Chitosan glucose complex – A novel food preservative

Chitosan glucose complex (CGC), a modified form of chitosan was prepared by heating chitosan with glucose. Fluorescence and the browning reaction of CGC indicated the presence of the Maillard reaction product (MRP). CGC showed excellent antioxidant activity while chitosan or glucose alone did not have any significant activity (p < 0.05). The IC₅₀ value of CGC for DPPH radical scavenging was 51.1 μg/ml. The efficacy of CGC in scavenging hydroxyl and superoxide anion radicals was also very high but it showed a low reducing power. The antimicrobial activity of CGC was similar to chitosan against E. coli, Pseudomonas, Staphylococcus aureus and Bacillus cereus, the common food spoilage and pathogenic bacteria. The minimum inhibitory concentration of CGC or chitosan was 0.05%. Addition of CGC to lamb meat increased its shelf life by more than 2 weeks during chilled storage. It also enhanced the shelf life of pork cocktail salami to 28 days. CGC is endowed with both antioxidant and antimicrobial activity and thus is a promising novel preservative for various food formulations.     

Quantum Dots-in-a-Well Focal Plane Arrays

In this paper, the basics and some of the recent developments in quantum dots-in-a-well (DWELL) focal plane arrays (FPAs) are reviewed. Fundamentally, these detectors represent a hybrid between a conventional quantum well infrared photodetector (QWIP) and a quantum dot infrared photodetector (QDIP), in which the active region consists of quantum dots (QDs) embedded in a quantum well (QW). This hybridization grants DWELLs many of the advantages of its components. These advantages include normally incident photon sensitivity without gratings or optocoupers, like QDIPs, and reproducible control over operating wavelength through ldquodial-in recipesrdquo as seen in QWIPs. Recently reported high-temperature operation results for DWELL FPAs now back up the conclusions drawn by the long carrier lifetimes observed in DWELL heterostructures using femtosecond spectroscopy. This paper will conclude with a preview of some upcoming advances in the field of DWELL FPAs.     

Stress relaxation behavior of glass fiber‐reinforced polyester composites prepared by the newly proposed rubber pressure molding

Stress‐relaxation behavior of glass fiber‐reinforced polyester composites, prepared by a recently developed manufacturing method called rubber pressure molding (RPM), is investigated with special reference to the effect of environmental temperature (−70°C to +100°C), fiber volume fraction (30–60%), and initial load level (1–5 kN). It is found that the stress‐relaxation rate decreases with an increase in the applied load of composites and a decrease in temperature. Below glass transition temperature, the rate of stress relaxation increases with an increase in volume fraction of fibers in the composites, whereas above glass transition temperature, it increases with a decrease in the volume fraction of fibers. The experimental results for a given composites are summarized by four values, the slopes of the two straight lines (two separate relaxation processes), and their intercepts upon the stress axis. Both the slopes are dependent upon the applied load, temperature, and volume fraction of fibers in the composites. Relaxation times in both primary and secondary are calculated over the wide range of temperatures, loads, and volume fraction of fibers in the composites. It depends strongly on the temperature, but does not depend strongly on the applied load and volume fraction of fibers. The performances of the composites are also evaluated through conventional compression‐molding process. The rate of stress relaxation is small when the composites are made of newly proposed RPM technique when compared with the conventional process. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers     

Ethanol steam reforming study over ZSM-5 supported cobalt versus nickel catalyst for renewable hydrogen generation

The renewable hydrogen generation through ethanol steam reforming is one of the anticipated areas for sustainable hydrogen generation. To elucidate the role of Ni and Co with ZSM-5 support, catalysts were prepared by wet impregnation method and ethanol steam reforming(ESR) was performed. The catalysts were characterized by HR-XRD, ATR–FTIR, HR-SEM, TEM with SAED, EDAX, surface area analyzer and TPR. It had shown complete ethanol conversion at 773 K, but the selectivity in hydrogen generation was found higher for 10% Ni/ZSM-5 catalyst as compared to 10% Co/ZSM-5. The 10% Ni/ZSM-5 catalyst has about 72% hydrogen selectivity at temperature 873 K. It indicates that Ni is a more sustainable catalyst as compared to Co with ZSM-5 support for ESR. The C_2H_4 was found major undesirable products up to 823 K temperature. Nevertheless, the 10% Ni/ZSM-5 catalyst had shown its stability for high temperature(873 K) ESR performance.     

Evaluation of Robustness of the Biosurfactant Derived from Balanites aegyptiaca (L.) Del.

Balanites aegyptiaca (L.) Del. is a widely distributed xerophytic multipurpose tree. The mesocarp of the fruit of B. aegyptiaca has detergent properties due to the presence of saponins. The stability potential of this biosurfactant at varying pH, temperature, and salinity has not been explored so far. In the present study, the relative surface tensions of five different concentrations of the biosurfactant were studied at different temperatures, salinity, and under pH conditions. This study reveals that this biosurfactant retains its activity over a wide range of pH (3–11) and at high salinity (7% NaCl). It is a thermostable cationic surfactant; surfactant activity was recorded even at 100 °C with the lowest relative surface tension of 0.47. High oil displacement (18.00 mm) was observed when studied with petrol. This biosurfactant was found to have a high emulsification index (E₂₄) of 70% with mustard oil. These results indicate that biosurfactant derived from B. aegyptiaca may find use in a wide range of sectors such as textile, food, cosmetics, oil recovery, and healthcare under a wide range of physical and chemical conditions. It offers an efficient, economically viable, and plant-derived alternative to synthetic detergents and adds a way to maintain a sustainable environment.     

