نشریه فرآوری و نگهداری مواد غذایی
سال هشتم شماره 2 (پیاپی 20، پاییز و زمستان 1395)

Especially in Iran, sour orange juice is known as a desirable food seasoning. Although thermal processing is a common method to improve safety of sour orange juice, it induced the nutritional loss and undesirable compounds formation. Generally, chemical changes in food products influence the product color. By considering the relation between product color and its chemical compounds, the objective of this work is to investigate the effect of thermal processing (temperature and time) on color changes of sour orange juice. The browning index of product was studied using two different methods, image processing and spectral analysis. The color changes was investigated using L*, a* and b* color parameters. The results showed that as temperature and time processing increase, Luminance (L*) of sour orange juice decreases. As well as, a* (redness) and b* (yellowness) parameters increase during thermal processing. Chroma index changes showed an increase in the color intensity during thermal processing. Total color changes (TCD), as an appropriate index in product color change, increased during processing. The reaction constant rate (k) of TCD, representing the color temperature affinity, increased about 1.66 times as temperature increases. The high amount of activation energy (Ea) signifies the high temperature tolerance of components color and TCD. Sour orange juice browning is highly dependent to juice ascorbic acid content. In conclusion, a good correlation was found between both of the applied methods to investigate the browning index.

The prediction of olive oil quality parameters is of great importance in Modern Approaches to Quality Control. One of the main problems when predicting oil quality during storage is the complexity of the physicochemical properties of raw material and the difference of data to various causes. Modeling oxidative stability of olive oil with fuzzy inference neural adaptation can help to improve the quality control process this product. One of the important parameters controlling of olive oil is oxidative stability. Parameters of the model design were used Acidity, peroxide value (PV) specific extinction coefficient K232, phenolic compounds as input variables and the extinction coefficient k270 as the output. In order to develop ANFIS model were used various membership functions types, number of membership functions, learning algorithms, learning cycles, Different membership function types by trial and error. The best model using trapezoidal membership functions, and 3 3 3 3 3 numbers of memberships and 50 training cycle were obtained that it was determined least mean square error 0.0012 and the best regression coefficient 0.997.Analysis of the model revealed that the Adaptive neuro fuzzy inference system a powerful tool to predict the oxidative stability of olive oil.

Wheat grain has an important value in the world nutrition. Physical and microbial properties of agricultural products (such as wheat, ...) play an important role during harvesting with machines, cleaning process and waste reduction. In this study, the first research in Iran, the optimized effects of cleaning and moisture content at 40 °C on the physical (Useful besatz, Unuseful besatz, hectoliter, weight thousand seed) and microbial (total count of microorganisms and mold counts) properties of wheat grain (n-80 variety) in Golestan province, were modeled.
After determining the basic moisture content, samples with three levels of cleaning (0-100%), and different moisture content (10-14% wet basis) at 40 °C were studied and modeled by response surface methodology using central composite design (face center) includes 21 tests with five repeats at the central point.
The results showed that by reducing moisture content and increasing cleaning levels, useful and unuseful besatz were decreased and hectoliter was increased. Also increasing the percent of cleaning was more effective than reduce the moisture content in reducing useful besatz and unuseful besatz. The lowest rate of hectoliter was 72.58 (0.01kg. lit-1) at 40 °C. The highest weight of thousand seed at moisture content 14% (wet basis) and cleaning level 100%, was 36.80 gr. Increase in weight of thousand seed in the higher moisture content was more effective than the higher level of cleaning. With increasing moisture content and reduction in cleaning, total count of microorganisms and mold counts were increased. Linear parameters of cleaning and moisture, in the linear model had a significant effect (p For all studied properties, due to non- significant lack of fit and high values of R2 and R2 adjusted, our selected models could accurately predict the experimental values.

