جستجوی مقالات مرتبط با کلیدواژه "انگور" در نشریات گروه "صنایع غذایی"

The growth of fungal pathogens on the grape fruit causes a decrease in its quality and shelf life. In this study, the antifungal activity of ginger (Zingiber officinale) essential oil was investigated against fungal pathogens that cause spoilage in grape fruit. Ginger essential oil was extracted using hydrodistillation method and the content of total phenol, total flavonoid, antioxidant activity based on the inhibition of DPPH and ABTS free radicals and its antifungal activity against Aspergillus niger, Rhizopus stolonifer and Botrytis cinerea strains based on disc diffusion agar, well diffusion agar, minimum inhibitory concentration, and minimum fungicidal concentration were evaluated. The results showed that ginger essential oil has 89.80 mg GA/g total phenol and 38.60 mg QE/g total flavonoid. Its antioxidant activity against DPPH and ABTS free radicals was 73.45 and 66.53 μg/ml, respectively. The results of antifungal activity showed that A. niger and B. cinerea were the most sensitive and resistant fungal strains to essential oil, respectively, and the diameter of the inhibition zone in the disc diffusion and well diffusion agar methods, the minimum inhibitory concentration, and the minimum fungicidal concentration for the A. niger strain was equal to 13.90 mm, 14.50 mm, 8 mg/mL and 64 mg/mL, respectively. In general, ginger essential oil can be used as an antioxidant and antimicrobial agent to increase the shelf life of agricultural products.

The increase in the production and consumption of grapes in the world has increased the need for research in the field of creating conditions for further preservation of this fruit, and the lack of sensors that can provide accurate information from the production and storage process to control systems for decision-making is obvious and evident. Therefore, this study aimed to determine some characteristics of grape fruit (taste index, pH, firmness, ion leakage, ∆E, number of mold and general acceptance) stored in cold storage in the range of storage time from 0 to 60 days was measured and according to the importance Achieving these characteristics during fruit storage, a model using fuzzy logic was created as an expert system with accuracy (with a correlation coefficient greater than 0.96) and very high speed capable of predicting and determining these product characteristics only by using It was time to save it. This system was able to obtain the value of each of these studied characteristics at any desired storage time in the range of 0 to 60 days with very high accuracy and in a fraction of a second. On the other hand, it was found that with increasing storage time, the amount of taste index, pH, number of molds, ∆E and ionic leakage of the samples increased, but the degree of hardness and overall acceptance decreased.

In this research, due to the lack of a study on the modeling of the storage conditions of grape fruits coated with maltodextrin containing potassium nanocarbonate and pyracantha extract using the fuzzy-neural inference system (ANFIS), different storage times (zero to 60 days), concentration Potassium nanocarbonate (zero to 2%) and concentration of pyracantha extract (zero to 1.5%) used in edible coating as input and the amount of Brix, the percentage of dropping berry, the amount of malondialdehyde, the browning of the grapes cluster, aroma and taste of samples were considered as output. Three Gaussian, triangular and trapezoidal membership functions with 2-2-2 and 3-3-3 membership functions were investigated. The results showed that trapezoidal function with 3-3 membership function and Gaussian function with 3-3 membership function were selected as the best model for Brix output variable and percentage of dropping berry, respectively. finally, triangular model with 3-3 membership function was selected for cluster browning and malondialdehyde variables. On the other hand, the results indicated that with the increase in storage time, the amount of Brix, the percentage of dropping berry, malondialdehyde and cluster browning increased in all samples, but the amount of aroma and tast of the samples decreased. the use of coating containing potassium nanocarbonate and pyracantha extract caused the speed of these changes to decrease. In the end, it can be said that the high correlation coefficients between the laboratory results and the model outputs indicate the acceptable accuracy and usability of these models in controlling the storage conditions of grape fruits coated with maltodextrin containing potassium nanocarbonate and pyracantha extract.

