JOURNAL OF FOOD RESEARCH (UNIVERSITY OF TABRIZ)
Year:2015 | Volume:25 | Issue:4|Papers Count:15

Iranian Feta cheese is a high fat product (45% FDM) and its low-fat type has been demanded by consumers regarding of health considerations. For low-fat Feta cheese production, the cheese milk standardization (0, 25 and 50% increasing of milk solids) with milk protein concentrate (MPC) powder was carried out. Then the effects of MPC on yield, chemical (fat, total solid, protein, acidity, pH and salt), sensory (taste, texture and color) and instrumental texture profile analysis (hardness, chewiness, gumminess, springiness, adhesiveness, and cohesiveness) of cheeses were investigated. Low-fat cheese samples were obtained due to milk standardization with MPC and 50% enhancement of milk solids caused about 50% decreasing of fat content in the cheese. The results showed that the addition of MPC to cheese milk caused a significant increase (P£0.05) in the yield, solid content, protein and salt of cheese samples. The sensory evaluation of cheese samples showed that the MPC hadn’t induce significant changes in the cheese flavor but the texture and color scores significantly (P£0.05) increased and reduced respectively. The texture profile analysis showed that MPC hadn’t change adhesiveness of cheese samples but hardness, cohesiveness, chewiness, gumminess and springiness significantly (P£0.05) increased.

Gundelia Tournefortii L. seed oil could be potent enough to consider as edible oil possessing antioxidant properties. To investigate that, the antioxidant activity of this oil and its effects as a natural antioxidant agent was studied. The oil was extracted by maceration method using ethyl ether as a solvent. Then, DPPH method was applied to investigate the radical scavenging activity of the oil and its fractions. Peroxide (PV) and TBA values of the soybean oil (including either 5% or 10% of G. Tournefortii L. seed oil) were determined through an oven test. Moreover, HPLC-UV was employed to qualify and quantify the phenolic compounds. The results indicated that radical scavenging activity of unfractionated oil (TF) was 123.26±0.42 mM; and the methanolic fraction (MF) (85.82±0.58 mM) had a lower scavenging activity than the ethanolic one (EF) (55.09±0.18 mM). However, it was vice versa for non-soluble methanolic (MLF) and ethanolic fractions (ELF) (106.28±0.64 mM and 145.76±0.09 mM, respectively). Luteolin 7-aglycone (0.1878 mg/g oil) and Chlorogenic acid (0.1113 mg/g oil) were determined by HPLC-UV as the most major phenolic compounds of this oil. Total amount of the phenolic compounds was 0.7935 mg/g oil. Finally, a 13-day oven test revealed that the highest antioxidant activity was measured during the 8th and 9th day of the test, considering PV and TBA, respectively. This study states that Luteolin 7-aglycone and Chlorogenic acid are among the most abundant phenolic compounds in G. Tournefortii L. seed oil and these compounds are mainly ethanol soluble.

Phenylketonuria (PKU) is an inborn genetic disorder, there is no cure and all PKU patients must use a special diet none or low in Phenylalanin (Phe) for preventing the onset of symptoms and intension of the retardation of the children. Therefore, production of foods containing no or very low Phe is essential. In the present study, nutritionally a suitable dairy drink suitable with high acceptability was produced for these patients. The drink was prepared on the basis of the permeate of the milk containing Glycomacropeptide (GMP) as the protein source with the addition of Corn Germ Oil as the source of essential fatty acids, flavoring agent, stabilizer and emulsifier. GMP was added at three different concentrations of 2.5, 3 and 3.5wt%. Protein, pH, fat, sugar (total reducing sugars and sucrose), ash and total solids of the samples were determined. The HPLC was used to determine the Phe content of the samples. Cacao flavor was used for increasing the acceptability of the prepared drinks and sensory evaluation was conducted. The results showed that increasing GMP increased the protein content, total solids and pH. Moreover, the results showed that the GMP content had no significant effect (P> 0.05) on the sensory characteristics of the prepared drinks and the samples with the cacao flavor were desirable drinks considering organoleptic properties. Results of Phe determination showed that prepared dairy drink had very low Phe levels (almost 0.58 mg/ml). It can be concluded that the diet dairy drink produced by this method is recommended for Phenylketonuria patients.

