Steroidal saponins from Asparagus dumosus

A new steroidal saponin, dumoside, characterized as (20S)-3 beta, 16 beta-dihydroxy pregn-5-ene-22-carboxylic acid (22, 16)-lactone-3-O-beta-chacotrioside, was isolated from the whole plant of Asparagus dumosus Baker and the structure was deduced from spectral data. In addition to dumoside three more steroidal saponins characterized as 3 beta-dihydroxy pregn-5,16-dien-20-one 3-O-beta-chacotrioside, 3 beta, 22 alpha, 26-trihydroxyfurost-5-ene-3-O-beta-chacotrioside-26-O- beta-D-glucopyranoside and its corresponding 22 alpha-O methoxy analogue were also isolated for the first time from this source. The structures have been identified with the help of FAB-MS, 1H NMR, 13C NMR and extensive 2D NMR spectroscopy, as well as comparison with reported spectroscopic data.     

Tomato (Solanum lycopersicum) Carotenoids and Lycopenes Chemistry; Metabolism,Absorption, Nutrition,and Allied Health Claims—A Comprehensive Review

Tomato (Solanum lycopersicum) is one of the most essential herbaceous plants that have been probed against various life sight related disorders owing to array of phytochemicals. It is important source of vitamin C, potassium, folic acid, and carotenoids, such as lycopene. Carotenoids are the pigments synthesized during fruit ripening and responsible for the final red color of the tomato. Consumption of tomato and tomato-based products contribute to the absorption of carotenoids and lycopenes in human serum. Lycopene is chemically acyclic carotene with 11 conjugated double bonds, normally in transconfiguration while isomerization occur in blood plasma for its better absorption. It has ability for adenosine deaminase inhibition that plays important role in the regression of tumor. Tomato also contain other active compounds, namely, neoxanthin, lutein, α-cryptoxanthin, α-carotene, β-carotene, cyclolycopene, and β-carotene 5, 6-epoxide. These components provide synergistic effect against various threats but still need further attention of the researchers. Both in vitro and in vivo studies have elucidated the potential of tomato against variety of metabolic syndromes. Latest research highlights the relationship between consuming tomato and its products with reduced risk of various maladies like obesity, hyperglycemic and hypercholesterolemic attributes, cardiovascular disorders, and cancer insurgences. Moreover, tomato and its bioactive components hold potential to become effective modules in diet-based regimens; however, integrated research and meta-analysis are still required to enhance meticulousness.     

Effect of sulphiting and drying methods on physico-chemical and sensorial quality of dried apricots during ambient storage

Fresh mature and ripe apricots after preparations were pre-treated with potassium meta-bisulphite (KMS) at concentrations of 2–8% for 30, 45 and 60 min followed by drying in solar tunnel dryer and in open air. After completion of drying, the samples were packed in polyethylene pouches and evaluated for various quality parameters at 0, 6 and 12 months of ambient storage. KMS pre-treatment at concentration of 6% for 60 min prior to drying helped significantly in improving and maintaining the quality of dried apricots for up to 12 months of ambient storage. Solar tunnel drying resulted in hygienic product and reduced the drying time to 3–4 days compared with 14–16 days in open air drying. Residual free sulphur dioxide of apricots pre-treated at KMS concentration of 6% for 60 min was within the prescribed limits of the Fruit Product Order (1955) specifications for dried products.     

Effect of compatibilizer on the dispersion of untreated silica in a polypropylene matrix

BACKGROUND: A new processing method for polypropylene–untreated precipitated silica (PP/SiO₂) composites based on the incorporation of a second polymer phase of polyamide 6 (PA6) is presented and compared with a more classic one making use of compatibilizers: glycerol monostearate (GMS), ethylene acrylic acid ionomer (IAAZE) and maleic anhydride grafted polypropylene (MA‐graft‐PP). The effects of processing methods and conditions on the microstructure and properties of PP/SiO₂ composites prepared by melt compounding are investigated with a view to reduce the size of aggregates of silica from the micrometre to the nanometre scale and to improve the link between filler and matrix. RESULTS: On the one hand, the presence of GMS and IAAZE compatibilizers significantly improves the dispersion of the silica particles. On the other hand, when using a PA6 second phase, the SiO₂ particles are dispersed in PA6 nodules. Within these nodules, SiO₂ appears dispersed at the nanoscale but with larger particles (‘aggregates’) of about 200 nm. Significant improvements in tensile strength and modulus are obtained using MA‐graft‐PP compatibilizer. An increase in impact strength is observed in the case of GMS compatibilizer. Thermal parameters indicate also that silica plays the role of nucleation agent for PP matrix. All improvements (tensile strength, modulus and impact strength) increase with the addition of compatibilized PA6 second phase. CONCLUSION: By the incorporation of masterbatch of silica in PA6 as a second polymer polar phase, a successful new production method for PP/SiO₂ nanocomposites has been developed. Interestingly, this method does not require any (expensive) pre‐treatment of the silica. Copyright © 2007 Society of Chemical Industry     