Grape is a very perishable fruit that has a short shelf life. Due to the increase in consumer awareness, the tendency to use natural preservative compounds instead of pesticides and chemical preservatives has increased. Plant essential oils are considered to be the most appropriate natural compounds due to their potentially effective compounds. Therefore, the aim of this research was to identify the chemical compounds of Foeniculum vulgare essential oil, determine its phenolic and flavonoid content, and investigate the antioxidant and antifungal activity of this essential oil against a number of molds that cause spoilage after grape fruit harvesting. The compounds identified in F. vulgare essential oil included limonene, fenchone, p-allylanisole and anethole, which made up 97.60% of the total essential oil. The total phenol content of F. vulgare essential oil was equal to 26.29 mg GAE/g and the total flavonoid content was equal to 19.23 mg QE/g. The antioxidant properties of the essential oil of this plant were obtained by DPPH, ABTS and beta-carotene-linoleic acid decolorization methods, respectively, 38.56, 42.12, and 30.30%. Also, , it was found that Foeniculum vulgare essential oil is capable of inhibiting and controlling Rhizopus stolonifera, Aspergillus niger, and Botrytis cinerea. Due to the antimicrobial and antioxidant compounds present in F. vulgare, the essential oil of this plant can be used as a compound with practical properties to increase the shelf life of agricultural products, including grapes.

Grape is a non-climacteric fruit with a low rate of physiological activity but is subject to serious physiological and parasitic disorders after harvest and during long term storage (Ciccarese et al., 2013). Currently, Edible coatings have been studied as potential substitutes for conventional plastics in food packaging. Edible coating is a thin layer of edible material formed as a coating on a food product. Edible coating can offer several advantages to the fresh fruit and vegetable industry such as improvement in the retention of color, acids, sugar and flavor components, the maintenance of quality during shipping and storage, the reduction of storage disorders and improved consumer appeal (Antoniou et al., 2015; Cazon et al., 2017; Fakhouri et al., 2015; Galus & Kadzińska, 2015). Farsi gum as a novel source of polysaccharides has drawn much attention in a wide range of various fields such as pharmaceutics, food and cosmetics industries. Functional properties of Farsi gum are influenced by its structure and molecular weight (Hadian et al., 2016; Joukar et al., 2017). By inclusion of bioactive compounds in the Farsi gum network the aforementioned impairments could be overcome and moreover, new protective and functional valences could be added. The inclusion of lipid-based component in Farsi gum gives it excellent light and moisture barrier properties. The benefic impact on human health of hemp seed oil is worldwide recognized. A recent study demonstrated the antimicrobial properties of hemp seed oil. Due to their abundance in biologically active compounds, hemp seed oil is promising natural alternatives that may extend the shelf-life, microbiological safety and nutritional values of food (Cozmuta et al., 2015; Leizer et al., 2000; Salarnia et al., 2018). Growing awareness of the quality of fruit has necessitated increasing effort to develop rapid and non-destructive methods for evaluating fruit quality (Bhargava & Bansal, 2020; Rachmawati et al., 2017; Tao & Zhou, 2017; Wu & Sun, 2013). The aim of this study was the consideration of image processing application for grape sorting based on visual surface characterize.  Coating emulsion was prepared using (Farsi gum (0%, 1.5% and 3%), hemp seed oil (0%, 0.075% and 0.15%) and glyceride (0.3%)). grape fruit were coated by immersion in coating dispersion for 5 min. Samples were then allowed to loss the excess coating dispersion. Coatings were developed at room temperature during an hour. Samples were refrigerated at 4± 1°C for 28 days and analyses were performed at days 0 and 28. Defect identification and maturity detection of grape fruits are challenging task for the computer vision to achieve near human levels of recognition. The image acquisition was performed in a homogenously controlled lighting condition. Considering the camera lens’s focal length, the samples were placed 25 cm under the camera’s lens to be under camera’s field of view. The images of grape were segmented from the background using thresholding of the high contrast images via MATLAB software (R2019a, image processing toolbox). The optimum threshold value was obtained to be 0.35, 0.45 and 0.30 for R, G and B channel, respectively.  The proposed techniques can separate between the defected and the healthy grape fruits, and then detect and classify the actual defected area. Classification is performed in two manners which in the first one, an input grape is classified with two different algorithms (RGB and binary). The Result showed that the accuracies for detecting the surface defects on grape were 97.73% and 96.30% using RGB and binary algorithms, respectively. Proposed method can be used to detect the visible defects of coated grape, and to grade the grape in high speed and precision.  The results of this research and similar ones can provide helpful recommendations in grading fruits for fresh consumption. The simplicity and the efficiency of the proposed techniques make them appropriate for designing a low-cost hardware kit that can be used for real applications.

