PHYSICAL CHARACTERISTICS AND ANTIOXIDANT ACTIVITIES OF ORGANIC GRAPES

Studies on antioxidative activities of fruits have focused mainly on grapes, which have been reported to inhibit oxidation of human low‐density lipoprotein (LDL) at a level comparable to wine. With regard to consumer attitude on the health benefits of the product, organic grapes were selected for study. Organic grapes of Vitis vinifera origin var. Semillon, Columbard, Cabernet sauvignon, Merlot, Grenache and Carignan produced under the control of International Nutrition and Agriculture Certification Company in Kemalpasa/Ulucak were studied. The order of grape varieties concerning grape cluster, stem and number (100) values from the highest to the lowest was determined as: Semillon > Merlot > Cabernet sauvignon > Carignan > Columbard > Grenache. Positive correlation was determined between antioxidant activities (AOA) and total phenols (r = 0.845; P = 0.034). The highest AOA were determined in Merlot (86.55%) and Cabernet sauvignon (83.60%) varieties. Considering LDL, low‐density lipoprotein‐diene values for Cabernet sauvignon and Merlot varieties were 82.73 and 65.48%, respectively. The values of low‐density lipoprotein‐malondialdehyde were different, with the highest percentage found for Semillon (80%). The highest value of total phenols was found in Merlot (4,200 mg/L gallic acid equivalents) variety. Evaluating all analyzed parameters, principal component analysis results demonstrated the similarities between Carignan and Grenache, between Merlot and Cabernet sauvignon and between Columbard and Semillon grape varieties.     

Si nanowire FET and its modeling

Because of its ability to effectively suppress off-leakage current with its gate-around conffguration, the Si nanowire FET is considered to be the ultimate structure for ultra-small CMOS devices to the extent that the devices would be approaching their downsized limits. Recently, several experimental studies of Si nanowire FETs with on-currents much larger than those of planar MOSFETs have been published. Consequently, Si nanowire FETs are now gaining significant attention as the most promising candidate fo...     

EVALUATION OF pH CHANGE KINETICS DURING DIFFERENT STAGES OF KASHAR CHEESE PRODUCTION FROM BOVINE, OVINE AND CAPRINE MILK

The objective of this study was to determine the pH change kinetics during Kashar cheese production from bovine, ovine and caprine milk. Kinetics of pH change were determined during milk ripening, cooking/holding and pressing/fermentation phases of Kashar cheese. The pH decreased logarithmically, nonlinearly, with time in the milk ripening period and was reduced linearly with time in the cooking/holding and pressing/fermentation stages. The time of pH decrease in cow's, ewe's and goat's milk was significantly different, except cooking/holding time, for three stages. There was no difference between bovine and caprine milk in cooking/holding time; however, ovine milk was significantly different from the other two kinds of milk. The shortest and the longest overall times were determined for caprine and ovine milk cheeses, respectively. The rate of change in milk pH of the three species was significantly different for three stages. The rate followed the pattern caprine  >  bovine  >  ovine milk.

PRACTICAL APPLICATIONS

Optimum acid development is essential to creating the desired cheese mass. For each major cheese type, lactic acid must develop in the appropriate time, usually not too rapidly or too slowly, and in a specific concentration. The progress of acidification is monitored by pH change in the industrial Kashar cheese production. The final pH of cheese is determined not only by the amount of lactic acid but also by the buffering capacity (BC) of the milk and curd. However, the BC is different between milk species. This study evaluates and compares the pH change kinetics during various stages of Kashar cheese making using cow's, ewe's and goat's milk. This work may help to compare milk and cheese curds made from bovine, ovine and caprine milk.     

The effects of carob juice concentrates on the properties of yoghurt

Plain and fruit-flavoured yoghurts were made by adding 2.5, 5.0, 7.5, 10.0 mL carob juice concentrate (CJC) portions to 100 mL milk. The titratable acidity, pH, viscosity, whey separation, yoghurt organisms and sensory properties were determined weekly over a period of 4 weeks. Addition of CJC caused an increase in the fermentation time and reduced viscosity and viable organisms, while increasing the pH and whey separation of the yoghurts ( P <  0.05). A lack of sweetness was the main criticism of the yoghurts with 2.5 and 5.0 mL CJC, while those with 7.5 or 10.0 mL were mostly preferred by sensory panellists.     

Statistical investigation of hydraulic driven circular interpolation motions

In this study, a twin-axis gantry has been structured to examine hydraulic driven positioning skills of the curvilinear motions based on ISO 230-4 standard entitled ??Circular tests for numerically controlled machine tools??. The system is controlled by a path and position control module of a PLC device. As a result of the experiments conducted based on the full factorial design, the effects of piston diameter, feed rate, radius and their two-way interactions on the circularity error are determined through analysis of variance. Accordingly, minimum circularity error is obtained with the piston diameter of 63 mm, inertia load of 12.5 kg, radius of 5 mm and feed rate of 50 mm/min as 0.345 mm. Circularity error increases with the increase of inertia load, radius and feed rate, and declines with the increase of piston diameter. Lastly, piston diameter has the greatest effect on the circularity error change and followed by radius, feed rate, piston diameter?Cradius, radius?Cfeed rate, piston diameter-feed-rate, inertia load, piston diameter?Cinertia load, and inertia load?Cradius factors and interactions.     

EFFECT OF HYDROGEN PEROXIDE ON SOUR CHERRY ANTHOCYANINS

Degradation of sour cherry anthocyanins was studied at different H₂O₂ concentrations (0.233‐11.63 mmol.L^?1) over the temperature range of 20‐55C. Degradation reaction fitted to a first order kinetic model progressed very rapidly even at low H₂O₂ concentrations. Thus, the t_1/2 values at 20C varied between 111‐20 h in the concentration range of 0.233‐2.327 mmol.L^?1 H₂O₂. The degradation of anthocyanins occurred at a faster rate with increasing temperature at 5.82 and 11.63 mmol.L^?1 H₂O₂ concentrations. Between 25‐55C, activation energies (E_a) were 9.53 and 10.60 kcal.mol^?1 for 5.82 and 11.63 mmol.L^?1 H₂O₂ concentrations, respectively. Higher E_a value at 11.63 mmol.L^?1 H₂O₂ concentration indicated that the effect of temperature increased at higher H₂O₂ concentrations. A quadratic relationship (y = ‐0.0031x²+ 0.0218x + 0.0008, R²= 0.996) was found between the degradation rates at 20C and H₂O₂ concentrations of 0.233‐2.327 mmol.L^?1. According to this equation, k of 1.12 × 10^?3 h^?1 and t_1/2 of 26 days at 20C may be expected at 0.5 ppm (0.0147 mmol.L^?1) H₂O₂ concentration, i.e., the max. allowable H₂O₂ level by FDA in the finished food packages.