Effect of thawing under an alternating magnetic field on rainbow trout (Oncorhynchus mykiss) fillet characteristics.

Low thawing rates affects the quality of the product, which necessitates the use of new thawing technologies. In this study, the effect of alternating magnetic field (MF) (1-80 Hz) on the thawing rate, physicochemical properties, protein denaturation, and structure of rainbow trout fillet was studied and compared with refrigerator thawing (RT) (4 °C). Thawing time remarkably decreased in MF thawing as compared to RT. The results revealed that the water holding capacity of RT was significantly lower than that of MF, which was consistent with the results of structural investigation characterized by Scanning electron microscopy. Particle size distribution, Fourier transform infrared spectroscopy, and Differential scanning calorimetry indicated that MF could unfold and aggregate the protein structure at 40 and 80 Hz. The findings of this study indicated the potential of the MF in accelerating the thawing process. However, more studies are needed to clarify all aspects of the process.

Tea pruning litter biochar amendment in soil reduces arsenic, cadmium, and chromium in made tea (Camellia sinensis L.) and tea infusion: A safe drink for tea consumers.

Effect of tea pruning litter biochar (TPLBC) on arsenic (As), cadmium (Cd) and chromium (Cr) content in made tea and successive tea infusions were investigated in a greenhouse experiment with two tea cultivars (TV23 and S.3A/3). Made tea prepared from TV23 and S.3A/3 clone, a decrease in the concentration of As, Cd, and Cr by 36.73%, 16.22%, 13.96%, and 36.63%, 27.78%, 10.54%, respectively over control on the application of the highest dose of TPLBC (500 kg TPLBC ha-1). Irrespective of treatments, studied element concentrations were significantly higher (p ≤ 0.05) in the first infusion and lower in the third. Considering Ten g made tea consumption per person per day, the maximum average daily intakes of As, Cd and Cr in a higher dose of TPLBC were far below the tolerable weekly intake prescribed by the World Health Organization. As hazard quotient values of selected elements were ≪ 1, no significant adverse health consequences are expected for tea consumers.

Targeted and untargeted techniques coupled with chemometric tools for the evaluation of sturgeon (Acipenser gueldenstaedtii) freshness during storage at 4 °C.

The physico-chemical, textural and color parameters and fluorescence spectra of aromatic amino acids and nucleic acids (AAA + NA), tryptophan residues, nicotinamide adenine dinucleotide (NADH) and vitamin A were scanned on sturgeon samples kept at 4 °C up to 12 days. Using the principal component analysis (PCA), the riboflavin and NADH spectra allowed clear differentiation between sturgeon samples according to their storage time. The best result was obtained by applying the common components and specific weights analysis (CCSWA) to the riboflavin and NADH data tables since better differentiation was achieved between the 4 group sturgeon samples aged: 2 days; 5, 6 and 7 days; 8 and 9 days and 12 days. The proposed methodology demonstrates the ability of CCSWA to evaluate sturgeon freshness level according to their storage time.

Characterization of thermo-oxidative behavior of ethylcellulose oleogels.

The thermo-oxidative behavior crucial to the applicability of ethylcellulose (EC) oleogels is characterized. Not only did we take into account the composition of the gel network in relation to textural attributes, but also the dynamic chemical changes occurred during formation, heating, and holding of the gels. EC oleogel oxidative stability showed that at 6.0% EC100 concentration in the oleogels the movement of liquid oil trapped in the gel network was hindered by its high viscosity and stable gel network, thus retarding oxidation. Processing temperature ≤ 120 °C for <2 h was recommended when incorporated in food systems to minimize oxidation. As for the measurement of oxidative stability in general, p-AnV was found suitable in depicting oxidation of EC oleogels. Meanwhile, both Rao and Rad acquired from 1H NMR spectra could serve as reliable oxidative indicators to gauge total oxidation of EC oleogels during storage.

Instability of common beans during storage causes hardening: The role of glass transition phenomena.

Long-term storage of common beans leads to loss of cooking quality and an ill-defined solution, appropriate storage, is recommended. Therefore, the polymer science theory of glasses that hypothesizes stability of a system below its glass transition temperature (Tg) was applied to determine bean stability during storage in relation to cooking behavior. Since composition influences Tg, powders of cotyledons and seed coats in addition to whole beans were equilibrated above different saturated salt solutions in order to generate materials with different moisture contents. A thermal mechanical compression test which measures compressibility changes in a system upon reaching its glass-rubber transition temperature region was conducted to obtain the Tg. A Tg-moisture relation was established, whose relevance was confirmed by storage and cooking experiments which showed development of hard-to-cook in beans stored above Tg but not below it. Therefore, this relation constitutes a stability map for storage of common beans.

Low cost in situ digital image method, based on spot testing and smartphone images, for determination of ascorbic acid in Brazilian Amazon native and exotic fruits.

