the range of sensoric detection methods of ZON for surveys in food and environmental safety assessment.

Mycotoxins, present in a wide range of food and feed commodities, are toxic secondary metabolites produced by a number of different fungi. Certain mycotoxins do not readily degrade at high temperatures, therefore are resistant to food processing, and consequently are present in the human and animal food supply. Optical waveguide lightmode spectroscopy (OWLS) was applied for the detection of aflatoxin B1, in a competitive immunoassay format, to compare the analytical sensitivity achieved with an immunosensor design allowing signal enhancement by increasing the sensor surface through immobilization of gold nanoparticles (AuNPs) of different size and origin (obtained by chemical or biotechnological synthesis). The effects of AuNPs median size, the methods of sensitization and the biochemical parameters on immunosensor performace were examined. After optimization of the sensitized sensor surface, an immunosensing method was developed for the analysis of aflatoxin in paprika matrix and the results were compared with HPLC reference measurements.

The effects of pesticide treatments of red pepper cultivation on spice paprika product quality were assessed in a cultivation modelling experiment using a mixture of three recommended insecticides (pirimicarb, chlorpyrifos and cypermethrin) and a fungicide (penconazole). An intensively cultivated red pepper field was treated 1–3 times with pesticide premixes at different dosages, and the harvested and processed red pepper was sampled and analysed for pesticide residues and bioactive component content. Pesticide levels in red pepper and spice paprika correlated well with the doses applied and the number of treatments. Residue levels of chlorpyrifos, cypermethrin and penconazole ranged between 0.125–1.75, 0–0.339 and 0–0.763 μg/g, respectively, while pirimicarb was found at limit of detection. Pesticide treatments affected the content of bioactive components: decreases in the levels of carotenoids (up to 16%) and tocopherols (up to 13%) correlated with the number and dosages of pesticide treatments. Reductions in the level of red but no changes in the yellow pigments were seen. Pesticide residue levels showed similar trends throughout processing; only 2.8-fold and 5.9-fold lower in post-ripened and raw red pepper fruit, correlating with the composition of these matrices and the loss in water content during processing. These results showed the stability of the residues during processing.

As microbial contamination of spices comes primarily from the soil, and soil microbiota are dependent on climate, geography, agriculture, etc a qualitative focus on the dominant microflora of spices instead of the quantitative determination of commonly studied spoilage and pathogenic microflora may give a better insight into the geological origin of the sample. The aim of the present study was to identify using molecular microbiological methods the dominant bacteria of spice paprika produced at different countries and to look for species characteristic of spices from the given regions. According to our data, no differentiation could be made among spice paprika samples of different geographical origin using the total bacterial count or extent of mould contamination. However, when the dominant microflora is examined, bacterial species could be identified in the spice paprika samples characteristic of a particular climate. According to our study, the presence of Bacillus mycoides and Bacillus licheniformis was characteristic of the microflora of spice paprika grown in Central Europe; Bacillus safensis could be detected in all four paprika samples examined from the tropical monsoon climate; the species common to all three samples of the tropical climate group were Bacillus amyloliquefaciens subsp. plantarum and subsp. amyloliquefaciens, while Bacillus mojavensis was detected as being characteristic of Spanish origin for paprika. No common species were found in the paprika samples originating from China.

Spice paprika powders from Bulgaria, China, Hungary, Peru, Serbia and Spain were examined to identify the most important differences in their major characteristics and to attempt to find chemical components revealing their origin. Bioactive components, contaminants, aroma and microbiological properties were determined: the amount of carotenoids, tocopherols, ascorbic acid and mycotoxins were determined by HPLC, flavoring properties by GC-MS, lead and cadmium content by atomic absorption spectrophotometry. Carotenoids were found at the highest concentration in samples from Peru and Spain and at the lowest, in Serbian samples. The concentrations of total tocopherol and ascorbic acid were found to be greater in samples from Hungary than from China. Aroma components characteristic to the location were detected in samples from each country of origin. The level of microbiological contamination was acceptable, while contaminants were found in Serbian, Spanish, Peruvian and Chinese samples. The effect of sample origin was also investigated using near infrared spectroscopy.

