نشریه نوآوری در علوم و فناوری غذایی
پیاپی 7 (بهار 1390)

Serum separation during milk- juice drinks storage is one of the major problems which happens due to low pH (≤4.00) and aggregation of casein. To prevent or reduce the sedimentation of milk protein (i.e. casein), milk- juice drinks are commonly stabilized with hydrocolloids. Therefore, in the present study the influences of pectin and Carboxymethylcellulose on the stability of milkraspberry juice drink and their blend synergistic effect were investigated. For this purpose, milkraspberry juice drink samples were prepared using pure pectin and Carboxymethylcellulose at concentration 0.2%, 0.3% and 0.35%, blend of pectin and Carboxymethylcellulose (ratios, 25:75, 33.4:66.6 and 34.3:65.7) at concentrations 0.2%, 0.3 % and 0.35%, during a certain process. Moreover, the stabilization mechanisms were studied using rheological, apparent viscosity and sedimentation percent measurements. Based on the findings of the present study, the best fitted rheological model for the samples was Power law. Samples including the blend of pectin and Carboxymethylcellulose were more stable and viscose than those including pure Carboxymethylcellulose (P<0.05).

In this study,physicochemical and microbiological properties and Aflatoxin content of 73raw water melon seed samples were analyzed. The results revealed that aflatoxin B1 (AF B1) was found in 30 samples with mean value of 12.43 ngg-1. The AFB1 levels in 13 samples exceeded the maximum tolerance limit accepted in Iranian national standard. The results also showed that 42.8% and 60% of the samples have the acidity and proxide value mare than 1%(w/w as oleic acid) and 2 meq/kg, respectively.In microbiological properties, 100%, 67% and 89 % of samples showed contamination by Coliforms, and moulds and Escherichia Coli, respectively.

Ice cream is one of the desserts which have the most consumption in the World and Iran. Consequently,on health grounds, the types and component content are very important for huge number of consumers.In this study,the effect of replacing skim milk powder and cream by Almond (%95 total solid)on the quality properties of ice cream was evaluated. Replacing Almond was carried out at four levels %15, %30, %45 and %60 associated with one control. The results showed that there was no significant difference among the attributes of replacing %15 sample and control concerning physical properties. Of course, the Aroma and Flavor of Almond was not traceable in it too. There was, fine aroma and flavor on %60 level. But it had significant differences with control as to physical properties. Finally the %45 level replacement was considered as the best.

A comparative study was conducted on concentration of metals Hg, Cd and Pb in the muscle and liver of Cyprinion macrostomus in Karoon River in winter 2011. Eighteen sample were collected in winter. Metals were extracted from the tissues using wet digestion method and concentration of the heavy metals were measured by Atomic Absorption Spectrophotometer Perkin Elmer 4100. The highest concentration of Hg, Cd, and Pb 20.06±1.62, 124.60±3.11 and 232.86±7.40 μg/Kg/wd in liver. Concentration of heavy metals in liver was higher than the muscles. Accumulation of the elements under study in muscles and liver of Cyprinion macrostomus had significant differences (P<0.05). Concentration of Hg, Cd and Pb in muscles Cyprinion macrostomus was lower than WHO and FDA standards.

In the present research, physico-chemical, texture, and organoleptic properties of low fatmayonnaise formulated with pectin and inulin were investigated. Mayonnaise fat wassubstituted at 25 and 50% by inulin, pectin, and their combinations. Samples were refered to as P-25, P-50, I-25, I-50, IP-25, and IP50. Mayonnaise containing 75% oil was used as control. The results showed that calorie of all low fat samples was significantly (p<0.05) lower than that of control. Moisture content of all low fat samples was significantly lower than that of the control sample. The highest firmness and viscosity belonged to the P25 sample, which was significantly higher than that of control. Results of sensory properties showed that the highest overall acceptability belonged to P25 and IP50 samples. It was concluded that inulin and pectin had the potential to be used as fat replaces in mayonnaise.

In this study, the effect of variety on geometrical properties (length, width, thickness, average arithmatic and geometrical mean diameter, equivalent diameter, surface area, volume and sphericity coefficient), gravimetrical properties (true and bulk density, porosity and a thousand grain mass), frictional properties (filling and emptying angle of repose, coefficient of static friction against surfaces of aluminum, steel, galvanized iron, rubber, cement and wood) and Aerodynamical property (terminal velocity) were determined. The effect of variety was significant (P<0.01) in all Physical properties (expected true density) investigated. The most geometrical diameter belongs to Pofaki with 8.62 mm. The most coefficient of sphericity belongs to Pofaki, with 84.47% and the least coefficient one belongs to Shamshiri, with 83.34%. Most bulk density related to the Shamshiri (673 Kg/m3) and the most filling angle of repose belongs to Pofaki (32.47 degree). The highest static coefficient of friction in both varieties belongs to surface of wood (Shamshiri 0.579 and Pofaki 0.611) and the lowest coefficient of static friction for Shamshiri related to surface of aluminum (0.543) and for Pofaki related to surfaces of aluminum (0.575) and steel (0.575). Maximum terminal velocity was related to the Pofaki (11.54 m/s).

Considering undesirable effects of synthesized antioxidants on human body and being aware of the subject that omission of antioxidants may provide some field for collection of useless materials resulted from oxidation of fat in foods so that some disorders are provided in the body, using antioxidants with natural resources in fats and edible oils is considered as a logical solution. Considering the above-mentioned reasons, in this research, first phenolic compounds of senna leaf were extracted by ethanol and methanol solvents using percolation method. The results showed that yield of extracting methanol extract is more than ethanol, and the relevant quantities were reported 14.17% and 10.3% respectively. Then total quantity of phenolic compounds existed in the extract was determined using Folin-Ciocalteu method. The results showed that quantity of such compounds equals to 665±0.003 in methanol extract as per gram ofGallic acid existed in1kg of dry material In the next stage, reducing power of such extract was examined, and finally antiradical activity of extract was measured according to DPPH method.Evaluation of relation between phenolic compounds and radical scavenging activity of extract showed that there are positive correlation between phenolic compounds and inhibition percent of extract (r=0.96) in level of 0.01. Accordingly, it was determined that the more phenolic compounds, the more power of antiradicals in such extract. Rancimat test was used for evaluating heat stability of soya oil which contained different quantities of methanol extract.Comparison of such treatments showed that there is a meaningful difference between total concentration of extract and sample (p<0.01). According to the results obtained, it was determined that limits of concentration of 750 ppm can be considered as critical concentration because induction period of resisted oil samples is decreased meaningfully by increasing concentration from 750 ppm to 3000 ppm.

Pumpkin samples were osmotically dehydrated through three different salt concentrations (5 % w/w, 10% w/w and 15% w/w and 50% w/w) sucrose solution at 25°c and 50°c. Osmotic solution - fruit weight ratio was 1:20. Artificial neural network was used for estimating water loss and solid gain values undergoing osmotic dehydration. Perceptron artificial neural network with gradient descent optimization algorithm was utilized by hyperbolic tangent function for outcomes prediction. The results indicated that artificial neural network with one hidden layer depicted the best fitting when the hidden layer had 10 and 18 neurons for solid gain and water loss respectively. Also, it was found that artificial neural network with 6-6 and 22-22 neurons in two hidden layers stated the optimum outcomes to approximate water loss and solid gain, respectively.