Mehmet D. Öner

Changes in properties of soaking water during production of soy-bulgur

Changes in soaking water properties (pH, absorbance, soluble solids content, conductivity and colour “L, a, b and YI values”) were investigated during soaking of soybean to produce soy-bulgur (as a new type food product) at 30°, 50° and 70° for 120 min. All the properties of soaking water were significantly affected by soaking time and temperature (P<0.05). Leaching of some nutritional compounds was also observed from soybean to the soaking water. pH, conductivity and soluble solids content of the water increased with increase in temperature indicating leaching of the acidic compounds, minerals and total soluble compounds, respectively. Maximum absorbance (turbidity) was obtained at 50 °C soaking. Yellowness and yellowness index were increased as temperature is increased in contrast to a decrease in lightness. Results reveal the fact that leaching and reabsorption of some nutritional compounds occurs simultaneously. Hence, the initial quantity of the soaking water should be adjusted to limit the loss of the nutritional compounds in the discharging water.

Influence of soaking on the dimensions and colour of soybean for bulgur production

Soaking of soybean was studied to produce the soy-bulgur as a new type food product by measuring the changes in the properties of soybean kernel. Soybeans were soaked in deionized water at different temperatures (30, 50, 70 °C) for 120 min. Dimensions (three-dimensional changes; x, y, z), weight, volume, density, moisture content and colour (L, a, b and YI-values) for soybean were determined during the soaking operation. All responses were affected by time and temperature (P<0.05) significantly during the soaking operation. Percent change in the length (x) increased to 63.3–75.6 (P<0.05) significantly at different temperatures. Widths (y and z) of the soybean also increased significantly (P<0.05). The y-value increased sharply at 100, 40 and 20 min for 30, 50 and 70 °C soaking, respectively. After the sharp rising, the change in the y-value decreased steadily. Percent change in the volume (129.6–146.3) was higher than the percent change in the weight (113.7–120.9%) at the end of the soaking operation due to high amount of swelling of the soybean kernel. A negative percent change in the density was obtained with respect to time at each temperature. The critical moisture content for ideal bulgur production for soybean (40%, w.b.) was reached at each temperature. L (lightness) and b (yellowness) values of soybean colour increased during the soaking in contrast to a (redness) and YI (yellowness index) values (P<0.05).

The effect of salt concentration on rancidity in Gaziantep cheese

Gaziantep cheese is a non-fermented and enzyme clotted type cheese. The changes in oxidative and hydrolytic rancidity in the cheese were analysed during its storage. Storage conditions were selected as 4, 10 and 20°C and 90, 170, 200 and 230 g kg−1 salt solutions by considering the traditional storage conditions. Oxidative rancidity increased with increasing temperature and NaCl concentration in the brine. Hydrolytic rancidity increased with increasing temperature and decreasing salt content of the cheese. The extent of oxidative rancidity was found to be higher than hydrolytic rancidity. The results of this study showed that the storage temperature should not be higher than 10°C and brine concentration must be higher than 90 g kg−1 and lower than 230 g kg−1 to minimize lipid oxidation. Gaziantep cheese was organoleptically examined after 2 months of storage at 20°C and in 90, 170 and 230 g kg−1 salt solutions, and it was found that even at a peroxide value around 1 meq kg−1, acceptable levels of changes in flavour were observed. Sensory analysis results showed that textural properties of Gaziantep cheese changed with salt concentration of the brine. © 1999 Society of Chemical Industry

Electrical Conductivity, Water Absorption, Leaching, and Color Change of Chickpea (Cicer arietinum L.) during Soaking with Ultrasound Treatment

The properties of soaking water of some cereals under high temperature were determined, but limited information is available on chickpeas in the literature. Change in electrical conductivity, turbidity, color, and soluble solids content of soaking water of chickpeas were studied at 87, 92, and 97°C without ultrasound, and with 25 kHz frequency and different ultrasound powers (100–300 W) for 260 min. Water absorption and color values of chickpea seeds were also studied during soaking. All the properties of soaking water and chickpea seeds were significantly (P < 0.05) affected by temperature, ultrasound treatment, and power of ultrasounds indicating leaching of some nutritional and anti-nutritional compounds. The moisture absorption rate of chickpeas increased with the increase of temperature and power of ultrasound, while color of chickpeas changed inversely with soaking water. Results showed that leaching and reabsorption of some nutritional compounds occur simultaneously and ultrasounds can be used to enhance cooking operations.

Thermodynamics of the Dimensional Changes in the Wheat Kernel during Cooking for Bulgur Production

Thermodynamics and physical properties of the dimensional changes in the wheat kernel during cooking was carried out for bulgur production at 87, 92 and 97°C for 140min. There were determined changes of the length (x-dimension), two widths (y- and z-dimensions), weight, volume and density of the wheat kernel. The length of the wheat kernel during cooking decreased, although crease-side width (y-dimension) and secondary width (z-dimension) significantly increased (p 0.05) at each cooking temperature between 6.95-68.05% and 9.95-69.00%, respectively. The volume of the kernel during cooking also significantly (p 0.05) increased (27.35-185.20%), and had a greater percentage change value than the weight (19.25-160.70%) due to swelling of the wheat kernel. Therefore, density decreased negatively. Activation energy, enthalpy, entropy and Gibbs free energy were used to describe the changes of physical attributes of the wheat kernel during cooking. Rate constant values for the length and density of the wheat kernel were negative in contrast to positive rate constant values of the widths, weight and volume of the wheat kernel. The influence of cooking temperature on the physical properties of the wheat kernel revealed that the rate of change in the secondary width (z-dimension), weight and density of the wheat kernel were more sensitive to temperature due to their greater activation energies, 5.95 107, 5.26 107 and 6.11 107 J, respectively. In contrast, the y-dimension of width of the wheat kernel required a lower amount of energy due to crease side. All of the changes in physical properties agreed with the positive values of Gibbs free energy.