Physicochemical Properties of Garden Cress (<Emphasis Type="Italic">Lepidium sativum</Emphasis> L.) Seed Oil

Garden cress (Lepidium sativum L.) is an edible, underutilised herb, grown mainly for its seeds in India. Physicochemical properties, minor components (unsaponifiable matter, tocopherols, carotenoids), fatty acid composition and storage stability of garden cress seed oil (GCO) were studied. Cold press, solvent and supercritical CO₂ extraction methods were employed to extract the oil. The total oil content of garden cress (GC) seeds was 21.54, 18.15 and 12.60% respectively by solvent, supercritical CO₂ and cold press methods. The physical properties of GCO extracted by the above methods were similar in terms of refractive index, specific gravity and viscosity. However, cold pressed oil showed low PV and FFA compared to the oil extracted by other methods. α-Linolenic acid (34%) was the major fatty acid in GCO followed by oleic (22%), linoleic (11.8%), eicosanoic (12%), palmitic (10.1%) erucic (4.4%), arachidic (3.4%) and stearic acids (2.9%). Oleic acid (39.9%) and α-linolenic acid (42.1%) were the predominant fatty acids at the sn-2 position. The total tocopherol and carotenoid content of GCO was 327.42 and 1.0 μmol/100 g oil, respectively. The oil was stable up to 4 months at 4 °C. Tocopherol and BHT offered the least protection, while ascorbyl palmitate (200 ppm) offered the maximum protection to the oil, when subjected to the accelerated oxidative stability test. Thus GCO can be considered as a fairly stable oil with a high content of α-linolenic acid.     

Evaluation of Biodegradation of Pineapple Leaf Fiber Reinforced PVA Composites

Composites of polyvinyl alcohol (PVA) reinforced with different weight percentages of pineapple leaf fibers (PALF) were fabricated and evaluated for biodegradation by soil burial test and plate test. FTIR analysis indicated the existence of a chemical interaction between PVA and PALF. The water uptake study showed that the composites with higher fiber content displayed high tensile strength and brittleness but possessed lower water uptake potential. In the soil burial test, the composites with low matrix to filler ratios exhibited higher rates of degradation as evident by the associated decrease in molecular weights. Plate test performed using Pseudomonas putida showed that the composites were susceptible for degradation by bacteria. The results of this study indicated that PALF-reinforced PVA composites were completely biodegradable and could find potential applications in industries such as agriculture and packaging and safely disposed after use without causing environmental damage.     

Measurement and targeting of thermophysical properties of carrot and meat based alginate particles for thermal processing applications

The objective of the study was to investigate the thermo-physical properties of meat and carrot based alginate particles as influenced by the formulation variables. A response surface methodology (RSM) was used to study the effect of sodium alginate concentration, calcium chloride concentration and dipping time in the calcium chloride solution, at five levels each, on the thermo-physical properties of the fabricated particles (9 mm in diameter and 9 mm in height). Density was similar for all conditions. Increasing sodium alginate concentration resulted in a significant decrease in the heat capacity and thermal conductivity values. These changes were primarily attributed to the lowering of moisture content of the particles resulting from the treatment. Using RSM, optimum conditions for fabricating particles having similar thermo-physical properties to real foods were obtained as 5.3% and 4.9% sodium alginate, 2.2% calcium chloride and 14.2 and 36.0 h immersion in the calcium chloride solution for meat and carrot alginate particles, respectively.     

Microscopic initiation mechanisms in energetic material crystals

Abstract

The sensitivity to initiation of different crystalline polymorphic forms of the same energetic material is known to differ. Similarly single crystals of energetic materials such as PETN and nitromethane show a shock initiation sensitivity anisotropy. The crystal structure of the energetic materials is thus known to control the initiation sensitivity of the same. As will be described in this paper there is evidence to indicate that the orientation of the molecules surrounding a given molecule in the crystal lattice, influences the initial decomposition reaction of the molecule. Several microscopic mechanisms of initiation have been postulated. It is shown here that added to and above these mechanisms the crystal structure can be taken into account in a metastable intermolecular trigger reaction which explains the observed differences in initiation as a function of crystal structure.     

Carotenoproteins from lobster waste as a potential feed supplement for cultured salmonids

Lobster waste (including the head and hard carapace, viscera, mandibles and gills) contains approximately 54 μg/g total astaxanthin, 29% protein, 23% chitin, 34% ash and 2.2% crude fat on a dry weight basis. Trypsin from bovine pancreas was applied to facilitate the recovery of carotenoid pigments and protein as carotenoprotein complex, which was subsequently air‐dried to a stable powder form at 45°C and 15% relative humidity. The product obtained was found to contain 60% protein, 15% crude fat, 6% ash, 8% chitin and 295 μg/g total astaxanthin. Thus, the process achieved a substantial reduction in the levels of anti‐nutrients associated with lobster waste (i.e., ash and chitin) while elevating the levels of carotenoid pigments and essential nutrients such as protein and fat in the recovered product These characteristics of the final product suggest that it could be used as an inexpensive source of pigment and protein in diets of cultured salmonid species.     

Recent developments in the fire retardancy of polymeric materials

The widespread applications of polymeric materials require the use of conventional flame retardants based on halogen and phosphorous compounds to satisfy fire safety regulatory standards. However, these compounds, particularly halogen-based examples, are persistent organic pollutants of global concern and generate corrosive/toxic combustion products. To account for eco-friendliness, ultimate mechanical/physical properties and processing difficulties, the window of options has become too narrow. Although the incorporation of non-toxic nanofillers in polymers shows positive potential towards flame retardancy, many obstacles remain. Moreover, most of the literature on these materials is qualitative, and often points to conflicting/misleading suggestions from the perspectives of short-term and long-term fire exposure tests. Hence, there is a renewed need to fundamentally understand the fire response of such materials, and complement experimental results with theoretical modelling and/or numerical simulation.