Stevia rebaudiana Bertoni, is an ancient perennial shrub of South America, with a great potential as a crop for the production of high-power natural sweetener. Due to its chemical composition and content of the phytochemical compounds, it is suitable as a raw material for production of functional foods. Stevioside has enormous sweetening power comparing to artificial sweeteners which are presented in various foods and beverages available in the market. This compound is about 300 times sweeter than sucrose. In this study to evaluate the antioxidant activity of water-methanol extract of Stevia rebaudiana Bertoni and its antioxidant effect in dairy desserts, phenolic compounds were extracted from its leaves by maceration in methanol.
Antioxidant activity of the extracts using reducing power test, DPPH radical scavenging activity and total antioxidant capacity of extract were comparable with synthetic antioxidant BHT. Antioxidant effects of Stevia rebaudiana Bertoni extract in dairy desserts, using reducing power test, DPPH radical scavenging activity were evaluated after 1, 3, 6, 9, 12 and 15 storage.
Average total phenolic compounds in the Stevia rebaudiana Bertoni extract was 10.64 grams Tannic acid per 100 grams dry matter. Evaluation of antioxidant activity of the extracts showed that DPPH free radical scavenging, reducing power, total antioxidant activity of the extracts are directly correlated with the amount of phenolic compounds. In all methods, antioxidant activity was concentration-dependent. Free radical scavenging activity of methanol extract of stevia was greater than BHT. Reducing power of BHT was higher than extracts and showed significant difference with the methanol extract. The total antioxidant capacity of BHT was much greater than the extract and showed significant difference with extract. Dessert samples containing stevia showed higher DPPH free radical scavenging activity and reducing power compared with control sample. During the sensory analysis conducted on desserts containing different percentages of Stevia rebaudiana Bertoni extract, respectively desserts containing percentage of , 0.75, 1, 0.25 due to high total acceptance and samples containing 0 percent (as control sample) and 100 percent (complete sugar replacement) was selected. Measurements of DPPH free radical scavenging and reducing power in dairy dessert showed that samples with higher amounts of Stevia rebaudiana Bertoni extract show higher DPPH free radical scavenging activity. In addition, dairy desserts containing Stevia rebaudiana Bertoni maintained high levels of free radical scavenging activity during two weeks storage, this led to a delay in fat oxidation and increasing shelf life during storage.
The results have shown that antioxidant capacity of Stevia rebaudiana Bertoni extract is considerable; therefore it can be used as a good source of natural antioxidants.

products drived from Plants have been used for medicinal purpose for centuries because of antimicrobial activity. Using preservatives and anti-microbial material is one way of controlling pathogen bacteria in food stuff. Developing anti-microbial drugs is one of the most important advance in the treatment. Due to their natural origin, herbal extracts are more compatible with body organism than antibiotics and their side effects are very scarce. Spinach is considered as a source of new plant. Botanical analysis of Spinach indicated important active components on its extract. These studies have proven that the extract of Spinach leave maybe used as an anti-oxidation and anti-microbial agent to deal with free radicals and microbial pollutions.The objective of this study was to evaluate the antibacterial effect of aqueous and alcoholic extracts of Spinach (varieties Mashhad) on pathogenic bacteria Staphylococcus aureus ATCC25923, Escherichia coli ATCC2592 and, Listeria innocua ATCC33090.
The susceptibility testing of bacteria was performed by disc diffusion, MIC and MBC (using broth micro dilution method) methods. In disc diffusion method as a positive control Erythromycin, Gentamicin and chloramphenicol were used on Listeria innocua, Staphylococcus aureus and Escherichia coli .
According to disc diffusion method the most resistance was observed by gram positive bacteria (Listeria innocua, Staphylococcus aureus) whereas, the most sensitivity was observed by Escherichia coli. Also, the results of MIC showed that the rang of MIC for the aqueous extract of Spinach (varieties Mashhad) were between 46000 to 54680 PPM, 48000 to 54680 PPM and 28000 to 54680 PPM on Listeria innocua, Staphylococcus aureus and Escherichia coli respectively. Accordingly, this range for the alcoholic extract was equal (41580 to 10393 PPM), on Listeria innocua, Staphylococcus aureus and Escherichia coli. The both of aqueous and alcoholic extract of Spinach (varieties Mashhad) had antimicrobial properties.
alcoholic extract of Spinach (varieties Mashhad) had more antibacterial effect than aqueous extract on Escherichia coli . Also, the effect of its alcoholic extract on Escherichia coli could be compared with Erythromycin antibiotic at disc diffusion test on Listeria innocua. This means that antimicrobial effect of alcoholic extract on Escherichia coli can be as powerful as Erythromycin antibiotic on Listeria innocua. Finally, it can be concluded that high percent of flavonoids and terpenes compositions, unsaturated fatty acids and inorganic materials are probably the most important deterrent factors of spinach on gram-negative bacteria such as Escherichia coli. As a result Spinach extract can be used as a natural antibiotic in food industries and pharmaceutical.

