ماندگاری

 The aim of this study was to evaluate the preservation effect of the lysozyme combination addition on gelatin-polycaprolactone composite film on the quality of mackerel Scomberomorus commerson via physicochemical analysis (pH, Total viable bases nitrogen, thiobarbitoric acid reactive substances and Free fatty acid), microbiological (total mesophilic and psychrotrophic bacteria) and sensorial assessments during refrigerated storage.  

Fish fillets were wrapped in three groups including: 1) control sample, 2) gelatin-polycaprolactone composite film, 3) gelatin-polycaprolactone+ lysozyme composite film.

The results showed that incorporating lysozyme into gelatin-polycaprolactone solution could significantly (P < 0.05) improve the quality of fish fillets. Among all treatments, total mesophilic and psychrotrophic bacteria of mackerel fish with the control treatment increased rapidly and was generally higher than other treatments (P < 0.05). Thus, gelatin-polycaprolactone film containing lysozyme can remarkably delay the growth of bacteria of mackerel fillets. The results indicated that the lysozyme could be effective in the reduction of TBARS and FFA values of mackerel wrapped due to antibacterial activity against bacteria which produced enzymes for hydrolysis of lipids. It was seen that the addition of lysozyme improved sensory quality of mackerel fish and these results are supported by the outcomes of bacterial and physicochemical analysis. The increase (>9 days) in the shelf-life was attributed to the antioxidant and antimicrobial characteristics of gelatin-polycaprolactone film containing lysozyme.

These results confirmed that gelatin-polycaprolactone+ lysozyme composite film was effective for the preservation of mackerel.

After catching, aquatic animals undergo chemical, microbial and sensory changes, which cause them to spoil and reduce the shelf life of the product. The purpose of this study was to use edible chitosan coating containing the alcoholic extract of Nannochloropsis sp. on the shelf life of Metapenaeus affinis. For optimization, different concentrations of algae extract (0, 1.5 and 3%), temperature (-10, -3 and 4°C) and storage time (0, 7 and 15 days) were considered as independent variables. Based on the output of RSM software, 15 treatments were selected, and variance analysis was used to determine the suitability of the obtained models. Peroxide value (PV), thiobarbituric acid (TBA), total volatile nitrogen bases (TVB-N), free fatty acids (FFA), total aerobic bacteria (TVC) and color changes (L*, a*and b*) were investigated. Based on the results, the amount of microbial, chemical and indicators of shrimp fillet decreased significantly with the increase in the concentration of algae extract compared to the control group (P<0.05). On the seventh and fifteenth days of storage, the ninth and twelfth treatments showed the lowest bacterial load with 3.22±0.64 Log CFU/g and 4.60±0.65 Log CFU/g (P<0.05). The increase in extract concentration and temperature caused the increase of a* and b* indices and the decrease of L* color index. The percentage of fat and weight yield of shrimp fillet increased significantly with the increase in extract concentration (P<0.05). Based on the results of quality indicators, shrimp fillet at -10°C and 3% extract concentration was favorable for human consumption. According to F-value, in all indicators, temperature was more influential compared to time. The proposed formulas for each index were able to predict the quality changes of shrimp fillet.

Bell pepper (Capsicum annuum L.) belongs to the Solanaceae family, it contains high amounts of bioactive compounds such as phenolic, flavonoid, and antioxidant compounds. These nutrients have anti-cancer properties. However, bell pepper can usually be stored for several days during transport or at the time of sale in the store, or after purchase by consumers. In this period of time, the surface of the fruit loses its appearance and begins to lose its nutritional content. In order to postpone the senescence of bell pepper, various methods can be used, such as the atmosphere changing during the storage period, using chemical compounds, or natural compounds treatment. Researchers are looking for a compound that, while having the least harmful effect on human health, can give pepper the longest lifespan. Melatonin is an organic compound that has been studied in recent years on various biotic and abiotic stresses. The purpose of this study is to investigate the effect of melatonin treatment on the physiology of post-harvesting of bell pepper through its effect on the content of enzymatic and non-enzymatic antioxidant compounds during four weeks of storage time.

