Ultrasound as an alternative method to increase the extraction yield from chicken mecanically separated meatresidue collagen.

The residue from chicken mechanically separated meat (MSM) is a potential source for the extraction of collagen. However, this process requires the removal of many covalent crosslinks, which makes it quite complex. Ultrasound has been successfully used to extract collagen; it reduces the process time and increases the yield. However, information regarding the effects of this treatment on the structural and functional properties of proteins is still very limited. Therefore, the aims of the present study were to obtain collagen from chicken MSM residue and to test the effects of pre-treatment with ultrasonic probe and enzymatic extraction with pepsin in its yield, as well as to evaluate the properties of extracted collagen using gel electrophoresis, Fourier-transform infrared spectroscopy, solubility, and differential scanning calorimetry. Both the ultrasound and the enzymatic extraction had a positive effect on the extraction yield of collagen from chicken MSM residue without affecting its integrity. Using ultrasound led to an increase of up to 40% in yield when compared to treatments without ultrasound application. Five extraction treatments were considered. The extracted collagen exhibited high thermal stability (43.9-47.0 °C) and mainly type I structure. The use of ultrasound as pre-treatment, together with enzymatic extraction with pepsin, were effective in increasing the extraction yield of collagen from chicken MSM residue, as well as preserving the triple helical structure of the native collagen.

Staining Power of Natural and Artificial Dyes after At-home Dental Bleaching.

INTRODUCTION: Bleached enamel surfaces may undergo changes and retain more dye, which is a reason to recommend the reduction/suspension of foods with dyes during dental bleaching. AIM: Evaluate the effects of the action of natural and artificial dyes on the bleached enamel of extracted human teeth. MATERIALS AND METHODS: Fifty human premolars were used, which were distributed in 5 groups (n = 10) according to the following staining solutions: GW (distilled water); GB (beet); Gca (caramel); GC (carmine); and GR (red 40). After the removal of the root and pulp section, the teeth were embedded in acrylic resin blocks, stored in artificial saliva, and kept at 37°C. At-home bleaching was performed using 16% carbamide peroxide (CP) for 3 hours daily for 3 weeks. After each daily session of bleaching, the specimens were exposed to the dye solution twice a day for 5 min; one of these exposures was performed immediately after bleaching. The color was recorded using a spectrophotometer according to the CIE Lab system (Δ E) for the following periods: baseline, during bleaching (after 1st, 2nd, and 3rd week) and post-bleaching (after 1 week and 1 month). The color was evaluated by two-way analysis of variance and Tukey's test (α=0.05). RESULTS: There was effective dental bleaching for all groups: GW (18.5 ± 6.1), GB (19.9 ± 4.4), Gca (18.9 ± 6.1), GC (20.2 ± 4.6), and GR (19.3 ± 4.2), p <0.01. No color rebound was observed after 1 week and 1 month (p >0.05). CONCLUSION: The exposure to beet, carmine, caramel, and red 40 dyes did not interfere with the effectiveness of dental bleaching using 16% CP. CLINICAL SIGNIFICANCE: Dyes consumption during bleaching did not affect the effectiveness of dental bleaching.

Effect of cryoconcentration process on phenolic compounds and antioxidant activity in apple juice.

BACKGROUND: Freeze concentration is an alternative process where bioactive compounds are preserved during the processing of juice concentrates. This study proposed a simple and cheaper cryoconcentration process assisted by centrifugation in apple juice. RESULTS: The levels of phenolics increased significantly (P < 0.05) with each freeze concentration cycle that was performed. Furthermore, the process resulted in an average increase in the concentration of phenolics of 1.9, 2.9 and 3.8 times for the first, second and third steps of the concentration, respectively. In relation to phenolics, the antioxidant potential, which was evaluated by radical scavenging activity and reduction power, also increased with the cryoconcentration steps. The influence of the phenolics on the in vitro antioxidant activity was confirmed by a significant correlation between the antioxidant assays and total phenolics, flavonoids, flavan-3-ols, and flavonols (r > 0.70). CONCLUSION: The increase in antioxidant activity may have been attributed to the increase in the phenolic compounds in the apple juices because of the cryoconcentration process. Therefore, this could be an excellent natural product to supplement and enrich blends, juices, ciders, smoothies, and jams in order to improve the sensorial, nutritional and antioxidant properties. © 2018 Society of Chemical Industry.

Nanocrystalline cellulose extracted from pine wood and corncob.