In this paper local pomegranate juice (50% v/v final solution) based gels made from gelatin or kappa-carrageenan with sucrose (2.6%, 5.8% w/v final solution) have been examined to determine the textural characteristics and viscoelastic properties. Pomegranate is one of the most important crops cultivated in Iran which extensively used as a source of variety of products as gels, juices, desserts and etc. However, this fruit has especial properties such as low pH, different tastes, red color, phenolic and anthocyanin compounds which may lead to variety effects on producing different products. In this regard, it is required to study the influence of applying natural pomegranate juice in final gel quality. Since gelatin and kappa-carrageenan are two popular examples of protein and polysaccharide hydrocolloids which are mostly available with low cost, in this work pomegranate gels are formed based on these hydrocolloids. Generally, gel formulations include sugar as a taste and texture improver so its interaction with gel components and its effect on textural properties of pomegranate gel is investigated.
In order to determine textural properties like hardness, cohesiveness and springiness, texture profile analyses have been used. Also, to investigate viscoelastic properties, dynamic oscillation measurements were used and their rheological behavior is interpreted by loss tangent, elastic and viscos modulus.
The result of texture profile analysis show that incorporation of sucrose in gelatin based gels effectively increases hardness, cohesiveness and springiness. Furthermore, the results of oscillatory dynamic rheological measurements show that Gelatin gels are more elastic and resist higher frequencies when sucrose concentration increased. Since gelatin has the protein nature, in different pHs has different electrostatic charge so lower/higher pHs than pI lead to positive/negative charge on it. In this condition, acidic pH of pomegranate juice which is lower than gelatins pI results in positive charge on it which can interact with anionic agents in the media. In this case, presence of phenolic compounds, flavonoids and tannins in pomegranate juice with anionic nature can enhance these interactions. The results of investigations have shown that applying pomegranate juice and sucrose for preparation gelatin gels leads to formation a high quality gel because of proper pH of the juice and adequate hydrogen and electrostatic interactions.
In the case of Ƙ-carrageenan gels, increasing the sucrose level enhances viscose modulus and leads to a week viscoelastic texture, which causes hardness and cohesiveness to decrease extremely. Although low concentration of sucrose can improve gel textural properties, high concentration of it inversely affects on carrageenan gel elasticity. Also, different compounds of pomegranate juice may have synergistic effect on decreasing textural quality of carrageenan gels by sucrose. The major reason of this effect may be due to sucrose prohibition from cross-linking interactions.
The results of textural analysis indicate that high quality pomegranate gels based on gelatin and Ƙ-carrageenan with optimum concentration of sucrose can be produced whereas natural conditions of pomegranate juice like pH and containing ions do not reduce its quality.

Fat reduction in cheese causes inappropriate changes in sensory properties and functional parameters. In order to imitate of various fat functions in low fat product, it should be given to issues such as product consistency, modified dry matter, the effect of particle size on mouth feel, color, flavor and rheological properties. In this respect, methods such as use of fat replacers and technical support like homogenization can improve these properties. The aim of this study was the effect of homogenization on the properties of Mozzarella cheese.
low fat Mozzarella less than 6% fat was produced by fat constitution with three whey protein concentrate up to 35, 53 and 90 percent of purity and in order to evaluation of homogenization effect the cream was homogenized at 120-130 bars and added to skim milk with fat replacer. Differences were measured by comparison of treatments to control group involved 2 treatment; low-fat Mozzarella without fat replacer that produced by homogenization and full-fat Mozzarella while process technology effects on compositional and sensory properties of Mozzarella were studied. Data were analysis using one-way analysis of variance (ANOVA) at 95% confidence interval and paired sample t-test using SPSS Treatments with a P value less than 0.05 and 0.001 were classified as statistically significant.
Moisture (54-61.59) and fat (6-6.5) content of low fat Mozzarellas produced by fat replacer were higher than full fat cheeses significantly. It was cleared that homogenization increased moisture content which was significant in two treatments (B&G), (p
Addition of fat replacer caused increasing the moisture content and homogenization cause low increasing in fat, lightening the color, improving flavor and chewiness of low fat Mozzarella. These results are briefly showed that although whey proteins are crucial in improving the taste but the effect of homogenization is more important.