نشریه فرآوری و نگهداری مواد غذایی
سال نهم شماره 2 (پیاپی 22، پاییز و زمستان 1396)

In spite of high advantages of UF-Feta cheeses, especially their high yield, ripening and aroma and flavor development in theses cheeses occurs more slowly than traditional cheeses. Cheese ripening is a complex and inevitable process to obtain a product with unique organoleptic and textural characteristics. During the ripening, the cheese is subjected to changes, including glycolysis, lipolysis and proteolysis. Proteolysis is the most important and complex event that occurs in a great number of cheese varieties during ripening and strongly affects the sensory properties of the cheese.Therefore, in this study the effect of cas-amino acids addition on acceleration of proteolysis and flavor and aroma development in these cheeses during 60 days ripening period was investigated.
Cheese samples were made in 3 trials on 3 consecutive days. Control treatment was produced according to the plant conventional method. In experimental treatment, cas-amino acids, were added into retentate in addition to starter and rennet. Chemical composition, pH 4.6-soluble nitrogen, urea-PAGE, peptide profiles, total and individual amino acids and sensory properties of cheese samples during 60 days ripening period were evaluated.
Results showed that there are no significant differences in terms of chemical composition and pH between one-day-old experimental and control cheeses. Soluble nitrogen in pH=4.6 was significantly (P Generally, the addition of free cas-amino acids into retentate had positive effect on the proteolysis acceleration and as a result, ripening and flavor and aroma improvement as well as overall acceptability of UF-Feta cheese.
Key words: Free Cas-amino acids, Proteolysis, UF-Feta cheese

Nowadays, different methods of hydrocolloid extraction has been studied and the effect of these methods has been investigated on functional properties of these hydrocolloids. According to these studies, it has been found that different variables has influence on hydrocolloids properties such as temperature, water to seed ratio, pH, salt concentration and extraction time. “Quince” tree is local tree in Asia and widely grow in north of Iran. The fruit of this tree has seeds which have extractable mucilage on its outer surface. Extraction of “Quince” seeds mucilage always was done by conventional methods and there is limited information about using new technology such as ultrasound on extraction. The objective of present study is to assess the effect of extraction by ultra sound wave in addition to some variables such as temperature and pH on extraction yield and rheological properties of extracted mucilage. In order to obtain optimum extraction yield and apparent viscosity, optimization of “Quince” seed mucilage extraction was done using “Response Surface Methodology” and “Central Composite Rotational Design” and Optimum operating condition of extraction was predicted.
“Quince” seeds were obtained from Gilan ecotype. In order to determine the effect of different parameters on yield (%) and apparent viscosity (mPa.s) of extracted mucilage, three independent variables including temperature (25–55ºC), ultra-sonication time (3–10 min), and pH (6–8) were investigated. Response Surface Method was used to design Experiments. Apparent viscosity of mucilage were measured by rotational viscometer Brookfield at 50 RPM in constant temperature 25ºC. Using regression analysis, a second-order polynomial model was developed for each response. Chemical composition of extracted mucilage was determined using AOAC standard methods.
among investigated variables, temperature and ultra-sonication time had significant effect on extraction yield and viscosity while pH was not significant (p “Quince” seed mucilage showed a non-Newtonian and shear thinning (pseudoplastic) behavior. Extraction yield and apparent viscosity has affected by some extraction parameters such as temperature and ultra-sonication time so optimum yield and viscosity can access with determining suitable conditions of mucilage extraction.

