Hydromagnetic non‐Newtonian nanofluid transport phenomena from an isothermal vertical cone with partial slip: Aerospace nanomaterial enrobing simulation

In this article, the combined magneto‐hydrodynamic heat, momentum, and mass (species) transfer in external boundary layer flow of Casson nanofluid from a vertical cone surface with convective conditions under an applied magnetic field is studied theoretically. The effects of Brownian motion and thermophoresis are incorporated in the model in the presence of both heat and nanoparticle mass transfer convective conditions. The governing partial differential equations (PDEs) are transformed into highly nonlinear, coupled, multidegree, nonsimilar PDEs consisting of the momentum, energy, and concentration equations via appropriate nonsimilarity transformations. These transformed conservation equations are solved subject to appropriate boundary conditions with a second‐order, accurate finite difference method of the implicit type. The influences of the emerging parameters, that is, magnetic parameter (M), Casson fluid parameter (β), Brownian motion parameter (Nb), thermophoresis parameter (Nt), Lewis number (Le), Prandtl number (Pr), velocity slip (S_f) and thermal slip (S_T) on velocity, temperature, and nanoparticle concentration distributions is illustrated graphically and interpreted at length. Validation of solutions with a Nakamura tridiagonal method has been included. The study is relevant to enrobing processes for electrically conductive nanomaterials, of potential use in aerospace and other industries.     

Stability of microencapsulated Lactobacillus acidophilus and Lactococcus lactis ssp. cremoris during storage at room temperature at low aw

The effect of freeze drying or spray drying, the use of desiccants to maintain the low a_w and the period of storage (at 25 °C) of Lactobacillus acidophilus and Lactococcus lactis ssp. cremoris on survival, acid tolerance, bile tolerance, retention of surface hydrophobicity and retention of β-galactosidase was studied; an estimation of the maximum storage period was also carried out. Sodium caseinate, vegetable oil, glucose, mannitol and fructooligosaccharides were used as protectant of L. acidophilus and L. cremoris during freeze drying or spray drying and during subsequent storage. NaOH, LiCl and silica gel were used as desiccants during 10 weeks of storage of microencapsulated L. acidophilus and L. cremoris kept in an aluminum foil pouch. The results showed that mainly freeze dried L. acidophilus and L. cremoris kept in foil pouch containing NaOH (a_w 0.07) or LiCl (a_w 0.1) showed higher survival (89–94%) than spray dried bacteria kept under the same conditions (86–90%) after 10 weeks of storage (P = 0.0005). Similar results were also showed by acid tolerance, bile tolerance and surface hydrophobicity of freeze-dried or spray-dried L. acidophilus and L. cremoris. Silica gel was less effective in protecting the functional properties of microencapsulated L. acidophilus or L. cremoris with percentage of survival between 81 and 87% at week 10 of the storage. However, retention of β-galactosidase was only influenced by a_w adjusted by desiccators (P < 0.05). Based on forecasting using linear regression, the predicted storage period for freeze dried L. acidophilus, spray dried L. acidophilus and freeze dried L. cremoris kept in foil pouch containing NaOH would be 46, 42 and 42 weeks, respectively; while spray dried L. cremoris under LiCl desiccant would require 39 weeks to achieve minimum required bacterial population of 10⁷ CFU/g.     

Antioxidant and anticancer activities of high pressure-assisted extract of longan (Dimocarpus longan Lour.) fruit pericarp

Longan fruit pericarp was extracted with 50% ethanol employing high pressure (500 MPa) and conventional extraction methods. Total phenolic contents of high pressure-assisted extract of longan (HPEL) and conventional extract of longan (CEL) were 20.8 and 14.6 mg gallic acid equivalents/g dry weight, respectively. Subsequently, the antioxidant activities of these extracts were analyzed employing various antioxidant model systems including 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, superoxide anion radical scavenging activity, total antioxidant capacity, and lipid peroxidation inhibitory activity. In addition, anticancer activity was also tested using HepG2, A549, and SGC 7901 cancer cell lines. HPEL showed excellent antioxidant and anticancer activities and were higher than CEL. Three phenolic compounds, namely gallic acid, corilagin, and ellagic acid, were identified and quantified by external standard methods. Compared with CEL, HPEL exhibited higher extraction effectiveness in terms of higher extraction yield, higher phenolic content, and higher antioxidant and anticancer activity with shorter extraction time.