The extraction of nanocrystalline cellulose from agro-residues is an interesting alternative to recover these materials. In the present study, nanocrystalline cellulose was extracted from pine wood and corncob. In addition, microcrystalline cellulose was used as a reference to compare results. Initially, the lignocellulosic residues were submitted to delignification pre-treatments. At the end of the process, the bleached fibre was submitted to acid hydrolysis. Additionally, microparticles were obtained from the spray-drying of the nanocrystalline cellulose suspensions. The nanocrystalline cellulose yield for the pine wood was 9.0-% of the value attained for the microcrystalline cellulose. For the corncob, the value was 23.5-%. Therefore, complementary studies are necessary to improve the yield. The spray-dried microparticles showed a crystallinity index of 67.8-% for the pine wood, 70.9-% for the corncob and 79.3-% for the microcrystalline cellulose. These microparticles have great potential for use in the production of polymer composites processed by extrusion.

GST activity and membrane lipid saturation prevents mesotrione-induced cellular damage in Pantoea ananatis.

Callisto(®), containing the active ingredient mesotrione (2-[4-methylsulfonyl-2-nitrobenzoyl]1,3-cyclohenanedione), is a selective herbicide that controls weeds in corn crops and is a potential environmental contaminant. The objective of this work was to evaluate enzymatic and structural changes in Pantoea ananatis, a strain isolated from water, in response to exposure to this herbicide. Despite degradation of mesotrione, probably due a glutathione-S-transferase (GST) pathway in Pantoea ananatis, this herbicide induced oxidative stress by increasing hydrogen peroxide production. Thiol fragments, eventually produced after mesotrione degradation, could be involved in increased GST activity. Nevertheless, there was no peroxidation damage related to this production, as malondialdehyde (MDA) synthesis, which is due to lipid peroxidation, was highest in the controls, followed by the mesotrione- and Callisto(®)-treated cultures at log growth phase. Therefore, P. ananatis can tolerate and grow in the presence of the herbicide, probably due an efficient control of oxidative stress by a polymorphic catalase system. MDA rates depend on lipid saturation due to a pattern change to a higher level of saturation. These changes are likely related to the formation of GST-mesotrione conjugates and mesotrione degradation-specific metabolites and to the presence of cytotoxic adjuvants. These features may shift lipid membrane saturation, possibly providing a protective effect to bacteria through an increase in membrane impermeability. This response system in P. ananatis provides a novel model for bacterial herbicide tolerance and adaptation in the environment.

Chemical characterisation and application of acid whey in fermented milk.

Acid whey is a by-product from cheese processing that can be employed in beverage formulations due to its high nutritional quality. The objective of the present work was to study the physicochemical characterisation of acid whey from Petit Suisse-type cheese production and use this by-product in the formulation of fermented milk, substituting water. In addition, a reduction in the fermentation period was tested. Both the final product and the acid whey were analysed considering physicochemical determinations, and the fermented milk was evaluated by means of sensory analysis, including multiple comparison and acceptance tests, as well as purchase intention. The results of the physicochemical analyses showed that whey which was produced during both winter and summer presented higher values of protein (1.22 and 0.97 %, w/v, respectively), but there were no differences in lactose content. During the autumn, the highest solid extract was found in whey (6.00 %, w/v), with larger amounts of lactose (4.73 %, w/v) and ash (0.83 %, w/v). When analysing the fermented milk produced with added acid whey, the acceptance test resulted in 90 % of acceptance; the purchase intention showed that 54 % of the consumers would 'certainly buy' and 38 % would 'probably buy' the product. Using acid whey in a fermented milk formulation was technically viable, allowing by-product value aggregation, avoiding discharge, lowering water consumption and shortening the fermentation period.

Mechanisms of tolerance and high degradation capacity of the herbicide mesotrione by Escherichia coli strain DH5-α.

The intensive use of agrochemicals has played an important role in increasing agricultural production. One of the impacts of agrochemical use has been changes in population structure of soil microbiota. The aim of this work was to analyze the adaptive strategies that bacteria use to overcome oxidative stress caused by mesotrione, which inhibits 4-hydroxyphenylpyruvate dioxygenase. We also examined antioxidative stress systems, saturation changes of lipid membranes, and the capacity of bacteria to degrade mesotrione. Escherichia coli DH5-á was chosen as a non-environmental strain, which is already a model bacterium for studying metabolism and adaptation. The results showed that this bacterium was able to tolerate high doses of the herbicide (10× field rate), and completely degraded mesotrione after 3 h of exposure, as determined by a High Performance Liquid Chromatography. Growth rates in the presence of mesotrione were lower than in the control, prior to the period of degradation, showing toxic effects of this herbicide on bacterial cells. Changes in the saturation of the membrane lipids reduced the damage caused by reactive oxygen species and possibly hindered the entry of xenobiotics in the cell, while activating glutathione-S-transferase enzyme in the antioxidant system and in the metabolizing process of the herbicide. Considering that E. coli DH5-α is a non-environmental strain and it had no previous contact with mesotrione, the defense system found in this strain could be considered non-specific. This bacterium system response may be a general adaptation mechanism by which bacterial strains resist to damage from the presence of herbicides in agricultural soils.