Underwent Heat Treatment Research Articles

Effect of Heat Treatment on Isothermal Oxidation of Fe-33Ni-18Cr Alloy at 1000°C

This research study was focused on the effect of heat treatment on the isothermal oxidation of Fe-33Ni-18Cr alloy at 1000 °C. The Fe-33Ni-18Cr alloy was undergone heat treatment at three different temperatures, namely 1000 °C, 1100 °C and 1200 °C for 3 hours soaking time followed by water quench to vary the grain size of the alloy. The heat-treated alloys was prepared for further isothermal oxidation test. The heat-treated alloys was ground by using several grit of silicon carbide papers as well as weighed by using analytical balance and measured by using Vernier caliper before the oxidation test. The heat-treated Fe-33Ni-18Cr alloys was isothermally oxidized at 1000 °C for 150 hours exposure time. The characterization of the oxidized samples was carried out using optical microscope and scanning electron microscope (SEM). The heat treatment result shows that, increasing the heat treatment temperature was increased the average grain size of the alloy. The kinetics of oxidation was followed the parabolic rate law which represent the diffusion-controlled oxide growth rate. Fine grain structure of 1000i-1000 sample shows minimum weight gain and lower oxidation rate compared to samples of 1000i-1100 and 1000i-1200. On the other hand, 1000i-1100 and 1000i-1200 samples indicate the formation of oxide spallation and crack propagation on the oxidized surface, respectively.

Safety of chia seeds (Salvia hispanica L.) subject to thermal processing in relation to the formation of process contaminants as a novel food for extended uses.

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the safety of chia seeds in foods subject to thermal processing which may result in the formation of process contaminants. The safety assessment of this novel food (NF) is based on previous assessments of chia seeds by the EFSA NDA Panel, information received from a public call for data by EFSA and information retrieved from an extensive literature search performed by EFSA. In 2019, during the overall safety assessment of chia seeds, the NDA panel retrieved one reference which, among others, investigated the formation of process contaminants, i.e. acrylamide, hydroxymethylfurfural and furfural, in wheat flour‐based biscuits with added chia seeds flour. Based on this study, the Panel considers that there is a potential for substantial acrylamide formation in biscuits with 10–20% added chia seeds flour with low residual moisture contents (≤ 2%). The Panel is not aware of further scientific evidence corroborating these findings. The extensive new literature searches performed by EFSA did not show any relevant articles regarding either asparagine content or formation of process contaminants in chia seeds and products thereof. Information received from the call for data were either limited or inconclusive. The available evidence does not provide a basis to conclude whether or not the addition of chia seeds to foods undergoing heat treatment (at temperatures above 120°C) results in increased formation of acrylamide as compared to these foods without chia seeds. Reported concentrations of hydroxymethylfurfural and furfural in heat‐treated chia seeds do not pose a safety concern. No information on other process contaminants in chia seeds was found.

Attenuation of exaggerated blood pressure responses to exercise: a byproduct of improved vascular function with passive heat therapy?

Attenuation of exaggerated blood pressure responses to exercise: a byproduct of improved vascular function with passive heat therapy?

Optimization and Validation of HS-SPME-GC-MS for the Determination of Furan and Alkylfurans in Chocolate-Based Products: Impact of Tempering and Laser Printing.

