مجله علوم و صنایع غذایی ایران
سال هفدهم شماره 6 (پیاپی 103، شهریور 1399)

The aim of this study was to determine the effect of temperature, pH, salt, citrus aurantium L. and modified atmosphere packaging (50% carbon dioxide, 45% nitrogen and 5% oxygen) on control of Staphylococcus aurous in fish tofu of type. Descriptive-analytic study was carried out in the year of 2017-2018. In this research, pH was 5.5, 6 and 7.5, and temperature was 4, 25 and 37 ° C, salt at 0, 1.5 and 3%, and orange essential oil at 0.025 and 0.05% was considered. According to the results, it is found that the lower the pH of the tofu samples is lower, Staphylococcus aureus is more restricted. For example, at pH 5.5 with 0.025 and 0.05% of orange essential oil in tofu samples, bacteria did not grow, but at pH 6 and 7.5 there was no growth of bacteria and growth was more than usual. There was an enormous increase in Staphylococcus aurous at pH 7.5 with 1.5% salts and orange essential oil 0.025% at temperatures of 4, 25 and 37 ° C. Increasing temperature to 25 ° C and 37 ° C, as well as at pH 5.5, 6 and 7.5, the growth of Staphylococcus aurous in tofu fish has been increased. In this study, the essential oil of orange herb was stored at 0.05 % at 4 ° C, 3% salt and pH 5.5, to control the growth rate of Staphylococcus aurous in tofu fish for 8 days.

The aim of this study was to investigate the effect of microencapsulation of probiotic bacteria with sodium alginate/resistant starch and sodium alginate/chitosan by extrusion method on qualitative and rheological properties and viability of bifidobactrium animalis subs lactis in Aloe vera doogh. 10% of aloe vera gel with different concentrations of whey (5, 10 and 15%) and inulin (0.5, 1 and 1.5%) added to probiotic doogh and their effect on the protection of Probiotic bacteria and qualitative properties were evaluated. The results showed that increasing the level of inulin had no significant effect on pH. Increasing the percentage of whey up to 5% had no significant effect on the pH, but increasing more than 5% significantly decreased the pH of the doogh samples during storage period. In terms of sensory properties samples containing 1% inulin and microencapsulated bacteria with sodium alginate/chitosan had highest scores in flavour while lowest score was observed in control treatment (without inulin and whey) and free bacteria. Doogh samples containing 1.5% inulin had the lowest serum separation and the control sample (without inulin and whey) showed the highest serum separation at the end of storage period. In general, samples containing microcapsules had a lower serum separation than samples containing free bacteria. The highest viscosity and consistency coefficients were observed in the doogh samples containing 1.5% inulin. The microencapsulation process increased the apparent viscosity, consistency index and loss modulus and decreased the flow behavior index of the doogh samples. Microencapsulation of probiotic bacteria by sodium alginate / resistant starch and chitosan and use of whey and inulin in doogh samples increased their viability during storage period.

Jujube is a functional fruit with a great source of fibers, vitamins and nutritional elements and has a sweet, delicious flavor. Replacement effects of wheat flour with varying levels of jujube powder (0, 5, 15 and 25 % w/w) on the physicochemical, texture and sensory properties of the cakes based on completely randomized design, was investigated. The viscosity of cake batter increased from 744.5 cp (% 0 jujube powder) to 9872.5 cp (% 25 jujube powder) as the replacement level of wheat flour with jujube powder increased (p <0.05). The physicochemical (moisture content, volume, porosity, firmness, fiber and ash) and sensory properties of the cake prepared by replacing wheat flour with jujube powder were changed significantly (p <0.05). As the replacement level of wheat flour with jujube powder increased, the volume and porosity of the cake were decreased and the hardness, fiber, ash, browning index and the lightness of them were increased (p <0.05). Cakes made with the % 5 and then the higher level (up to % 15) as compared to control, received the highest sensory overall scores (p <0.05).  The cakes containing % 5 jujube powder, showed the least physicochemical changes similar to control samples and found to be more acceptable from sensory points as compared to other treatments (p <0.05).

