IRANIAN JOURNAL OF FOOD SCIENCE AND TECHNOLOGY
Year:2016 | Volume:13 | Issue:51|Papers Count:25

Freshness of vegetables and fruits in the short term and long term is one of the important challenges of postharvest process. In this research, the effects of packaging type, modified atmosphere and temperature on the post harvest quality of tomato were investigated during storage. The treatments were considered as modified atmosphere packaging (passive and active) with two gas combinations (4%O2+8%CO2+88%N2 and 8%O2+4%CO2+88%N2), two types of package (polypropylene and polyethylene films) and two storage temperatures (4±1) and (20±2)oC. The effects of above mentioned treatments were investigated using Completely Randomized Design with three replicates on the weight loss, firmness, soluble solids, titratable acidity and pH of tomato during 20 days storage. Analysis of variance results indicated that the effects of all treatments on the measured factors were significant (p<0.01). Tomatoes stored in polypropylene due to less thickness and more O2 permeability preserved the quality of tomatoes better than those of polyethylene film. Also, storage temperature of (4±1)oC maintained the quality of tomato much better than (20±2)oC due to slow down metabolic activities. The first gas combination (4%O2+8%CO2+88%N2) was suitable due to higher CO2 and respiration reduction. Tomatoes stored in polypropylene film and first gas combination at (4±1)oC had the best quality after 20 days storage. In general, storage of products in the packages with modified atmosphere resulted in preserving quality and shelf life.

The aim of the study was to evaluate antimicrobial effect of extract of Lamiaceae plants (Thymus vulgaris L., Mentha spp. and Ziziphora tenuir L.) to prevent growth of pathogenic bacteria (Staphylococcus aureus, Geotrichum candidium) was studied industrial Doogh samples. For this purpose, three levels of concentration of extract that containing (0, 0.075, 0.15 v/v) was prepared. Survival or decrease in the bacterial population in 40 treatments (3 times repeated) in the samples of sterilized Doogh, which that contain a suspension of pure specific strains of Staphylococcus and Geotrichum in the during 24 hours and 14 days by measuring the kinetics of bacterial pathogens was investigated using response surface design. Analysis Results in the inhibition effects of natural antibiotic agent in the Doogh samples revealed that concentrations of thymus extract % 0.14 (v/v) , Mentha oil % 0.11 (v/v) and Ziziphora oil % 0(v/v) is the inoculation rate, which in most circumstances Reduction Staphylococcus aureus in 24 h 2.84Log/ml, 7 days in the 1.63 Log/ml

Nowadays, finding new resources of vegetal antioxidants in order to use them in food (as an additive or alternative with artificial antioxidants) is an important research subject in the field of food science and technology. In this research methanolic extracts of green and black raspberry leaves were examined in antioxidant properties, total phenolic content (TPC) and antimicrobial activity against Escherichia coli, Staphylococcus aureus, Entherococcus faecalis, Salmonella typhimurium, Yercinia enthrocolitica and Shigella dysenteria. then, three concentrations of each extract (200, 400, and 600 ppm) were applied in free antioxidant-purified soybean oil. The oils were kept in 60oC for a period of one month. After storage, Peroxide index, Iodine index, and Acidity value of oil samples were determined. According to the results, in all concentration of extracts, green leaves extract (GLE) had more antioxidant activity (0.7-87%) and TPC (103±0.1 mg/g dry matter) significantly than black leaves extract (BLE). In antimicrobial activity, GLE in the minimum concentration of 7.12 mg/ml had an antimicrobial effect on Staphylococcus aureus and in the minimum concentration of 28.5 mg/ml inhibited the growth of Salmonella typhimurium, Yercinia enthrocolitica. But BLE did not show any effects on growth of investigated microbes. In the quality tests of oil samples, with an increase in the concentration of GLE, acidity, Iodine index, and peroxide index increased significantly. At the end, it was concluded that oil samples containing 200 ppm, had better quality and stability than samples containing 200 ppm Propyl Gallate (market soybean oil).