Furan and its alkyl substituted (2-methylfuran, 3-methylfuran, 2,3-dimethylfuran, 2,5-dimethylfuran) are found in a range between ppm to sub-ppb levels in many foodstuffs undergoing heat treatments like coffee, chicory, or even chocolate. Two major objectives are presented. First, we aim at optimizing and validating a HS-SPME-GC-MS method for the quantification of five alkylfurans in chocolate. Second, we focus our study on measuring the quantitative impact of engraving technique on the formation of furan and its derivatives in chocolate, from the raw callets to processed end-products. HS-SPME-GC-MS method operating in SIM mode and using isotope dilution technique with deuterated homologue internal standards was used to quantify alkylfurans in chocolate. Good repeatability (RSD% = 0.1-8%, in duplicate) and intermediate precision (RSD% = 1.7-7%, n = 6) were obtained for these five process contaminants at 10, 25, and 50 µg/kg. Trueness was varying between 81 and 109%. LoQ ranged from 0.48 to 2.50 µg/kg. Relative expanded measurement uncertainties ranged from 6 to 30%. Finally, tempering is responsible for a 24% increase in furan contamination, while the laser engraving technique results in an additional 31% increase in furan. A similar trend was also observed for 2-methylfuran and 3-methylfuran, whereas no significant increases were observed for 2,3-dimethylfuran and 2,5-dimethylfuran. A reliable and sensitive method of HS-SPME-GC-MS was reported for the first time for the analysis of furan and four alkylfurans in chocolate. This paper demonstrated that engraving using laser-based techniques can increase the levels of these compounds by up to 30%.

Recyclability of Dental Gypsum via Calcination

Nowadays, either keeping or throwing out the final product of dental cast is the most common thing to do. The waste from dentistry can be considered toxic if not handled specifically and separately to other waste. Hence, the recycling process can reduce its effect and the waste of dental casts. It can also reduce the cost of producing new high-grade dental gypsum. This paper studies the behavior of before-after recycle and heat treatment to several grades of dental gypsum that will be used as impression material or dies. As it is designed to be an impression material that will undergo heat treatment, Simultaneous Thermogravimetry and Differential Scanning Calorimetry (TGA-DSC) will be applied to understand the Phase Transformation to its mass change and the behavior to a temperature difference. The result will be validated using an experimental approach. X-ray Diffraction (XRD) and Scanning Electron Microscope will also be done to identify the crystalline phases and the surface microstructure, and it will be validated using an experimental approach as well. A range of gaps between parameter values is expected between the fresh/new dental gypsum and the recycled one. However, it is expected some similar values between the heat-treated and the fresh/new dental gypsum.

Сообщество метозойных паразитов язя Leuciscus Idus (L.) в осенний период жизненного цикла (р. Иртыш)

The article describes the specific features of the fish stocks in the Irtysh River, the main share of which is made up of representatives of ide Leuciscus idus (Cyprinidae). The parasitic community of the Irtysh ide in the autumn period of the life cycle has been studied. A total of 15 individuals of fish of various sexes, aged 1+ to 6+, weighing 174-1,086 g, length 25.2-44.6 cm, were examined. The invasion of ide by 15 species of parasites belonging to 5 systematic groups was established: Monogenea – 2, Cestoda – 1, Trematoda – 9, Nematoda – 1, Copepoda – 2. The dominant species in this community are R. campanula and Metorchis sp (gills, fins). Monogenes have a limited presence: D. ramulosus and P. megan. There has been marked 100% infection of ide muscles with metacercaria O. felineus. Fish fins are invaded by R. campanula and Metorchis sp. in 100% of cases. The ureter is invaded by P. elongatum with EI by 13.3%. A massive parasitizes of cyprinids – S. globiporum- parasitizes in the intestines of ide with EI = 60.0%. The larval stage of R. acus was noted on the mesentery in 60.0% of the examined fish. The crustaceans E. sieboldi and T. polycolpus parasitized on the gills and fins of ide, respectively. It has been stated that the described composition of the parasitic community is typical for ide regardless of its habitat. The invasion of the Irtysh ide by the pathogen of opisthorchiasis is at a high level, the intensity of infection of ide with metacercaria O. felineus in the Irtysh is 100%, which is dangerous for the population when eating fish that have not undergone heat treatment

Effect of heat on the hardness of glass carbomer cement used in atraumatic restorative treatment

This study aimed to evaluate the effect of heat treatment on the microhardness of two glass ionomer cements: EQUIA Forte (GC Corporation) and GCP Glass Fill (GCPDental). Material and methods: Twenty specimens of the two glass ionomer cements were prepared following the manufacturer’s instructions, and 10 specimens of each material received heat treatment with a light curing unit (Carbo LED lamp, GCP-Dental). After seven days of storage in distilled water at room temperature (23°C), the 40 specimens were submitted for Vickers microhardness test (microhardness HMV 2T). Five indentations were performed on each specimen with a load of 100g, with a 10 second penetration time. Results: For both materials, the average microhardness value were higher in the groups that did not undergo heat treatment, the group presenting with the highest microhardness value was EQUIA Forte (GC Corporation) without heat treatment (125.3), and the lowest value was found for GCP Glass Fill (GCP-Dental) with heat treatment (72.9). Conclusion: The heat treatment had no influence on the microhardness of the glass ionomer cements tested.

