Physicochemical and functional properties of cassava flour grown in different locations in Sabah, Malaysia

The tuber of cassava is used as raw materials in the bakery, food, pharmaceutical and garment industries. The nutritional value of cassava roots is important because they are the main part of the plant consumed in developing countries. However, there is much variation in the nutrient quality of the cassava root depends on the several factors, such as geographic location, variety, age of the plant, and environmental conditions. This study was performed to compare and provide information on physicochemical and functional properties of cassava flour planted in two different districts in Sabah, Malaysia, namely Tawau and Semporna. Proximate analysis showed significant differences (p<0.05) in crude protein (2.07 and 2.69%), crude fat (0.55 and 0.68%) and dietary fibre contents (2.38 and 2.09%). Determinations on physicochemical and functional characteristics of the cassava flour showed significant differences (p<0.05) in bulk density (0.57 and 0.79 g/ cm3 ), pH (6.75 and 6.72), colour and foam capacity (3.66 and 7.33%) while there was no significant difference shown in water and oil absorption capacities as well as emulsion capacity. Cassava planted in Semporna was observed to have high values of all pasting property parameters relative to the one planted in Tawau except for the setback viscosity. Gelatinization properties of flours showed significant differences (p<0.05) in onset (70.59 and 68.99°C) and end temperatures (79.81 and 80.03°C)

Physicochemical properties of tarap (Artocarpus adoratisimus) starch

The objective of the research was to investigate the physicochemical characteristics of Tarap fruit starch. In this study, young Tarap fruit starch was extracted and the percentage of total starch, resistant starch, amylose and amylopectin were determined. Scanning electron microscope was used to evaluate the morphological features of the starch granule. Swelling, pasting, gelatinization, retrogradation and in vitro digestibility were also investigated. A total of 17.85% starch was successfully extracted from unripe Tarap fruit, whereas the amount of total starch and resistant starch were 89.14% and 47.82%, respectively. The amounts of rapid digestible starch and slowly digestible starch were 6.58% and 23.25%, respectively. Results found that the amylopectin content was higher than amylose (77.15% and 11.97%). The starch granules were round and polygon in shapes with smooth surfaces. The average of starch granules size was range from 6.50 to 8.30 μm with 7.4 μm of mean granule diameter. Pasting properties showed that peak viscosity was observed at about 6.5 min at 73.5oC. Tarap starch gelatinization temperatures (onset, 71.63°C; peak, 74.56°C; conclusion, 78.24°C) and enthalpy of gelatinization (ΔHgel) (3.74 J/g) were higher while the retrograded starches show lower retrogradation temperature and enthalpy than native starches. Unripe Tarap starch showed good potential to be utilized as adhesives and thickener for industrial applications

Influence of pectinase–assisted extraction time on the antioxidant capacity of Spent Coffee Ground (SCG)

Spent Coffee Ground (SCG) comprises a range of functional components with high antioxidant potential and health benefits. Although SCG has many advantages, antioxidant values obtained using enzymes is still scarce. Several studies reported that the use of enzyme-assisted extraction techniques could improve the detection of antioxidant compounds in samples of by-products. In this study, SCG was extracted using enzymeassisted techniques for different periods (0, 20, 40, 60, 80 and 100 mins). The total antioxidant capacity was measured using Peroxidase, Catalase, Ferric reducing antioxidant power (FRAP), Superoxide radical scavenging assay (SRSA) and 2,2-diphenyl-2- picrylhydrazyl (DPPH) analysis. 60 mins extraction was found to exhibit antioxidant activity in DPPH, SRSA, Catalase and Peroxidase of 84.18±7.01%, 32.83±6.75%, 76.65±5.52% and 75.01±7.67%, respectively. Besides that, the extraction also gave a high amount of content with 267.17±26.69 mg TAE/mL and 58.30±2.36 mg QE/g in total phenolic content and total flavonoid content respectively. Flavonoids such as quercetin, kaempferol, rutin, gallic acid, catechin, epigallocatechin, p-Coumaric acid and myricetin were found to be present in SCG extract. A high amount of catechin was found in all periods of extraction, whereby 60 mins had the highest concentration of 1741.65 mg/L, while 40 mins had the lowest concentration which was 389.85 mg/L. In conclusion, 60 mins extraction using a pectinase-assisted method was the best extraction period. Additionally, the individual flavonoid catechin in SCG showed that it has potential as an antioxidant. Finally, there is a strong correlation between antioxidative activity and both phenolic and flavonoid content

Passively mode-locked ultrashort pulse fiber laser incorporating multi-layered graphene nanoplatelets saturable absorber