In this work, we propose a method that employed a smartphone to capture images obtained from a colorimetric spot test to determine ascorbic acid (AA) in Brazilian Amazon native and exotic fruits. The spot test reaction was based on reduction of Fe(III) by AA and further complexation with 1,10-phenanthroline. After optimization, the limit of detection was 8.5 × 10-7 mol L-1. Brazilian Amazon native fruits such as bacuri, cupuaçu, muruci, yellow mombin, as well as others as cashew, mango, orange and passion fruit, were analyzed. In order to determine the accuracy of this method, iodometric titration was used; results were in close agreement with a confidence level of 95% (paired t-test). Moreover, recoveries ranged from 87.1 to 116%. The method is economic, environmentally friendly, and portable, and might useful for small producers and family agriculture businesses unable to afford specialized laboratory analysis in the north region of Brazilian Amazon.

Potentiality of front-face fluorescence and mid-infrared spectroscopies coupled with partial least square regression to predict lipid oxidation in pound cakes during storage.

The potentialities of front-face fluorescence (FFF) and mid-infrared (MIR) spectroscopies coupled with partial least square regression (PLSR) were compared to predict the lipid oxidation of pound cakes. The level of lipid oxidation in pound cakes determined using classical methods showed some changes. Similarly, the fluorescence emission (305-490 nm) and excitation (252-390 nm) spectra and MIR spectra scanned in the 4000-700 cm-1 region showed some changes in pound cakes as a function of both storage time and the type of oil used in the formulation. The application of PLSR to the MIR spectra, provided excellent predictive results for free fatty acid (R2 = 0.97) and peroxide values (R2 = 0.87). Similar results were obtained from both tryptophan and MIR spectra for the prediction of TOTOX (R2 > 0.86) demonstrating the efficiency of the MIR and FFF spectroscopies to qualify and quantify the level of lipid oxidation in pound cakes.

Characterization of lipid oxidation process of beef during repeated freeze-thaw by electron spin resonance technology and Raman spectroscopy.

In this study, electron spin resonance (ESR) and Raman spectroscopy were applied to characterize lipid oxidation of beef during repeated freeze-thaw (RFT). Besides the conventional indexes including peroxide values (PV), thiobarbituric acid-reactive substances (TBARS) and acid values (AV) were evaluated, the radical and molecular structure changes were also measured by ESR and Raman spectroscopy. The results showed that PV, TBARS and AV were increased (P<0.05) after RFT. This suggested that lipid oxidation was occurred during RFT. With the increase of radical signal intensity, lower oxidation stability was presented by ESR. Raman intensity of ν(CC) stretching region (1655cm-1) was decreased during RFT. Furthermore, lower Raman intensity ratio of I1655/I1442, I1655/I1745 that determine total unsaturation was also observed. Significant correlations (p<0.01) were obtained among conventional methods, ESR and Raman spectroscopy. Our result has proved that ESR and Raman spectroscopy showed great potential in characterizing lipid oxidation process of beef during RFT.

Novel nanoliposomal encapsulated omega-3 fatty acids and their applications in food.

The aim of the present research was to evaluate the application, stability and suitability of ω3 polyunsaturated fatty acids (PUFAs) incorporated nanoliposomes in food enrichment. Nanoliposomal ω3 PUFAs was prepared by Mozafari method, and their application in bread and milk was compared with unencapsulated (fish oil) and microencapsulated ω3 PUFAs. Sensory evaluation was conducted to determine the perceptible sensory difference/similarity between control, unencapsulated, microencapsulated, and nanoliposomal ω3 PUFAs enriched foods. Results showed no significant (p=0.11) detectable difference between control and nanoliposomal ω3 PUFAs enriched samples while, samples enriched with unencapsulated or microencapsulated ω3 PUFAs showed significant (p=0.02) fishy flavor. Moreover, significantly (p<0.01) higher ω3 PUFAs % recovery and lower peroxide and anisidine values were observed in nanoliposomal ω3 PUFAs enriched samples in comparison with other samples. In conclusion, an effective and reproducible method for application of ω3 PUFAs in the food system was developed.

Characterization of Lentinus edodes ß-glucan influencing the in vitro starch digestibility of wheat starch gel.

Lentinus edodes ß-glucan (abbreviated LEBG) was prepared from fruiting bodies of Lentinus edodes. The average molecular weight (Mw) and polydispersity index (Mw/Mn) of LEBG were measured to be 1.868×106g/mol and 1.007, respectively. In addition, the monosaccharide composition of LEBG was composed of arabinose, galactose, glucose, xylose, mannose with a molar ratio of 5:11:18:644:16. After adding LEBG, both G' and G″ of starch gel increased. This is mainly because the connecting points between the molecular chains of LEBG and starch formed so that gel network structures were enhanced. The peak temperature in the heat flow diagram shifted to a higher temperature and the peak area of the endothermic enthalpy increased. Furthermore, LEBG can significantly inhibit starch hydrolysis. The predicted glycemic index (pGI) values were reduced when starch was replaced with LEBG at 20% (w/w). It might indicate that LEBG was suitable to develop low GI noodle or bread.

An iodine supplementation of tomato fruits coated with an edible film of the iodide-doped chitosan.