Materials and methods:

In this research, bell pepper fruit at the stage of physiological maturity was purchased from a local producer located in Tehran and immediately transferred to the research laboratory of Qom University. In the laboratory, the fruits that had damage or defects in appearance were discarded, and the rest were disinfected by immersing in a 1% (v/v) sodium hypochlorite solution for two minutes. In a preliminary experiment, bell peppers were treated with 25, 50, 100, 200, 250 and 300 µmol/L melatonin. Preliminary test results showed that 100 μmol/L melatonin had a significant effect on post-harvest appearance quality (primary test results not shown). Based on an initial experiment and selection of the best effective concentration in maintaining fruit quality, the treatment of 100 micromol/liter melatonin was used as a reference for the studies in this article. Bell peppers were divided into two groups, control and treatment, and after 2 hours immersion in 100 μmol/L as the treatment group and distilled water as the control group. Then it was kept for 4 weeks at a temperature of 4±1 degrees Celsius. In this research, the indicators of weight loss percentage, chilling injury percentage, antioxidant enzyme activity such as CAT and SOD, free radical content such as H2O2 and superoxide free radicals, and total phenol content, flavonoid content, and Phenylalanine amino lyase (PAL) and Tyrosine ammonia lyase (TAL) enzyme activity as enzymes controlling the phenylpropanoid pathway in weeks 0, 1, 2, 3 and 4 were evaluated after storage and with three repetitions.

The results of this study showed that the melatonin treatment of bell peppers was more effective in maintaining fresh weight during storage compared to the control group. In the first to the fourth week, the weight loss percentage of the melatonin treatment in the 2nd, 3rd and 4th weeks of storage was reduced by 39, 20 and 26.15%, respectively, compared to the control group. The results showed that there is a significant difference in the percentage of chilling injury in different weeks of storage between the control and the melatonin-treated group. The results showed that there is a significant difference in total phenol and flavonoid content between the control group and the melatonin-treated group during storage, and this increase was in line with the effect on the activity of PAL and Tal enzymes as key enzymes in the propanoid pathway. In both control and treated groups with melatonin, the content of hydrogen peroxide radical and superoxide radical showed a significant increase (p ≥ 0.05) during four weeks of storage at 4 ± 1 °C (Figure 3). However, in the second, third and fourth weeks of storage, the amount of hydrogen peroxide was significantly (p ≥ 0.05) lower in bell peppers treated with melatonin than in the control group. Compared to the control group, in bell peppers treated with melatonin during the second week of storage, the highest percentage decrease in hydrogen peroxide content was observed.The content of H2O2 and superoxide free radicals during the storage period showed a significant decrease compared to the control group, which showed that this result is consistent with the data obtained with the activity of antioxidant enzymes CAT and SOD.

The results of this research showed that the treatment of bell pepper with melatonin significantly reduced the effect on enzymatic and non-enzymatic antioxidant compounds compared to a control group, and these results confirm the results and the findings of previous studies about exogenous effect of melatonin. Harvested bell peppers during storage are susceptible to freezing stress, which increases the accumulation of reactive oxygen species such as superoxide radicals and hydrogen peroxide, and these compounds induce aging and reduce quality and marketability of agricultural products. The increase in the activity of PAL and TAL enzymes, especially in the first weeks of storage, may be due to the effect of exogenous melatonin on the expression and biosynthesis of genes involved in the phenylpropanoid pathway, and as a result, it leads to an increase in the activity of PAL and TAL enzymes. Increased production of enzymatic and non-enzymatic antioxidant system and activation of key enzymes of phenylpropanoid pathway (PAL and TAL) and increasing the content of total phenol and flavonoid compounds were observed. It seems that the enhanced antioxidant system has maintained the cell stability by reducing the concentration of reactive oxygen species and has increased the tolerance of the fruit to chilling stress. Phenolic and flavonoid compounds make plants resistant to abiotic and biotic stresses. In this study, the decrease in phenolic and flavonoid content due to storage at cold temperature in control group; was significantly increased in the pericarp of pepper treated with melatonin treatment. Based on the results obtained in this research, it can be said that melatonin treatment is beneficial on the post harvesting life of bell peppers and maintaining the appearance as well as the quality and levels of nutrients. Of course, for the final confirmation of this result, we need more studies on this or other fruits.

The aim of this study was to increase the shelf life of traditional yogurt, to improve its consistency and to prevent whey syneresis by adding tarragon essential oil. Yogurt was produced by industrial procedures and then the essential oil was inoculated into yogurt in different concentrations (10, 25, 30 ppm). Samples were examined for water storage capacity and microbial evaluation during 3 weeks of storage at two temperatures (refrigerator temperature and room temperature). The results showed that different concentrations of tarragon, temperature and storage time had a significant effect (p <0.05) on water holding capacity as well as the number of starter bacteria, molds, and yeasts. Tarragon essential oil reduced the number of bacteria, molds, and yeasts that spoil yogurt. The final results showed that the use of tarragon was not effective in water retention of yogurt samples, but it affected the number of initiator bacteria and yeast. Yogurt samples with high concentration of tarragon had the highest score in terms of consistency and sour taste. While samples with low concentration of tarragon, in terms of yogurt taste, had the highest sensory score.

