نشریه پژوهش های علوم و صنایع غذایی ایران
سال هشتم شماره 1 (پیاپی 19، بهار 1391)

Recently great afford have focused on the production of food and beverages which are rich in phenolic and antioxidant components. The epidemiology investigations have proved that the regular Composition of food and beverages are richer in phenolic and antioxidant components can strongly decrease the cardiovascular disease. This was done after the preparation of components such as soymilk mixed with sour cherry and barberries juice. In this research, the DPPH free radical method bas been used in order to analyses the antioxidant activity, Folin-Ciocalteau and pH differential method were to estimate the amounts of phenolic compounds and antioxidant and anthocyanin. Also the amount of vitamin c was estimated by standard method which is used for fruit juice. The data's were analyzed by SAS software. The maximum scavenging capacity of radical DPPH wsa seen in sample (20 %soymilk and 80% juice) with the average of 41. 88 %SC (ppm), 85. 5 mg/100ml of anthocyanin content,10. 12 mgGAE /gr dry extract phenolic contents and 4. 192 mg/100ml of vitamin c were reported which showed reduction in order samples. corrolational researches shows appositive and significant relation ship between the phenolic contents and anthocyanin and vitamin c of compound and their ability in neutralization of DPPH radical.

Lycopene is a natural and dominant pigment in tomato with coloring and antioxidant properties, which nowadays the demands for its extraction enhancement from tomato and tomato products are increasing. In this study, the effect of pectinase enzyme pre-treatment at 2- 10 ml/kg and also washing with 94% ethanol at 60°C for 5 seconds was studied. In these conditions, treating with 10 ml/kg enzyme concentration at 90 minutes effective time resulted in maximum extraction of lycopene (279.5 mg/100g oleoresin) while for samples treated with pectinase and ethanol, maxmum extraction was 160.87 mg/100g olearesin. Also lycopene extraction yield from 100 g sample was 0.113609 and 0.089478 mg respectively. Totally in this study it was shown that pectinase treatment without ethanol treatment for extraction of lycopene is better in tomato waste.

Soy protein concentrate (SPC) is a functional and nutritional product which is produced under conditions where soy proteins are immobilized in soy flour and soluble carbohydrates are removed. In this study, four different soy flours including defatted soy flour (fat content 3.67, PDI 55.10), defatted and toasted soy flour (fat content 3.78, PDI 10.72), low fat soy flour (fat content 14.34, PDI 32.71), and whole soy flour (fat content 22.08, PDI 28.72) and two washing methods including alcohol washing and acid washing were used to produce SPC Then yield, changes in chemical and functional properties including PDI, dispersible solids, water holding and fat binding capacity, emulsifying and foaming properties were determined. The results showed that SPC from whole soy flour had higher yield and higher increase in fat content but presence of fat reduced protein concentration. Acid washing had lower production yield than alcohol washing due to better removalg of soluble carbohydrates but it increased fat and protein content. Functional properties of SPC from defatted soy flour was changed significantly during its process while fat content or heat denaturation occurred during toasting diminished its effect except for emulsification stability. During the process, water holding capacity increased specially in products with higher amounts of fat content. Although most of PDI changes arose from drying step, but the effect of processing on emulsification and foaming properties was much higher than drying.

In this research, the production of plum pastille-like with starch and gelatin was studied. Thirteen formulation of plum pastille-like were prepared according to a second-order composite rotatable design (with five central points). Response surface methodology (RSM) was used to optimize product formulation with: gelatin concentration ranging from 3.85 to 6.925 % (w/w), and starch concentration ranging from 0 to 3.85 % (w/w) as independent variables. The dependent variables were texture objective evaluation and total acceptance obtained from sensory analysis. The texture and flavor attributes of the samples were identified and evaluated by a trained descriptive panel. The thickeners strongly affected texture and flavor attributes of the samples. The resulting polynomial equation (R2=0.9325) revealed that a formulation with 5.38% gelatin and 3.85% starch had a maximum total acceptance.

In multi-stage drying of various rough rice varieties, determination of the optimum drying and tempering conditions is important to accelerate the operation and reduce energy consumption, as well as produce a high quality product. In this research, two rice varieties namely, Shafagh (long-grain) and Sazandegi (medium-grain) were dried under high (air temperature and relative humidity of 60°C and 17%) and low (air temperature and relative humidity of 40°C and 12%) drying conditions at four various durations of 1.5, 3, 4.5 and 6 points percentage moisture content removal (PPMR) in the first stage of drying. Immediately after drying, the tempering operation was performed at the same temperature of drying in sealed bags at seven durations of 0, 40, 80, 120, 160, 200 and 240 min. Finally, all samples were dried to 12.5% (w.b.) moisture content as the second drying stage. After hulling and milling, the indices of mass degree of milling (DOMm), and the optical degree of milling (DOMmm) determined by a milling meter were measured and statistically compared for each sample. The experiments were conducted in factorial split with a completely randomized design. The results revealed that during dehydration of the tested varieties under low condition in the first stage, the tempering operation had not significant effect on DOMm and DOMmm. But during drying under high drying condition in the first stage, the tempering effect was significant on both quality indices. So that, for Sazandegi and Shafagh varieties, 6 PPMR in the first drying stage followed by 240 and 200 min tempering for the highest DOMm, and 160 and 240 min tempering for the maximum DOMmm, is recommended, respectively.