In general, the risk of numerous thyroid cancers inevitably increases among people with iodine deficiencies. An iodide-doped chitosan (CT-I) solution was prepared for dipping tomatoes to coat the fresh surface with an edible film (1.5 µm), thereby providing iodine-rich fruits for daily intake. Characterisation of the thin film was conducted by FTIR and SEM. Stability of the CT-I film was studied via water immersion at various time intervals, and no residual iodide leached out due to intrinsic interactions between the cationic amino group of chitosan and iodide ions. Moreover, the iodide supplement exhibited no effect on the antioxidant activity of tomatoes. The iodine content in the film-coated tomato was determined by ICP-OES. The tomato coating with 1.5% (w/v) CT-I contained approximately 0.4 µg iodide per gram fresh weight. In addition, the freshness and storability of iodine-doped tomatoes were also maintained for shelf-life concerns.

Copper(II) oxide nanoparticles augment antifilarial activity of Albendazole: In vitro synergistic apoptotic impact against filarial parasite Setaria cervi.

Mass treatment of lymphatic filariasis with Albendazole (ABZ), a therapeutic benzimidazole, is fraught with serious limitations such as possible drug resistance and poor macrofilaricidal activity. Therefore, we need to develop new ABZ-based formulations to improve its antifilarial effectiveness. CuO nanoparticles were used as an adjuvant with ABZ to form ABZ-CuO nanocomposite, which was characterized by UV-vis spectroscopy, FT-IR, AFM and SEM. Antifilarial activity of nanocomposite was evaluated using relative motility assay and dye exclusion test in dark and under UV light. ROS generation, antioxidant levels, lipid peroxidation and DNA fragmentation in nanocomposite treated parasites were estimated. Biophysical techniques were employed to ascertain the mode of binding of nanocomposite to parasitic DNA. Nanocomposite increases parasite mortality as compared to ABZ in dark, and its antifilarial effect was increased further under UV light. Elevated ROS production and decline of parasitic-GST and GSH levels were observed in nanocomposite treated worms in dark, and these effects were pronounced further under UV light. Nanocomposite leads to higher DNA fragmentation as compared to ABZ alone. Further, we found that nanocomposite binds parasitic DNA in an intercalative manner where it generates ROS to induce DNA damage. Thus, oxidative stress production due to ROS generation and consequent DNA fragmentation leads to apoptosis in worms. This is the first report supporting CuO nanoparticles as a potential adjuvant with ABZ against filariasis along with enhanced antifilarial activity of nanocomposite under UV light. These findings, thus, indicate that development of ABZ-loaded nanoparticle compounds may serve as promising leads for filariasis treatment.

Xylan-degrading enzymes from Aspergillus terreus: Physicochemical features and functional studies on hydrolysis of cellulose pulp.

Two endo-ß-1,4-xylanases named XylT1 and XylT2, previously purified from Aspergillus terreus, were structurally investigated by fluorescence quenching and characterized with respect to their binding properties with phenolic compounds. Neutral and charged quenchers had access to both enzymes in neutral and alkaline pHs. The greatest access was noted for the negative quencher, possibly due to positive amino acid residues in the vicinity of tryptophan. These tryptophan environments may partially explain the conformational differences and lower binding constants of phenolic compounds for XylT2 than XylT1Phenolic compounds had lower binding constants for XylT2 than XylT1. These results show that xylanases present structural and functional differences, despite belonging to similar families. XylT1 and XylT2 were also evaluated for their ability to hydrolyze cellulose pulp in different stages of bleaching. Both enzymes promoted hydrolysis of cellulose pulps, which was confirmed by the release of total reducing sugars, pentoses and chromophoric material. Analysis of released xylooligosaccharides demonstrated a preferential release of xylobiose. None of xylanases released glucose, showing that they do not hydrolyze the cellulose present in the pulp, making both enzymes excellent choices for bio-bleaching applications.

Modelling and optimising of physicochemical features of walnut-oil beverage emulsions by implementation of response surface methodology: effect of preparation conditions on emulsion stability.

The major purpose of this study is to apply response surface methodology to model and optimise processing conditions for the preparation of beverage emulsions with maximum emulsion stability and viscosity, minimum particle size, turbidity loss rate, size index and peroxide value changes. A three-factor, five-level central composite design was conducted to estimate the effects of three independent variables: ultrasonic time (UT, 5-15 min), walnut-oil content (WO, 4-10% (w/w)) and Span 80 content (S80, 0.55-0.8). The results demonstrated the empirical models were satisfactorily (p < 0.0001) fitted to the experimental data. Evaluation of responses by analysis of variance indicated high coefficient determination values. The overall optimisation of preparation conditions was an UT of 14.630 min, WO content of 8.238% (w/w), and S80 content of 0.782% (w/w). Under this optimum region, responses were found to be 219.198, 99.184, 0.008, 0.008, 2.43 and 16.65 for particle size, emulsion stability, turbidity loss rate, size index, viscosity and peroxide value changes, respectively.