The use of chemical compounds to prevent corruption and increase the shelf life of agricultural products, including grapes, has many applications. Due to the harmful effects of these compounds on human health and also the tendency of people to use organic products, today the use of low-risk and alternative methods has increased. The use of antimicrobial, antibacterial and antifungal compounds, such as natural essential oils, can be a good way to increase the shelf life of crops. In this study, the effect of thyme essential oil on increasing the shelf life of Fakhri cultivar grapes by two methods of immersion (direct contact) and fumigant (indirect contact) in concentrations (0, 150, 300 and 450 μl / l) In the cold storage with a temperature of 1±2° C and a relative humidity of 90% was tested for 60 days. Traits such as percentage of changes in fruit weight, titratable acidity, total soluble solids, sensory evaluation including fruit texture firmness, Smell and flavor, antioxidant capacity and browning of cluster wood were evaluated. The least percentage of changes in fruit weight and titratable acidity were observed at a concentration of 450 μl /l of thyme essential oil. The control treatment had the highest amount of total soluble solids in fruits (25.2 degrees Brix). Also, the results of sensory evaluation of fruit texture firmness showed that the fumigant method was better than the immersion method with gradual release of essential oil to maintain the firmness of fruit texture better. Sensory evaluation of grape fruit Smell and flavor and taste showed that at high concentrations of essential oil, the sensory evaluation index was lower. Antioxidant capacity was declining in the whole process and fumigant and immersion methods were not significantly different from each other.

Nowadays, the use of tissue culture technique in the production of plant secondary metabolites, such as phenolic compounds, as a natural food additive has become very widespread in the food industry. The aim of this study was to investigate and compare the content of phenolic compounds and antioxidant activity of grapevine Rasha and Qzel Ozum cultivars that were produced by tissue culture under in vitro condition. For this purpose, the terminal buds of grape cultivars were cultured in Murashige - Skoog Medium to produce complete seedlings. Then the methanolic extract was prepared from healthy grapevine leaves and to perform polyphenol composition tests using high performance liquid chromatography with ultraviolet detector, functional groups using Fourier-transform infrared spectroscopy, total phenol content, total flavonoids, total anthocyanins, total carotenoids, acid content, ascorbic acid, free radical scavenging 2,2-diphenyl-1-picrylhydrazyl (DPPH), and hydroxyl  (OH−). The results showed that the amount of total phenolic compounds, total flavonoids, total anthocyanin and total carotenoids of methanolic extracts of Rasha cultivar were 50.35±0.10, 29.72±0.05, 10.41±0.20, and 1.82±0.50 mg/g, respectively, and in Qzel Ozum cultivar were 23.06±0.31, 20.76±0.15, 7.28±0.15, and 94.94±0.42 mg/g, respectively. Ascorbic acid, DPPH and OH− free radicals scavenging activity in methanolic extracts of Rasha leaves were 1.83±0.04, 25.38±1.52, and 75.04±2.74 %, respectively, and in Qzel Ozum leaves were 0.85±0.01, 18.71±2.05 and 68.96±3.61 %, respectively. As a general result, the results showed that the grape leaves of the Rasha cultivar were more than the grapevine leaves of Qzel Ozum cultivar in terms of all studied characteristics (p <0.05). This study also showed that grape leaves are rich in phenolic compounds and natural antioxidants and have the potential to be used in the food and pharmaceutical industries.

Grape berries contain rather high amounts of polyphenolic compounds such as anthocyanins, which contribute significantly to their quality, appearance, and taste. Grape berries produce significant amounts of phenolic compounds. Phenylalanine ammonia-lyase (PAL), is first enzyme in the phenylpropanoid pathway which catalyses the conversion of phenylalanine to flavonoids, phenolics and anthocyanins. Phenylalanine ammonia-lyase (PAL) (EC 4.3.1.24) is an essential enzyme in the phenolic biosynthesis pathway that catalyzes the conversion of L-phenylalanine to trans-cinnamic acid and ammonia. Thus, PAL is the first and decisive step in the phenylpropanoid pathway and is therefore involved in the biosynthesis of phenolic compounds in the plants.The phenylpropanoid pathway involves in the synthesis of secondary compounds such as phenylalanin and phenolics. Considering the positive impacts of phenolic compounds on human health due to their antioxidant properties, their enhancement in fruits and vegetables especially by natural products such as phenylalanin might be considered as promising strategy to fight against cancerous cells and important diseases. Moreover, the increased concentration of phenolics in berries is a critical property benefitting health. In recent years, widespread attention has been focused on the potential beneficial properties on human health of anthocyanins in grapes and their products. Free radical scavenging, antioxidant, antimicrobial, and antiviral activities, nutraceutical and pharmaceutical activities like prevention of cardiovascular disease, protective effects against hepatic damage and disease, anticancer, antitumor, and antimutagenic activities, suppression of inflammatory responses, protection against age-related decline in cognitive behavior, and neuronal dysfunction are some top health beneficial properties of phenolic compounds.