Mussel shells: A canning industry by-product converted into a bio-based insulation material

The canning industry in Galicia produces 25 thousand tonnes of mussel by-product (i.e. unconsumed shells) per year, having a significant environmental impact. Mussel shell becomes suitable for different uses after undergoing heat treatment such as poultry feed or bedding, etc. However, other end uses for this by-product must still be explored. Building insulation material (for instance expanded polystyrene, extruded polystyrene, polyurethane, etc.) has a significant harmful effect on the environment, which is especially seen when analysing its entire life cycle (use of large amounts of energy and water for production, difficulty recycling or reusing waste in the event of demolition or refurbishment, etc.). The aim of this research is to prove the feasibility of using mussel shell as a building solution. Mussel shell has been found to have thermal and acoustic characteristics suitable for using it as building insulation material. Mussel shell confined inside an enclosed space (e.g. a wooden box) has a thermal conductivity similar to that of a light conifer wood, so it can be considered a material with low thermal conductivity. Furthermore, several acoustic studies indicate that a section of confined mussel shell displays a behaviour similar to that of commercialised insulation material. The embodied energy of mussel shell as a loose-fill material is similar to that of other bio-based insulation materials. The main goal of this paper is to demonstrate that it is possible to design mussel shells building solutions, that actively participate in environmentally responsive architecture.

New Edible Packaging Material with Function in Shelf Life Extension: Applications for the Meat and Cheese Industries.

Nowadays, biopolymer films have gained notoriety among the packaging materials. Some studies clearly test their effectiveness for certain periods of time, with applicability in the food industry. This research has been carried out in two directions. Firstly, the development and testing of the new edible material: general appearance, thickness, retraction ratio, color, transmittance, microstructure, roughness, and porosity, as well as mechanical and solubility tests. Secondly, testing of the packaged products—slices of cheese and prosciutto—in the new material and their maintenance at refrigeration conditions for 5 months; thus, the peroxide index, color, and water activity index were evaluated for the packaged products. The results emphasize that the packaging is a lipophilic one and does not allow wetting or any changes in the food moisture. The results indicate the stability of the parameters within three months and present the changes occurring within the fourth and fifth months. Microbiological tests indicated an initial microbial growth, both for cheese slices and ham slices. Time testing indicated a small increase in the total count number over the 5-month period: 23 cfu/g were found of fresh slices of prosciutto and 27 cfu/g in the case of the packaged ones; for slices of cheese, the total count of microorganisms indicated 7 cfu/g in the initial stage and 11 cfu/g after 5 months. The results indicate that the film did not facilitate the growth of the existing microorganisms, and highlight the need to purchase food from safe places, especially in the case of raw-dried products that have not undergone heat treatment, which may endanger the health of the consumer. The new material tested represents a promising substitute for commercial and unsustainable plastic packaging.

Experimental study of factors affecting the failure of the cyclical nature of rotary endodontic instruments