The starch based films have some disadvantages such as weak mechanical and poor water barrier properties that restrict their applications in food packaging. In the present research, the polyvinyl alcohol (POVH), as a compatible polymer, and montmorillonite (MMT) nanoclay, as a nanofiller, were added to plasticized starch film (PS) to improve its properties and also to produce PS-MMT-PVOH nanocomposits with different MMT content (3,5,7%). The results of X-ray diffraction (XRD) villustrated that the nanostructure of investigated starch based nanocomposites films has an exfoliated structure which can be attributed to the good dispersing of filler in polymer matrix. DSC results showed that with adding MMT and increasing its content from 0 to 7%, melting point and Tg increased from 242ᵒC to 262ᵒC and 148ᵒC to 188ᵒC. The results of tensile test showed that addition of PVOH and MMT increased the ultimate tensile strength (UTS) and decreased the water vapor permeability (WVP) of nanocomposite films.

In this study, response surface methodology was used to determine the optimum raw sugar beet juice purification process conditions using bentonite to produce inverted liquid sugar. For this purpose, impact of factors on the purification process such as bentonite concentration (1-5 gr/li), pH (3.5-6) and temperature (35-95 ˚C) was investigated. For each response, a second-order polynomial model was developed using multiple linear regression analysis. Correlation coefficients of fitted regression models of color, turbidity, ash, adjusted purity and invert sugar for juice purification process were determined as 0.95, 0.89, 0.90, 0.91 and 0.96 respectively. Results showed that while increasing the bentonite concentration increased the turbidity content but the adjusted purity decreased, and had no significant effect on other parameters. At lower pH levels, separation of color and turbidity causes by bentonite, but was in creased it decreased separation of ash and also increased invert sugar levels. With increasing temperature from 35˚C, to 95˚C, Separation of color and turbidity causes and invert sugar and adjusted purity content as well as increased, while this variable has no significant effect on syrup ash content. The optimum conditions of raw sugar beet juice purification process using bentonite was determined to obtain minimum color, turbidity and ash with maximum invert sugar and adjusted purity which were verified experimentals were found to be bentonite concentration of 1.70 gr/li, pH of 4.47 and temperature of 75˚C. At this optimum point, color, turbidity, ash, adjusted purity and invert sugar content were found to be 1664 ICU420, 6.3 NTU, 0.55 %, 93.9 % and 1.60 %, respectively.

Despite the potential of high intensity ultrasound treatment on homogenization of milk and dairy based products, this treatment, under certain conditions, may lead to produce off-odors which can influence its applicability in the food industry. Therefore, in this research, cacao flavored milk (chocolate milk) was treated using ultrasound at various levels of power intensity, exposure time, and treatment temperature. A light microscope equipped by high resolution digital camera was used to evaluate the size distribution of cocoa particles. Finally, the color, flow and viscosity, and sensory characteristics of stabilized samples were determined. According to the findings, increase of power intensity and exposure time led to a significant increase on the degree of homogenization, and subsequently a paramount decrease on the size of cocoa particles. The cocoa particle diameters of chocolate milk which sonicated at 65 ºC were significantly smaller than the other temperatures. Moreover, the stabilized samples showed Newtonian behavior where the viscosity of control was lower than those treated by ultrasonic. With increase of ultrasound power intensity and exposure time, the viscosity of treated samples decreased. In terms of color, the sonicated samples showed higher L* values and the increase of power intensity and exposure time led to a significant increase on L* value. These samples gained lower sensorial scores than control mostly due to their ‘rubbery’ aroma. But, overall acceptance of treated samples had no significant difference against control. The ultrasound is an effective, rapid, and novel technique which can reduce the size of cocoa particles in order to produce stabilized chocolate milk where its color, sensory and rheological properties was very similar to one treated by conventional heat treatment. These findings can open new approaches in terms of its applicability in dairy industry.

Limonene is a major flavor Producing Compound in orange - flavored soft drinks. It is an important parameter in marketability of products. Effect of molar fraction, time and CO2 on Limonene activity coefficient was evaluated using Dortmund-UNIFAC thermodynamic model. Results showed that activity coefficient decreased by increasing molar fraction. Also, activity coefficient was in minimum level at 30 days storage and increased before and after this period of time. CO2 had a negative effect on Limonene activity coefficient.

In this research, modeling of limiting flux in membrane filtration of skimmed milk as well as the results of simulation by MATLAB is presented. The presented model is actually a force balance approach and consists of drag, gravitational and lift forces, and forces between colloidal particles (electrostatic repulsive and van der Waals attractive forces). To consider the back diffusion phenomenon in modeling, the Brownian and shear-induced diffusions have also been considered.To evaluate the ability of the presented model in this study for prediction of limiting flux of membrane filtration of skimmed milk, comparisons between the results of the present model and experimental data and the results of the model presented by Samuelsson et al. have also been made in this research. By surveying some statistical parameters obtained from these comparisons, it was found that in order to predict the limiting flux in membrane filtration of skimmed milk, interaction forces between particles should be considered.