At this study, effect of paddy drying method with three levels (shadow drying, sun drying and oven drying), paddy grain moisture content at four levels (8, 10, 12, 14 w.b.%) and common paddy varieties in Guilan province at three levels (Hasani, Hashemi and Alikazemi) were investigated on broken grains percent duo to milling process. The results that breakage percent of grains was least at tests with shad drying method. The mean highest breakage percent of grains at husking stage (14.061%) was obtained at tests with Hashemi variety and oven drying method. The mean least breakage percent of grains at husking stage (5.351%) was obtained at tests with Alikazemi variety and shad drying method. With increasing of grain moisture content of milling from 8 to 14 w.b. %, breakage percent of grains at husking and whitening stages were decreased from 11.616 % to 7.717 % and 21.025 to 12.841%, respectively. The mean highest (21.340%) and least (13.841%) breakage of grain whitening obtained at tests with sun drying and shad drying methods, respectively. The mean highest (20.539) and least (14.150%) breakage percent of grain whitening obtained at tests with Hasani and Hashemi and Alikazemi varieties, respectively.

Honey is a natural sweet substance produced by honeybees from the nectar of plants (nectar honey), secretion of living parts of plants or secretion of plant-sucking insects (honeydew honey). The aim of this study was determination of composition and evaluation of physicochemical properties of 10 honey samples (Coriander, Dill, Ziziphus, Thyme, Parsley, Qnqal, Astragal, Alfalfa, Tamarisk and Orange blossom honeys) collected from different regions of Iran especially Isfahan. Therefore physiochemical tests such as moisture content, total soluble solids, acidity, specific gravity, viscosity and total sugars on honey samples was done. Also the total amount of phenolic compounds using Folin-Ciocalteu reagent and antioxidant activity by DPPH method was evaluated. According to the obtained results, it can be concluded that Dill honey is the most viscous honey because of the lowest moisture content among honey samples. Thus, it has the longer shelf life compared to other samples during the storage. Ziziphus honey had the highest phenolic compounds and antioxidant activity while Orange blossom honey had the lowest phenolic compounds and Astragal honey possessed the lowest antioxidant activity. Thus it can be said that Ziziphus honey had the highest nutritional value among 10 samples of honey. High correlation coefficients between phenolic compounds and antioxidant activity indicated that these compounds are main responsible for the antioxidant properties of honey.

One of the most favorable results of roasting process is increasing in antioxidant activity which is mainly due to the formation of mailard reaction products. Roasting of domestic pistachio nut (Ahmad Aghayi cultivar) and wild pistachio nut (P. mutica) was performed by two methods of oven and microwave. After oil extraction, the extract meals of pistachios were prepared and their phenolic content and antioxidant activities were determined. Phenolic content of pistachio meal extract was in the range of 915-797 mg Gallic acid in kg oil. By comparing phenolic compounds before and after roasting, it can be realized that roasting can increase the amount of phenolic compounds and antioxidant activity of pistachio meals. Pistachio meal extracts were added to soybean oil without antioxidant. The soybean oil samples containing pistachio extracts as a natural antioxidant, BHT as synthetic antioxidant and an oil without antioxidant as control maintained in oven at the temperature of 60oC in 30 days to evaluate the antioxidant stability and sampling was performed in 1, 15 and 30 days. The results of peroxide and thiobarbituric acid during the storage period showed that the extract of pistachio meal can be used as a good source of natural antioxidant to prevent oxidation in oils.

In this study the effect of grape fiber and chitosan on Lactobacillus Fermentum viability, physicochemical and sensorial properties in yoghurt containing kiwi was investigated during storage, using response surface methodology (RSM). Amounts of grape fiber, chitosan and storage time were in the range of 0-1.2 %, 0-1 % and 3-21 day, respectively. The results indicated that with increasing the amount of chitosan, Lactobacillus Fermentum viability decreased, but it was increased by increasing grape fiber during storage significantly (P<0.05). Moisture and syneresis of samples reduced significantly by increasing the amounts of chitosan and fiber (P<0.05). According to sensory evaluation, increasing the amounts of chitosan caused decrease in color scores. Flavor scores decreased as grape fiber increased significantly (P<0.05). In conclusion, using 0.9% grape fiber, 0.1% chitosan, and 12 day storage were found as optimum conditions for producing probiotic kiwi fruit yogurt.