This experiment was conducted in a completely randomized block design using four replications. All reagents and solvents were purchased from Sigma-Aldrich, St. Louis, MO, USA, and used without further purification. Each experimental unit consisted of two plants that each had at least three clusters of approximately the same size, maturity, and development. Vines were sprayed with four concentrations of Phenylalanin (0, 50, 100, and 200 µM) at pre-véraison (in which berries are green and hard) stage. The final volume was reached using distilled water and the pH was set with NaOH (1.0 N) to 7.0. The solutions of Phenylalanin with surfactant TWEEN® 20 were sprayed fifth at 5 days intervals (to ensure that all clusters received sufficient amounts of Phenylalanin solution at pre-véraison stage in case of any rain, deficiency or late development of some berries) on the whole cluster in the early morning. The clusters had little or no evidence of asynchrony and the berries were mostly green and hard. An equal amount of distilled water plus TWEEN® 20 was sprayed to the untreated plants (concentration 0.0 mM). The sprays were carried out with a hand sprayer. At harvest, although not all berries in a cluster were at the same developmental stage, most of the berries should have a particular coloration, softness, and level of development to be harvested.

The results showed that total phenolics and flavonoids content were significantly enhanced in Phenylalanin -treated (100.0 and 200.0 µM) berries compared to untreated ones. Phenylalanin treatment at all concentrations considerably improved the total antioxidant capacity (DPPH) in the berries and, compared with untreated berries, the activity of phenylalanine amino-lyase enzyme was higher in Phenylalanin -treated fruits. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging capacity of the fruits treated with Phenylalanin were significantly higher than those of the untreated berries. The activity of phenylalanine ammonia-lyase (PAL) in phenylalanin treated fruits significantly increased as compared with the untreated clusters. The remarkable effects of the PAL enzyme in increasing production of phenolic compounds in various plant tissues have been established for a long time, and it seems that the increases in concentrations of phenolic compounds in the present study are significantly related to this enzyme. The PAL enzyme causes the production and accumulation of secondary phenolic metabolites in plant tissues by causing a shift from primary to secondary metabolic pathways, and this accumulation usually increases the nutritional value of plant products. The PAL enzyme causes the production and accumulation of secondary phenolic metabolites in plant tissues by causing a shift from primary to secondary metabolic pathways, and this accumulation usually increases the nutritional value of plant products. Therefore, PAL plays a crucial part in improving the quality of crops by stimulating the production of secondary metabolites. The results of current research indicated that the increased activity of the PAL enzyme was entirely related to concentrations of phenylalanin, and its maximum activity was recorded in the treatment with the highest level (200.0 µM) of the phenyalanin. Moreover, a considerable increase was also observed in the evaluation of the total content of flavonoids, one of the major subgroups of phenolic compounds in plants, in grape berries. At the highest concentration of phenyalanin application, an increase of about 100% was recorded in the production of flavonoids, which can significantly help in the marketability of grape berries in addition to their increased nutritional value.

A general evaluation of the results of the present experiment leads us to the conclusion that phenylalanin might be a suitable and recommendable treatment to improve the quality and nutritional value of grape berries. The phenylalanin is an essential amino acid and is safe for human consumption as it is present in almost all plant tissues that have always been consumed by humans without causing any problems. The improvement in the quality of berries, achieved in this research, is partly due to their improved visual quality and partly due to their increased healthful quality, which results from the increase in their antioxidant property and from the accumulation of compounds in them that enjoy high nutritional value. In summary, therefore, it seems that spraying grape berries at pre-véraison can be a suitable and convenient strategy for increasing the quality and nutritional properties of grape berries.