For the quick and reliable quantification of special active substances derived from herbs, a new type of immunosensor based on optical waveguide lightmode spectroscopy (OWLS) detection was investigated. Artemisinin, an antimalarial drug derived from the sweet wormwood plant Artemisia annua is a sesquiterpene lactone endoperoxide, and it is distilled from the dried leaves or flower clusters of A. annua. Numerous derivatives of artemisinin, including artesunate and artemether, are also being used in the treatment of malaria, and these compounds have recently gained utility also as anticancer agents. To quantitatively determine the presence of these biologically effective substances in various herbs, a novel OWLS-based immunosensor was investigated. To create regenerable sensitized surfaces in the OWLS technique so that the sensor can be applied several times, the antigen or the antibody were immobilized by covalent attachment to the silanized surfaces of the OWLS chips. When measuring with the antibody capture mode antibodies raised against the appropriate artemisinin derivative (artemisinin, artesunate or artemether) were immobilized on the sensor surface and the linear measuring range was determined. During the antigen capture measurement the protein conjugate of the analyte was immobilized on the waveguide surface. Standard solutions containing different amounts of the appropriate standard were mixed with antibodies at optimized concentration, the mixture was incubated and injected into the flow-injection analysis system of OWLS. Binding of the antibodies in the sample to the coated surface is competed for with free antigen in the sample, and only antibodies that remained in free form in the mixture bound to immobilized antigen-conjugates. The amount of antibodies bound to the surface of the chip was inversely proportional to the active substance content in the samples. The dynamic measuring range and the relative substrate specificity of the serum on artemisinin and its derivatives were studied. Herbs of different origin and herbal supplement products were analyzed using the newly developed method and a correlation was studied with HPLC/DAD/MS reference method.

In soybean, at least 16 seed proteins have been identified as causing allergenic reactions in sensitive individuals. As a soybean genebank accession low in the immunodominant protein P34 (Gly m Bd 30K) has recently been found, introgression of the low-P34 trait into adapted soybean germplasm has been attempted in order to improve the safety of food products containing soybean protein. Therefore, marker-assisted selection and proteomics were applied to identify and characterize low-P34 soybeans.; Results: In low-P34 lines selected from a cross-population, concentrations of the P34 protein as identified with a polyclonal antibody were reduced by 50-70% as compared to P34-containing controls. Using 2D electrophoresis and immunoblotting, the reduction of P34 protein was verified in low-P34 lines. This result was confirmed by liquid chromatographic-tandem mass spectrometric analysis, which revealed either a reduction or complete absence of the authentic P34 protein as suggested from presence or absence of a unique peptide useful for discriminating between conventional and low-P34 lines.; Conclusion: Marker-assisted selection proved useful for identifying low-P34 soybean lines for the development of hypoallergenic soy foods. The status of the P34 protein in low-P34 lines needs further characterization. In addition, the food safety relevance of low-P34 soybeans should be tested in clinical studies. © 2016 Society of Chemical Industry.; © 2016 Society of Chemical Industry.

We are developing the instrumentation for in situ measurement of several characteristic parameters of water quality using direct and immunofluorescence techniques. The instruments and our first results are presented.

Waterless transport is an alternative method to realize the larger volume and higher survival rate of live aquatic products, this paper aims to investigate the effects of transport multi-stressors on the blood physiology and flesh quality, then optimize the setting of ambient parameters during waterless live transportation. Amur sturgeon, Acipenser schrenckii is selected as research objective because it is a representative fish of Chinese farmed sturgeon species. Fish were divided into three groups, Group I, Group II, and Group III. The fish in group I were cultured in the normal living environment (21 °C, with water), and Group II were transported in a lower temperature but normal living environment (4 °C, with water), but fish in Group III were transported in a waterless environment (4 °C, without water). Blood and muscle for assay were sampled at every 8 h intervals (0 h, 8 h, 16 h, 24 h and 32 h). The results indicate that temperature and oxygen are the critical ambient parameters in waterless live transportation, and significantly influence the fish survivability and blood physiology; blood glucose (GLU) and serum cortisol (COR) could be regarded as the representative indexes to assess the physiological stress level. Furthermore, the fish in waterless condition (Group III) exhibit no significant changes in flesh quality, such as total protein and crude fat after transport. These findings provide the theoretical evidence to understand the effects of multi-transport stressors on live fish and apply waterless transport in actual situation.