In this study, emulsified nanocomposite films based on carboxymethyl cellulose (CMC) - titanium dioxide (TiO2) (rutile phase) were made by casting method. In order to investigate the resulting films characteristics, different tests including X-ray diffraction (XRD) analysis, water vapor permeability (WVP), Atomic force microscopy (AFM), UV-VIS transmittance spectra and differential scanning calorimetry (DSC)were performed. TiO2 nanoparticles, as a filler, were added to the CMC –oleic acid emulsion at different concentrations (0.5, 1, 2% w/w) after homogenization by an ultrasonic device. Study of nanocomposite structure by XRD test showed that nanofiller have been homogeneously dispersed in the biopolymer matrix. The WVPsof the films were reduced significantly from 7.15×10 -8 g/m.h.Pa in the control sampleto 6.09×10 -8 g/m.h.Pa in the films containing2% nanoparticle. Topography images obtained from AFM showed that addition of TiO2nanoparticles increased the roughness of CMC based films. The ultraviolet and visible radiation transmittance values in the nanocomposite containing 2% TiO2 nanoparticles were 15.13% and 30.58%, respectively, i.e., 85% of UV radiation and 70% of VIS radiation were absorbed or scattered. DSC test showed that, the glass transition temperature increased from 86.65oC in the control film to 81.4oC in the film containing 2% nanoparticle.

Evaluation of quality and biochemical indices during ripening is necessary to achieve high quality and extend fruit postharvest life. In this study, the effect of harvest time on the some quality attributes of table grape cv. ‘Bidaneh Sefide’ was investigated during two months storage at temperature of 1±0.5 °C and in 90-95% relative humidity. The study was conducted as a factorial experiment based on completely randomized design with four replicates. The fruits were harvested from a commercial Vineyard in Urmia, at three different maturity stages from 4 September to 29 September. Total soluble solids content, titratable acidity, vitamin C, total phenolics content, total antioxidant content, polyphenol oxidase and catalase enzymes activity were evaluated at harvest times and 20 days intervals during storage for two months. The results showed that by delay in harvest time, TSS increased but total acidity decreased. Total phenolics content and vitamin C increased with delay in harvest time but decreased during storage period. The activity of polyphenol oxidase significantly increased with delay in harvest time but first decreased and then increased during storage. The total antioxidant activity showed no change during ripening but it was affected by storage time. During storage, the activity of catalase enzyme was decreased. According to the results of this study, most of qualitative attributes in ‘Bidaneh Sefid’ table grape fruit is preserved for 40 days storage without any chemical treatment.

Campylobacter species, especially Campylobacter jejuni is the most common cause of bacterial gastroenteritis around the world, often through the consumption of meat and poultry products, including chicken gizzard, are transmitted. In winter 1392 to spring 1393, This study has been aimed to determine the prevalence of Campylobacter species in poultry gizzard in Urmia, 80 samples of gizzard from the Protein Gostar Sina slaughterhouse located in the city of Urmia collected after culture, gram- negative and catalase- positive isolates selected, of the 16S rRNA gene was random and their General primers were amplified by PCR technique. The results showed that 62/5% of gizzards using selective culture of Campylobacter positive were detected. Diversity of Campylobacter isolates to the case: 40 percent Campylobacter jejuni, 20 percent Campylobacter coli and 40 percent Campylobacter lari detection in chicken gizzard was given. Contamination levels were also significantly higher in spring than in winter, which may be due to the high temperature of environment that was created the right conditions for Campylobacter. Therefore, sanitation and accurate monitoring of the destruction and packaging process for control of critical points and minimize the transmission of pathogenic bacteria such as Campylobacter Foodborne to meatand poultry products useful.

Pistachio nuts, especially roasted pistachio is very sensitive to oxidation. Oxygen concentration is one of the most important environmental factors affecting lipid oxidation. Lipid oxidation can be inhibited by using a good packaging material. Therefore, the present study was investigated the effects of storage temperature and oxygen permeability of packaging material on quality retention of roasted pistachio nuts. Pistachio nuts were packaged in two different pouches including polyethylene terephthalate/ polyethylene metalized (PET/metPE), and Biaxial Oriented Polypropylene/Aluminum/ Cast Polypropylene (BOPP/Al/CPP and stored for a period of 3 months at 35oC and 50oC. Quality parameters monitored were: peroxide value (PV), free fatty acid, moisture and gases (O2 and CO2) content and hardness. The statistical analysis of result showed that the highest PVs were found in pistachio nuts stored at 50oC in BOPP/Al/CPP packaging material. The oxygen content of this package was more than another packaging. The highest value of moisture content was recorded for roasted pistachio nuts packaged in the PET/metPE. Packaging material and time storage on instrumental hardness were significant and hardness was more in BOPP/Al/CPP. There wasn’t significant different between Free fatty acid content of pistachio nut. CO2 content of PET/metPE packaging was more. The research results indicate that sustainability of roasted packaged pistachio nuts is affected by the selection of packaging material and the shelf-life was higher in the samples packed in PET/metPE pouches and the samples packed in BOPP/Al/CPP had lowest moisture content and highest hardness and lipid oxidation.

