Oxidative stability, volatile components and polycyclic aromatic hydrocarbons of cold-smoked sardine (Sardina pilchardus) and dolphinfish (Coryphaena hippurus)

Although a wide variety of compounds are deposited during the smoking process, much more attention has been given to phenols and polycyclic aromatic hydrocarbons (PAHs). However, even though phenols have an important role to play as food antioxidants, some PAHs have cytotoxic and mutagenic effects. In the present work, two fish species differing in composition (dolphinfish (Coryphaena hippurus) and sardine (Sardina pilchardus)) were salted and cold-smoked. Two different smoking treatments were selected in order to compare phenol content and muscle antioxidant activity employing the ferric reducing power (FRAP) method. Both smoking treatments increased fish lipid oxidation stability compared with the salted muscle. The characterization of the volatile components of the headspace of the more intensely processed smoked products was carried out by SPME/GC/MS, which revealed the presence of typical phenol and carbonyl derivatives, as well as some oxidation products and PAHs of low molecular weight. PAH composition was further investigated by extracting and identifying the PAHs by GC/MS. Neither benzo(a)pyerene nor other high molecular weight PAHs were detected, naphthalene and its derivatives being the most abundant compounds in the smoked products.     

Enzymatic hydrolysis of fish gelatin under high pressure treatment

The effect of high pressure treatment on the hydrolysis of fish skin gelatin and the antioxidant properties of the hydrolysates was evaluated. Hydrolysis was performed by Alcalase, collagenase, trypsin and pepsin both at atmospheric pressure and under high pressure (100 MPa/15 and 30 min, 200 MPa/15 and 30 min, 300 MPa/15 min). The degree of hydrolysis (DH) was determined according to the base consumption via pH‐stat as well as the percentage of soluble nitrogen in trichloroacetic acid (TCA). About 16% of nitrogen in the gelatin was still soluble in 10% TCA, indicative of a significant amount of low molecular weight components. The high pressure treatment increased the DH with all the enzymes used between 5% and 10%. However, in comparison with the hydrolysates obtained at atmospheric pressure after 3 h of digestion under controlled conditions (using a pH‐stat), the radical scavenging capacity of the pressured hydrolysates was only significantly enhanced when Alcalase or collagenase were used. High pressure may be a useful tool for the quick obtaining of gelatin hydrolysates with antioxidant capacity.     

Relationship between wood elastic strain under bending and cellulose crystal strain

Wood is a natural composite material with a complex multi-scale structure. Its stiffness is mainly due to crystalline cellulose fibrils reinforcing the cell walls. In order to quantify the contribution of cellulose to wood elastic properties in both tension and compression, the change in cellulose (0 0 4) lattice spacing (cellulose crystal strain) was measured by X-ray diffraction during a bending test on poplar specimens. A detailed methodology is presented to accurately quantify this cellulose crystal strain. Results show that during elastic loading, cellulose crystal strain is roughly proportional to wood strain. The strain ratio (cellulose crystal strain/wood strain) was close to 0.75, and did not differ significantly in tension and compression. Interpretation of the strain ratio with respect to cellulose orientation shows that part of the wood strain occurs without inducing cellulose crystal strain. This contribution amounts to 10–15% of wood strain, and its possible origin at different levels of wood ultra-structure is discussed.     

Effect of Different Vanadate Salt Composition on Oil Ash Corrosion of Boilers

Corrosion in oil-fired boilers is accelerated in the presence of V, Cl and S which derive from low-grade fuels or the environment. 10CrMo9-10 steel is commonly used in such boilers. In order to evaluate the salts corrosion behavior of such low Cr steels, samples were immersed in several vanadate salt combinations of Cl, S, Na and Ca in air at 600 °C. Even during short-term exposure, different dominant corrosion mechanisms could be identified such as active oxidation, sulfidation and acidic or basic fluxing, depending on the exact salt composition. The aggressiveness of the different salt mixtures was ranked with regard to the metal loss. It is also demonstrated that corrosion can be reduced by the addition of a calcium-containing inhibitor.     

On-the-fly calibrating strategies for evolutionary algorithms

The issue of controlling values of various parameters of an evolutionary algorithm is one of the most important and interesting areas of research in evolutionary computation. In this paper we propose two new parameter control strategies for evolutionary algorithms based on the ideas of reinforcement learning. These strategies provide efficient and low-cost adaptive techniques for parameter control and they preserve the original design of the evolutionary algorithm, as they can be included without changing either the structure of the algorithm nor its operators design.     

The effect of washing water parameters (pH, hardness and sodium pyrophosphate content) on the water-holding capacity and gelation characteristics of sardine (Sardina pilchardus) mince

In order to determine the effect of washing water parameters [pH, hardness and tetrasodium pyrophosphate (TSPP) content] on the water-holding capacity (WHC) and gelation properties of sardine (Sardina pilchardus) mince, two experiments designed by response surface methodology were carried out. The WHC of the mince was maximum when washed in the pH range of 6.5–7.0, with TSPP>1.7?g???l^-1, and CaCO₃ between 30 and 60?mg???l^-1. With the exception of breaking deformation and the folding test, where the highest values were obtained at 60?mg???l^-1 CaCO₃, the variation of water hardness did not induce any significant changes in the other rheological parameters. The use of relatively high concentrations of TSPP in the leaching water contributed to the achievement of high values of breaking deformation, though beyond 2.5?g???l^-1 a detrimental effect on breaking force was observed, and consequently also on gel strength.     

Contribution of Leu and Hyp residues to antioxidant and ACE-inhibitory activities of peptide sequences isolated from squid gelatin hydrolysate

Squid gelatin obtained from inner and outer tunics was hydrolysed with Alcalase to isolate antioxidant peptide sequences. The ACE-inhibitory activity of the isolated peptides was also evaluated. After fractionation by ultrafiltration and size-exclusion chromatography into four fractions, the antioxidant activity of the peptide fractions was determined by radical scavenging ability and ferric reducing power. Fraction FIII showed the highest antioxidant activity, although slight differences could be expected in the antioxidant activity of the different fractions based on the amino acid composition. FIII was subjected to liquid chromatography and tandem mass spectrometry (LC–MS/MS) and two major compounds were identified: the compound with m/z 952.42, which could be mostly comprised by the carbohydrate fucose, and the peptide with m/z 1410.63. Three possible sequences were proposed and synthesised for this peptide, and the contribution of Leu or Hyp residues to the antioxidant and ACE-inhibitory activities of the resulting sequence was evaluated. The presence of Leu residues in the peptide sequence in replacement of Hyp seems to play an important role in the antioxidant and ACE-inhibitory activity.     

Evaluation of an innovative system for improving readability of passive UHF RFID tags attached to reusable plastic containers

Radio frequency identification (RFID) is a contactless identification technology that has proven to work well in conjunction with reusable plastic containers (RPCs). The impact of this technology on returnable containers has been explored by several past studies. This study evaluates an innovative system for improving readability of passive UHF RFID tags in conjunction with RPCs. The system involves an energy transfer device (ETD), which when attached to the RPCs, passively transfers radio frequency signals to interior regions of a unitized load thereby improving the readability of all RFID tags attached to the RPCs. This study included an evaluation of the improvement in readability of tagged RPCs in a unitized load with forklift truck speed, product type and pallet pattern as the variables and with readability as the main control variable. It was observed that ETDs vastly improve the readability rates by nearly 97%. Results are also included in this paper describing the effects of the product type, pallet patterns and forklift truck speeds on the readability of tagged RPCs in a unitized load. Copyright © 2011 John Wiley & Sons, Ltd.