Malachite Green is extensively used as an antiparasite and antifungal agent in aquaculture. Treatment with malachite green leads to the remaining of the metabolite of this compound (luecomalachite green) in aquatic animal tissues and the production of carcinogenic compounds. The aim of this study was to investigate the presence of luecomalachite green in the flesh of Rainbow trout in Mazandaran province. Fish specimens with approximate weight of 0.5 and 1 kg were collected from 20 farms in Mazandaran province (Haraz and Tonekabon) during 2018. Luecomalachite green was measured in samples using ELISA 96-well kit produced by Europroxima Co. (Netherlands). The highest and lowest levels of luecomalachite green (0.0001 mg/kg) were obtained from samples of 0.5 kg and 0.22 mg/kg in 1 kg samlpes, respectively. In some samples of 0.5 and 1 kg collected from Tonekabon, luecomalachite green content was less than the detection limit of the kit, and the highest amount of luecomalachite green was equal to 0.0047 mg/kg in 1 kg samples. Comparison of the results of all samples showed that the lowest contamination of luecomalachite green was observed in samples of 0.5 and 1 kg of Tonekabon region and the highest level of luecomalachite green were observed in samples of 1kg of Haraz area. The results of luecomalachite green contamination in this study were lower and also in the allowed standard range compared to previous studies, this indicates the improvement of sanitary condition of aquaculture stations, effective monitoring and control strategies, use of substitutes and safe alternatives to reduce fungal contamination and hence less malachite green consumption.

The pectinase enzyme has a great importance in the food industry. It is capable of decomposing Pectin significantly, which is the substantial element of turbidity of the juices. As a result, it plays an important role in clarification also ability to maintain organoleptic properties and quality of nutrients. The usage of enzymes in the industry is costly and some measures should be taken to allow the enzyme to be used several times without altering its efficiency. In this research the commercial pectinase enzyme was immobilized on calcium alginate beads. Free and immobilized enzymes activities in different temperatures and pH were determined. Then storage stability and reusability of enzyme were investigated. For optimized clarification of tomato juice by immobilized enzyme, the response surface methodology was used. Three factors including temperature (30-45°C), time (15-45 min) and enzyme concentration (2-6%) in 3 levels were used to evaluate the effect of parameters on turbidity of tomato juice as a model system, the importance of interacting the effects of factors also determined. Optimization has been conducted to achieve the lowest turbidity of tomato juice at the lowest used enzyme. Optimized conditions achieved by concentration of immobilized enzyme 2%, temperature 45◦C and time 45min, and with yield of clarification 27/09 times for tomato juice. Results showed that the best temperature and pH for free and immobilized enzymes were 45°C and 3, respectively.

in this project, study of production of food by products (Spent coffee – wheat bran) in order to producing fiber solid foam using extrusion was carried out. Central composite design was used for evaluation of variables containing spent coffee: wheat bran ratio (75:25, 50:50, 25:75), feed moisture content (14, 17, and 20) and screw speed (120, 160, 200 RPM) on final moisture, water activity, expansion index, hardness and microstructure of extrudates. Results showed that by increasing spent coffee and moisture, water activity and humidity of solid foams were increased significantly. However screw speed had no effects on both properties. Improvement of spent coffee: wheat bran concentration in formulations in order to higher concentration of nonsalable fiber caused an increase in hardness and decrease in expansion index significantly. Increasing feed moisture content (14, 17, and 20) and screw speed simultaneously, showed an increase in expansion index and decrease in hardness. Microstructure Survey of solid foams illusterated that increasing spent coffee: wheat bran ratio leaded porosity reduction and improvement of cell wall size and reducing in air buble diameter. Based on optimization results, in order to production of solid foam with appropriate characteristics such as final moisture content (4.73%), wateractivity (0.29), expansion index (1.23), hardness (68.51 N), the process conditiond were determined at spent coffee: wheat bran ratio (69:31), feed moisture content (14.1) and screw speed (190 RPM)

The purpose of present study was preparation of the carnauba wax/adipic acid combined oleogel and its application as a replacer of shortening in the cake. As results, the replacement of 50% shortening with carnauba wax/adipic acid oleogel significantly (p < 0.05) caused to maintain of moisture content of cake samples during storage time. However, the addition of oleogels decreased the values of moisture, specific volume and porosity in the cake samples. The results of texture profile analyses exhibited that the replacement of 50% shortening with carnauba wax/adipic acid oleogel improved the texture profile of cake especially its hardness. The lowest peroxide value (0.96 ± 0.05 meqO2/kg) was attributed to the formulated cake by carnauba wax/adipic acid oleogel at the end of 90-day storage. Additionally, the formulated cake by carnauba wax/adipic acid oleogel showed nearest sensory acceptance to control sample. In conclusion, the application of carnauba wax/adipic acid combined oleogel as a replacer of shortening in the cake and other bakery products can provide the great promise for develop healthier and safety food products.