Nowadays yogurt is produced as the most important probiotic dairy product around the world. Probiotics are alive microorganisms that when consumed in sufficient quantities on a regular basis, have beneficial effects on the health of their host. Also, prebiotics are indigestible carbohydrate compounds for human that have ability to improve growth or activity of one or a limited number of probiotic bacteria (Enteric bacteria). Combination of prebiotic and probiotic is called symbiotic that consult health benefits. Nowadays yogurt is produced as the most important probiotic dairy product around the world. Probiotics are alive microorganisms that when consumed in sufficient quantities on a regular basis, have beneficial effects on the health of their host. Also, prebiotics are indigestible carbohydrate compounds for human that have ability to improve growth or activity of one or a limited number of probiotic bacteria (Enteric bacteria). Combination of prebiotic and probiotic is called symbiotic that consult health benefits. Nowadays yogurt is produced as the most important probiotic dairy product around the world. Probiotics are alive microorganisms that when consumed in sufficient quantities on a regular basis, have beneficial effects on the health of their host. Also, prebiotics are indigestible carbohydrate compounds for human that have ability to improve growth or activity of one or a limited number of probiotic bacteria (Enteric bacteria). Combination of prebiotic and probiotic is called symbiotic that consult health benefits. In this study Lactobacillus acidophilus type LA5 was used as probiotic culture. To determine optimal conditions of symbiotic yogurt production, three factors including inulin concentration (0-2/5%), gum tragacanth concentration (0-0/06%) and shelf life (1-19 day) was considered as independent variables and their effects on hardness, synersis and probiotic count sample used analyze response surface method. The overall coefficient of determination (R2) for hardness, Synersis and probiotic count characteristics were 0/98, 0/98 and 0/99 respectively. Analysis of variances of overall effect variables process in regression model Synbiotic yogurt showed significant effect of each independent variable on the dependent variables. Optimum conditions in Synbiotict yogurt for maximum hardness and probiotics count and the least Synersis determined combination 2/5% inulin with 0/04% Gum tragacanth in 18 days. In relation hardness and probiotics count increasing concentration inulin and shelf life improves the texture. Increasing tragacanth Gum concentration to 0/03% improves the texture while the concentration of 0/06% had negative effects. The increasing tragacanth Gum and inulin concentration have positive effect on the probiotic count, but in maintenance time probiotics count reduced.

The results have shown that storage of olives at temperatures of 5-6°C for two months keep olives properly. Storage of olive in this temperature conditions decrease resistance to oxidation and fruit hardness and increase acidity, carbonyl compounds, bitter and hot taste in oil. The aim of this study was to evaluate the effect of different storage conditions of olive (yellow variety) harvested from different regions of the Ardabil province (Parsabad and Aslandouz) on the changes of phenolic compounds content, thiobarbituric acid index, fatty acids profile and color of olive oil in the different conditions of olive storage.
In this study, olives were packed in polyethylene bags and stored at temperatures of 20°C, 5°C and -18°C for 60 days. Then, olive oil was extracted with cold method during the storage time and finally olive oil was evaluated in terms of various properties by standard methods. Phenolic compounds and thiobarbituric acid index were detected by spectrophotometer and fatty acids profile and oil color were determined by gas chromatography and digital photography Hunter lab simulator, respectively. This study statistically was carried in factorial design with 6 treatments of olives harvested from two different regions and also comparison of means was performed by Duncan's test at different times.
The results showed that the harvest region and different storage conditions of olive had a significant effect (P In general, the olives related to Parsabad region which were stored at temperature -18°C, had lower oil content, thiobarbituric acid index and L and a indexes of olive oil and had higher phenolic compounds and b index than the other olives (P

The aim of this study was to investigate the effect of microencapsulation with sodium alginate/ resistant starch and sodium alginate/chitosan on microstructure, rheological properties and viability of Lactobacillus acidophilus and bifidobactrium animalis subs lactis in drinking yoghurts. Role of different encapsulation parameters, such as resistant starch and chitosan concentration (0, 0.5, 1 and 2 %) and encapsulation time (0, 10, 20 and 30 min) in providing protection to the bacteria were also evaluated. Results showed that the addition of starch and chitosan at 1% concentration to alginate mix and 10 min resulted in increased viable counts of lactobacillus acidophilus and bifidobactrium animalis subs lactis cells after 7 days storage at 4˚C. Drinking yoghurts with alginate/resistant starch microcapsules had shown more viability (3.6×1011 and 6.6×1011 for Lactobacillus acidophilus and bifidobactrium animalis subs lactis, respectively) than encapsulated samples with alginate/chitosan (2.1×1010 and 6.8×1010 for Lactobacillus acidophilus and bifidobactrium animalis subs lactis, respectively). Optical microscopic image of 50 beads at 40× magnification showed that the bead shape was spherical with a mean diameter of about 300–500 µm, and cross-section and internal appearance of coated alginate-resistant starch bead at 100× magnification showed that bacterial cells were located inside of beads. The distribution of beads in drinking yoghurt texture was uniform. Encapsulation increased apparent viscosity and consistency coefficient and decreased flow behaviour index. The best fitted rheological model for the control (without microcapsules) was Power law and for rest of the samples was Herschel-Bulkley.

