Effects of different food commodities on larval development and α-amylase activity of Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae)

The present work was undertaken to study the influence of four commodities (wheat flour, dates, sorghum and barley) on Plodia interpunctella post-embryonic development. Larval weight, larval mortality, pupation and adult emergence were recorded. The study also aimed to find out the effect of these commodities on protein and glycogen production as well as on α-amylase activity. Results indicated that the weight of fourth instar larvae placed on dates increased gradually. Percentage mortality was low. Pupation and adult emergence were delayed. In contrast, the weight of larvae placed on wheat flour, sorghum or barley remained low. Pupation and adult emergence occurred sooner than among those placed on dates and the percentage mortality was highest for larvae placed on barley. Results also showed that protein content and α-amylase activity were lower for larvae placed on dates than for those placed on other commodities. The biochemical composition of different commodities showed that dates are a rich source of glucose, while their protein and starch contents were very low as compared to the other commodities. In contrast, wheat flour, sorghum and barley contained large amounts of starch and protein and low amounts of glucose. Thus, the reduction in α-amylase activity was probably due to the high levels of glucose in dates.     

Extraction and functional properties of gelatin from the skin of cuttlefish (Sepia officinalis) using smooth hound crude acid protease-aided process

The characteristics and functional properties of gelatin from skin cuttlefish (Sepia officinalis) were investigated and compared to those of halal bovine gelatin (HBG). The gelatin extraction efficiency was improved by an acid-swelling process in the presence of smooth hound crude acid protease extract (SHCAP). The yields of gelatins from cuttlefish skin after 48 h with acid and with crude acid protease (15 units/g alkaline-treated skin) were 2.21% and 7.84%, respectively. The gelatin from skin cuttlefish had high protein (91.35%) but low fat (0.28%) contents. Compared to HBG, the cuttlefish-skin gelatin (CSG) has different amino acids composition than halal bovine gelatin. CSG contained slightly low hydroxyproline and proline (180‰) than HBG (219‰), whereas the content of serine was higher (49‰ versus 29‰). The gel strength of the gelatin gel from CSG (181 g) was lower than that of HBG (259 g) (p < 0.05) possibly due to lower hydroxyproline content. Cuttlefish-skin gelatin exhibited a similar emulsifying activity but greater emulsifying and foam stability than the halal bovine gelatin (p < 0.05). Foam formation ability, foam stability and water-holding capacity of CSG were slightly lower than those of the HBG, but fat-binding capacity was higher in the cuttlefish gelatin.     

Characterization of the absorption of theophylline from immediate- and controlled-release dosage forms with a numerical approach using the in vitro dissolution-permeation process using caco-2 cells

After oral administration, drug absorption rate is recognized to be dependent on two major factors: dissolution and intestinal cells permeability. Caco-2 monolayer cells have been largely used as a permeation study model. In this study, a numerical approach funded on an exponential first-order time relationship was tested to compare immediate- and controlled-release tablets of theophylline using a dissolution-permeation system. The dissolution performance using USP II paddle apparatus was coupled to the permeability studies investigated in Caco-2 cell monolayers. The dissolved samples were taken at different times; their pH and osmolarity were adjusted to render them suitable to Caco-2 permeability studies (osmolarity = 300 mosm, pH = 7.4). The experimental data show that the dissolution fits the exponential first-order relationship rate. The permeability values were in a range of 4.45 10(- 6)-5.28 10(- 6) cm/s, and percentages of absorbed drug dose were dependent on the fraction initially present in the donor compartment, indicating that absorption of theophylline was dissolution rate limited. Plotting experimental absorbed fractions (F(a)) against experimental dissolved fractions (F(d)) show that permeation is the rate-limiting step in drug absorption process in the extended release form of theophylline. Our results demonstrate a general agreement between observed F(a)/F(d) relationships and theoretical F(a)/F(d) relationships obtained with our approach funded on dissolution and permeation behavior. We concluded that the couple dissolution-caco-2 system could be a useful tool to characterize intestinal permeation for a new formulation of a drug compared with the conventional one.     

Chemiluminescence of isotactic polypropylene induced by photo‐oxidative degradation and natural weathering

The analysis of the chemiluminescence (CL) kinetic parameters (induction time, oxidation rate, and activation energy) after the UV irradiation and outdoor exposure of isotactic polypropylene (i‐PP) films have been studied. The initial CL emission intensity increased with increasing photodegradation time of i‐PP films. On photodegradation, the activation energies were found to decrease linearly with time of UV‐irradiation and outdoor exposure. The slopes of these linear dependences were used to indicate the degree of photodegradation of the polymer and also for the characterization of the stabilizing effect of the additive. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 4623–4629, 2006     

Kinetics of tungsten‐catalyzed sunflower oil epoxidation studied by 1H NMR

Sunflower oil (SO) is a renewable resource that can be epoxidized, and the epoxidized SO has potential uses as an environmentally friendly and reactive material in polymeric formulations, especially for polyvinyl chloride. SO was epoxidized with peracetic acid, which was either preformed or prepared in situ. In order to optimize the formation of oxirane rings, the epoxidation and the extent of the side reactions were studied at different temperatures. The peracetic acid was obtained by acidic catalysis in the presence of a cation‐exchange resin. The optimum conversions were obtained within a 4‐h reaction period at 55 °C by the in situ epoxidation technique. The epoxidation was also carried out with hydrogen peroxide in the presence of peroxotungstic acid complexed with lipophilic phosphorus‐based ligands. ¹H NMR was used to define the new indices Δ and Ω, which are the mean numbers of C=C double bonds and oxirane rings per fatty acid chain, respectively. This allowed monitoring of the reaction and quantification of the results. Peroxotungstic catalysts appeared less performing than peracids in the epoxidation of SO, but were found very efficient for the epoxidation of the SO methyl esters.     