Relevance. The properties of shape memory, superelasticity and plasticity in nickel-titanium tools make the visual prediction of breakage as difficult as possible. Therefore, an important role is given to research, the purpose of which is to predict the time of their work and to identify the main factors affecting the probability of a fracture.Aim. Comparison of cyclic fatigue resistance of Ni-Ti rotary endodontic instruments of various manufacturers.Materials and methods. The influence of the autoclaving procedure and the angle of bending of the root canal on the resistance of a rotating endodontic instrument to cyclic loads was studied using an author's patented device that simulates the rotation of an instrument in a real channel; the number of cycles completed by each instrument before its fracture was recorded. The morphology of fractures, the microstructure of specimens under fractures, and the microhardness of specimens of endodontic instruments after testing were studied.Results. It has been established that resistance to fatigue fractures of instruments of various endodontic systems decreases with an increase in the bending angle of the root canal. For Endostar E3 Basic Rotary System tools, the number of cycles decreased by 1.2 times, for Protaper Universal tools by 2.9 times. The tools of the Protaper Next system reduced the number of cycles at a bending angle of the artificial root canal of 60 degrees by 1.5 times compared with the number of cycles at a bending angle of 45 degrees. At the same time, statistical data and the study of the microstructure of samples of new and past 6 cycles of autoclave tools did not show a connection between the autoclaving procedure and a decrease in their resistance to cyclic loads.Conclusions. When working in complex bent over 45 degrees channels, it is rational to choose an endodontic instrument that has undergone heat treatment at the production stage (in the framework of this study, it was Protaper Next 25/06 M-Wire alloy). This will reduce the likelihood of a file fracture and associated dangerous complications of endodontic treatment.

Studying stirred yogurt microstructure using optical microscopy: How smoothing temperature and storage time affect microgel size related to syneresis

A grainy texture and high syneresis are 2 defects in low-fat stirred yogurt that are often disliked by consumers. In this study, a rheometer controlling the shear rate and temperature was used to simulate the smoothing step of yogurt manufacture. Identical formulations containing whey protein isolate or whey protein concentrate were compared. After the yogurt milk underwent heat treatment, inoculation, and fermentation at 42°C, the yogurt was smoothed at 42°C (Y42) or 20°C (Y20) or during a cooling ramp from 42°C to 20°C (YR). Induced syneresis (serum expelled by centrifugation) was measured on d 3. Sizes of microgels (dense protein aggregates) were investigated on d 0, 4, and 7 by laser diffraction and by image analysis using optical microscopy. Optical microscopy was also used to characterize the reorganized protein network embedding microgels. The type of whey protein ingredient had only a slight effect on the induced syneresis of YR and Y20 treated yogurts, and the major effect came from the smoothing temperature. The Y42 treatment presented the highest induced syneresis; YR and Y20 had similar low induced syneresis values. Images showed a heterogeneous microstructure (large microgels, reorganized gel) and serum separation for Y42; the YR and Y20 networks were homogeneous. Both the image analyses and laser diffraction showed that the microgel size depended on the smoothing temperature. However, only the image analyses made it possible to identify a time dependency effect on microgel size during storage. The number of microgels >104 µm2 continued to increase over time, whereas the number of microgels <103 µm2 decreased. Microscopic observations were less destructive than laser diffraction and highlighted the presence of microgel aggregation during storage.

Variable optical properties of La0.5Sr0.5Co1-xNixO3-δ for high-temperature resistant code application

La0.5Sr0.5Co1-xNixO3-δ (x = 0, 0.1, 0.3, 0.5) ceramics were prepared via tape casting and solid state reaction process. The influence of Ni concentration on the optical properties of La0.5Sr0.5Co1-xNixO3-δ has been investigated. Results showed that the reflectance in the range of 0.3–15 μm decreased with the increment of Ni concentration, thereby causing a change in the color phase parameters and emissivity. Based on the difference in L* values and emissivity, the letters (HOT) and QR codes (NJTECH) were fabricated. The developed letters and QR codes could be identified both at room and high temperatures. Furthermore, the QR codes were read out successfully even underwent heat treatment at 1000 °C. The results in this work demonstrate a new application of La0.5Sr0.5Co1-xNixO3-δ ceramics.