In this study, the kinetics of total antioxidant activity changes by DPPH radical evaluation, brown pigment formation (BPF), and phenol total with folin–ciocalteu reagent intestinal tract in heated alfalfa honey at different temperatures (45, 55 and 65 °C) over a period of 10 days it placed. The results showed that the amount of antioxidant activity, BPF, and total phenol content increased with increasing temperature and time. Also, the kinetics of changes in BPF and total phenol showed that these parameters follow zero-order kinetics and the activation energy was 86.1 and 71.7 kJ / mol, respectively, at 45-65 °C. However, due to the diversification of antioxidant activity at different temperatures, second order, first order, and zero order kinetics were obtained at 45, 55 and 65 ° C, respectively. Honey heating at 65 ° C was more effective than 45 ° C and 55 ° C for all three parameters. The results showed that antioxidant activity was associated with an increase in both browning factors and total phenol, and also with increasing brown pigment formation, the total phenol content increased so that the highest amount of phenol was related to the darkest honey sample.

Determination of antibiotic residues in food including honey is very important. To data, various methods have been developed to determination of antibiotics in honey and other animal products. In recent years, the fabrication of electrochemical biosensors in combination with nanomaterial has attracted much attention. In the present study, an impedometric biosensor based on nanomaterial including reduced oxide grapheme (RGO) and gold nanoparticles (GNP) was developed for antibiotic detection of tetracycline in honey samples. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were used to evaluate the working electrode surface. Peak current values in different modes were 0.034, 0.048, 0.09, 0.020 and 0.015 μA for unmodified electrode, RGO, GNP, aptamer and antibiotic, respectively. Biosensor characteristics including reproducibility, reproducibility, stability, and selectivity were evaluated using resistance charge transfer data, the results showed that they were acceptable. In order to calculate recovery percentage, concentrations of 1×10-9 and 1×10-11 M were prepared from tetracycline and injected into honey samples. The results showed that the proposed biosensor provides 94.1% to 104.4% recovery rate for tetracycline in honey samples.

In order to investigate the effect of different levels of bentonite and pH of the extract on exposure to bentonite on the healing rate of stevia extract (Stevia rebaudiana Bertoni), a study was conducted on two factors in a completely randomized design with four replications. The first factor contains bentonite in four levels with concentrations of 0 (control), 10, 20 and 30 g / l and the second factor contains different pH of crude extract in five levels with 5.9 (control), they were 5.5, 5, 4.5 and 4, respectively. The results of analysis of variance showed that treatment with different amounts of bentonite had a significant effect on phenol, carotenoid, chlorophyll a, chlorophyll b and chlorophyll and flavonoid extracts. Also the best level of bentonite with the least amount and maximum clarification was 20 g / l with 0.07 mg / ml phenol, 0.36 mg / l carotenoid, chlorophyll a 1 mg / l, Chlorophyll b.03, Chlorophyll 3.03 mg / l and flavonoid content of 2.69 µg / ml were selected for subsequent experiment. The pH of the extract showed a significant effect on the phenol content of the extract and a significant effect on other traits. The best level of pH of the extract with the highest clarification and attention to human health, pH (5) with 0.15 mg/ml phenol, 1.42 mg / l carotenoid, 0.77 mg chlorophyll a Chlorophyll b 0.84 mg/l, chlorophyll b 1.61 mg / l and flavonoid with 2.17 µg / ml were selected. Therefore, the results of this study show that by considering appropriate amounts of dye compounds such as bentonite (20 g / l) at a suitable pH (5), the crude extract, color and transparency of stevia extract can be improved.

Pasta is one of the most popular foods consumed in the world because of its low price, easy cooking and good taste. It is rich in calories (complex carbohydrates), but it is poor in dietary fibers, minerals, phenolic compounds and vitamins. Due to the limited number of raw materials in pasta production, its popularity among all segments of society as well as the simple production process, it can be used as a suitable carrier for enrichment. In this study, the effect of pasta enrichment using fruits and vegetables on physicochemical and nutritional properties of the pasta was investigated. The results of this study showed that the addition of vegetables and fruits to formulation of past considerably increased content of bioactive compounds such as phenolic compounds as well as antioxidant activity. In between pasta production steps, pasta cooking had the most impact on the reducing of bioactive compounds. Vegetables and fruits can leach into boiling water (cooking water) or can be thermally degraded. The enrichment has a dilution effect of the gluten network, leading to changing of cooking and texture properties. Due to the type of compounds added to the pasta formulation, their effect on glycemic index was different. Therefore, enrichment is successful only if processing conditions are optimized to keep in the final product the desired nutritional characteristics of the vegetables and fruits

