The Effect of Ultrasound on the Extraction and Functionality of Proteins from Duckweed (Lemna minor).

The inclusion of protein in the regular human diet is important for the prevention of several chronic diseases. In the search for novel alternative protein sources, plant-based proteins are widely explored from a sustainable and ecological point of view. Duckweed (Lemna minor), also known as water lentil, is an aquatic plant with potential applications for human consumption due to its protein content and carbohydrate contents. Among all the conventional and novel protein extraction methods, the utilization of ultrasound has attracted the attention of scientists because of its effects on improving protein extraction and its functionalities. In this work, a Box-Behnken experimental design was proposed to optimize the alkaline extraction of protein from duckweed. In addition, an exploration of the effects of ultrasound on the morphological, structural, and functional properties of the extracted protein was also addressed. The optimal extraction parameters were a pH of 11.5 and an ultrasound amplitude and processing time of 60% and 20 min, respectively. These process conditions doubled the protein content extracted in comparison to the value from the initial duckweed sample. Furthermore, the application of ultrasound during the extraction of protein generated changes in the FTIR spectra, color, and structure of the duckweed protein, which resulted in improvements in its solubility, emulsifying properties, and foaming capacity.

Investigation of the Mechanical Properties of Parts Fabricated with Ultrasonic Micro Injection Molding Process Using Polypropylene Recycled Material.

This research focuses on investigating how physical and mechanical properties of polypropylene (PP) recycled material are modified when ultrasonic micro injection molding (UMIM) technology is used to produce material specimens. Experimental characterization by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), Fourier transform infrared (FTIR) spectra, and rheology tests show that the fabricated PP samples were able to withstand up to five times recycled processing before some signs of mechanical and physical properties degradation are observed. Surprisingly, uniaxial extension tests show an increase of 3.07%, 10.97% and 27.33% for Young's modulus, yield stress and ultimate stress values, respectively, and a slight reduction of 1.29% for the samples elongation at break when compared to the experimental data collected from virgin material samples. The improvement of these mechanical properties in the recycled samples suggests that ultrasonic microinjection produces a mechano-chemical material change.

Investigation of the Effect of Carbonyl Iron Micro-Particles on the Mechanical and Rheological Properties of Isotropic and Anisotropic MREs: Constitutive Magneto-Mechanical Material Model.

This article focuses on evaluating the influence that the addition of carbonyl iron micro-particles (CIPs) and its alignment have on the mechanical and rheological properties for magnetorheological elastomers (MREs) fabricated using polydimethylsiloxane (PDMS) elastomer, and 24 wt % of silicone oil (SO). A solenoid device was designed and built to fabricate the corresponding composite magnetorheological material and to perform uniaxial cyclic tests under uniform magnetic flux density. Furthermore, a constitutive material model that considers both elastic and magnetic effects was introduced to predict stress-softening and permanent set effects experienced by the MRE samples during cyclic loading tests. Moreover, experimental characterizations via Fourier transform infrared (FTIR), X-ray diffraction (XRD), tensile mechanical testing, and rheological tests were performed on the produced MRE samples in order to assess mechanical and rheological material properties such as mechanical strength, material stiffness, Mullins and permanent set effects, damping ratio, stiffness magnetorheological effect (SMR), and relative magnetorheological storage and loss moduli effects. Experimental results and theoretical predictions confirmed that for a CIPs concentration of 70 wt %, the material samples exhibit the highest shear modulus, stress-softening effects, and engineering stress values when the samples are subject to a maximum stretch value of 1.64 and a uniform magnetic flux density of 52.2 mT.

Physicochemical and Functional Properties of Vegetable and Cereal Proteins as Potential Sources of Novel Food Ingredients.

Proteins from vegetable and cereal sources are an excellent alternative to substitute animal-based counterparts because of their reduced cost, abundant supply and good nutritional value. The objective of this investigation is to study a set of vegetable and cereal proteins in terms of physicochemical and functional properties. Twenty protein sources were studied: five soya bean flour samples, one pea flour and fourteen newly developed blends of soya bean and maize germ (five concentrates and nine hydrolysates). The physicochemical characterization included pH (5.63 to 7.57), electrical conductivity (1.32 to 4.32 mS/cm), protein content (20.78 to 94.24% on dry mass basis), free amino nitrogen (0.54 to 2.87 mg/g) and urease activity (0.08 to 2.20). The functional properties showed interesting differences among proteins: water absorption index ranged from 0.41 to 18.52, the highest being of soya and maize concentrates. Nitrogen and water solubility ranged from 10.14 to 74.89% and from 20.42 to 95.65%, respectively. Fat absorption and emulsification activity indices ranged from 2.59 to 4.72 and from 3936.6 to 52 399.2 m2/g respectively, the highest being of pea flour. Foam activity (66.7 to 475.0%) of the soya and maize hydrolysates was the best. Correlation analyses showed that hydrolysis affected solubility-related parameters whereas fat-associated indices were inversely correlated with water-linked parameters. Foam properties were better of proteins treated with low heat, which also had high urease activity. Physicochemical and functional characterization of the soya and maize protein concentrates and hydrolysates allowed the identification of differences regarding other vegetable and cereal protein sources such as pea or soya bean.