In this study, effect of ultrasound and osmotic dehydration pretreatments on shrinkage of fried potato strips was examined. Potato strips pretreated with ultrasound at 28 and 40 kHz frequencies and osmotic dehydration at salt solution concentrations of 2 and 4% were fried for 60, 120, 180 and 240 seconds at temperatures of 150, 170 and 190oC. Also, in order to control the optimal process conditions and improve the final quality of fried product, changes in the shrinkage were modeled in terms of frying time, oil content, dimensionless moisture content and apparent density. Ultrasound pretreatment at 28 and 40 kHz frequencies at 150°C led to a decrease in shrinkage compared to control samples. Application of osmotic dehydration and its combination with ultrasound pretreatment increased the shrinkage. In addition, experimental data were well fitted by proposed models in terms of frying time, oil content, dimensionless moisture content and apparent density parameters having high correlation coefficients.

Osmotic dehydration is a new method to reduce the moisture content of food. In this method, moisture is reduced by direct contacting food with salt and sugar concentrated osmotic solutions through the cell membrane based on natural and nondestructive osmosis. Application of osmotic dehydration prior to hot air drying improves product quality. In this study the effect of osmotic dehydration prior to hot air drying on the quality properties of button mushroom was studied. Sliced mushrooms were immersed in sodium chloride solution with concentrations of 5 and 10%, sample to solution ratio of 1:20 at temperatures of 30 and 40oC for 60, 120, 180 and 240 min. Optimal osmosis condition based on the highest WL/SG were found to be a temperature of 40oC and a concentration of 5% and an osmosis time of 120 min. Samples followed by air drying at 60oC to a final moisture content of 0.2 (g water per g dry matter). Shrinkage, rehydration ratio and color parameters were measured. Results showed increasing temperature, osmotic solution concentration and osmosis time led to an increase in WL and SG. Osmotic pretreatment reduced shrinkage, rehydration ratio and "L" color parameter in hunter lab system; but had no significant effect on overall color change and "a" and "b" values.

Fried foods are high in fat and cause many human health problems. The use of edible coatings is a suitable method to reduce oil uptake in fried foods. In this study the effect of gum arabic and soybean soluble polysaccharide, as coating agents, with concentration (1, 3, 5 w/v%) and also immersion times of strips in coating solutions (2 and 4 minutes), temperatures (170, 180, 190oC), and time of frying (5, 6, 7 minutes) on moisture, oil uptake, color, crispiness and organoleptic characteristics of french fries were evaluated, using Response Surface Methodology. The findings showed that the effects of experimental variables on moisture content, color parameters, hardness and oil content of french fried were Significant (p < 0.01). The moisture content decreased with increasing temperature and frying time, but the amount of oil uptake and hardness increased. Results indicated that coated french fries resulted better product in oil uptake, as gum arabic and soybean soluble polysaccharide (5% solution and 2 min immersion) and fried in 170oC for 6 min showed the lowest oil content (18.09 and 18.12 %, respectively) and reduced oil uptake of french fries up to 31.13% and 33.55%, respectively. Additionally, color and sensory properties in french fries that were prepared with gum arabic and soybean soluble polysaccharide coating were not significantly different than French fries without coating. According to the results of this study, soybean soluble polysaccharide can be considered as suitable and competitive coating material with gum arabic to reduce oil uptake of french fries.

The effect of grape fiber, chitosan and storage time on physicochemical and sensory properties in probiotic fruit yoghurt containing kiwi were investigated by using CCRD experimental design and response surface methodology (RSM). The amount of grape fiber, chitosan and storage time were in the range of 0-1.2 %, 0-1 % and 3-21 days respectively. The results showed that with increasing the amounts of chitosan and fiber syneresis was also decreased and water holding capacity (WHC) and viscosity were increased significantly (P<0.05). It was also found that with increasing the amount of chitosan and fiber, color and flavor scores were decreased (P<0.05). The empirical models obtained by response surface methodology for studying the relationship between variables except a*was evaluated properly. According to the obtained results, to production of probiotic fruit yogurt containing kiwi, the amount of fiber 1.1%, chitosan 0.1% and the storage time 12 days were found to be the optimal processing conditions.

