Mehmet Mendeş

Characterization of aroma-active compounds, sensory properties, and proteolysis in Ezine cheese.

Ezine cheese is a white pickled cheese ripened in tinplate containers for at least 8 mo. A mixture of milk from goat, sheep, and cow is used to make Ezine cheese. Ezine cheese has geographical indication status. The purposes of this study were to determine and compare the changes in basic composition, aroma, and sensory characteristics, and proteolytic activity of Ezine cheese stored in tinplate containers and plastic vacuum packages during storage. Aroma-active compounds were determined by thermal desorption gas chromatography olfactometry. To evaluate the proteolytic activity, casein and nitrogen fractions were determined. The results indicated that compounds identified at high intensities were dimethyl sulfide, ethyl butyrate, hexanal, ethyl pentanoate, (Z)-4-heptenal, 1-octen-3-one, acetic acid, butyric acid, and p-cresol. Characteristic descriptive terms were cooked, whey, creamy, animal-like, sour, and salty. The level of proteolysis increased in Ezine cheese during storage. Ezine cheese can be ripened in small-size packaging after 3 mo of storage. Approximately 6 mo is sufficient to produce the characteristic properties of Ezine cheese.

Regression tree analysis for predicting slaughter weight in broilers

Abstract In this study, Regression Tree Analysis (RTA) was used to predict and to determine the most important variables in predicting the slaughter weight of Ross 308 broiler chickens. Data for this study came from 224 chickens raised during three different seasons, namely spring (n=66), summer (n=66), winter (n=92). Second week body weight, shank length, shank width, breast bone length, breast width, breast circumference and body length were used to predict the slaughter weight. Results of RTA showed that among the seven independent variables only four were selected, namely; body weight, breast bone length, shank width, and breast circumference. These selected independent variables were more efficient than the others in predicting the slaughter weight. RTA indicated that the birds which had values of second week body weight >295.95 g, breast bone length >55.82 mm and breast circumference >14.18 cm or that of body weight ≤295.95 g, breast bone length >60.26 mm and shank width >8.32 mm could be expected to have higher slaughter weights.

Comparison of ANOVA-F and ANOM tests with regard to type I error rate and test power

A Monte Carlo simulation was conducted to compare the type I error rate and test power of the analysis of means (ANOM) test to the one-way analysis of variance F-test (ANOVA-F). Simulation results showed that as long as the homogeneity of the variance assumption was satisfied, regardless of the shape of the distribution, number of group and the combination of observations, both ANOVA-F and ANOM test have displayed similar type I error rates. However, both tests have been negatively affected from the heterogeneity of the variances. This case became more obvious when the variance ratios increased. The test power values of both tests changed with respect to the effect size (Δ), variance ratio and sample size combinations. As long as the variances are homogeneous, ANOVA-F and ANOM test have similar powers except unbalanced cases. Under unbalanced conditions, the ANOVA-F was observed to be powerful than the ANOM-test. On the other hand, an increase in total number of observations caused the power values of ANOVA-F and ANOM test approach to each other. The relations between effect size (Δ) and the variance ratios affected the test power, especially when the sample sizes are not equal. As ANOVA-F has become to be superior in some of the experimental conditions being considered, ANOM is superior in the others. However, generally, when the populations with large mean have larger variances as well, ANOM test has been seen to be superior. On the other hand, when the populations with large mean have small variances, generally, ANOVA-F has observed to be superior. The situation became clearer when the number of the groups is 4 or 5.

A Study on the Relationships between Some Morphological and Reproductive Traits of the Turkish Crayfish, Astacus leptodactylus Eschscholtz, 1823 (Crustacea: Decapoda)

This study was carried out to investigate relationships between some morphological and reproductive traits of the Turkish crayfish, A. leptodactylus, collected from a controlled irrigation lake in the Yenice province (Çanakkale, Turkey), between July 2007 and June 2008. For this objective, two multivariate analysis techniques, namely canonical correlation analysis and multivariate multiple linear regression analysis, were used. The results of the canonical correlation analysis have shown that the morphological traits may be used to predict the changes in the reproductive traits. For instance, canonical correlation analysis results suggested that the egg weight and the number of eggs are related to the total length, carapace length, and carapace width. The results of multivariate multiple linear regression analysis, on the other hand, show a slightly different picture. Therefore, it is possible to conclude that both canonical correlation and multivariate regression results can be taken into consideration together when investigating the relations between two variable sets.

Growth Curves for Body Weight and Some Body Measurement of Ross 308 Broiler Chickens

Abstract Mendeş, M. 2009. Growth curves for body weight and some body measurement of Ross 308 broiler chickens. J. Appl. Anim. Res., 36: 85–88. To investigate the growth characteristics of Ross 308 male broiler chickens 30 male broiler chickens were used. Results of growth curve analyses suggest that the Gompertz growth model fitted the weight-age, shank width-age, shank length-age and body length-age data very well, while the linear growth model fitted the breast bone length-age, breast width-age and breast circumference-age data. The growth rate (b) for body weight (0.04) was found obviously smaller than that of shank width (0.23), shank length (0.18) and body length (0.23). Inflection point (k) for shank width and body length was found similar. For one weak increase in age a 19.49 mm enhancement in breast bone length, 6.41 mm enhancement in breast width and 4.06 cm enhancement in breast circumference are expected. All regression slope estimates (except for breast width) were significant.