Thermohydrodynamic analysis of infinitely wide cycloidal profiled pad thrust bearing with rough surface and a comparison to plane profiled pad

This work reports the thermal analysis of hydrodynamically lubricated cycloidal profiled pad thrust bearing (CPPTB) using an efficient numerical method based on Lobatto quadrature technique. The performance parameters with smooth and rough surfaces of cycloidal and plane profiled pads are presented for various operating inputs. Significant increase in magnitude of pressure and substantial reduction in coefficient of friction are observed in the presence of relatively large amplitude of roughness over the surface of stationary pads. Comparisons are made for performance parameters achieved with plane profiled pad thrust bearing (PPPTB) and CPPTB. The load carrying capacity of CPPTB is found significantly high than the PPPTB for the provided set of operating parameters. Copyright © 2008 John Wiley & Sons, Ltd.     

Effect of silica on the ZnS nanoparticles for stable and sustainable antibacterial application

Silica-capped Zinc Sulfide (ZnS) nanoparticles were synthesized for the use as stable and long-term antibacterial agents because silica is a very important component in food packaging applications for moisture absorption in tune with its property of biocompatibility and water solubility. The variation in morphological and optical properties of core-shell nanostructures was studied by changing the concentration of silica in a core-shell combination. The structural and morphological properties of silica-capped ZnS have been observed by powder X-ray diffraction (PXRD) and transmission electron microscopic (TEM) studies, respectively. Uncapped ZnS nanoparticles with particle size of 2-4 nm in a highly agglomerated state have been observed from TEM, which shows that they can be used only for short-term antibacterial action despite its excellent zone of inhibition (antibiotic sensitivity). However, ZnS/SiO₂ core-shell nanostructures are highly monodisperse in nature and the particle size increases up to 5-8 nm with increase in silica concentration. Fourier-transform infrared spectroscopy (FTIR) analysis confirms the formation of silica capping on the ZnS surface. The inhibition of defect-related emission by silica capping in energy-resolved photoluminescence studies also shows the formation of very stable ZnS nanoparticles. To study the antibacterial properties of the pure and silica-capped ZnS nanostructure the agar-well diffusion method was employed against both gram-positive and gram-negative bacteria. The obtained results indicate that pure ZnS shows excellent antibacterial action but it can last only for few days.     

Rheokinetic studies and compressive response of high performance polybenzoxazine syntactic foams

Polybenzoxazines are finding increasing usage in demanding applications where high temperature stability is required, especially in the field of aerospace. In this work, thermally stable bisphenol F-based polybenzoxazine [poly(BF-a)] syntactic foams containing varying volume fractions (30–60%) of hollow glass microballoons (HGMs) were prepared and their mechanical response in the quasi-static regime was established. The effect of introducing glass microballoons on the curing profile of benzoxazine resin was studied using both nonisothermal differential scanning calorimetry and rheometry. Temperature-sweep experiments were performed to arrive at the optimal processing window of the benzoxazine-glass microballoons formulations, particularly in terms of viscosity, gelation temperature, and time. Thermally accelerated ring-opening polymerization of the benzoxazine resin led to complete curing of the syntactic foam formulations, as assessed by calorimetric studies. The thermal degradation behavior of the poly(BF-a)/HGM was studied using thermogravimetric analysis. As expected, the density of the syntactic foam specimens decreased with increasing microballoon content. Maximal increase in the specific compressive properties of the poly(BF-a)/HGM samples was observed in formulations containing 40% volume fraction of glass microballoons. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47234.     

Role of Flaxseed Meal Feeding for Different Durations in the Lipid Deposition and Meat Quality in Broiler Chickens

This study investigated the role of flaxseed meal (FSM), a rich terrestrial source of ω-3 fatty acids, in the alteration of the fatty acid profile and metabolism, health indices, physicochemical properties, and sensory quality of broiler chicken meat. The broiler chickens were fed 100 g FSM kg⁻¹ diet for different time periods (1, 2, 3, 4, and 5 weeks). The results revealed that 100 g FSM feeding in broiler chickens for at least 3 weeks increased (P < 0.01) the EPA, DHA, MUFA, PUFA, ω-3 PUFA, and ω-6 PUFA of broiler chicken meat with the corresponding decrease in palmitic acid, stearic acid, and SFA content. 100 g FSM feeding up to 3 weeks has increased the Δ⁹-desaturases (P < 0.05), thioesterase index (P < 0.01), and Δ⁵-desaturase + Δ⁶-desaturase activity (P < 0.01) along with an improvement in health indices (P < 0.01) of chicken meat. Similarly, a reduction in meat cholesterol and fat content of thigh meat (P < 0.01) was observed by feeding 100 g FSM for at least 3 weeks with no effect on the pH, color scores, and sensory evaluation of broiler chicken meat. The water-holding capacity (WHC) and extract release volume (ERV) decreased, whereas, drip loss of meat increased (P < 0.01) due to the feeding of 100 g FSM beyond 3 weeks. Thus, this study concluded that 100 g FSM feeding for 3 weeks in broiler chickens significantly improves the fatty acid profile, lipid metabolism, and health indices of meat, without compromising the physicochemical properties of broiler chicken meat.