Effect of Foam-mat Drying on Bioactive, Powder and Thermal Properties of Carrot Juice Powders.

Foam-mat drying is a promising method due to involvement of proteins as foaming agent which acts like a wall material wrapping around bioactives and retards their degradation. In this study, powder properties of foam-mat dried carrot juice powders including 15% egg albumen (EA) and 15% egg albumen+ 10% whey protein isolate (WPI) during 90 days of storage at room conditions were evaluated by means of physical, chemical, thermal (DSC and TGA) and microstructural (SEM) analyses. The powder flow properties (wettability, hygroscopicity, degree of caking, Carr index and Hausner ratio) have been significantly affected from the moisture uptake during storage; however, powder flow properties of 15% EA+ 10% WPI powders were found to be better than 15% EA powders as it was also confirmed by particle diameter distributions that remained the same before and after the storage period. Besides, the total antioxidant, phenolic and carotenoid contents of 15% EA+ 10% WPI carrot powder was found comparably higher than 15% EA powders due to possible encapsulating mechanism of whey proteins. In addition to delaying of physical and chemical deteriorations in powders with WPI incorporation, thermal stability of the foam-mat dried carrot juice powders was also improved in 15% EA+ 10% WPI powder.

Biotransformation of Tetracyclines by Fungi: Challenges and Future Research Perspectives.

Tetracycline antibiotics are used worldwide in human and veterinary medicine. On the basis of low metabolization and through organic fertilizers, tetracyclines enter the environment in a biologically active form. This can have toxic effects on microbial communities and promote the selection of resistant strains. The use of fungi could be a promising approach to deactivate tetracyclines by degradation or derivatization as a result of their particular enzyme endowment. Here, we highlight the current analytical and biotechnological challenges associated with the bioconversion of tetracyclines by fungi and propose research approaches to advance the technology for wastewater and manure treatment.

Electrochemical Sensor for Determination of Various Phenolic Compounds in Wine Samples Using Fe3O4 Nanoparticles Modified Carbon Paste Electrode.

Phenolic compounds contain classes of flavonoids and non-flavonoids, which occur naturally as secondary metabolites in plants. These compounds, when consumed in food substances, improve human health because of their antioxidant properties against oxidative damage diseases. In this study, an electrochemical sensor was developed using a carbon paste electrode (CPE) modified with Fe3O4 nanoparticles (MCPE) for the electrosensitive determination of sinapic acid, syringic acid, and rutin. The characterization techniques adapted for CPE, MCPE electrodes, and the solution interface were cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS). Scan rate and pH were the parameters subjected to optimization studies for the determination of phenolic compounds. The incorporation of Fe3O4 nanoparticles to the CPE as a sensor showed excellent sensitivity, selectivity, repeatability, reproducibility, stability, and low preparation cost. The limits of detection (LOD) obtained were 2.2 × 10-7 M for sinapic acid, 2.6 × 10-7 M for syringic acid, and 0.8 × 10-7 M for rutin, respectively. The fabricated electrochemical sensor was applied to determine phenolic compounds in real samples of red and white wine.

Investigation of the effect of sodium nitrite on protein oxidation markers in food protein suspensions.

The aim of this study is to investigate the effect of sodium nitrite (NaNO2 ) on protein oxidation and the use of 3-nitrotyrosine (3NT) as a protein oxidation marker in suspensions of the food protein. Food proteins, namely bovine serum albumin, casein, and myofibrillar protein, were suspended in 100 mM sodium phosphate buffer and nitrated with 25 µM iron (III) chloride, 2.5 mM hydrogen peroxide, and 150 mg/kg NaNO2 at 37°C for a period of 24 hr. The food protein suspensions were analyzed at different sampling periods for the loss of tryptophan (TRY) residues as well as the formation of Schiff bases (SBs), protein carbonyls, 3NT, and dityrosine (DT). It was found that NaNO2 has pro-oxidant activity in NaNO2 -added food protein suspensions due to the increased amounts of SBs, protein carbonyls, 3NT, and DT as well as decreased TRY fluorescence. Positive correlations between the 3NT and other protein oxidation markers except for TRY fluorescence were found in NaNO2 -added food protein suspensions. In conclusion, these findings on the detection of 3NT indicate that it might be a useful tool as a new protein oxidation biomarker in food samples. PRACTICAL APPLICATIONS: Sodium nitrite (NaNO2 ) supports protein oxidation in different food protein suspension. 3-nitrotyrosine (3NT) was found in food protein suspensions and can be a potential biomarker for protein nitration in food sample due to potential relationship between 3NT and other oxidation markers. The results showed that this study has formed novel insight into interaction between NaNO2 and food proteins and indicate that it might affect the food quality and its nutritional value. Moreover, the relationship between protein oxidation/nitration and food quality as well as the comprehension of the scientific and technological meaning of these phenomena has been hindered because of the lack of knowledge about the basic chemistry behind the protein oxidation and nitration pathways. For the clarification of these phenomena, further studies are still needed.