Fresh grapes (Vitis vinifera L.) show severe lesions at the post-harvest stage and during the storage period. Decreasing the quality of grapes in the post-harvest stage limits its consumption and commercialization. Some methods such as using bio-control agents, natural antimicrobials, physical methods, disinfectants agents ,GRAS, (ozone, ethanol, acetic acid) have been used to control Botrytis cinerea after harvest. Encapsulation of the essential oils will increase their ability by increasing the effectiveness of the essential oils. Currently, chitosan has been interested for encapsulating bioactive compounds, as they are generally known to be safe and possess superior biological properties such as biodegradability, biocompatibility and non-toxicity. The aim of this study was to encapsulate thyme essential oil in chitosan nanogels to enhance and maintain its antifungal effect against B. cinerea in vitro and in vitro on Shahroodi red grape.

For the purpose of this study, chitosan nanogels were first prepared and the infrared spectrum of chitosan-meric acid nanogels was measured using FT-IR430 infrared spectrophotometer at 20 ° C. The morphology of chitosan-meric acid nanogels and encapsulated essential oil was analyzed by SEM. Release test was then performed to determine the release rate of thyme essential oil encapsulated in chitosan-meric acid nanogels. Effect of chitosan-meristic acid nanogels at three levels of 0, 150 and 300 µl/L, pure thyme essential oil and thyme essential oil encapsulated in chitosan-meristic acid nanogels at three levels of 0, 75 and 150 µl / L in vitro and on the shelf life of grape fruits was studied under modified atmospheric conditions during 72 days storage at 2 to 4 °C. During storage, some traits such as firmness by manual penetrometer, electrical conductivity of fruit tissue, some components of fruit skin color and soluble solids were assessed by a refrectometer.

 Infrared spectroscopy (FTIR) results confirmed the successful coupling between chitosan amin groups and carboxylic acid-meristic acid groups and scanning electron microscopy image showed that the particle size of chitosan-meric acid nanogel was than 100 nm. The Comparison of the particle size in the present study with the previous studies on the size of chitosan-meric acid nanogels was smaller and more uniform. These differences could be related to several reasons, transform the long chitosan chain into smaller fragments by initial sonication, the important role of ultrasound in the reduction of the particle size and passing the nanogels through the filter. Release test showed that the diffusion of thyme essential oil from chitosan-meric acid nanogels has a two-step process. The chitosan-meric acid nanogels prepared in this study have hydrophilic (chitosan polymer) and hydrophilic (meristic acid fatty acid chain) regions, which led to the gradual release of thyme essential oil due to their hydrophobic nature. The results of the infected packaged berries confirmed that with increasing concentration of thyme essential oil, the antifungal effect was also increased. Evaluation of the effects of essential oil and nanogels - essential oils on grape berries infected with pathogenic spores showed the highest number of spores in control treatment (10.125 × 105 per ml) and the lowest number in NE2 (1.375 × 105 per ml) were observed. Coating treatments of chitosan-meric acid nanogel and thyme essential oil encapsulated in chitosan-meric acid nanogels showed better results at higher concentrations, but in the case of essential oil, lower spores were observed. The lowest electrical conductivity and discoloration, the highest L * component and chroma index were observed in thyme essential oil treatment with concentration of 75 µl/l. The results showed that the lower concentrations of the essential oil in the control of botrytis cinerea was better than the pure essential oils, whereas in the experiments on the storage of grape fruit, the treatment of thyme essential oil with a concentration of 75 µl/l It showed the most favorable result. Based on the results of the present study, the effect of essential oil nano-gel and essential oil alone on the shelf life after harvesting of grapes packed with polyethylene film confirmed that the essential oil performance was better than the essential oil nanogel. The lower performance of the essential oil nanogel than that of the essential oil alone can be due to inhibition of the essential oil diffusion through the packaging film while, the encapsulated essential oil release slower than the essential oil alone, it is likely to have an effect longer than expected in this study for the storage period of the grape. Considering this case and the antimicrobial capability of essential oil nanogel, it is necessary to investigate the effect of essential oil nanogel compared to essential oil on longevity of grapes for a longer of storage period.

The most important post harvesting factors that limiting grape berries after post harvesting are water losing and fungal decay. In this study, effect of titanium dioxide (TiO2) and soy protein isolate edible coating against postharvest decay and increasing the storage life of table grape cultivar was investigated. Uniform clusters with no disease and physical damage were packed with coated and uncoated (control) TiO2 nanoparticles. Then clusters were maintained for 31 days in cold storage at 0 ± 1 °C and RH 90 ± 5%. Grape berries abscission rate, total soluble solids (TSS), titratable acidity (TA), total phenolic content, color and clarity of grape berries, pH, antioxidant activity and total sugar characteristics were measured at intervals 6 days. The statistical analysis of results showed that the TiO2 nanoparticles treatment had significant effects in cluster and grape berries weight losing, fungal infection, TA, total phenol content and coefficient of ripening. This treatment had best flavor, quality, appearance and marketability compared with the samples without TiO2 nanoparticles treatment. In addition, the samples that treated with TiO2 nanoparticles showed higher TSS, TA, antioxidant activity, total sugar and total phenolic content. In the present study, two varieties of grapes treated with TiO2 nanoparticles in the comparison of control samples had higher quality at the end of the storage period.