A label-free, optical waveguide lightmode spectroscopy based immunosensor was developed for frog (Bombina orientalis) vitellogenin (Vtg) determination in biological samples as a biomarker for exogenous oestrogen compounds. Antibody against Vtg was produced in rabbits immunised with purified lipovitellin (Lpv), a precursor of Vtg, from the homogenised ovary of oriental fire-bellied toads (B. orientalis). The purified protein and Lpv/Vtg-specific serum were applied in both competitive and direct immunoassay formats using optical waveguide lightmode spectroscopy immunosensor. When measuring Vtg in direct manner, the Lpv antibody (1.76 µg mL−1) was immobilised on the sensor surface, and the linear measuring range for Vtg was 0.1–10 µg mL−1. During the competitive measurement, 100 ng mL−1 Lpv was applied for the immobilisation. The linear measuring range for Vtg was 0.5–50 ng mL−1. We studied the relative substrate specificity of the antibody, and it was concluded that the method is suitable for the sensitive ...

An enzyme-based amperometric biosensor was developed for the determination of the lysine content of pharmaceutical products, food and feed samples. Lysine decarboxylase (EC 4.1.1.18) from Bacterium cadaveris was coupled with diamine oxidase (EC 1.4.3.6) from Pisum sativum and horseradish peroxidase (EC 1.11.1.7). The enzymes were co-immobilized on a graphite electrode with an Os polymer. The biosensor worked in flow injection analysis system (FIA). Optimal working conditions were pH 7.0 and −50 mV potential vs. Ag/AgCl. The linear measuring range was 0.005–0.500 mM. Different pharmaceutical products and feed samples were analysed by the lysine biosensor and by HPLC method for validation.

In the last years, a new group of enzymes, the so-called silicateins, have been identified and characterized, which form the axial filaments of the spicules of the siliceous sponges, consisting of not only amorphous silica among others. These enzymes are able to catalyze the polycondensation and deposition of silica at mild conditions. Silicateins can be expressed in Escherichia coli. The recombinant proteins are expressed on the surface of the cell wall and are able to catalyze the formation of a polysilicate net around the bacterial cells providing the possibility for further attachment to the surface of SiO2 containing sensor chips. With this mild immobilization process it is now possible to prepare novel microbial sensors based on Optical Waveguide Lightmode Spectroscopy. In the present study, the immobilization of silicatein modified E. coli BL21AI cells onto the SiO2-type chips was optimized (buffer concentration, pH, temperature, reaction time, and so on) and then the biological properties, in particular the inhibitory effect of stressors/environmental pollutants on the novel bacterial sensor were studied in real time. The effect of oxidative stress was investigated by exposing the sensors containing biosilica-immobilized E. coli BL21AI cells to various concentrations of hydrogen peroxide. The effect of antibiotics was tested using chloramphenicol (CAP) which is effective against a variety of Gram-positive and Gram-negative bacteria and penicillin G which destroys the bacterial cell wall. In addition, the inhibition by carbofuran (CF) pesticide was also tested. CF is a highly toxic compound which inhibits cholinesterase activity. According our results we can conclude that the novel bacterial sensor consisting of the silicatein modified E. coli BL21AI cells immobilized on OWLS sensor surface could be an effective tool to detect the presence of different type of pollutants in real time measurement. However penicillin G and CF are not specifically inhibitors of E. coli strain, but some inhibitory effect could be still determined beside the well expressed signals for H2O2 and CAP obtained with the novel microbial sensor.