Temperature dependent studies on nutritional, total polyphenols, flavonoids content and antioxidant activities of Aframomum citratum (C.Pereira) K.Schum and Tetrapleura tetraptera (Schum. &amp; Thonn.) Taub. fruits

Description. Hard shelled fruits, Tetrapleura tetraptera and Aframomum citratum nonwood forest products are used as spices and for many medicinal recipes. Mostly used together, they undergo heat treatment before being milled when cooking Mbongo Tchobi, a black spicy stew from central and coastal regions in Cameroon. Objectives. Evaluate the impact of roasting these spices on the physicochemical properties (dry matter, ash, raw protein, total sugar, raw fibre, pH, aw, total energy, total fat), phytochemical content (total polyphenol, total flavonoids) and the antioxidant activities (total antioxidant activity, FRAP, DPPH and lipid peroxidation inhibition assays) of their aqueous extracts in a home food consumption context. Method. Tetrapleura tetraptera and Aframomum citratum fruits from Ngola locality in Yokadouma (east region in Cameroon) locality were collected, sorted, cleaned and dried (72 h, 45 °C) in an oven. Cut into small pieces, a part was heated using roasting parameters deduced from preliminary tests (140 °C/10 min; 180 °C/20 min and 150 °C/12 min respectively for T. tetraptera, A. citratum and a formulation 95/5 of the two spices). The heated and unheated spices were ground and an infusion was prepared from boiling water in the proportion of 1/5 (g·ml-1) for both types of spices. Physicochemical and phytochemical characteristics (dry matter, total ash, fat, sugar, crude fibre and energy contents, pH, aw, total flavonoids and polyphenols) as well as the antioxidant activities of the aqueous extracts of the two spices and a mix of the two spices were evaluated before and after the heat treatment. Results. Heat treatment significantly (p &lt; 0.05) reduces fat and total sugars contents but improves raw fiber contents for all spices. Phenolic content is more important for heated spices and percentage differences before and after heat treatment are between 8.0 and 23.2% for both spices. Extracts obtained with heated spices possess the best antioxidant potential. Strong significant positive correlations have been established between the phenolic compounds and the reductive antioxidant activities and negative correlations with the antiradical antioxidant activities as they are expressed as IC50 (mg·ml-1). Conclusions. In most of the features studied, the heated formulation (95/5) possesses the highest characteristics studied. The choice of heating these spices under the roasting parameters identified should be guided by the desire of improving their antioxidant potential because of the nutritional losses observed after heat treatment.

Effect of interfacial intermetallic compounds evolution on the mechanical response and fracture of layered Ti/Cu/Ti clad materials

Three-layered Ti/Cu/Ti clad materials fabricated by cold roll-bonding process and in the following underwent heat treatment cycles. Microstructure evolution and mechanical properties of as-rolled and annealed samples studied by SEM, XRD, microhardness and tensile examinations. According to the results, as-rolled and treated samples contained several IMCs at their Ti/Cu interfaces while thickness of the reaction layer enhanced noticeably by annealing. Examined average IMC layers' thickness were 1.34, 1.61, 2.39 and 5.39 μm, for as-rolled, 300, 500 and 700 °C annealed specimens, respectively, consisting four different phases of CuTi2, CuTi, Cu3Ti2, and Cu4Ti. However, continuity, uniformity and thickness variation as well as the growth rate during treating for each layer was distinct. From SEM and XRD results that acquired from separated surfaces, major debonding occurred at CuTi2/CuTi and CuTi/Cu3Ti2 interfaces suggesting that bonding strength for these IMC layers were weaker than those for the other IMC/IMC interfaces and the parent-metal/IMCs. The stress-strain curves demonstrated that the strength decreased and subsequently ductility improved by annealing up to 700 °C. Meanwhile, SEM analyses revealed that cracks within IMC layers during tensile deformation emerged only in specimen annealed at 700 °C; however, it did not lead debonding or layer separation similar to other clad metals reported in literature. By fractography, it is indicated that dimples formed in the whole fracture surface of as-rolled and annealed specimens at 300 and 500 °C. For the 700 °C annealed specimen, however fracture mode was ductile, dimples hardly noticed since the cracks propagation and extension path was along the weak IMC interfaces. In addition, this sample unlike others exhibited limited necking extension before failure. According to the obtained results and as the current research's novelty, it is claimable that intermetallics formed in Ti/Cu clad materials would be more ductile comparing with other compounds reported for talented cladding metals in literature.

