JOURNAL OF FOOD RESEARCH (UNIVERSITY OF TABRIZ)
Year:2010 | Volume:19/1 | Issue:2|Papers Count:9

One of the most important steps to determine phytosterol oxidation products (POPs) in foods is their enrichment and purification with different methods before GC or GC-MS analysis. In this study, a new SPE method (1 g, silica) was developed to enrich and separate POPs from transesterified oils. This method showed high recovery (88-96%) for oxidation products. New method was applied to olive, hazelnut and corn oils. Eleven oxidation products were characterized which corn oil had the highest amount (24 ppm). Among oxidation products in oils, 6b-hydroxysitostanol and 6b-hydroxycampestanol had the highest amounts. This new method had high sample capacity (up to 1 g oil) and could be also applied for food products with high phytosterol content. The new method developed in this study was simple and rapid, which simplifies separation and enrichment of POPs for further analysis by GC and GC-MS.

In commercial, technological and scientific aspects, control of colorants compounds, produced from tow different source: sugarcane and processing is very important. As an example of colorants with plant source, anthocyanins, xanthophylls, flavonoids and beta-carotene can be mentioned. Some material like bentonite can act like as active carbon and dioxide sulfur in absorbing polyphenol oxidase, phenols, charged molecules and etc. The adsorption of phenols from extracted products reduces the rate of enzymatic reaction colorful materials are usually affecting the efficiency and quality of final products and should be removed from raw sugarcane juice. In this study, first of all, raw sugarcane juice treated by bentonite compared with the sample purified with lime and so optimum quantity of bentonite and pH were recognized. Experimental results indicated 1.5gr/l bentonite and pH=4.5 had the best results in reduction of syrup color. As a second step, in order to increasing the effectives of bentonite adding gelatin was checked and it is compared by pure bentonite for optimizing the time and temperature of process. The experimental results indicated that 0.02gr/l gelatin in 100Co for 60 min are optimum conditions for purification of raw sugarcane juice in processing with bentonite.

In this project we aimed to find the best drying conditions to produce dehydrated diced potatoes from Mojeni and Pashandi varieties. The samples were peeled and cut into 10×10×10 mm and 20×20×20 mm cubes. Diced potatoes were blanched in boiling water containing 0.5% calcium chloride, for 3 and 5 minutes. Blanched potato cubes were immersed in ascorbic acid solution and dried at 50, 60 and 70oC. Degree of rehydration, shrinkage and specific gravity of dried samples were determined. Statistical analysis of results showed that the effect of all factors on the shrinkage were significant (p<0.01). Drying temperature (p<0.05) and variety (p<0.01) had a +significant effect on the degree of rehydration. Specific gravity of dried potatoes was significantly affected by the size and the variety of samples. According to the results the best drying temperature and blanching time were 50oC and 5 minutes respectively. At the end the drying temperature of 50oC, three minutes of blanching, slice size of 20×20×20 mm and the Mojeni variety was selected as the best treatment combinations.

The objective of this study was the design, development and evaluation of weight sorting automatic machine for apple. A sorting machine was designed and developed in Kurdistan University, Faculty of Agriculture in 2003. After weighting and data processing, fruit was delivered through conveying duct to one of the six inserted gates for sorting. The apple bruising critical height of drop was statistically determined on steel plate. This critical height was 6 cm for a local variety of apple called Golab. To avoid mechanical damage in fruit the duct slope angle fixed at 22 degree thereby the fruit velocity at 1 m/s. Theoretical impact force analyzing on fruit in the duct showed that the machine has no harmful effect on fruit in sorting process. It was approved by actual results of machine evaluation.

Treatment of raw milk with CO2 as a procedure for preventing of microbial growth, control of psychrotrophic bacteria and extending of self life of milk products was studied using normal raw milk, as control samples, and raw milks treated with CO2 up to pH=6.4, 6.2 and 6. Experimental milk samples were stored for 10 days at 4oC and used for microbial assessment at 1, 5, 8 and 10 days of storing. The experimental design was split plot based on randomized complete blocks with four replications. Results showed adding of CO2 to raw milk up to pH=6.2 and 6 inhibited significantly (P<0.05) microbial growth and those samples had a difference of 1.082 and 0.85 logarithmic unit in total count and also 1.089 and 0.923 in Psychrotrophic bacteria populations with control samples, respectively. It is concluded that adding of CO2 to raw milk up to pH=6.2 and 6 can be considered as an effective pretreatment for preventing of increasing microbial population and preservation of raw milk. Samples treated by CO2 with pH=6 had a self life of 3 days longer than control samples and was selected as the most effective treatment, although there were not significant differences in most parameters between pH=6 and pH= 6.2.