Salicylic acid (SA) an endogenous plant growth regulator, has been found to generate a wide range of metabolic and physiological responses in plants thereby affecting their growth and development. The aim of this study was evaluation the effect of different levels of Salicylic acid foliar application on quality and some antioxidant activity of Vitis viniferaL. cv. Shahani. The grape wines variety of Shahani is selected from one suitable garden in Maragheh and for every treatment is marked 5 grape plant. This experiment performed in frame completely randomize block design whit three replications in (0, 0.5, 1 and 2 mM) levels of SA treatments. The result showed that in foliar application of Salicylic acid with high concentrations (2 mM) increased of leaves and fruits phenol content, vitamin C, TA and total nthocyanin compound. Finally, maximum amount of total antioxidant has been stablished in 2mM SA concentration that demonstrated 18% increase in compare with control. SA foliar application caused to decrease of total soluble solid (TSS) content but had not any significant effects on flavonoid and total carotenoid of grape berries. These results further indicated that the effects of Salicylic acid in grape is associated with induce defensive systems and increase biological performance such as antioxidant activity and different quality fields in grape.

Grape is one of the most important fruits in the world. Phenolic compounds are antioxidants are important compositions of grape. Phenolic compounds phrase includes all the aromatic molecules consisting amino acids to complex molecules like tannins and lignin’s. Near infrared spectroscopy is one of the most common nondestructive methods for fruits and vegetables qualification analysis. This research is conducted to evaluate the possibility of the quantification of total phenol in grape by near infrared spectroscopy and artificial neural network (perceptron). The number of 444 samples (107 Asgari, 106 Bidane, 111 shahroodi and 120 khoshnav varieties) were selected to model calibrating and test as well. Developed ANNs were compared on phenol prediction by residual prediction deviation (RPD) index in the test sample dataset (101 samples).The maximum RPD was 1.66 by 8-5-1 topology with correlation coefficient and root mean square (RMSE) equal to 0.79 and 48.66 respectively. It was concluded that NIR spectroscopy and back propagation perceptron ANN could be used to discriminate low and high amounts of grape total phenol as a nondestructive method.

The present study investigated the effect of lipid coatings and atmosphere of packaging on instrumental and sensory properties (texture and color) of raisin. Raisins were coated with carnauba- wax (0.5% w/w) and stearic monoglyceride (0.5% w/w) and raisins packaged under two different atmospheric conditions: normal and vacuum. The changes occurred in the moisture content, texture, color parameter (L*, a*, b* and ΔE* values) and sensory attributes of raisin were determined during 12 weeks of storage at 20°C, 35°C and 50°C. Instrumental and sensory attributes were correlated with Pearson Correlation Coefficient. In all samples, the hardness value increased along with storage time, while the moisture content decreased. But presence of lipid coating on rainsin significantly (P

In this paper¡ the simultaneous effect of coating with methylcellulose and Zataria multiflora Boiss extract on the quality of grapes has been studied. The methylcellulose was used in 0.1¡ 0.3¡ and 0.5 g and Zataria multiflora Boiss extract was used in 0¡ 125¡ and 250 µL. Glycerol was used in preparing coatings with the percentage of 25¡ 45¡ and 65 in proportion to the amount of methylcellulose used as plasticizer. After preparation of the different treatments with the aforementioned densities¡ the coating of grapes was started with the dipping method. Treatments were done in 6± 1 degrees centigrade and 70% relative humidity. The grapes were examined every 5 days for 21 days. The examinations included the evaluation of weight loss percentage¡ TSS¡ TA¡ Hardness¡ color¡ and appearance. After statistical analysis of the findings by response surface methodology (RSM)¡ a decrease in weight loss of the fruit was seen. Fruit firmness and color has not changed during this period. The coating formulations in this study had low effect on TSS and no effect on TA. The results for optimized quantities of coating formulation to achieve the best responses¡ 0.1 g methylcellulose¡ 499.99 microliters extract and 0.1 ml glycerol¡ respectively. From the results¡ it was concluded that the use of this edible coating leads to increased grape shelf life.