Dynamic moisture loss explored through quantitative super-resolution microscopy, spatial micro-viscosity and macroscopic analyses in acid milk gels

Molecular interactions and dynamic changes at a range of length scales affect the structuring of food materials, as such it is essential to explore structure at a range of different length scales. Herein, four acid milk gel samples are produced from either fresh or reconstituted skim milk that either had no heat treatment or had undergone heat treatment at 85 °C for 10 min. Milk acid gels demonstrate complex structure on a range of length scales of interest in colloidal materials and exhibit different macroscopic and water binding properties. A method is presented to measure the dynamic moisture loss in these samples, without applying external force. Super-resolution microscopy images are quantitatively analysed to describe the gel microstructure with precise features. Fluorescent Lifetime Imaging Microscopy is used to spatially resolve differences in molecular confinement across the sample's microstructure, which is quantified for each sample. Moisture loss and microstructural analyses are correlated to bulk and macroscopic properties determined through rheological and texture analysis, pH and conductivity measurements. More severe thermal and processing treatments leads to a reduction in moisture loss over time. Differences in moisture loss and mechanical properties relate to different thermal processing histories, but are not fully explained by levels of denatured whey proteins, and appear related to changes in mineral balance. The methods presented provide a comprehensive and complementary overview of material properties across relevant length scales and relevant sample conditions.

Pterostilbene enrichment of dry convenience food for instant muffins

Modern society is overloaded with uncontrolled flows of information, emotions and stress. On top of that, despite promoting a healthy diet, the populations of many countries are overweight, obese, and having type 2 diabetes. The role of genes in the development of diabetes, obesity and senile dementia is not so great. Vast majority of people obtain eating habits that appear to be significant factors in the onset of syndromes of demetia. Flour confectionery products, which include muffins, have gained popularity in many countries in the world, according to this, the development of technologies related to the enrichment of classical formulations with useful substances or components has relevance and necessity. This is also due to the expansion of the market for flour confectionery products that meet the strategy of a balanced and healthy diet. The aim of the article is to develop recipes and technology for instant muffins from dry semi-processed goods with the addition of dry blueberry powder as a source of pterostilbene, a substance that reduces the risk of early aging, Alzheimer's disease, type 2 diabetes, the effects of stress and depression. The proposed technology ensures the preservation of the beneficial effect of the biologically active substance that undergone heat treatment, due to the afore proposed short-term effect of the prepared mixture when exposed to microwaves. Developed dry mixes for muffins can be recommended for everyone, because they do not contain fat and sugar. Sweetness to the finished product is provided with the extract from stevia leaves. Muffins do not contain chemical disintegrants.

METHODS OF IDENTIFICATION OF MUSCLE TISSUE IN MEAT PRODUCTS. PREREQUISITES FOR CREATING A MULTI–LEVEL CONTROL SYSTEM

Unfair production and products that do not comply with the declared labeling are currently an acute problem in the field of technical regulation, including with regard to food safety and quality. Given the high added value and multicomponent composition, finished meat products are among the most susceptible to adulteration. Despite the best efforts of regulatory agencies to counteract these inconsistencies, the hidden substitution of cheaper or lower-grade meats is still widespread. One of the main tasks facing research laboratories and testing centers today is the detection of falsification of food products, as well as standardization and certification of techniques necessary to solve such problems. The manufacturer, aware of the current control methods, can go to the deception, using vegetable protein, new unregistered feed additives. To determine the complex changes that occur in products, it is necessary to use methodological approaches in which it is possible to reliably determine these changes. The paper presents an overview of the most commonly used methodologies for assessing the component composition of meat products. Quality assessment of meat products includes control of components of finished products. The most difficult task is to determine the proportion of muscle protein in multicomponent meat products that have undergone heat treatment.