Flour is main component forming bread that is major diet for many people. Therefore, for improve bread quality, is necessary that is decreased wastage of basic and strategic staple. In this research, three types of flour (nol, setare, without bran) were prepared from Arddaran company and were placed phostoxin pill for prevention of attack pesticides and insects, then were packaged in plastic bags and were storage at autumn and winter in environmental condition, then, was investigated chemical, rheological and microbial attributes during six months, interval once months .From results can find that quality attributes of low rate of extraction flour (nol) are better than high rate of extraction flours (without bran). Quantity attributes of flours (such as, ash, protein and gluten) are not changed significant during storage of flour, except, moisture is decreased. But, quality attributes (such as, gluten index, zeleny, farinograph quality number) are improved, oxidation with subjecting air cause new disulfidryl bonds (S-S) between different chains of protein, or disulfidryl groups interact with exist disulfidryl bonds and form new disulfidryl bonds, that increase strength and quality of flour. According to the analysis of wheat flour quality parameters (zeleny, gluten index and farinograph quality number) is required at least 4 months storage for improve of quality of flour. Components of flour especially gluten and enzymes change during storage of flour. Sum of these changes result aging flour, therefor, is improved it is quality and moisture, also, flour is aged rapidly with preparation sufficiently and good ventilation. Considering that after six months of storage, the flour reached a maximum and during this period, the microbial load of the samples exceeded the standard has not been exceeded, The flour is stored for six months, it will be strengthened, especially in the case of weak flour, they must be stored and used later.

Functional drinks are a new generation of fermented products that have microorganisms with medical properties which give benefit to their host by increasing nutritional value and improving sensory-textural specifications. In this study ability of lactic acid bacteria by Lactobacillus acidophilus DSM 20079 and Lactobacillus delbruekii DSM 15996 in fermentation of celery juice, production of organic acids and effect of phenolic compounds and even sensorial properties in 37 Ċ at 24 h are evaluated. Results demonstrated that both strains were capable of growing and being active in celery juice and the greatest effect in decreasing pH, increasing acidity and also fabricating organic acids was observed by Lactobacillus acidophilus.

The main functions of the packages are: Physical protection, barrier protection, convenience and information. Tendency to minim process food products, quality, safety and preventing of food born disease and strict requirements in relation to consumer health caused ways to use antimicrobial agents in food packaging and prevent the development of microorganism growth. Active packaging is one the methods of efficient packaging, that protect safety and quality of foods. The material of these packages is a suitable base for adding a wide range of different combinations such as antimicrobial agents to them. Pursuant to this, movie bionanocomposite films of Bitter vetch seed’s protein with zinc oxide nanoparticles to produce an antimicrobial packages with %5 w/w of Bitter vetch protein isolate and 0.25, 1 and 2% zinc oxide nanoparticles. Glycerol was used as plasticizer. The mechanical and barrier properties of bionanocomposite films assessment and determined that the addition of zinc oxide nanoparticles as an antimicrobial agent to the protein film caused a sharp decrease of oxygen permeability through the films. The rate of water vapor permeability of bionanocomposite films decreased comparing with control film. The results indicated that lower levels concentrations of nanoparticles cause better functional properties of bionanocomposites films because of fewer particles coagulation. Effect of nanoparticles on the mechanical properties, tensile strength and modulus of elasticity were increased, but elongation of the film was reduced.

Today, many studies are doing to identify the lipolytic microorganisms because of the important role of them in the production of microbial lipases. Oilseed meals are a good place to achieve these microorganisms. In this field, yeasts are more important in comparison with other microorganisms. In this study, we isolated 27 types of fungi from Yazd sesame meal. After the evaluation of macro and micro morphological features, it was identified that 16 of them were from yeast group. Lipolytic yeasts were screened using Tween 80 agar medium and were identified to genus and species by colony and cell morphology observations and evaluation of fermentation reactions and the use of carbon and nitrogen sources. 4 lipolytic screened yeasts were included Sporidiobolus pararoseus, Sporobolomyces salmonicolor, Cryptococcus albidus and Yarrowia lipolytica .The ratio of areola diameter to the well diameter was between 2.314-2.714. S. pararoseus showed the maximum ratio of areola to well diameter (2.714) .Lipase activity of these four types of yeasts was measured in submerged cultures with Cezepek Dox medium for 7 days at 30oC and 200 rpm by using of photometry method and p-nitrophenyl palmitate substrate. Lipase activity range was between 0.866-4.333 U/ml, and Cryptococcus albidus had the highest lipase activity 4.333 U/ml, while it showed the least biomass growth among other yeasts (OD=0.577). Yarrowia lipolytica showed lipase activity of 3.466 U/ml and also, the highest biomass growth OD=0.806.