As one of the most important nuts, hazelnut (Corylus avellana L. ) contain a valuable set of antioxidants and nutrients. The quality of hazelnut kernel was strongly affected by kernel compounds. The antioxidant capacity and biochemical compounds depends more on the cultivar, climatic conditions and the interaction between climatic conditions and genotypes. The present study was conducted to determine the quality properties including vitamin C, antioxidant activity, total phenol, flavonoid and mineral element in 11 cultivars and genotypes included seven imported cultivars (Ronde dupimont, Negreta, Segorbe, Sivri, Morfineski, Fertile decotard and Sochi), and four local Iranian genotypes (Eshkevar1, Eshkevar2, Eshkevar3 and Eshkevar 4) in the Rudsar Eshkevarat region in 2017. Analysis of variance results were showed that there was significant difference (P≤0. 01) among examined cultivars for all characters and showed high genetic variation in all of the studied cultivars. Correlation analysis showed the existence of significant positive and negative correlation among some important traits. According to the cluster analysis dendrogram performed by "Ward" method, cultivar and genotypes of hazelnut in Euclidian distance 27 were classified into four clusters.

The present study was aimed at investigating the effect of enrichment of sponge cake with pumpkin powder (0, 4, 8 & 12%) on the physicochemical, textural, nutritional and sensory properties of the final product during storage. The results showed that while increase in the level of pumpkin powder promoted the moisture content of the sponge cake, storage time affected it negatively. The changes in peroxide value revealed that pumpkin powder improved the oxidative stability of the product so that the control sample had higher peroxide value than the treatments throughout the storage period. The results of image processing showed that addition of pumpkin powder into the formulation of sponge cake was concomitant with a decrease in lightness and an increase in redness, yellowness and browning index. It was also observed that the highest porosity was belonged to the sample containing 8% pumpkin powder. The instrumental texture analysis indicated that increase in the level of pumpkin powder increased the hardness, the force required to punch and the force required to cut the samples and decreased the cohesiveness and elasticity. The storage time almost had the same effects on the textural parameters as the pumpkin powder. The pumpkin powder improved the nutritional quality of sponge cake in terms of fiber, beta-carotene and potassium contents, which remained unaffected during storage. The sponge cakes enriched with pumpkin powder were more appreciated by consumers compared to the control sample; however, the sample containing 8% pumpkin powder received the highest sensory scores. In conclusion, pumpkin powder could be used for the development of a functional sponge cake with desirable sensory properties and long shelf life.

In this study, the possibility of microencapsulation of Oliveria decumbens essential oil (ODEO) was investigated on the microstructure of microfibers. The fibers were produced using polymeric cellulose acetate (CA) and the essential oil was added to the electrospun solution at different concentrations (0, 15, 25, 35 and 45%). The samples were analyzed using SEM and FTIR. SEM micrographs showed that all of fibers had homogenous structure without nodes. However addition of ODEO at 45% significantly increased the diameter of fibers compared to control sample. FTIR results of control and 45% ODEO fibers showed that in both samples there are distinct peaks of CA, and in fiber containing essential oils in addition to the CA peaks, the peaks in the 812 belong to the compound containing para and in 771 and 899 are related to compounds containing meta bonds. Both of them represent the aromatic compounds of the essential oil. The results of the antimicrobial activity of the fibers showed that the inhibition of the ODEO fibers against Staphylococcus aureus was generally higher than E. coli. Antimicrobial activity was increased with increasing ODEO concentrations.

Various methods have been developed to detect the presence of contamination with Coliforms and E. coli in foods. The pour plate technique using VRBA medium is confirmed as a standard method in Iran. The biggest disadvantage of this method is the need to spend a lot of time, high volume of laboratory operations, multiple stages and ultimately long time to achieve the results. Today, due to the mass production of various foodstuffs, the need for faster methods with high sensitivity to control the quality of food is necessary for the responsible oversight centers. The use of chromogenic medias is also one of the fastest diagnostic methods that have been developed. According to this matter, a comparative study was considered from the results of application of three chromogenic media and reference method in food quality control. Totally 100 samples of foodstuffs were evaluated for contamination to Coliform and E.coli using standard method and three chromogenic medias. Based on the obtained results, 86, 79, 85 and 80 samples were contaminated to Coliform using the standard method, Coliform Agar ES, ChromAgar ECC and Rapid E.coli 2/Agar respectively. Also, using four mentioned methods, contamination to E.coli was reported at 66, 80, 84 and 80, respectively. Cochrane test showed that there was no significant difference between the four methods in Coliform diagnosis (p>0.05). However, four methods did not have the same function in the detection of E. coli so that the chromogenic methods showed significant difference with the standard method (p< 0/001). But there was no significant difference between these chromogenic methods in detecting E.coli (p>0.05). According to the statistical analysis of present study, three chromogenic medias can be used instead of the standard method for the detection of Coliform, but the use of these chromogenic medias is not recommended for the identification of E.coli.