Nesimi Aktaş

Effect of starch type and its modifications on physicochemical properties of bologna-type sausage produced with sheep tail fat

Gelatinized, solubilized/dispersed and retrograded starches were produced from normal (unmodified) corn and potato starches, and were used with sheep tail fat for sausage batters. Emulsion stability, jelly and fat separation, water holding capacity (WHC), emulsion viscosity and batter pH were determined. Penetrometer reading after cooking of the batters, and tenderness of the end-product were determined. Modified starches statistically (p<0.01) affected emulsion stability and emulsion viscosity. The modification process was not significant for pH, WHC, jelly and fat separation and penetrometer values (p>0.05). While type of used starch had a significant effect on jelly and fat separation (p<0.05), for the other measurements it was not significant (p>0.05).

Influence of weak organic acids and salts on the denaturation characteristics of intramuscular connective tissue. A differential scanning calorimetry study

Intramuscular connective tissue obtained from Longissimus dorsi muscle of a 4-year-old beef carcass was treated with NaCl solutions of 2, 4, and 6% (w/v), and CaCl(2) solutions of 50, 100, and 150 mM, and citric and lactic acid solutions of 0.5, 1.0, and 1.5% for three different marinating periods (24, 46, and 72 h). Changes in denaturation characteristics were investigated using differential scanning calorimetry and it was found that the denaturation onset temperature (T(o)) and the denaturation peak temperature (T(p)) increased as the NaCl concentration increased but decreased as the CaCl(2) concentration increased, irrespective of marinating time. Lactic and citric acid decreased T(o) to about 39°C, from over 60°C breaking the structure of fibrils.

Moisture adsorption properties and adsorption isosteric heat of dehydrated slices of Pastirma (Turkish dry meat product).

Moisture sorption characteristics of dehydrated pastirma were investigated at 15°C, 20°C and 30°C over a water activity (a(w)) range of 0.2-0.9. Sigmoidal (type-II) adsorption isotherms were observed for pastirma. The experimental sorption data obtained were applied to the Halsey, Harkins-Jura, Smith, BET, Henderson, Freundlich and GAB isotherm equations to test fitness of these equations to pastirma. The order of the best fit of sorption data obtained for pastirma at 15°C, 20°C and 30°C in all the range of a(w) studied (0.2-0.9) was Harkins-Jura>Halsey>BET>Smith>Freundlich>GAB>Henderson, respectively. In the range a(w) 0.2-0.55, BET model has a better fit than in the range a(w) 0.2-0.9. Isosteric heats of adsorption were evaluated by applying the Clausius-Clapeyron equation to experimental isotherms and decreased with increasing moisture content.

Determination of glass transition temperature of beef and effects of various cryoprotective agents on some chemical changes

Sucrose (2%), sorbitol (2%), mannitol (2%), gum arabic (0.15%), carrageenan (0.15%) and meat stabilizer (0.5%) were blended with ground beef and stored for 6 months separately at -9°C, -13°C (glass transition temperature (T(g)) of beef determined by Differential Scanning Calorimetry (DSC)) and -18°C. Total volatile basic nitrogen (TVB-N) and Thiobarbituric acid-reactive substances (TBARS) were determined at 1, 3 and 6th months of storage. Cryoprotectants and storage period had a significant effect (P<0.05) on the TVB-N and TBARS values. Although there were no statistically significant differences between storage at -13°C (T(g)) and -18°C, storage at -9°C had different effects on TVB-N and TBARS.

Fractionation and characterization of edible sheep tail fat

Edible sheep tail fat was effectively fractionated by an acetone crystallization. Each of the fractions and filtrates were analyzed for melting point, refractive index, iodine value, fatty acid composition, and characterized by differential scanning calorimetry. Fatty acid analysis indicated that as the fractionation temperature decreased, the concentration of unsaturated fatty acids in the fractions increased. The liquid fraction had a differential scanning calorimetry melting curve similar to commercial salad oil and the curve of one of the filtrates resembled that of cocoa butter.

Effect of sodium chloride, sodium nitrite and temperature on desorption isotherms of previously frozen beef.

Moisture desorption isotherms of beef were determined in the relative humidity range of 23 to 90% at 5, 15 and 25°C and at 2.5% NaCl and 2.5% NaCl+150 ppm NaNO(2) content. Desorption isotherms were found to be typical type II sigmoid. The water content at equilibrium was higher in beef with NaCl and NaCl+NaNO(2) than control samples. Experimental data were fitted to various mathematical models and it was found that the Peleg model was best in describing the equilibrium moisture content relationship for beef samples over the entire range of temperatures. The net isosteric heat of sorption was estimated from equilibrium desorption data, using the Clausius-Clapeyron equation. Isosteric heats of desorption were found to increase with decreasing moisture content.