نشریه پژوهش های علوم و صنایع غذایی ایران
سال پنجم شماره 1 (پیاپی 9، نیمه اول سال 1388)

Color and appearance are among the first parameters perceived by consumers to judge the quality of foods. L*a*b* are used to report foods’ colors quantitatively. In this study the use of digital imaging and Photoshop software was evaluated for measurement of L*, a* and b* color parameters. The results showed that L*, a*, and b* values from Hunter colorimeter and the digital imaging method had a good correlation with R2 more than 0.95, but the values from digital imaging method can be used only to monitor the trend of color changes and the actual numbers of digital imaging L*, a* and b* obtained by digital imaging do not have the same value as the L*, a* and b* given by a Hunter colorimeter. Using two equations for the three parameters the values obtained from digital imaging method can be successfully converted to Hunter Lab color corresponding parameters. The color change of Mazafati date during accelerated ripening using acetic acid solutions was monitored by the proposed method. L*, a*, and b* of the samples all decreased over the ripening.

One of the most important stages in sugar industry that making wastewater and contamination is the water obtained to washing of CO2 in mazoot furnace and related pumps. Amount of water consumption in this stage is about 30 to 35 percent of weight of sugar beet, so amount of this stream is considerable. Mixing of carbon black and water compose the colloid in liquid phase. These colloids do not separate easily. This water is black, thus it is unuseable. In this study used liming to refining of wastewater. Samples obtained from tow factories (sugar plant of torbat heydariyeh and joveyn). Lime was added into samples directly. Relationship of pH to amount of added liming, rate of deposition of carbon black, volume of mud and coagulation percent was investigated. the results shown that there is a strong correlation between amount of lime milk and given parameters and rate of deposition of carbon black, volume of mud and coagulation percent evaluate with obtained equations. Additionally the results shown that carbon black separate completely in pH = 11.65, and obtain glassy water.

The tissue of fruit varies at different stages of growth and storage and by determining its characteristics; the stage of fruit maturity can be found. Depending on the type of tissue, the ultrasonic waves will attenuate and its speed will change too while crossing the fruit tissue. Thus, by calculating the attenuation coefficient value and its speed in no destructive way, the characteristics of fruit tissue and the rate of its maturity will be determined. In this study, peach fruits -the Tabrizi variety- were classified in ripen, semi-ripen, large and small groups and the validity of ripen and semi-ripen groups were confirmed by taste panel. Then, in addition to measuring the attenuation coefficient and velocity of ultrasonic wave parameters, the physic-chemical parameters of fruit, including dimensions, mass, density, hardness, reducing sugar, acidity, pH, dry weight and soluble solids contents, which are the maturity indices of peach, were measured and compared with ultrasonic parameters. Results showed that fruit size and degree of maturity significantly affect on the wave attenuation and wave velocity, respectively. The correlation coefficients between attenuation coefficient and hardness (without skin) in ripen and semi ripen groups were higher than 0.8 and also the correlation coefficients of attenuation coefficient in relation with the hardness (by skin) in ripen and semi ripen groups were higher than 0.7. Also, the correlations for both attenuation coefficient and wave velocity in relation with the pH were higher than 0.8 as well as correlation between wave velocity and acidity.