In the last years, a new group of enzymes, so-called silicateins, have been identified and characterized, which form the axial filaments of the spicules of the siliceous sponges, consisting of amorphous silica. Silicateins are able to catalyze the polycondensation and deposition of silica at mild conditions (low temperature and physiological pH). By means of these enzymes it is possible for the first time to produce silica nanostructures biocatalytically, which opens new ways for construction of biosensors. The cDNAs encoding the responsible enzymes have been isolated and the proteins can be produced in a recombinant way. Here we demonstrate the silicatein-mediated biosilica formation on the surface of SiO2 sensors in model measurements using Optical Waveguide Lightmode Spectroscopy (OWLS) for real-time evaluation. The efficiency of the enzyme reaction on the surface of the SiO2 chips was studied and the parameters of this process were optimized. Silicatein can be expressed in Escherichia coli and the resulting recombinant protein is able to catalyze the formation of silica shell around the bacterial cells. The described immobilization strategy provides a novel technology for the development of microbial biosensors.

Nanosensor technology has a great potential to significantly impact food safety monitoring by using different types of physical, chemical sensors, or even biosensors. Nanosensors based on the evanescent field effect include surface plasmon resonance (SPR) sensors (the most notable type), as well as interferometry, optical waveguide, and optical ring resonator-based sensors. As SPR sensors are discussed in another section of this book, this chapter focuses on the latter types, including reflectometric interference spectroscopy (RIfS), interferometry, optical waveguide lightmode spectroscopy (OWLS), resonant mirrors (RMs), fiber optics, total internal reflection ellipsometry (TIRE), and total internal reflection fluorescence (TIRF) spectroscopy. Novel nanobiosensors are presented through their applications in food safety. A wide range of nanobiosensors for the determination of different residues (eg, pharmaceuticals and pesticide residues) in environmental matrices and foods, as well as for monitoring haphazard microbial or mycotoxin contamination in cereals or other food products will be summarized.

Label-free, optical waveguide lightmode spectroscopy (OWLS) based immunosensors were developed for vitellogenin (Vtg) determination in carp ( Cyprinus carpio ). Purified polyclonal serum raised in rabbits against lipovitellin (Lpv) purified from carp ovary and shown to fully cross-react with Vtg was applied both in direct and indirect measurement formats, and analytical features (limit of detection, specificity, matrix effects) were investigated. The direct OWLS immunosensor and the sandwich ELISA assay developed showed linear measuring range in 600–12,000 ng mL −1 and 200–3000 ng mL −1 Lpv concentrations in standard solutions, respectively. The competitive immunosensor allowed a sensitive detection range for Lpv between 3 and 100 ng mL −1 . Vtg content in blood and liver samples from male and female carp were determined by indirect OWLS. To reduce the matrix effect, calibration curves were obtained using Vtg-free blood and liver samples from male carp spiked with Lpv. Vtg levels in the liver of female carp was lower than determined in the blood samples, therefore, blood occurs to be a more proper tissue to monitor elevated Vtg in male carp due to possible exposure to water-contaminating endocrine disrupting chemicals.

Ten different Persian walnut cultivars were examined for their compositional data, including eight Hungarian and two introduced varieties. Oil content and fatty acid composition were determined, as well as oxidative stability (indicated by induction time). Antioxidative capacity, total polyphenol measurements, and individual phenolic compounds were also determined. Not only dry samples but fresh and stored samples were included in this study. Large differences were found among the varieties within these parameters, for example in oxidative stability, which contributes to antioxidative capacity. In conclusion, the nutritional value of Hungarian walnut cultivars was the same or even higher than those of foreign ones.

A novel biosensor for l-ascorbic acid determination in different beverages was elaborated. The ascorbate oxidase enzyme (AAO) from Cucurbita sp., EC 1.10.3.3, was immobilized on a screen-printed carbon electrode with poly(ethylene glycol) (400) diglycidyl ether (PEGDGE) as a crosslinking agent. The standards and samples were measured first with a blank electrode. An inert protein, bovine serum albumin (BSA), was immobilized on the surface of this electrode with PEGDGE. The BSA mass was equivalent to the mass of 10 U of AAO enzyme immobilized on the electrodes (0.021 mg). The linear measuring range for l-ascorbic acid was between 5 and 150 μmol/L. As l-ascorbic acid is a vital vitamin and a common antioxidant used in food industry, fruit juices and vitamin C effervescent tablets were examined. The results were compared to HPLC measurements.

