Microencapsulation of Propolis in Protein Matrix Using Spray Drying for Application in Food Systems

Propolis presents several health benefits due to the presence of bioactive compounds, mainly phenolic compounds; however, its application in food is limited due to undesirable odor and low water solubility. The bioactive compounds are usually susceptible to degradation by exposure to light, heat, or oxygen or by interaction with other compounds, which may limit its biological activity. The study aimed the propolis extract microencapsulation using rice, pea, soybean, and ovoalbumin proteins as wall material by spray drying and to analyze their in vitro digestion. The propolis extract presented a high concentration of apigenin. Encapsulation efficiency was greater than 70%, and it was maintained the antioxidant activity of propolis (88% inhibition of DPPH for propolis extract and >?73% for the microparticles). The DSC, ATR-FTIR, and X-ray diffraction techniques confirmed the encapsulation. The microparticles showed different shapes, sizes, and physical characteristics. The microparticles encapsulated with pea protein could be used in formulations of Minas Frescal cheese due to the controlled released, whereas the other microparticles could be used in pudding formulations.     

Modeling,simulation, and optimization of a microalgae biomass drying process

The aim of the present work was to develop a transient mathematical model focused on microalgae biomass drying, considering two phases: solid (wet biomass) and gas (drying air). Mass and thermal energy balances were written for each phase producing a system of ordinary differential equations (ODE). The solution of the ODE set delivers the temperature and air humidity ratio and biomass profiles with respect to time. The numerical results were directly compared with temperature experimental measurements—for both phases—and with the biomass humidity content. Data from experiment 1 were used to carry out the mathematical model adjustment, whereas data from experiment 2 were used for the experimental validation of the model. The model was adjusted by proposing a new correlation for the mass transfer coefficient and by calibrating the heat transfer coefficient. The transient numerical results were in good quantitative and qualitative agreement with the experimental results, ie, within the experimental error bars. Then the experimentally validated mathematical model was utilized to optimize the following parameters: (i) the electric heater power ( ) and the dry air mass flow rate ( ) and (ii) the convection oven length to width ratio (L/W). The goal was to minimize system energy consumption (objective function). The optimization procedure was subject to the following physical constraints: (i) fixed convection oven total volume and (ii) fixed biomass and drying air contact surface area. For the oven original geometry,  = 3.0 kW and  = 9 g s^?1 were numerically found for minimum energy consumption, so that 36.9% and 43.5% energy consumption decreases were obtained, respectively, in comparison with the measurements of experiment 1. Next, the numerical geometric optimization found (L/W)_opt = 9, with and , which was capable to reach a 51.6% energy consumption reduction in comparison with the original system tested in experiment 1. The novelty of this work consists of the development and experimental validation of a physically based microalgae biomass drying mathematical model, ie, instead of using empirical correlations to predict the drying time and temperature profiles and then minimize system energy consumption. Therefore, the results show that it is reasonable to state that the model could be used to design, control, and optimize drying systems with configurations similar to the one analyzed in this study.     

The Bark Beetle Dendroctonus rhizophagus (Curculionidae: Scolytinae) Has Digestive Capacity to Degrade Complex Substrates: Functional Characterization and Heterologous Expression of an α-Amylase

Dendroctonus-bark beetles are natural agents contributing to vital processes in coniferous forests, such as regeneration, succession, and material recycling, as they colonize and kill damaged, stressed, or old pine trees. These beetles spend most of their life cycle under stem and roots bark where they breed, develop, and feed on phloem. This tissue is rich in essential nutrients and complex molecules such as starch, cellulose, hemicellulose, and lignin, which apparently are not available for these beetles. We evaluated the digestive capacity of Dendroctonus rhizophagus to hydrolyze starch. Our aim was to identify α-amylases and characterize them both molecularly and biochemically. The findings showed that D. rhizophagus has an α-amylase gene (AmyDr) with a single isoform, and ORF of 1452 bp encoding a 483-amino acid protein (53.15 kDa) with a predicted signal peptide of 16 amino acids. AmyDr has a mutation in the chlorine-binding site, present in other phytophagous insects and in a marine bacterium. Docking analysis showed that AmyDr presents a higher binding affinity to amylopectin compared to amylose, and an affinity binding equally stable to calcium, chlorine, and nitrate ions. AmyDr native protein showed amylolytic activity in the head-pronotum and gut, and its recombinant protein, a polypeptide of ~53 kDa, showed conformational stability, and its activity is maintained both in the presence and absence of chlorine and nitrate ions. The AmyDr gene showed a differential expression significantly higher in the gut than the head-pronotum, indicating that starch hydrolysis occurs mainly in the midgut. An overview of the AmyDr gene expression suggests that the amylolytic activity is regulated through the developmental stages of this bark beetle and associated with starch availability in the host tree.     