Industrial relevance

This study was focused to evaluate the antioxidant and anticancer activity of longan fruit pericarp by high-pressure treatment. The high-pressure treatment provided a better way of utilizing longan fruit pericarp as a readily accessible source of the natural anticancer and antioxidant in food and pharmaceutical industry.     

Sulfonation and Antioxidative Evaluation of Polysaccharides from Pleurotus Mushroom and Streptococcus thermophilus Bacteria: A Review

Human beings are equipped with antioxidant defense systems to neutralize free radicals as free radicals could damage macromolecules, subsequently resulting in serious diseases. Researchers have been attracted to search for potential natural antioxidants to reduce oxidative damage. Pleurotus and Streptococcus thermophilus have been chosen as sources of sustainable bioactive compounds that have been consumed for thousands of years. Polysaccharides are important bioactive components produced by Pleurotus mushrooms and Streptococcus thermophilus bacteria. Additionally, there is a continued interest in sulfonation of crude polysaccharides from both sources, since sulfonation has been found to improve or create new bioactive properties in polysaccharides. Both crude and sulfated polysaccharides with good antioxidant capacities have great potential for the further development as commercial products. This review focuses on characterization, sulfonation methods, and antioxidant capacity evaluations of polysaccharides from Pleurotus and S. thermophilus. Common antioxidant capacity assays, including the mechanisms underlying each assay, and various experimental procedures are also discussed.     

Structures and properties of hydroentangled nonwovens: effect of number of manifolds

Hydroentangling is a process in which fibers are entangled by impinging of a curtain of high-speed water jets to form mechanically strong, soft, and textile-like fabrics. Hydroentangled nonwovens are finding a gamut of applications without knowing the entangling mechanisms. In most applications, hydroentangling is carried out using multiple manifolds. This study focuses on the formation of hydroentangled web structures with multiple manifolds and their properties. The 3D analysis revealed the internal structures of hydroentangled nonwovens disclosing formation of fiber loops at jet impact regions. We also report changes of fiber orientations and fiber interlocking within web structures in nonwovens hydroentanged with multiple manifolds.     

Effect of methylation on the structure and radical scavenging activity of polysaccharides from longan (Dimocarpus longan Lour.) fruit pericarp

Polysaccharides of longan fruit pericarp (PLFP) were purified by gel filtration chromatography and methylated by methyl iodide. The structure of methylated PLFP was identified by gas chromatography/mass spectrometry. The results indicated that the percentages of methylated Ara, Glc and Gal increased gradually to a maximal value with increasing volume of methyl iodide. Methylation resulted in a decrease in the DPPH radical scavenging activity of PLFP, while the superoxide anion radical scavenging activity of PLFP decreased with increasing the degree of methylation. When the degree of methylation reached up to 47.4% or a higher value, a promoted effect on the generation of superoxide anion was observed. Furthermore, a high correlation coefficient between degree of methylation and superoxide anion radical scavenging activity of PLFP was determined, which indicated the important role of hydroxyl groups of monosaccharide units in the radical scavenging activity of PLFP.     

Identification of phenolic compounds and appraisal of antioxidant and antityrosinase activities from litchi (Litchi sinensis Sonn.) seeds

Antioxidant and antitryrosinase compounds from Litchi sinensis Sonn. seeds were extracted with five different types of polar solvents. The five extracts, namely ethanol extract (EE), 50% ethanol extract (50% EE), methanol extract (ME), 50% methanol extract (50% ME), and water extract (WE), were used for the evaluations of total phenolic content, antioxidant capabilities and antityrosinase activity. The 50% EE showed the highest total antioxidant capacity, scavenging the 1,1-diphenyl-2-picryl hydrazyl (DPPH) radical and inhibitory activity against lipid peroxidation, and it was comparable to the activity of the synthetic antioxidant, butylated hydroxyl toluene. Fifty percent EE showed a better antityrosinase activity compared to the other extracts. After application of reverse phase high performance liquid chromatography, coupled to a diode array detector and electrospray ionisation mass spectra, five phenolic compounds, namely, gallic acid, procyanidin B2, (−)-gallocatechin, (−)-epicatechin and (−)-epicatechin-3-gallate were identified from 50% EE. This study suggests that litchi seed can potentially be used as a readily accessible source of natural antioxidants.     