Ketchup sauce is a favorite product and it is useful for flavor and color improvement of foods. Addition of hydrocolloids to ketchup sauce in order to physicochemical, rheological, textural improvement and to understand rheological behavior such as viscoelastic properties is important for quality control, process designing, storage condition and textural properties. So, the objective of this research is investigating effect of Xanthan gum and Ispharzeh and Basil seeds mucilage on the viscoelastic behavior of ketchup sauce.
at present study, treatments were determined based on combination of hydrocolloids (0-1%) by mixture statistical design of design expert software 9. For investigating viscoelastic properties of samples, strain sweep (at 0.01-1000%) and frequency sweep (at 0.01-100 Hz) test was done. The best model for test results was fitted and effects of each parameter were determined.
the results of oscillating strain sweep showed that at low and moderate strain, all of samples had linear viscoelastic behavior. In terms of crossover, the highest crossover was seen at sample K1 (0.5% xanthan gum, 0.5% basil seed mucilage) and the lowest of that was seen at samples k9 (0.16% xanthan, 0.66% ispharzeh seed mucilage, 0.16% basil seed mucilage) and K10 (0.5% xanthan and 0.5% ispharzeh seed mucilage). The finding of oscillating frequency sweep showed that storage moduli were higher than loss moduli at all samples. Loss tangent lower than 1 revealed solid viscoelastic of samples. The highest and the lowest of storage moduli, loss moduli and complex viscosity belonged to K4(1%basil seed mucilage) and k10 (0.5% xanthan and 0.5% Ispharzeh seed mucilage) respectively. Except crossover, added hydrocolloids had significant effect on the all parameter in ketchup sauce.
oscillating rheological measurements is a useful method to determine effect of hydrocolloids addition to food systems. Using strain sweep and frequency sweep test, it is possible to investigate flow capability and structure maintenance capability at storage condition. It was concluded that regarding unique functional properties of Ispharzeh and Basil seeds mucilage, they could use as a commercial hydrocolloid accompanied by other hydrocolloids.
Using strain sweep and frequency sweep test, it is possible to investigate flow capability and structure maintenance capability at storage condition. It was concluded that regarding unique functional properties of Ispharzeh and Basil seeds mucilage, they could use as a commercial hydrocolloid accompanied by other hydrocolloids.
Using strain sweep and frequency sweep test, it is possible to investigate flow capability and structure maintenance capability at storage condition. It was concluded that regarding unique functional properties of Ispharzeh and Basil seeds mucilage, they could use as a commercial hydrocolloid accompanied by other hydrocolloids.

Potato faced with various pests and damages during growth and storage. Some of these damages caused by environmental conditions or different mechanical tensions. Although these damages do not have any traces on potato surface, but have bad effect on potato quality. There are some methods for determining these damages. One of these methods is applying microwave. Therefore, the aim of this research was the probability of recognition of healthy and unhealthy potato by using microwave, based on dielectric constant.
For preparing defected potato samples, healthy samples were stored in nylon bag at 25 0C and 40% relative air humidity for 4 months to get unfavorable surface quality. Also a 20.6 * 13.1 millimeter brazen cylindrical in connector were used for measuring the samples impedance. High-frequency wave telecom was sent to the given sample, some of these waves were absorbed by the sample and the rest were returned. The amount of wave absorption sent by the sample depended on the texture temperature and frequency of the initial wave. By analysis of this parameter, samples dielectric constant could be measured. In this research, for measuring dielectric constant of three varieties of Agria, Arinda and Savalan potato, short circuit transmission line system was used. Dielectric constants of both healthy and unhealthy potatoes were measured at two temperature levels of 0 0C and 25 0C and three frequency levels of 915, 1800, and 2450 MHz .
The results showed that different levels of temperature and frequency had significant difference (p Generally, for unhealthy potatoes, the mean values of dielectric constant is 1-2 units lower than that of corresponding values. The dielectric constant increases with increasing temperature. Missing of moisture content in storage period is the main reason of this behavior. Also due to different texture of potato variety, Arinda, Savalan and Agria get the maximum score of dielectric constant respectively. Therefore, this character is very good option for quality sorting, packing and so on.