Bread is traditional food generally prepared from wheat flour. Flat breads are the oldest and well known kinds of bread worldwide. The main wheat component responsible for bread quality is gluten, which is an essential structure-binding protein. Although important, this protein can cause health problems in predisposed individuals with celiac disease. Consequently hydrocolloids are used to substitute for gluten and mimic the viscoelastic properties of it. In order to consider the influence of xanthann and CMC on dough rheological properties, they used in 0.5, 1, 1.5% to evaluate the influence of each level separately and in 0.5, 1% (flour basis) for incorporative effects of them. In farinogragh measuring, treatment 4 (1.5% Xanthan) and treatment 11 (1% CMC, 1% Xanthan) resulted in highest water absorption. Increasing the level of xanthan led to increasing water absorption significantly in comparison to CMC. Xanthan and CMC decrease and increased dough time development respectively. Addition of xanthan resulted in a farinogram which resembled that of a standard farinogram obtained by wheat flour. In dough dynamic measuring, hydrocolloids caused higher viscoelastic modulus and increasing the level of them made them greater. The highest G' was in treatment4, between used separate gum treatments. tanδ in treatments contain CMC was more than treatments contain xanthan and it was the most in treatment 7 (1.5% CMC). G' and G" in treatments contain incorporative gums was more than treatments contain separate gums. In these treatments, Xanthan decrease the tanδ resulted in treatments including CMC seperately. Treatment 11 has higher dynamic modulus and tanδ than treatment 4. In all cases xanyhan had affect on increasing water adsorption, decreasing dough time development, elastic modulus acceleration and decreasing tanδ.

In current investigation a quality control ultrasonic system has been presented for detecting microbial contamination of UHT milk packages. This system is able to detect microbial contamination of milk packages without opening them. Microorganisms’ growth causes some changes in physical and chemical properties of milk resulting in changes of ultrasonic properties of milk. In this study amplitude and time of flight of ultrasonic waves were measured. The center frequency of piezoelectric discs was 1.02 MHz and all of experiments were done in temperature 35oC. Ultrasonic tests were conducted for microorganisms Escherichia coli, Staphylococcus aurous and Bacillus cereus. The results showed that different bacteria’s metabolisms affected chemical properties of milk and detecting process of microbial contamination. Ultrasonic system was able to detect microbial contamination after 7.25 to 12.5 h. from microbe injection. Also, the results showed that ultrasonic system can detect microbial contamination in various values of acidity and pH of milk packages.

Salep composite films containing 0±30% (w/w) oleic acid or stearic acid- were prepared through emulsification and their physical, mechanical, and barrier properties were evaluated and compared. Emulsified films were softer than pure films. Addition of the fatty acids to salep films significantly improved the WVP (P<0.05), but lowered the tensile strength. Stearic acid was more effective than oleic acid in reducing the WVP, but films with oleic acid showed better mechanical properties overall than those with stearic acid. Also the presence of fatty acids decreased solubility in water and caused the films to become opaque. On the other, fatty acids showed different effects on the elongation at break. This work showed that when taking all the studied variables into account, films formulated with oleic acid were found most suitable for various food applications.

In recent years, extensive researches has been done on use of edible coating in food packaging. Edible coatings can increase the shelf life of coated foods and they are suitable alternative for synthetic packaging. In this research, the effect of carboxy methyle cellulose based edible coatings with thyme extract on reducing moisture absorption and decreasing lipid oxidation productions have been evaluated. The edible coatings were prepared at different concentration levels of carboxy methyle cellulose (0.0, 0.5, and 1.5% W/V) and thyme extracts (0.0, 0.5 and 1% V/V). The moisture content, peroxide, thiobarbituric acid and acid number changes were determined for samples. The experiment was performed by Dunnett statistical tests in three replications using factorial design based on completely random design. The results indicated that the coating containig of 1.5% W/V of carboxy methyle cellulose and 1% V/V of thyme extract showed better results in reduction of peroxide value in fresh hazelnut. Carboxy methyl cellulose coating can delay the lipid oxidation of fresh hazelnut by providing a barrier against moisture and oxygen permiability to the texture of hazelnut. Adding of thyme extract into coating formulation, in addition to increasing the shelf life of hazelnut, is important regarding functional aspects of hazelnut. This coatings have both edible and environmentally friendly properties and preferable to synthetic packaging.

