Microbiological evaluation of stuffed mussels

Stuffed mussel is a traditional food, sold by street vendors in coastal parts of Turkey and other Mediterranean countries. In the present study, the microbiological quality of not only the stuffing mixture, but also the outer surface of the stuffed mussels was evaluated for 1 year, and the effect of the ambient temperatures on the prevalence and the count levels of the microorganisms were evaluated. Fifty samples (750 stuffed mussels in total) were collected periodically, and microbiological analyses were performed by standard procedures for aerobic plate count, coliforms, fecal coliforms, Enterobacteriaceae, Staphylococcus aureus, Bacillus cereus, and Vibrio spp. Aerobic plate counts above 5 log CFU/g were obtained in 16 and 72% of stuffing mixture samples at high and low ambient temperatures, respectively, and average aerobic plate counts of outer surface samples at high and low ambient temperatures were 3.21 and 4.34 log CFU/ml, respectively. The prevalence and the count levels of coliforms, fecal coliforms, Enterobacteriaceae, and Vibrio spp. (except for the prevalence of Vibrio spp. in stuffing mixture samples) in the samples at high ambient temperatures were considerably higher compared with those at low ambient temperatures (P < 0.05). High frequencies of pathogens S. aureus and B. cereus were found in stuffing mixture samples at high ambient temperatures, with averages of 2.84 and 2.94 log CFU/g, respectively (P < 0.05). The result of this investigation indicates that stuffed mussels as a street food may constitute a potential health hazard, especially at high ambient temperatures, depending on contamination level and lack of sanitary practices, and therefore, handling practices should require more attention and improvement.     

Genetic algorithm with local search for the unrelated parallel machine scheduling problem with sequence-dependent set-up times

In this paper, a genetic algorithm (GA) with local search is proposed for the unrelated parallel machine scheduling problem with the objective of minimising the maximum completion time (makespan). We propose a simple chromosome structure consisting of random key numbers in a hybrid genetic-local search algorithm. Random key numbers are frequently used in GAs but create additional difficulties when hybrid factors are implemented in a local search. The best chromosome of each generation is improved using a local search during the algorithm, but the better job sequence (which might appear during the local search operation) must be adapted to the chromosome that will be used in each successive generation. Determining the genes (and the data in the genes) that would be exchanged is the challenge of using random numbers. We have developed an algorithm that satisfies the adaptation of local search results into the GAs with a minimum relocation operation of the genes’ random key numbers – this is the main contribution of the paper. A new hybrid approach is tested on a set of problems taken from the literature, and the computational results validate the effectiveness of the proposed algorithm.     

Synthesis of <Emphasis Type=Italic>α</Emphasis>- and <Emphasis Type=Italic>β</Emphasis>-Rhombohedral Boron Powders<Emphasis Type=Italic> via</Emphasis> Gas Phase Thermal Dissociation of Boron Trichloride by Hydrogen

The α-rhombohedral and β-rhombohedral crystal structures of pure elemental boron powders have been synthesized via gas phase thermal dissociation of BCl₃ by H₂ on a quartz substrate. The parameters affecting the crystal structures of the final products and the process efficiency, such as BCl₃/H₂ molar ratio (1/2 and 1/4) and reaction temperature (1173 K to 1373 K [900 °C to 1100 °C]), have been examined. The experimental apparatus of original design has enabled boron powders to be obtained at temperatures lower than those in the literature. The surface/powder separation problem encountered previously with different substrate materials has been avoided. Boron powders have been synthesized with a minimum purity of 99.99 pct after repeated HF leaching. The qualitative analysis of exhaust gases has been conducted using a Fourier transform infrared spectroscope (FTIR). The synthesized powders have been characterized using an X-ray powder diffractometer (XRD) and scanning electron microscope (SEM) techniques. The results of the reactions have been compared with equilibrium predictions performed using the FactSage 6.2 (Center for Research in Computational Thermochemistry, Montreal, Canada) thermochemical software.     