In this study diversification and specialization in production, export and import of meats in Iran were investigated applying Herfindal index to time series of 1961to 2004. Moreover, the cost stability of import was examined using the import cost function. The results exhibit the specialization for red meat from 1961to 1968 and for chicken from 1982 to 2004. During the period of study, meat production had gradual changes towards producing more chicken meat. Iran had specialization in meat export for most of the period however, in the recent years diversification in export is created. For the country, the diversification (1961-1964 and 1973-1986) and specialization (1965 to 1972 and 1987-2004) of import were existed for some periods. The overall results demonstrated that the import cost fluctuation had been related to quantity of import, and not import price.

The numerous application of castor oil in order to extraordinary physicochemical properties in pharmaceutical, chemical, hygienic, cosmetics, biodiesel industries and nowadays in food science was resulted that was carry out copious research on it. In this research was investigation quality, oil content and physicochemical properties of castor oil in Eastern Azarbaijan area’s. in analysied samples oil content were (%35-52), moisture content (%0.3-0.7), refractive index (1.404-1.42), chlorophyll content (0.17-0.39 mg Pheophytin/kg Oil), acid value (0.2-0.9 mg NaOH/g Oil), peroxide value (0-0.012 meq O2/kg Oil), soponification value (167-178.5 mg KOH/g Oil) and iodine value (75-86 g I2/100 g Oil). The results of the study revealed a significant difference (p<0.05) of oil content, moisture and chlorophyll content, acid value, soponification value and iodine value but There was no significant difference (p>0.05) among of samples refractive index and peroxide value. Content oil of Marand Area’s had most Percentage. This is the first detailed report on the oil physicochemical properties and oil content of castor beans from Eastern Azarbaijan different area’s.

The survival of the probiotic strains Lactobacillus casei (ATCC 39392 Collection, Australia) was investigated in the Iranian white cheese produced by ultrafiltration technique. Four treatments of UF Iranian white cheese were produced: control I (C1), with a commercial starter culture mix including Lactoccocus lactis subsp. cremoris, Lactococcus lactis spp diacetylatis), control II (C2), with commercial starter culture mix and the probiotic L. casei, LC with a commercial starter culture mix and probiotic L. casei (uncapsulated) and LCC with commercial starter culture mix and probiotic L. casei capsulated with Sodium Alginate by extrusion method. The cheese samples were ripened at 8-12 oC for 60 days and the viability of cultures and also moisture, salt, protein, fat in solids, pH were determined biweekly. Cheese samples also were analyzed for sensory evaluation at the end of 60 days of ripening. At day 1, the log10 numbers of L. casei in the samples C2, LC and LCC were 8.61, 8.60 and 8.69 cfu g-1 respectively. These figures reached to log10 6.57, 7.01 and 8.20 cfu g-1 after 60 days of storage, respectively. The reduction was significant (P>0.01). The final numbers of L. casei, in all of the cheese samples were greater than the minimum numbers of the recommended therapeutic products (106-107 cfu /g). Moisture content and pH of all cheeses were decreased and salt and protein content increased during ripping, while the fat in Dry matter (FDM) content of all cheese were not change significantly during storage (P<0.01). The maximum and minimum range of loss of moisture at the end of ripening period was 6.1 and 3.34% which belonged to LCC and C1 respectively. Therefore it was concluded that the type of starter affects the moisture content. The maximum and minimum range of loss of pH at the end of ripening period belonged to C1 and LC respectively and the loss of pH in the LCC was the least (9.26%). The sensory evaluation showed that there was no significant difference between the experimental samples from a texture and flavor point of view. While C2 acquired the high score of texture and flavor but not significantly. Therefore probiotic Lb. casei both form free and microencapsulated can be used successfully in Iranian white cheese produced by ultrafiltration technique without adversely affecting the cheese quality during ripening. Also L. casei can be use as starter culture in the Iranian white cheese produced by ultrafiltration technique.