The aim of this study was to evaluate the quality characteristics of bread produced by yeasts and lactobacillus isolated from native Iranian sourdough. Initially for the preparation sourdough, fresh microbial cells with certain number of colonies, by centrifugation were isolated of initial culturing bacteria and yeasts. Then equivalent 10% weight flour, microbial cells mixed with equal amounts of water and flour. After processing identical samples to assess the quality characteristics of bread used of sensory evaluation test, image processing and Texture analysis. The experiments in a completely randomized design and completely randomized block with three replications were performed. The results showed that the samples significant effect on the quality characteristics. The results indicate that sourdough can be increasing the porosity of the sample So that e treat with 42 percent had the highest degree of porosity also sourdough delaying staling. According to the results from this study, treatment of Lactobacillus reuteri and Saccharomyces cerevisiae had best Sensory evaluation, porosity and texture.

Bread is the main source of a large part of the energy, protein, minerals and vitamins required by humans. Aloe Vera is one of the oldest medicinal plants that beside of fiber, minerals, vitamins, amino acids and natural sugars, have antimicrobial agents, anti-inflammatory and antioxidant Therefore, its use helpful for the prevention and treatment of Alzheimer's, heart disease, digestive problems. This study examined the effect of addition of aloe vera powder in quantities of 1, 3, 6 and 9% (w/w based on flour) on the quality of Barberi bread, as well as changes in microbial, texture, color and water absorption properties of bread within 72 hours in order to produce the functional bread. The results showed that the adding of aloe vera powder, causing controlling the activity of microorganisms and mold and yeast, increase swelling power and reduce staling the bread. However, volume, brightness, Points smell, taste and the ability to chewing has declined. In general, investigation of breads characteristics in this study showed that the adding powder of aloe vera until 1%, causing improve the quality of shelf life and increase the healthly value of Barbari breads that is produced.

The goal of this study was applying the genetic algorithm–artificial neural network (GA-ANN) modeling to predict the antibacterial effect of annatto dye on Escherichia coli population in mayonnaise. Annatto has antimicrobial and antioxidant properties in foods. Annatto dye was extracted and after filtration and concentration, was dried by vacuum oven. In this study, sauce samples containing 0, 0.1, 0.2 and 0.4 percent of annatto dye were prepared and stored at 4 and 25oC. Sampling and colony counting were performed during 17 days and in triplicate. In order to predict the Escherichia coli population multi-layer perceptron neural network with 3 inputs and 1 output were used. Genetic algorithm method was used to optimization number of neurons in ANN hidden layer. The results showed a network with 7 neurons in hidden layer and using a Sigmoid tangent transfer function and the Levenberg-Marquardt (LM) optimization technique and 30%-20%-50% for training/ testing/ validating process can be well predict the Escherichia coli population (r=0.999) in the presence of annatto dye. Sensitivity analysis results by optimum ANN showed the storage time as the most factor for the predicting the Escherichia coli population.

Reduction of wheat consumption utilization in bread and wheat flour products is one of the main ways to reduce the costs and get more economical processes. So the aim of this study was evaluation of sanginak (latirus sativus) flour (in four levels of 0, 10, 20 and 30%) and guar gum (in three levels of 0, 0.25 and 0.5%) on moisture content, special volume, texture and sensory properties of semi bulked Barbari bread. The results showed by adding sanginak flour moisture content and firmness was increased and specific volume were decreased. However the panelists gave the highest score to the control samples. contain 10 and 20% sanginak flour. On the other hand the moisture content, specific volume, porosity and overall acceptability were increased and firmness was decreased by increasing the amount of guar gum. The final results of this project showed the sample contains 20% sanginak flour and 0.5% gaur gum In terms of specific volume, rheological and sensory properties was Competitive with that of the control sample (100% wheat flour).

In this study, the effects of full fat soy flour (FFSF) addition and drying temperature changes on sensory evaluation and textural characteristics of spaghetti was assessed (P<0.05). The addition of 2%, 5% and 8% of FFSF and different Levels of temperature, Low Temperature (LT), High Temperature (HT) and Ultra High Temperature (UHT) drying caused the significant changes in organoleptic and textural characteristics of spaghetti. In texture analysis of spaghetti, Hardness factor was increased and Adhesiveness, stickiness factors were decreased significantly when used of HT and FFSF combination at the same time. Springiness factor in HT and UHT drying has been shown an insignificant changes in spaghetti. The results of sensory evaluation shown, color, odour, taste, texture and overall acceptability was improved when used of HT for heat treatment, but Mailard Reaction (non-enzymatic browning) developed when used of UHT drying. LT drying didn’t has an efficient result and beany flavor was sensible in dried spaghetti with 5% and 8% of FFSF. The result shown that using of HT drying has a positive effect on sensory and textural characteristics of dried spaghetti.