Optimization of MnO2-Graphene/polythioaniline (MnO2-G/PTA) hybrid nanocomposite for the application of biofuel cell bioanode

This study reports the synthesis of a nanocomposite comprised of graphene (G) supported manganese dioxide (MnO₂) incorporated into the network of polythioaniline (MnO₂-G/PTA). The hybrid composite was applied as an electrode material for the development of a bioanode. The bioanode was fabricated by the electrochemical entrapment of ferritin (Frt) as mediator and glucose oxidase (GOx) enzyme in the matrix of the as-synthesized MnO₂-G/PTA deposited on glassy carbon electrode (GCE) surface. The structural features and electrochemical behaviour of the modified electrodes were investigated by Fourier transform infrared spectroscopy (FTIR), cyclic voltammetry (CV), linear sweep voltammetry (LSV) and electrochemical impedance spectroscopy (EIS). The results unfolded that the hybrid electroactive support (MnO₂-G/PTA) employed for the immobilization of the enzyme (GOx) established an appropriate electrical cabling between the redox enzyme (GOx) and the electrode surface with the assistance provided by the biocompatible mediator (Frt) working to enhance the electrical signals. The developed GCE/MnO₂-G/PTA/Frt/GOx bioanode attained a maximum current density of 3.68 mAcm^?2 at 35 mM glucose concentration at a scan rate of 100 mVs^?1. Thus, the MnO₂-G/PTA/Frt/GOx modified electrode possesses high potential and good biocompatibility for bio-electricity production from glucose.     

Dielectric characterization of thermally aged recycled Polyethylene Terephthalate and Polyethylene Naphthalate reinforced with inorganic fillers

In order to assess the influence of the operating temperature on the dielectric properties of recycled Polyethylene Terephthalate (PET) and Polyethylene Naphthalate (PEN) reinforced with inorganic fillers, a dielectric and thermal investigation was undertaken. Specimens were thermally aged at several temperatures between 90 and 200°C for 360 h. The effect of thermal aging time on dielectric and thermal properties was also investigated. The dielectric response and breakdown strength properties were evaluated. Differential scanning calorimetry (DSC) measurements showed that the degree of crystallinity and the glass transition temperature increased with aging temperature and duration. The data obtained showed that these materials exhibited a good resistance to thermal aging at temperatures below 140°C. Furthermore, it was found that the dielectric strength of the recycled PET and PEN and their composites decreased considerably for temperatures of over 170°C. POLYM. ENG. SCI., 2017. © 2017 Society of Plastics Engineers     

Oxidative Stability of Cooking Oil Blend Stabilized with Leaf Extract of Eucalyptus citriodora

The present study was conducted to assess the effects of Eucalyptus citriodora (E. citriodora) leaf extract on the oxidative stability of blend of canola, rapeseed, and sunflower oils (45:20:35 v/v, respectively) under accelerated storage. The blended oil was stabilized with 300 mg/L ethanolic extract (source of total phenolic content and total flavonoid content [5.23 ± 0.19 and 1.18 ± 0.04 g/100 g d.wt. of extract]) of E. citriodora leaves. The oxidative stability was measured on the basis of parameters such as free fatty acid contents, peroxide value, sponification value, iodine value, color, cloud point, and refractive index. After a 100 day incubation period, the increase in refractive index, free fatty acid, and peroxide, and sponification values in stabilized and non-stabilized oil blends were 0.0028 and 0.0047, 0.20 and 2.37% as oleic acid, 12.54 and 21.12 meq/kg of oil and 10.04 and 17.01 meq of KOH/g of oil, respectively, as compared with initial values. However, a decrease of 10.0 and 16.9 g of iodine/100 g of oil was recorded in oil iodine values of both stabilized and non-stabilized blended vegetable oils. Results showed that E. citriodora leaf extract was found effective to maintain the oxidative stability of blended vegetable oils for long duration (6 months) as compared with control oil samples. Therefore, it can be concluded that E. citriodora leaf extract is a cheap rich source of natural antioxidants that can be easily used for the stabilization of vegetable oils in the food processing industries.     

Creep and shrinkage behaviour of CFRP-reinforced mortar

This paper deals with the reinforcement of mortar with external composite materials. The mortar specimens were strengthened with CFRP (Carbon Fibres Reinforced Polymer) plates on two or four faces. Creep tests were run for 7 or 28 days with applied stress level at 30% of ultimate stress. Experimental results show a clear improvement of short-term creep behaviour for the reinforced mortar. There is no evidence of shrinkage reduction due to the reinforcement. Drying is modelled using a non linear diffusion equation and shrinkage is numerically calculated. In both cases, accurate predictions of experimental results were obtained.