Although cold storage and freezing are a good way to preserve fish, they do not completely prevent the microbial and chemical reactions that lead to reduced fish quality. Polysaccharide- based edible films are considered for their high nutritional quality, good sensory properties, transparency, flexibility and adequate protection for use in the food industry. The performance of edible coatings is not only influenced by the type of coating method but also by the specificity of coating materials such as material type, amount and density and viscosity. Inulin is currently one of the most common prebiotics in Europe, Japan and Australia, and much research is focused on it. Although inulin has been used as a prebiotic in the feeding of cold and hydrothermal fish today, its use as a natural coating of fish meat alone or in combination with different packages can be considered as another useful application, as well as problems Due to the use of synthetic preservatives as well as environmental concerns due to the accumulation of synthetic polymers in some packages, the use of environmentalist coatings with different antioxidant and antibacterial properties has been suggested as a suitable alternative. The purpose of this study was to determine the importance and potential of using inulin in the packaging of fish meat. Therefore, by a library study, we used various articles published in related journals

Edible coatings have been used to preserve, improve the quality and increase longevity of fruits and vegetables. The aim of this study was to investigate the effect of two types of edible coatings on based natural gum on qualitative attributes and storage life of grape cv. Hosseini as a factorial experiment and completely randomized design. Fruits were immersed in Arabic gum (0, 5, 10 and 15 concentrations) and Almond gum (0, 3, 3.5 and 4 concentrations) in tree sampling times (at harvvest, 15, 30 and 45 day).  All treated fruits were stored in a cold storage in 1±0.5 °C and 95% RH for 45 days. Every 15 days, the percentage of weight loss, firmness, ripening index (TSS/TA), total phenol, vitamin C, amount of photosynthetic pigments, total carbohydrate and antioxidant activity of the skin and flesh of berries were measured. The results of the present study showed that coated samples had lower weight loss and better firmness than uncoated samples. Also, coated fruits could be able to preserve vitamin C, total phenol, pigments and antioxidant activity of the skin and flesh of berry better and the amount of TSS/TA and total carbohydrates increased lower than control samples. It is concluted that the concentrations of %5 Arabic gum and %3.5 Almond gum had a significant defference in most of the parameters with other concentrations and the qualitative and sensual attributes of berry could be preserved better than other treatments and extended fruit storage life.

This study for Effect of EC Irrigation Water on Quality and Quantity of Rosa cv. Dolce Vita in Hydroponic Culture, in a completely randomized design experiment with 4 treatments, 3 replication, were conducted. Pot without irrigation with sodium chloride was used as control. To perform the experiment, cuttings of roses were prepared and cultured in 5-kg pots containing 70% cocopeat and 30% perlite. Irrigation was carried out twice a day at the beginning of the experiment with saline water and after the third day irrigation was done by applying salinity treatments in all treatments equally (with equal volume ratio). Quantitative and qualitative traits of plant such as fresh and dry weight of shoot, flower number, bud diameter, stem diameter, petal length, anthocyanin of petals, total chlorophyll of leaf, potassium and calcium content and longevity of rose on plant were evaluated. The results showed that application of all salinity levels due to sodium chloride salt reduced all evaluated traits compared to control. Also, analysis of variance table showed that the effect of treatment on all traits was statistically significant at 1% level and there was a positive and significant correlation between all traits at 1 and 5% level

Refrigerated storage is the simplest of preserving for short time of fish. The aim of the study was to investigate the effects of refrigerated storage on the microstructure, proximate composition (moisture, protein, fat and ash), chemical (total viable nitrogen, pH, thiobarbituric acid, free fatty acid, water holding capacity), microbial (mesophillic count and psychrotrophic count) and sensory changes of Lutjanus argentimaculatus fillet during a 12-day period at 4 ºC. Fat and protein contents of Lutjanus argentimaculatus of fillet significantly decreased during refrigerator storage and moisture and ash contents of Lutjanus argentimaculatus fillet significantly increased during refrigerator storage (p