Thermal stability evaluation of polypropylene protected with grafted amine

Summary Polypropylene containing a grafted amine as oxidation protector was subjected to γ-irradiation for the evaluation of thermal stability. Several formulations were prepared containing hindered amine, Sanduvor PR 31 (0.1, 0.2 and 0.3% w/w) and CaCO₃ (0.6% w/w). The stability assessment was carried out in air by oxygen uptake procedure under isothermal and isobaric conditions (165 °C and normal pressure, respectively). The exposure doses were placed in the range from 0 to 70 kGy. The changes appeared in the main kinetic parameters (oxidation induction time and oxidation rate) evaluated for thermal degradation of irradiated PP specimens are presented and the stability analysis is explained starting from the behaviour differences of various formulations of radiation processed polypropylene. On the low dose range, the drop in thermal stability of modified polypropylene films occurs more abrupt than it was observed for the samples irradiated at higher doses.     

Bioreactors Based on Monolith‐Supported Ionic Liquid Phase for Enzyme Catalysis in Supercritical Carbon Dioxide

Bioreactors with covalently supported ionic liquid phases (SILP) were prepared as polymeric monoliths based on styrene–divinylbenzene or 2‐hydroxyethyl methacrylate–ethylene dimethacrylate, and with imidazolium units loadings ranging from 54.7 to 39.8 % wt IL per gram of polymer. The SILPs were able to absorb Candida antarctica lipase B (CALB), leading to highly efficient and robust heterogeneous biocatalysts. The bioreactors were prepared as macroporous monolithic mini‐flow systems and tested for the continuous flow synthesis of citronellyl propionate in supercritical carbon dioxide (scCO₂) by transesterification. The catalytic activity of these mini‐flow‐bioreactors remained practically unchanged for seven operational cycles of 5 h each in different supercritical conditions. The best results were obtained when the most hydrophobic monolith, M‐SILP‐ 8 ‐CALB, was assayed at 80 °C and 10 M Pa, reaching a total turnover number (TON) of 35.8×10⁴ mol product/mol enzyme. The results substantially exceeded those obtained for packed‐bed reactors with supported silica‐CALB‐Si‐4 catalyst under the same experimental conditions.     

A Novel Consideration of Species Distribution of Copper(II)/Histidine System at Physiological pH

Abstract

The copper(II)–L‐histidine system plays a pivotal role in copper transport across cell membranes. The coordination mode of copper(II)–L‐histidine species at physiological pH has been elusive in aqueous solution for the last four decades, despite exhaustive characterization studies. Recently, the isolation and the X‐ray crystal structure of the physiological [Cu(His)₂] complex have been reported. The X‐ray structure is different from all the structures suspected for this complex in solution.

We carried out a polarographic analysis to identify copper(II)–L‐histidine species at physiological pH. In our experimental conditions, three copper(II)–L‐histidine species coexist around the physiological pH. These novel considerations can explain the controversy encountered in the investigation of the coordination mode in aqueous solution.     

Changes in nutritional and sensory properties of orange juice packed in PET bottles: An experimental and modelling approach

Sensitivity to oxidation of an orange juice was investigated through packaging in standard PET or active PET with oxygen scavenger bottles. The evolution of dissolved oxygen was found to be similar in all bottles, whereas ascorbic acid degradation was related to the oxygen transfer with higher losses in standard PET (53%) against active PET (31%). Moreover, when juice was exposed to high intensity light, a fold faster degradation of ascorbic acid was observed compared to total darkness. Depending also on the light intensity and regardless of the package permeability, changes in the aromatic profile of the juice were observed due to the degradation of limonene and the formation of α-terpineol, an off-flavour. A mechanistic model was developed to predict the shelf life of orange juice. This model, coupling O₂ transfer and ascorbic acid oxidation reaction in the bottled juice, confirmed that oxygen permeation through packaging material could not be neglected.     

Evidence of in vivo satietogen effect and control of food intake of smooth hound (Mustelus mustelus) muscle protein hydrolysate in rats

Protein hydrolysates are of a significant interest, due to their potential application as a source of bioactive peptides in nutraceutical and pharmaceutical domains. The present study was focused on the effect of protein hydrolysate from smooth hound (Mustelus mustelus) (SHPH) in the regulation of components of the food intake control such as satiety. SHPH was produced by intestinal digestive proteases from the same species. The amino acid analysis by GC/MS showed that the hydrolysate was rich in leucine, alanine, glycine, threonine, serine, lysine and glutamate. The molecular weights of peptides in SHPH were estimated by ESI-MS to be between 200 and 2500 Da. Biological in vivo capacities of SHPH in rats were evaluated by determination of the CCK-like peptides and insulin content using a clinical human radioimmunoassay. The food intake and the body weight of rats were measured during the period of treatment. Rats treated with SHPH showed a significant decrease in body weight at the end of treatment, as well as a decrease of food intake. Our findings revealed a possible mechanism of the beneficial effects of SHPH in appetite regulation, and this might be important to prevent the risk of a number of medical conditions including type II diabetes.