In this paper, a passive mode-locked erbium-doped fiber laser (EDFL) incorporating graphene nanoplatelet (GNP) powder-based saturable absorber (SA) with short pulse duration in femtosecond range is demonstrated. A good synthesis of GNP can be simply produced via a combination of thermal, chemical, and mechanical exfoliation of expandable graphite. The GNP-SA is fabricated by mechanically imprinting the powder onto the tip of a single mode fiber ferrule. The characterization of SA is done via focus ion beam scanning electron microscope, energy dispersive X-ray spectroscopy, as well as Raman spectroscopy. The fabricated GNP-SA has 1.8 % modulation depth and C-band transmission loss of less than 1.8 dB. The ring-configuration EDFL integrated with GNP-SA yields a mode-locking threshold of 22.6 mW pump power. Net anomalous dispersion of the laser cavity is validated by the observation of Kelly’s sideband in the optical spectrum. At maximum pump power of 115.8 mW, the mode-locked EDFL has a pulse repetition rate of 13.11 MHz, sech2 profile fitted pulse duration of 694 fs, peak-to-pedestal extinction ratio of 58.2 dB, average output power of 6.7 mW, and pulse energy of 507.2 pJ. Our proposed GNP-SA is feasible as a mode-locker for ultrashort pulsed fiber laser with advantage in terms of simple synthesis and fabrication technique

Introducing a true internal standard for the Comet assay to minimize intra- and inter-experiment variability in measures of DNA damage and repair

The Comet assay (CA) is a sensitive/simple measure of genotoxicity. However, many features of CA contribute variability. To minimize these, we have introduced internal standard materials consisting of ‘reference’ cells which have their DNA substituted with BrdU. Using a fluorescent anti-BrdU antibody, plus an additional barrier filter, comets derived from these cells could be readily distinguished from the ‘test’-cell comets, present in the same gel. In experiments to evaluate the reference cell comets as external and internal standards, the reference and test cells were present in separate gels on the same slide or mixed together in the same gel, respectively, before their co-exposure to X-irradiation. Using the reference cell comets as internal standards led to substantial reductions in the coefficient of variation (CoV) for intra- and inter-experimental measures of comet formation and DNA damage repair; only minor reductions in CoV were noted when the reference and test cell comets were in separate gels. These studies indicate that differences between individual gels appreciably contribute to CA variation. Further studies using the reference cells as internal standards allowed greater significance to be obtained between groups of replicate samples. Ultimately, we anticipate that development will deliver robust quality assurance materials for CA

High-performance liquid chromatography (HPLC) analysis for flavonoids profiling of Napier grass herbal tea

Natural plant products are becoming more and more essential in helping to promote safe well-being worldwide. This leads to a substantial rise in the consumption of various herbal teas. The presence of beneficial bioactive ingredients such as flavonoids may be correlated with Napier grass herbal tea having health benefits associated with their intake. Studies have shown that herbal teas have preferentially high antioxidant activity due to the presence of flavonoids in them. The purpose of this study was to identify the Napier grass herbal teas flavonoids prepared under different conditions. Napier grass herbal teas have been formulated using green tea and black tea processes, respectively. The tea samples were extracted in water (95°C, 30 mins) and 60% (v/v) aqueous methanol (30 mins), respectively. Approximately, 1% (v/v) aqueous acetic acid solution (solvent A) and acetonitrile (solvent B) were used as the mobile phase. The flow rate was adjusted to 0.7 mL/min, the column was thermostatically controlled at 28°C, and the injection column was kept at 20 μL. HPLC chromatograms were detected using a photodiode array UV detector at 272 nm. Gallic acid, P-coumaric acid, catechin, epigallocatechin gallate, quercetin, rutin, myricetin and kaempferol were found in both Napier grass water and methanolic extracts, respectively. The findings suggested that the HPLC techniques are ideal for the detection and identification of flavonoids in Napier grass teas

Suitability of pressmud as an adsorption material in wastewater treatment and as a booster in soil fertility and productivity

Press mud is one of the most abundant wastes produced by the sugarcane industry. However, it has received far too little attention as a reactive material for pollutant removal, although its beneficial effect on soil fertility and crop productivity is well established. This paper investigates the potential of press mud to minimize heavy metal migration while boosting soil fertility and productivity. Firstly, the adsorbent was characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Field-Emission Scanning Electron Microscopy (FESEM) analyses, which showed the presence of functional groups such as carbonyl, hydroxyl, and silica capable of adsorbing metal ions. The cation exchange capacity (CEC) of press mud is very high, ranging between 44.9 and 45.2 meq/100 g. Along with removal efficiency testing and evaluating breakthrough curves, characterization, and adsorption analyses (batch equilibrium and column test) were carried out. The press mud reveals promising adsorption characteristics, including a high organic content (17.62%) and the presence of carbon, which significantly affects its excellent removal effectiveness. Based on the removal efficiency test, press mud successfully removes metal ions at the highest value, such as zinc (Zn), at 99.7%. Meanwhile, its breakthrough curve reveals that it efficiently retained all heavy metals, as these metals do not reach 1 to 10 pore volumes (p.v.), indicating that press mud is a good material for heavy metal adsorption and soil productivity. This possible use establishes a new cyclical flow for the material and contributes to its minimization and reuse, adhering to circular economy ideas. However, press mud must be disposed of properly to avoid adverse effects on humans and the environment

Investigation of tungsten trioxide as a saturable absorber for mode-locked generation