In this project, the effect of salvia officinalis extract coating in three treatments (at concentration of 1, 2, and 3%, respectively) was investigated on chemical and microbiological characteristics of fillets prepared from hypophthalmichthys molitrix during the 14-day refrigeration storage (4 °C) period. On days 1, 4, 7, 10 and 14 of storage, the treatments were chemically analyzed in terms of thiobarbituric acid (TBA) and total volatile base nitrogen (TVB-N), microbial load (total bacterial load) and moisture content, acidity (PH), and water holding capacity (WHC). Based on the obtained results, the amount of TVB-N in all treatments was significantly reduced compared to control treatment (p < 0.05). The increasing trend of bioaburic acid during storage period in all treatments was significantly lower than the control treatment. Considering total bacterial load, all of the coated specimens had significantly lower bacterial load compared to the control group except for the first day. Based on the evaluation results of treatments moisture during the storage period, there was a significant difference in all indices except on day 14. There was also no significant difference between samples with regard to samples WHC. Considering pH, a significant difference was observed in indices on different days between samples except on days 4 and 14. In relation to pressurized water, the obtained data from treatments showed no significant difference except on day 4. Considering that treatment 3 (treatment coated with 3% salvia extract) showed more advantages in most indices compared to other coated treatments, the above mentioned coating was therefore recognized as the best treatment in this study and its application is recommended for effective preservation of the chemical and microbial properties of food products during the storage period.

In order to investigate the effect of nicine and rosemary extract (Rosmarinus officinalis) on sensory and microbial spoilage indicators of rainbow trout in cold storage conditions, four treatments were used including: control treatment (uncoated fillets), fillet coated with 0.1% nisin, fillets coated with 0.5%  nisin and 1% rosemary extract and fillet coated with 0.1% nisin and 2% rosemary extract. Quality control tests were carried out in 4 day interals during the 12 day period including microbial tests, counting the total number of bacteria, counting the psychrotrophic bacteria and counting the lactic acid bacteria, and sensory assessments such as color, odor and texture. The results indicated that increasing the storage time caused the significant increase in the total number of the bacteria, the number of the psychrotrophic bacteria and the lactic acid bacteria, and color, odor and texture indices in the control treatments (p <0.05). The effect of coating by 0.5% nisin plus 1 and 2% of rosemary extract on the total number of bacteria, the number of the psychrotrophic bacteria and the lactic acid bacteria and color, odor and texture indices during the storage period was significant (p<0.05). The treatments coated with 0.1% nisin, had no significant effect on the control of the samples’ spoilage compared to the above samples. The results indicated that the use of higher doses of Rosemary extract is effective in increasing the shelf life of rainbow trout in cold storage conditions.

Peroxidase is one of the most important genes in the lignin biosynthesis pathway. Polymerization of the phenolic derivatives into lignin, a connection between cell wall polymers such as monolignules, consequently, cell wall strength are the main functions of this enzyme. Accordingly, endogenous POD gene was isolated and cloned into gateway expression vector (PK7WG2) containing CAMV 35S promoter. Agrobacterium-mediated transformation was performed to introduce the construct into gerbera 'Panorama' cultivar. Following regeneration, putative transgenic plantlets were transferred to a soilless greenhouse. Molecular analysis of second-generation of transgenic plants by real-time PCR confirmed the presence of both internal and transgene in transgenic plants. In compared to wild-type, the POD enzyme activity was increased significantly in transgenic plants. Based on the results, transgenic plants showed higher enzyme activity and as a consequence less stem bending disorder than wild-type with lower enzyme activity and higher stem bending degree. Also, flower quality indices such as vase life and cell membrane stability in transgenic plants increased significantly compared with control. Transfer of transgen POD, in addition to improving the qualitative parameters of flower and increasing the water uptake by the flowering stem, significantly reduced the stem bending disorder of gerbera cut flower.

In this study changes chemical compounds and textural, color and sensory properties were measured to investigate the shelf-life of the whole, gutted and filleted yellow fin Seabream (Acanthopagrus latus) in modified atmosphere packaging (MAP) (45% CO2, 50% N2 and 5% O2) during frozen condition in 4 months storage. Results showed that no significant different in protein, ash and moisture contents were observed (p> 0.05). The lowest fat content (2.67 % ± 0.1%) was observed in sample containing the whole fish (p< 0.05). In all treatments the WHC was showed a significant decrease during storage time (p< 0.05) and the lowest value was found in gutted and filleted samples (22.1 % ± 0.39 and 22.34 % ± 0.34%, respectively). The results also showed a significant decrease in textural properties (including hardness, resilience, cohesiveness, gumminess and chewiness) compared with initial values (p< 0.05). However, the lowest values of these factors were found in whole fish samples. Evaluation of the color showed a significant increase in factor b* as well as decrease in factors a* and L* during storage. The results in all treatments revealed a significant decrease in sensory factors; however gutted and filleted fish in MAP packaging were judged to be more acceptable than whole fish samples. Considering of textural, color and sensory properties, it seems that filleting and gutting fish compared with whole fish samples resulted in better quality in MAP packing under frozen storage.