The purpose of this research was to study the effect of thin layer drying conditions (temperature at three levels of 60,70, and 80 oC, air velocity at two levels of 1/5 and 2/5 m/s, and four pretreatments including potassium carbonate and Paksan drying oil, olive oil, hot water without pretreatment (control)) on cabinet drying process of grape and color of obtained raisin. Six mathematical models were fitted on drying data and the best one was selected according to coefficient of determination (R2), Root Mean Square Error (RMSE) and coefficient of relative average deviation (P). The results showed that temperature, air velocity and pretreatment have significant effects on drying rate and color of raisin. Among these models, two term and page models showed more ability to evaluating and describing drying behavior of grape. Diffusion coefficient values were between 4/6274×10-10 to 8/6541×10-10 m/s2 and activation energy obtained 13470/83 J/mol. The best values of lightness and redness were related to dried raisin at 60 oC and the maximum value of yellowness was related to dried raisin at 70o C. Drying air velocity just significantly affected the redness. Increasing drying air velocity decreased the redness. It was also found out that potassium carbonate and Paksan drying oil pretreatment caused the best raisin color.

Water losing and fungal decay are the main limiting factors of grape berries during storage. In this study, the effects of plastic film covered with titanium dioxide nanoparticles were investigated on the controlling of postharvest decay and increasing the shelf-life of three table grape cultivars (BidaneSefid, Gezel Ozom, and Rish Baba). The results showed that grape packed in plastic film covered with titanium dioxide nanoparticles considerably decrease berries shedding, decay incidence and weight loss. In addition to, this treatment suppresses decreasing color hue during the storage time. There was no significant difference between treated and untreated samples for berry firmness. Table grape CV. Gezel Ozom showed the best shelf life than two other cultivars. Overall, grapes packed in plastic film coated with titanium dioxide nanoparticles showed better taste, flavor, marketability and general appearance than the control because of lower decay incidence and weight loss.

Toxicogenic potential of Aspergillus tubingensis isolates occurring on grape and raisin in southern regions of East Azerbaijan province were evaluated using of ammonia vapor, UV photography and high performance liquid chromatography (HPLC) methods. For this purpose, fungal isolates were grown on Capek Yeast Autolysate Agar (CYA) and Coconut Cream Agar (CCA) media and Ochratoxin A (OTA) production was evaluated. The results of this study showed that toxin production was detectable on 69%, 41% and 65% of the isolates using ammonia vapor, UV photography and HPLC methods, respectively. The compatibility of ammonia vapor vs. HPLC, HPLC vs. UV, ammonia vapor vs. UV and three mentioned methods was 50%, 69%, 62% and 42%, respectively. According to the results of this study, UV photography method appeared to be more efficient for detection of toxigenic isolates of A. tubingensis in comparison to ammonia vapor. The amount of OTA produced by isolates was determined 29-1089 μg/kg using HPLC.

Moisture sorption isotherms are useful in predicting shelf-life stability and in calculating the variations of moisture content during drying, storage and packaging. In this study, the moisture sorption isotherms for pretreated seedless grape were determined using a static-gravimetric method at 40, 50, 60 and 70 C, and the effect of pretreatment solutions on the isotherms was investigated. In order to describe the sorption moisture isotherms, the BET, GAB and Halsey equations were tested to fit the experimental data by using non-linear regression analysis method. According to the modeling results, the GAB and Halsey equations gave the best fit for the samples. The net isosteric heat of desorption was calculated according to the obtained isotherms at different moisture content.

In this study, optimization of quality properties of grape during cold storage was investigated by Response Surface Methodology (RSM). Effect of harvesting time in the ranges 5 - 35 days and cold storage time from 0 to 180 days on the flavor index, dextrose, total soluble solute, pH and acidity of Sorkh Fakhri Shahrood cultivar were investigated by Central Composite Design (CCD). Furthermore, the results showed that optimum conditions for harvesting and cold storage time were 18 and 123 days, respectively. At this optimum point, maturity index, dextrose, total soluble solute, pH and acidity were found to be 52.8, 277.06, 16.9, 4.12 and 0.32, respectively. Also, harvesting time after 5 days ripeness was realized as the worst conditions in order to preserve grape during 160 days.