Low-dimensional materials as saturable absorbers (SA) for pulsed laser applications have gain wide interest due to high nonlinearity and strong light-matter interaction. Various materials have been investigated such as graphene, transition metal oxides (TMO), transition metal dichalcogenides, and topological insulators. Tungsten trioxide (WO3); a cheap and nontoxic type of TMO has not yet been investigated for mode-locked pulsed fiber laser (MLFL) generation despite extensive employment as applications in other fields. WO3 is very attractive with spectral absorption extending in the broad near infra-red region, good mechanical strength, high resistance to photo corrosion, and is one of the few oxides that has high thermal and chemical stability. A tungsten trioxide (WO3) based saturable absorber (SA) fabricated via deposition of WO3 composite on tapered fiber was demonstrated. The WO3 weight percentage was varied from 0.005 to 1.235 wt% to investigate the effect on nonlinear saturable parameters and on mode-locked lasing performance. It was determined that the nonlinear saturable parameters were not dependent on weight percentage within its working range; 0.025 to 1.103 wt%. The generation self-started with 35–70 mW pump power, where the pulse durations and spectral bandwidths fall within the range of 810–940 fs and 8–12 nm, respectively. This experimental investigation provides insight on WO3 as a saturable absorber for mode-locked pulse laser generation. The utilization of this nanomaterial is aimed to cut down the cost the existing SA technology while providing enhanced durability and shelf-life

Preliminary study of the antioxidant properties of flowers and roots of Pyrostegia venusta (Ker Gawl) Miers

<p>Abstract</p> <p>Background</p> <p>Free radical stress leads to tissue injury and can eventually to arthritis, atherosclerosis, diabetes mellitus, neurodegenerative diseases and carcinogenesis. Several studies are ongoing worldwide to find natural antioxidants of plant origin. We assessed the <it>in-vitro </it>antioxidant activities and screened the phytochemical constituents of methanolic extracts of <it>Pyrostegia venusta </it>(Ker Gawl) <it>Miers</it>.</p> <p>Methods</p> <p>We evaluated the antioxidant potential and phytochemical constituents of <it>P. venusta </it>using 1,1-Diphenyl-2-picrylhydrazyl (DPPH), 2, 2'-azinobis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) and ferric reducing antioxidant power (FRAP) assays. Gas chromatography-mass spectroscopy (GC-MS) studies were also undertaken to assess the phytochemical composition of the flower extracts.</p> <p>Results</p> <p>Phytochemical analyses revealed the presence of terpenoids, alkaloids, tannins, steroids, and saponins. The reducing ability of both extracts was in the range (in μm Fe(II)/g) of 112.49-3046.98 compared with butylated hydroxytoluene (BHT; 63.56 ± 2.62), catechin (972.02 ± 0.72 μm) and quercetin 3208.27 ± 31.29. A significant inhibitory effect of extracts of flowers (IC₅₀= 0.018 ± 0.69 mg/ml) and roots (IC₅₀= 0.026 ± 0.94 mg/ml) on ABTS free radicals was detected. The antioxidant activity of the extracts of flowers (95%) and roots (94%) on DPPH radicals was comparable with that of ascorbic acid (98.9%) and BHT (97.6%). GC-MS study revealed the presence of myoinositol, hexadecanoic acid, linoleic acid, palmitic acid and oleic acid in the flower extracts.</p> <p>Conclusion</p> <p>These data suggest that <it>P. venusta </it>is a natural source of antioxidants. The extracts of flowers and roots of <it>P. venusta </it>contain significant amounts of phytochemicals with antioxidative properties and could serve as inhibitors or scavengers of free radicals. <it>P. venusta </it>could be exploited as a potential source for plant-based pharmaceutical products. These results could form a sound basis for further investigation in the potential discovery of new natural bioactive compounds.</p

Tooling design and microwave curing technologies for the manufacturing of fiber-reinforced polymer composites in aerospace applications

The increasing demand for high-performance and quality polymer composite materials has led to international research effort on pursuing advanced tooling design and new processing technologies to satisfy the highly specialized requirements of composite components used in the aerospace industry. This paper reports the problems in the fabrication of advanced composite materials identified through literature survey, and an investigation carried out by the authors about the composite manufacturing status in China’s aerospace industry. Current tooling design technologies use tooling materials which cannot match the thermal expansion coefficient of composite parts, and hardly consider the calibration of tooling surface. Current autoclave curing technologies cannot ensure high accuracy of large composite materials because of the wide range of temperature gradients and long curing cycles. It has been identified that microwave curing has the potential to solve those problems. The proposed technologies for the manufacturing of fiber-reinforced polymer composite materials include the design of tooling using anisotropy composite materials with characteristics for compensating part deformation during forming process, and vacuum-pressure microwave curing technology. Those technologies are mainly for ensuring the high accuracy of anisotropic composite parts in aerospace applications with large size (both in length and thickness) and complex shapes. Experiments have been carried out in this on-going research project and the results have been verified with engineering applications in one of the project collaborating companies