Fermentation of Allium chinense Bulbs With Lactobacillus plantarum ZDY 2013 Shows Enhanced Biofunctionalities,and Nutritional and Chemical Properties

In this study, fermentation of Allium chinense bulbs was carried out with Lactobacillus plantarum ZDY 2013. A decrease in pH from 6.8 to 3.5 and a stable lactic acid bacteria population were observed during 7‐d fermentation. The total phenolic content increased by 2.7‐fold in the aqueous and ethanol extracts of A. chinense bulbs after fermentation. Antioxidant capacity including 2,2‐diphenyl‐1‐picrylhydrazyl radical‐scavenging effect and reducing power of both extracts was significantly (P < 0.05) improved after fermentation. Antagonistic test against 6 pathogens showed that fermentation significantly (P < 0.05) enhanced the antimicrobial activity in both extracts of fermented bulbs, especially in the ethanol extracts of fermented bulbs against L. monocytogenes. Analysis of the free amino acid (FAA) profile by ion‐exchange chromatography revealed that fermentation significantly (P < 0.05) increased total FAA content. In addition, among 27 kinds of volatile components analyzed by headspace–solid phase microextraction–gas chromatography–tandem mass spectrometry, sulfur‐containing compounds accounted for 65.23%, but decreased to 43.65% after fermentation. Our results suggested that fermentation of A. chinense bulbs with L. plantarum could improve their biofunctionalities, and nutritional and chemical properties.     

Sulfonation of Lactobacillus plantarum WLPL04 exopolysaccharide amplifies its antioxidant activities in vitro and in a Caco-2 cell model

Exopolysaccharide (EPS) of Lactobacillus plantarum WLPL04 and its sulfated EPS were systematically investigated for their antioxidant activities and effects on protecting the oxidative damage of Caco-2 cells from H₂O₂. Exopolysaccharide was successfully sulfonated from purified EPS as confirmed by Fourier-transform infrared spectroscopy, and the degree of sulfonation was 0.30. Both EPS and sulfated EPS showed antioxidant activities in vitro determined by 1,1-diphenyl-2-picrylhydrazyl, superoxide, and hydroxyl radical scavenging tests, and those activities of sulfated EPS were significantly enhanced at 1,000 μg/mL. Cell viabilities of Caco-2 in the range of 1 to 100 μg/mL of EPS and sulfated EPS showed no significant difference. In H₂O₂-damaged Caco-2 cells models, EPS and sulfated EPS significantly inhibited the enhancement of reactive oxygen species and malondialdehyde levels, and sulfated EPS enhanced the effects by 40.86% and 61.11% when compared with the purified EPS at the same concentration of 100 μg/mL, respectively. For the activities of antioxidant-related enzymes (superoxide dismutase, catalase, and glutathione peroxidase) and expression of genes (SOD2, GPX2, MT1M) on Caco-2 cells, strong protection abilities against the oxidative stress were displayed from both EPS and sulfated EPS, and sulfated EPS exhibited significant enhancement as compared with either EPS or control groups. In summary, sulfonation is an effective strategy for improving the antioxidant activities of EPS from L. plantarum WLPL04 in vitro and on Caco-2 cells.     

Carotenoids and antioxidant capacities from Canarium odontophyllum Miq. fruit

Carotenoids were isolated and identified from peel, pulp and seed fractions of Canarium odontophyllum Miq., and their antioxidant capacities were evaluated. all-trans-β-carotene was present in a large amount in peel (69.5 ± 1.0 mg/kg), followed by pulp (31.1 ± 0.76 mg/kg) and seed (15.1 ± 3.0 mg/kg). Additionally, 15-cis-β-carotene, 9-cis-β-carotene and 13-cis-β-carotenes were also major contributors to carotenoid contents in peel, pulp and seed fractions. Pulp exhibited excellent β-carotene bleaching activity, significantly higher than peel and seed; high 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity, whereas peel exhibited significantly higher scavenging activity of 2,2’-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) radicals. All the extracts exhibited good inhibitory effect against hydrogen peroxide-induced haemoglobin oxidation, ranging from 45.3 to 59.7%. This is the first report about carotenoids and antioxidant capacities from C. odontophyllum fruit, and indicates that this fruit can be explored and promoted as a potential source of natural antioxidants.