An enzyme-based amperometric biosensor was developed for the rapid determination of adenine in biological and food samples. Recombinant adenine deaminase (EC 3.5.4.2) from Schizosaccharomyces pombe was co-immobilized on graphite electrode with xanthine oxidase (EC 1.17.3.2), peroxidase (EC 1.11.1.7) and an Os mediator. Optimal working conditions were pH 7.0 and −150 mV vs. Ag/AgCl. The novel method was characterized by a detection limit of 1 µM and a linear measuring range of 0.005–0.1 mM. Different beer and tea samples were analyzed by the newly elaborated adenine biosensor. The results obtained correlate with the adenine content measured by the reference HPLC method.

A Quartz Crystal Microbalance (QCM) based direct immunosensor was developed for real-time detection of probiotic bacteria. To optimize the immunosensor system, model measurements were carried out with bovine serum albumin (BSA) and anti-BSA IgG (a-BSA) antibody. During the model experiments, two kinds of self-assembled monolayers were created to compare their efficiency on antigen binding. Sulfosuccinimidyl 6-[3-(2-pyridyldithio)propionamido] hexanoate (sulfo-LC-SPDP) and 16-mercapto-hexadecanoic acid (MHDA) cross-linking agents were used for immobilizing anti-BSA antibody onto the gold surface of the AT-cut quartz wafer. Two different measuring procedures, flow-through and stopped-flow methods, were applied, and the frequency responses obtained by both analytical methods were compared. After the model experiments probiotic bacteria, Bifidobacterium bifidum O1356 and Lactobacillus acidophilus O1132 serotypes were detected from buffer solution and from real samples (spiked milk samples, acidophilus, and bi...

Three enzyme based amperometric biosensors for biogenic amines were applied for meat spoilage monitoring. With diamine oxidase (EC 1.4.3.6), the total biogenic amine content was measured. Monoamine oxidase A (EC 1.4.3.4) was used for determination of tyramine, tryptamine and phenylethylamine content. Putrescine was selectively detected with putrescine oxidase (EC 1.4.3.10). The enzymes were separately co-immobilized on graphite electrodes with peroxidase and Os mediator (PVI7-dme-Os). A fast extraction method using special centrifugal separator was applied for pork and fish samples stored at different conditions. Although partial extraction was achieved, the results correlate with total biogenic amine content measured by HPLC method.

A thermostable lactate oxidase (from Aerococcus viridans) based bioreactor was elaborated for L-lactate determination in dairy products. The enzyme was immobilised in a thin-layer enzyme cell connected into a flow injection system with an amperometric detector. The linear measuring range was 0.1–1 mmol/L L-lactate (R2=0.99; linear regression equation: y=81.2x+3.3). The detection limit was 0.05 mmol/L. 40 Samples were analyzed per hour. Considering reproducibility: the signals measured were very stable for over 800 injections, after this period the activity of the cell decreased slowly. The method was used for the control of dairy products and for monitoring milk freshness.

Contamination by deoxynivalenol (DON), a trichothecene mycotoxin produced by Fusarium species, occurs in cereals worldwide; therefore, efforts have been made toward the development of rapid and sensitive methods for the detection of this compound. In our investigation, optical waveguide lightmode spectroscopy (OWLS) technique has been applied to label-free detection of DON in both competitive and in direct immunoassay formats using DON-specific polyclonal antibodies. After immobilizing the antibody or the antigen conjugate for the direct or indirect measurement, the sensor chip was used in a flow-injection analyzer system. The direct method was found to result in an unstable sensor response and sensitivity insufficient to determine DON in different grains. In contrast, a competitive immunosensor format provided reproducible quantitative detection in the sub-ppt range. For competitive sensor investigation with the sensitized chip, first the optimal dilution rate of polyclonal antibodies was determined. For the measurements, antibody stock solution was diluted to 8 μg mL−1. During the competitive measurement, standard solutions were mixed with the antibodies at the appropriate concentration, and the mixture was incubated for 1 min and injected into the OWLS system. The sensitive detection range of the competitive detection method was between 0.01 and 50 ng mL−1. After the establishment of the indirect method, spiked wheat flour samples were investigated. Results obtained with spiked samples showed that OWLS detection has a potential for quick determination of DON in wheat samples.