Design of highly porous SnO2-CuO nanotubes for enhancing H2S gas sensor performance

Highly porous SnO2-CuO hollow nanofiber mats were synthesized by electrospinning combined with thermal processing for high performance H2S gas sensing applications. The porous morphology generated in the one-dimensional (1-D) nanocomposite led to an improvement in surface-to-adsorbate molecule interactions. Our novel concept lies in fabrication of SnO2-CuO with a 1-D highly porous structure by electrospinning coupled with generation of hollow nanostructures drawing on nanofiber-to-nanotube transformation affected by Kirkendall effect during thermal processing. The fibrous structure was synthesized by electrospinning with mixed solution of Sn and Cu precursors, which then underwent heat treatment under various temperature conditions. The hollow structures were generated based on the different diffusion rates between SnO2-CuO and Sn/Cu. The SnO2-CuO nanotubes have low operating temperatures and high H2S sensing performance. The increased surface area for detecting H2S resulted in great enhancement of the response (Ra/Rg = 1395) and a very fast response time of 5.27 s with a stable recovery time to a low concentration of H2S to 5 ppm at 200 °C. The porous SnO2-CuO hollow nanofiber gas sensor proved to be a promising candidate for gas sensor systems due to increased surface area with metal oxide catalyst. The mechanisms involved in enhancement of gas response and extended applications are also discussed.

Disposable Amperometric Immunosensor for the Detection of Adulteration in Milk through Single or Multiplexed Determination of Bovine, Ovine, or Caprine Immunoglobulins G

This paper reports the first immunoplatforms for the detection of adulteration in milk with milk or colostrum from other animals. The developed electrochemical bioplatforms allow the reliable determination of immunoglobulins G (IgGs) from cows, sheeps, or goats. They rely on sandwiching each animal species-specific IgGs with selective antibody pairs [unconjugated and conjugated with horseradish peroxidase (HRP)] onto magnetic microbeads (MBs) used as solid supports and amperometric transduction with the H2O2/hydroquinone (HQ) system at disposable electrodes. The immunoplatforms allow achieving limits of detection (LODs) of 0.74, 0.82, and 0.66 ng mL-1 for bovine, ovine, and caprine IgGs, respectively, which are lower than those obtained with conventional enzyme-linked immunosorbent assay (ELISA) methodologies and in 2-5 times shorter time. The bioplatforms were successfully applied to the determination of the individual content of the target IgGs in milk samples of different animals (cow, sheep, and goat) and type (colostrum, raw, and pasteurized), without matrix effect and after just a sample dilution. They were also applied to the detection of adulteration with milks from other animals at levels below than those required by the European legislation (1.0%, v/v). The possibility to detect milk adulteration with colostrum using a strategy based on the measurement of the total content of the three target IgGs in raw milks is also demonstrated. Multiplexing platforms were constructed to be used in routine surveillance of milk. They are able to provide in a single run and in just 30 min relevant information regarding the milk sample including its animal origin, the undergone heat treatment, and whether it was adulterated with milk or colostrum from other species.

Insight into the transformation of 4’-O-methylpyridoxine and 4’-O-methylpyridoxine-5’-glucoside in Ginkgo biloba seeds undergoing the heat treatment

Overconsumption of Ginkgo biloba seeds leads to poisoning. 4’-O-methylpyridoxine (MPN) and 4’-O-methylpyridoxine-5’-glucoside (MPNG) are responsible for poisoning by intaking ginkgo seeds. It had been reported that heat treatment could increase the MPNG content but decrease the MPN content in ginkgo seeds. However, the definite mechanism for the transformation of MPN and MPNG in ginkgo seeds undergoing heat treatment has not been elucidated to this day. In this work, a Chinese ginkgo cultivar was firstly employed to investigate the effect of heat treatment on the levels of MPN and MPNG. Similar syngenetic succession between the MPN and MPNG contents was also found. Several groups of experiments were further designed to explore the interconversion mechanism between MPN and MPNG under heat treatment. The results showed that non-enzymatic and enzymatic glycosylation mechanisms could not explain the transformation between MPN and MPNG. Enzymatic hydrolysis mechanism could better explain the dynamic relationship between the MPN and MPNG. Therefore, inactivating the endogenous enzymatic hydrolysis before HPLC analysis is needed to accurately determine the contents of MPN and MPNG in the ginkgo seeds.