Spray-dried solid dispersions containing ferulic acid: comparative analysis of three carriers,in vitro dissolution,antioxidant potential and in vivo anti-platelet effect

This article aimed to improve the relative solubility and dissolution rate of ferulic acid (FA) by the use of spray-dried solid dispersions (SDs) in order to ensure its in vitro antioxidant potential and to enhance its in vivo anti-platelet effect. These SDs were prepared by spray-drying at 10 and 20% of drug concentration using polyvinylpyrrolidone K30 (PVP-K30), polyethylene glycol 6000 (PEG 6000) and poloxamer-188 (PLX-188) as carriers. SDs and physical mixtures (PM) were characterized by SEM, XRPD, FTIR spectroscopy and TGA analysis. Spray-dried SDs containing FA were successfully obtained. Relative solubility of FA was improved with increasing carrier concentration. PVP-K30 and PEG 6000 formulations showed suitable drug content values close to 100%, whereas PLX-188 presented mean values between 70 and 90%. Agglomerates were observed depending on the carrier used. XRPD patterns and thermograms indicated that spray-drying led to drug amorphization and provided appropriate thermal stability, respectively. FTIR spectra demonstrated no remarkable interaction between carrier and drug for PEG 6000 and PLX-188 SDs. PVP-K30 formulations had changes in FTIR spectra, which denoted intermolecular O–H???O?=?C bonds. Spray-dried SDs played an important role in enhancing dissolution rate of FA when compared to pure drug. The free radical-scavenging assay confirmed that the antioxidant activity of PEG 6000 10% SDs was kept. This formulation also provided a statistically increased in vivo anti-platelet effect compared to pure drug. In summary, these formulations enhanced relative solubility and dissolution rate of FA and chosen formulation demonstrated suitable in vitro antioxidant activity and improved in vivo anti-platelet effect.     

Ozonated Mineral Oil: Preparation,Characterization and Evaluation of the Microbicidal Activity

The ozonation of vegetable oils has been studied, since the produced ointments have antibacterial and fungicidal activities. However, the ozonation of mineral oils has not been reported in the literature yet, opening an interesting field for examination. In this work, we have shown the ozonation of a commercial mineral oil (Nujol). The main goal was to produce oils containing free ozone, so that this gas could act as antimicrobial agent. It was found that in Nujol, ozone remains for at least 40 days and in the sample ozonized for 15 h its concentration was 7.5 mg mL^?1. Neat Nujol showed no antimicrobial activity against the tested microorganisms, however, when ozonated it showed antimicrobial activity against Enterococcus faecalis, Staphylococcus aureus and Escherichia coli.     

On the influence of the shear deformation and boundary conditions on the transverse vibration of multi-walled carbon nanotubes

The vibrational properties of multi-walled carbon nanotubes (MWCNTs) are studied, especially the influence of the shear deformation and the boundary conditions on the non-coaxial frequencies. A high order continuum beam model is proposed, which can be applied to study the transverse vibrations of MWCNTs, including those that could have initial deformations due to defects or external actions. Using the model it was found that the non-coaxial intertube frequencies are independent of the shear deformation and the boundary conditions. This result is important considering that the concentric structure of MWCNTs is a crucial geometrical characteristic and a non-coaxial vibration would affect their electronic and optical properties.     

Synthesis and Characterization of Allyl Fatty Acid Derivatives as Reactive Coalescing Agents for Latexes

This work evaluated the use of allyl fatty acid esters derived from vegetable oil (palmitic acid, soybean and sunflower oils) as reactive coalescing agents in a waterborne latex system. Allyl fatty acid derivatives (AFAD) from vegetable oils were synthesized by two different processes. The synthesis was monitored by IR-spectroscopy and the final product characterized by FT-IR, GC–MS, ¹H and ¹³C NMR. The presence of conjugated double bonds in the aliphatic chain was confirmed, which is a determinant for the proposed autoxidative latexes drying mechanism. Each of the AFAD were subsequently added to a standard acrylic emulsion, in order to study its potential as reactive coalescing agent. The minimum film-forming temperature (MFT), glass transition temperature (T _g), drying time and rubbing resistance to solvents were evaluated. The results showed that, when added to water-borne acrylic resins, an AFAD acts as a non-volatile plasticizer capable of autoxidative crosslinking with itself.     

Energy storage and control optimization for an electric vehicle

Two big issues involving electric vehicles are energy supply and power management control. To deal with the energy supply problem, this paper proposes the application of a hybrid energy source system, composed of battery pack and ultracapacitor bank. The power management control between the energy supplies was defined by a fuzzy logic with inference rules optimized through genetic algorithm. The genetic algorithm optimizes lower and upper limits of membership functions aiming to reduce the hybrid energy source system total mass while maximizing the electric vehicle drive range and performance. Through the Pareto frontier, we found the best trade‐off solution.