Bioautography can be extended to a complex system called BioArena by linking different steps to it, for example dissolving a variety of compounds in the cell suspension to affect biological activity, measuring putative mediators of antibiosis, for example formaldehyde (HCHO) and hydrogen peroxide (H 2 O 2 ) in the inoculated layer, and performing densitometric and ex and in situ spectroscopic examination to follow the changes in the inhibition zones and active compounds (e.g. antibiotics and toxins). Possibilities of the basic elements of BioArena system are illustrated in this paper by results with aflatoxin B1 (AFB1). Target bacterial cells in the logarithmic growth phase were found to be the most sensitive for direct bioautography. Densitometric signals of bioautograms (negative densitometry) of 0.125–1 μg AFB1 spots showed logarithmic correlation with the amount of AFB1. The HCHO capturer L-arginine decreased whereas the HCHO generator-mobilizer Cu(II) ions increased the antibacterial-toxic effect of ...

The study examined several types of compounds can be suitable to characterise wines made from botrytised grapes and to determine their origin and authenticity. Amines, acids, macro- and microelements of botrytised sweet wine specialities, coming from Hungary and different countries, were analysed. Measured values of twenty-one Tokaji aszu wines and twenty-three foreign botrytised wines were compared by multivariate statistical methods. Characterising the effect of Botrytis cinerea and the winemaking technology, amines were the most suitable components for determination of authenticity and origin of wines from the three types of compounds studied. However, in acids and elemental composition, differentiation of wine samples by principal component analysis was not complete but a tendency can be observed for separation according to origin. The knowledge on composition of acids and elements can support the results of amine analysis in reaching the goal to determine the origin of wines.

Determination of sucrose content is one of the most important routinely performed tests for quality control in the beverage industry. Thus, it is rather important to have a fast, simple and sensitive method that can be used for determination of sucrose in sweet-drink processing. The biosensor investigated was based on a thin layer enzyme cell in which glucose oxidase, invertase and mutarotase were immobilized on a protein membrane. Hydrogen peroxide as the product of the consecutive enzyme reaction was detected by amperometric technique. The optimum enzyme composition of invertase, mutarotase, and glucose oxidase for immobilisation was found to be 8498, 672, and 120 U using 2.2 mg BSA as protective agent dissolved in 200 μL phosphate buffer solution. To achieve the best measuring technique, changes in several parameters such as pH value, temperature and flow rate were studied. Having found the optimum conditions, the statistical parameters of the analysis were established. The linear range of the determination was between 1.0 × 10−4 and 2.5 × 10−3 mol/L with a correlation coefficient of 0.99. The sucrose content of several fruit juices was determined with this sensor, and the results were compared with an enzymatic reference method. The correlation between the two sucrose determination methods was found to be 0.97.

Lactic acid bacteria play an important role in the fermentation of different food products. During the fermentation processes, lactobacilli are confronted with many inhibitor factors. These factors by themselves or in combination can influence the growth of lactic acid bacteria and their acidification capacity. The subject of our study was to monitor with a newly developed biosensing technique how the different chemical stress factors influence the survival of lactic acid bacteria. Electrochemical optical waveguide lightmode spectroscopy combines evanescent-field optical sensing with electrochemical control of surface adsorption processes. For optical sensing, a layer of indium tin oxide served as a high refractive index waveguide and as a conductive electrode, as well. Lactobacillus plantarum 2142 suspended in Jerusalem artichoke syrup was used in the experiments. Electrochemical optical waveguide lightmode spectroscopy measurements were undertaken by using OW 2,400c indium tin oxide coated waveguide sensors (MicroVacuum, Budapest, Hungary) and were performed in a flow-injection analyzer system. The bacterial cells were adsorbed in native form without any chemical binding on the surface of the sensor by ensuring polarizing potential (1V) and were exposed to different concentration of acetic acid/Jerusalem artichoke syrup, lactic acid/Jerusalem artichoke syrup and hydrogen peroxide/Jerusalem artichoke syrup solution for 1h, respectively, and the effect on bacteria cells was monitored. Results were compared to the traditional micro-assay method, and it can be assumed that after further investigations this new technique could be used in real-time application.