Production of probiotic non-dairy food has a great attention. The objective of this study was to investigate the survival of Lactobacillus acidophilus type LA-5 and L. casei type 431 in red grape juice during storage at refrigerated condition for 4 weeks. Red grape juice with Brix 15 prepared and pasteurized at 80oC for 4 min. A preliminary fermentation of juice containing both bacteria was done at 37oC for 3 days was done and all treatments were maintained at 4oC for 4 weeks. Survival of bacteria, Brix, titrable acidity, pH, and total sugar contents were measured during fermentation and storage period. The results showed that after 4 weeks of storage at 4oC, the viable cell counts of L. acidophilus were stabilized at 2.1×108 cfu/mL, while L. casei did not survive the low pH and high acidity conditions in red grape juice and declined to its lowest level as 5 ×104 cfu/mL. The results also showed that L. acidophilus made increase in acidity during the stages of fermentation (P³ 0.05) and the storage time and the sugar consumption and reducing of Brix was also higher in L. acidophilus compared with L. casei. It is concluded that red grape juice could serve as a raw material for the production of probiotic juice by L. acidophilus as compared by incorporating L. casei.

Given that tea bag paper is imported, production of them with other suitable materials is necessary so that porous film can be used for this application. Porous film of cellulose acetate was prepared by the dry phase inversion process and the acetone was used as solvent and ethanol as non-solvent solutions. The effect of the film permeability was investigated by changing the ratio of the solvent to non-solvent and the concentration of cellulose acetate in solutions. The ratio had a great influence on the pore size of cellulose acetate (CA) film. The best porous film was produced only in 6:4 ratio of solvent to non-solvent. Increasing the CA content (%10) in the casting solution decreased the permeability of the films. In contrast, the solubility, mechanical properties and opacity of the films increased, hence, white index did not have a significant different in the films. SEM photos illustrated that addition of low concentration of CA (%2/5) to the casting solution created a highly porous structure in the film. This study showed the good potential for application of porous CA films to achieve permeable paper as an alternative to the tea bag paper.

Tofu is a nutritional, gel-like soy food. The present study was carried out to investigate the effects of withania coagulans extract on the soymilk coagulation for producing tofu. For this purpose we coagulated soymilk by withania coagulans extract, and analyzed the properties of prepared tofu.Then Tofu properties include pH, moisture, yield, protein content, fat content, textural character ic-es (hardness, cohesiveness, springiness, gumminess) and Sensorial properties were studied and were compared with the characteristics of calcium sulfate tofu (control). In order to improve the sensory properties of tofu different additives were used. Then the sensory properties were compared with control samples. All tests were performed in triplicate and mean values were performed using t-tests, Friedman test was performed on the sensory characteristics (at the 95 percent confidence lev-el). The results indicated that extract of withania coagulans as a coagulant significantly (P<0.05) reduced yield and moisture content when compared with calcium sulfate tofu, but fat and protein contents of withania coagulans tofu and calcium sulfate tofu were the same. The result showed that the type of coagulant had significant effect on textural properties of tofu. Results of sensory evalua-tion showed that Sensorial properties of withania coagulans tofu are not different from that of cal-cium sulfate tofu. In this way, it was concluded that extract of withania coagulans fruits could be used as a natural coagulant in coagulation process of soymilk.

In order to enhance palatability and storage of edible oils, it needs to refine the oil in several stages. Bleaching is one of the most important stages of refining process. Acid activation is usually used to improve the bleaching capacity of the clay and reduce environmental threats and energy usage. On the other hand, pigment removal would lead to increasing of oil shelf life and consumer acceptance. In this study, sepiolite clay was activated in three different conditions of time (8-12 hours), temperature (70-90oC) and acid amount (15%-45% w/w) using response surface methodology (RSM) and D-Optimal design. The oils were then bleached in 90C for 30 minutes by 1.5% bleaching clay. The results showed that the best condition of acid activation was obtained using 32.25% acid at 83.8 oC and bleaching time of 8.75 hours. This condition decreased chlorophyll and b-carotene amounts from 12.98 and 39.83 to 4.02 and 18.86 ppm, respectively. The maximum bleaching capacity of activated sepiolite clay was found to be 90.85%.