Protein oxidation and in vitro digestibility of heat-treated fermented sausages: How do they change with the effect of lipid formulation during processing?

In the present work, it was aimed to evaluate the oxidative stress indicators and in vitro digestibility during the processing of heat-treated Turkish sausages (sucuk) manufactured using different lipid formulations. The utilization of olive oil in sausage formulations had considerable impacts on proximate composition, pH, and water activity. The increased olive oil content increased primary lipid oxidation products, whereas it decreased the secondary ones. The use of olive oil increased the total carbonyl content, while it decreased the α-aminoadipic semialdehyde concentration. In general, pepsin, trypsin, and α-chymotrypsin activities of the treatments were similar to each other. The heat treatment during the processing significantly increased most of the oxidation markers. Though strong correlations were recorded between specific oxidation markers, no relationship was detected between oxidation parameters and in vitro digestibility. The results indicated that the lipid formulation and processing operations had significant impact on chemical and functional properties of heat-treated fermented sausages, within the complex interrelationships between oxidation mechanisms. PRACTICAL APPLICATIONS: The present work pointed out the changes and correlations between specific oxidation markers and in vitro digestibility of heat-treated fermented sausages during the production procedure. Oxidation reactions that occur in both proteins and lipids could have drastic impact on overall quality; for this reason, it is of great importance to provide the data for lightening these impacts regarding the product types and production applications. Since heat-treated muscle foods are widely manufactured to meet industrial needs, the data obtained from this research would contribute to understand the effects of formulation and processing operations in the formation of oxidation products and change in digestibility, thereby to pioneer further research on this topic.

Nitration of tyrosine and its effect on DNA hybridization.

One major marker of nitrosative stress is the formation of 3-Nitrotyrosine (3-NT) from Tyrosine (Tyr) by adding a nitro group (-NO2) with nitrating agents. Nitration of Tyr often causes loss of protein activity and is linked with many diseases. In this article, we detect 3-NT and discriminate it from Tyr with Differential Pulse Voltammetry (DPV) as it is a very important biomarker. We first examined redox (oxidation/reduction) properties and stability of 3-NT in detail. Second, we provided the Tyr and 3-NT discrimination with DPV and compared with the chromatography. We then explored the interaction of 3-NT and DNA oligonucleotides. Our findings demonstrate that 3-NT can be used as a new electrochemical indicator, which is able to detect hybridization of probe (single stranded DNA-ssDNA) and hybrid (double stranded DNA-dsDNA) both via 3-NT reduction and guanine oxidation signal changes at the same time. The signal differences enabled us to distinguish ssDNA and dsDNA without using a label or a tag. Moreover, we achieved to detect hybridization of DNA by using the reduction signal of 3-NT obtained at -0.4V vs. Ag/AgCl. More importantly, we observed the changes of the reduction signals of 3-NT after the interaction of probe and hybrid sequences. We showed that 3-NT signal decreases more with hybrid than the probe. Our platform, for the first time, demonstrates the detection of hybridization both guanine oxidation and indicator reduction signal changes at the same time. Moreover, we, for the first time, demonstrated the interaction between 3-NT and DNA.

Determination of 3-nitrotyrosine in food protein suspensions.

To explain the formation of protein nitration marker, 3 nitrotyrosine (3NT), in food products was the basis for the present study. For the accurate detection as protein nitration marker of 3NT in food products, i) a new method was improved, which is optimized parameters affected the formation of 3NT, ii) HPLC-DAD was applied as a straightforward and rapid methodology and iii) finally the suspensions representing meat and dairy products were prepared and this method was used to these suspensions to evaluate the convenience of it. For comparative purposes, the spectrophotometric method of the determination of 3NT level was also employed to assess the 3NT level. The results showed that optimized method enabled detection of 3NT level in food systems and 3NT could act as a protein nitration biomarker in food. This study will shed light on the understanding of precise mechanisms about protein nitration and contribute to the change of amino acids during processing and storage.

Effect of food processing on the physicochemical properties of dietary fibre.

Products derived from the manufacturing or processing of plant based foods: cereals, fruits, vegetables, as well as algae, are sources of abundant dietary fibre. Diets high in dietary fibre have been associated with the reduced risk of cardiovascular disease, diabetes, hypertension, obesity, and gastrointestinal disorders. These fibre-rich products and byproducts can also fortify foods, increase their dietary fibre content and result in healthy products, low in calories, cholesterol and fat. Traditionally, consumers have chosen foods such as whole grains, fruits and vegetables as sources of dietary fibre. Recently, food manufacturers have responded to consumer demand for foods with a higher fibre content by developing products in which highfibre ingredients are used. Different food processing methods also increase the dietary fiber content of food. Moreover, its chemical and physical properties may be affected by food processing. Some of them might even improve the functionality of fibre. Therefore, they may also be applied as functional ingredients to improve physical properties like the physical and structural properties of hydration, oil-holding capacity, viscosity. This study was conducted to examine the effect of different food processing methods on the physicochemical properties of dietary fibre.