Cooking quality and sensorial properties of noodle supplemented with oat flour

Effects of oat flour addition (10, 20, 30, and 40%) on the quality characteristics of noodle were investigated. Noodles were evaluated in terms of cooking quality, color, chemical, and sensory properties. As oat flour level increased, protein, crude fat, ash, Mn, Fe, Zn, and Mg contents of noodles increased. Oat flour caused increases in cooking loss of noodles. Sensory and cooking characteristics of noodles were negatively effected when oat flour level was increased compared with the control. Noodle with 10% oat flour received the highest sensory scores in all noodle samples containing oat flour. Overall acceptability scores of control and in only the noodle with 10% oat flour were found statistically (p<0.05) similar. Especially, the usage of 10% oat flour in noodle formulation gave satisfactory results in terms of acceptability.     

Enrichment of Functional Properties of Ice Cream with Pomegranate By‐products

Pomegranate peel rich in phenolics, and pomegranate seed which contain a conjugated fatty acid namely punicic acid in lipid fraction remain as by‐products after processing the fruit into juice. Ice cream is poor in polyunsaturated fatty acids and phenolics, therefore, this study was conducted to improve the functional properties of ice cream by incorporating pomegranate peel phenolics and pomegranate seed oil. Incorporation of the peel phenolics into ice cream at the levels of 0.1% and 0.4% (w/w) resulted in significant changes in the pH, total acidity, and color of the samples. The most prominent outcomes of phenolic incorporation were sharp improvements in antioxidant and antidiabetic activities as well as the phenolic content of ice creams. Replacement of pomegranate seed oil by milk fat at the levels of 2.0% and 4.0% (w/w) increased the conjugated fatty acid content. However, perception of oxidized flavor increased with the additional seed oil. When one considers the functional and nutritional improvements in the enrichment of the ice cream together with overall acceptability results of the sensory analysis, then it follows from this study that ice creams enriched with pomegranate peel phenolics up to 0.4% (w/w) and pomegranate seed oil up to 2.0% (w/w) could be introduced to markets as functional ice cream. Enrichment of ice creams with pomegranate by‐products might provide consumers health benefits with striking functional properties of punicalagins in pomegranate peel, and punicic acid in pomegranate seed oil.     

An approximate method for static and dynamic analyses of multi‐bay coupled shear walls

In this study an approximate method based on the continuum approach and transfer matrix method for static and dynamic analyses of multi‐bay coupled shear walls is presented. The whole structure is idealized as a sandwich beam in this method. Initially the differential equation of this equivalent sandwich beam is written, then shape functions for each storey can be obtained by the solution of differential equations. By using boundary conditions and storey transfer matrices which are obtained by these shape functions, system modes and periods can be calculated. Reliability of the study is shown with a few examples. A computer program has been developed in MATLAB and numerical samples have been solved for demonstration of the reliability of this method. The results of the samples display the agreement between the present method and the other methods given in the literature. Copyright © 2007 John Wiley & Sons, Ltd.     

Effect of self-etching ceramic primer on the bond strength of feldspathic porcelain repair

The purpose of this study was to evaluate the effect of a self-etching primer on the bond strength of feldspathic porcelain with composite resin. Forty-eight feldspathic porcelain specimens (13 mm × 13 mm × 2 mm) were sectioned from CAD/CAM blocks. Specimens were randomly divided into 4 groups (n = 12) as regards to surface treatment method; HF acid etching (HFE), Monobond Etch and Prime (MEP), sandblasting (SB), and MEP + SB. After silane application for group HFE and SB, an adhesive bond was used as a bonding agent in all groups. Composite resin cylinders were build up onto the specimens. Specimens were stored in distilled water, thermocycled 5–55 °C for 5500 cycles, and subjected to shear bond strength (SBS) test in a universal testing machine. Data were statistically analyzed by Kruskal-Wallis and Mann Whitney U test (α=.05). Type of failures was evaluated under optical microscopy and surfaces were examined by SEM at ×500 and ×2500 magnifications. There was a significant difference among groups. (p = .019) HF group had the highest mean SBS value (17.54 ± 2.98 MPa) which was significantly higher than other groups (p<.05). Followed by the MEP + SB group (14.68 ± 3.41 MPa), SB group (13.98 ± 3.34 MPa) and MEP group (12.75 ± 2.33 MPa). Nevertheless, the HFE group significantly has higher SBS value than other groups all of the tested surface treatment methods have reached the convenient bond strength values for repair. Although MEP showed clinically acceptable SBS values, further researches with another type of porcelains should be tested.