Study the effect of silisum spray in rosa flowers, experiment in a completely randomized design with 7 treatments included 3 replications and each replications with 3 pots were conducted. Treatments include sodium silicate, calcium silicate and potassium silicate, each with two levels of 25 and 50 ppm and the pot was considered as control without spraying. Pots, two times in the first week of spraying was conducted on the same basis and traits such as petals antocyanin, leaf total chlorophyll, phenyl alanin amonialyase activity and flowers longevity on plant were evaluated. The results showed that the treatment of CaSi 50 ppm had the greatest effect on correction the traits. Result at 1% statistical level had significant effect.

An important issue in microbial biotechnology is linkage between screened beneficial strains in laboratory and industry. Therefore, to develop beneficial microbial biocontrol agents optimization of nutritional and physiological condition for high level production and selection of carrier for final formulation are necessary. In this research we tried to find the best growth condition and suitable formulation for biocontrol Streptomyces rimosus strain C-2012. For optimization of growth condition of strain C-2012, utilization of carbon sources, growth in different media, effect of temperature, pH and NaCl were investigated. Then the effect of different carriers and additives in final formulation and shelf life of microbial community were studied. Study on utilization of carbon sources showed that glucose, fructose and mannitole were suitable carbon sources for growth and the best initial pH and temperature were 7 and 28°C, respectively. Results showed that the culture medium containing glucose, yeast extract and malt extract was the best medium. Investigation on NaCl effect showed that from 0 up to 300 mM sodium chloride could increase microbial community and salinity more than this range decreased microbial community. Based on the results we found that sand is suitable as microbial carrier comparing hydrogel polymers. Viability test during 36 months showed that formulation with NaCl content could keep 200 times (8*106 cfu/g) more than samples without salinity at last month.Discussion and Using suitable carbon sources such as glucose at 28 °C and pH at 7 are important items in optimum growth and preparing final formulation with good level of microbial community. Capability in secondary volatile and liquid metabolites production and fungal pathogen control by Streptomyces rimosus in the presence of NaCl showed that this strain has high potentiality to apply in both normal and saline area. Long shelf life (3 years) without any saprophytic contamination of this strain in final formulation is important in industry and it can prepare a lucrative business.

Aim and Sperm motility is a critical factor for fertilization. Glucose and citric acid can be metabolized by these cells. We study the role of these two on Bovine sperm motility in BO medium. Testicles were removed from tunica albuginea. Epididymes were incised and 4-6 *106 sperm cells/ml were transferred into BO medium containing different concentrations of glucose (G1 & G2) with or without citric acid, and incubated in a %5 Co2 incubator in humid air at 38 C for up to 8 hours. Sperm cells were observed under CASA system (computer assisted sperm analyzer) and data for the Class A, Class A+B, Live ratio, Straight Line Velocity (VSL), Curvilinear Velocity (VCL), Average Path Velocity (VAP), Beat Cross Frequency (BCF) were recorded. The results showed that Class A was significantly higher at G1 & citric acid at 6 hours post incubation (p<0.05). Class A+B was significantly higher at G1 & citric acid at 4 & 6 hours post incubation (p<0.05). Live-ratio was significantly higher at G1 & citric acid too. Such effects didn’t observe at G2 & citric acid medium. The results showed that citric acid has an increasing effect on these parameters. This effect can be affected by concentrations of glucose. Our results didn’t show any significant difference in comparing motility patterns at G1 and G2 concentrations of glucose with or without citric acid. This part of the results suggests that citric acid has no any effect on these parameters.

For study the effect of silisum spray in rosa flowers, experiment in a completely randomized design with 7 treatments included 3 replications and each replications with 3 pots were conducted. Treatments include sodium silicate, calcium silicate and potassium silicate, each with two levels of 25 and 50 ppm and the pot was considered as control without spraying. Pots, two times in the first week of spraying was conducted on the same basis. Morphological traits such as flower fresh weight, flower dry weight, flower diameter, stem diameter and flowers stem lenght were evaluated. The results showed that the treatment of CaSi 50 ppm had the greatest effect on correction the traits. Result at 1% statistical level had significant effect.