Mycotoxins are toxic secondary metabolites produced by a number of different fungi, and can be present in a wide range of food and feed commodities including cereal grains, oil seeds, dried fruits, apple juice, wine and meat products from animals fed contaminated meal. Many mycotoxins are highly resistant, and survive food processing, and therefore enter the food chain and provide a threat to human health. The optical waveguide lightmode spectroscopy (OWLS) technique has been applied to the detection of Aflatoxin and Ochratoxin in both competitive and in direct immunoassays. After immobilizing the antibody or antigen conjugate for the direct or indirect measurement, respectively, the sensor chip was used in flow-injection analyser (FIA) system. When using non-competitive method, sensor responses were obtained first only at analyte concentrations of 5-10 ng ml(-1). In both cases, the responses were very unstable. For competitive sensor investigation with the sensitized chip first the optimal dilution rate of monoclonal antibodies was determined, for the measurement of Ochratoxin A and Aflatoxin B1 the monoclonal antibody stock solution was diluted to 1 microg ml(-1) and to a 1:400 dilution, respectively. During the competitive measurement standard solutions were mixed with monoclonal antibodies at the appropriate concentration, the mixture was incubated for 1 min and injected into the OWLS system. The sensitive detection range of the competitive detection method was between 0.5 and 10 ng ml(-1) in both cases. After the establishment of the indirect method, barley and wheat flour samples were measured, and the results were in good correlation by those measured by enzyme linked immuno-sorbent assay (ELISA). Regression coefficient between the two methods for Ochratoxin and Aflatoxin was determined as 0.96 and 0.89, respectively.

In soybean, at least 16 seed proteins have been identified as causing allergenic reactions in sensitive individuals. As a soybean genebank accession low in the immunodominant protein P34 (Gly m Bd 30K) has recently been found, introgression of the low-P34 trait into adapted soybean germplasm has been attempted in order to improve the safety of food products containing soybean protein. Therefore, marker-assisted selection and proteomics were applied to identify and characterize low-P34 soybeans.In low-P34 lines selected from a cross-population, concentrations of the P34 protein as identified with a polyclonal antibody were reduced by 50-70% as compared to P34-containing controls. Using 2D electrophoresis and immunoblotting, the reduction of P34 protein was verified in low-P34 lines. This result was confirmed by liquid chromatographic-tandem mass spectrometric analysis, which revealed either a reduction or complete absence of the authentic P34 protein as suggested from presence or absence of a unique peptide useful for discriminating between conventional and low-P34 lines.Marker-assisted selection proved useful for identifying low-P34 soybean lines for the development of hypoallergenic soy foods. The status of the P34 protein in low-P34 lines needs further characterization. In addition, the food safety relevance of low-P34 soybeans should be tested in clinical studies. © 2016 Society of Chemical Industry.

This article compares two different immunosensors developed for important food analytical and environmental problems. The label-free detection techniques were the piezoelectric quartz crystal microbalance measurement (QCM) and the optical waveguide lightmode spectroscopy (OWLS). Immobilizing anti- Escherichia coli IgG onto the gold electrode of QCM, E. coli bacterial cells were measured. Resonant frequency responses of the sensor system were determined at various concentrations of E. coli (1.7 × 10 5 –8.7 × 10 7 CFU/ml). The same antibody was immobilized onto the amino silanized sensor of OWLS by glutaraldehyde covalent coupling. The measuring range was between 3 × 10 4 and 3 × 10 7 CFU/ml. Chloramphenicol (CAP) antibiotic was measured in standard solutions with immunosensor based on label-free techniques to study the possibility of direct sensing of molecules with low molecular weight. Anti-chloramphenicol antibody immobilization have been performed onto the gold surface of the crystal by using 3-mercaptopropionic acid (MPA) and dimethylaminopropyl-ethylcarbodiimide–hydroxysuccinimide ester (EDC-NHS) chemistry. The linear measuring range was found between 5 × 10 −6 and 5 × 10 −2 M chloramphenicol. Experiments were performed for measuring chloramphenicol with the same method with OWLS detection. After glutaraldehyde cross-linker immobilized the antibody, the signal measured was proportional to the analyte content in the range of 10 −7 –10 −3 M.