جستجوی مقالات مرتبط با کلیدواژه « acidity » در نشریات گروه « زراعت »

Food safety is one of the important issues related to fresh fruits and vegetables. Most natural compounds are degradable and can be a safe compound for human health and the environment and an alternative to synthetic compounds. Research has shown that the combination of bioactive substances such as essential oils, plant extracts and nanocomposites increases the active effect of the coating as fruit packaging and reduces the rate of fruit deterioration.

In this research, physalis fruits were obtained from Khorramabad research greenhouse. Nanocellulose and pure carvacrol (extracted from Satureja khuzistanica Jamza ( were prepared from Nanovin Nano Polymer Company and GC/MS analysis from Khorramabad Pharmaceutical Company, respectively. Also, the combination of nanocellulose with carvacrol was prepared in the laboratory. The experiment was conducted as a factorial experiment with two factors in a completely randomized design with 4 replications. The first factor of material type in specific concentrations at nine levels (control, Car 0.3%, Car 0.6%, CNF 0.5%, CNF 1.5%, Car 0.3 + CNF 0.5%, Car 0.3 + CNF 1.5%, Car 0.6 + CNF 0.5 %, Car 0.6+CNF 1.5% and the second storage time factor was investigated at four levels (0, 45, 90 and 135 days). First, the fruits of Physalis were washed with distilled water, and then the extra leaves and damaged fruits were removed. The fruits were placed in the prepared solution for 2-3 minutes and after applying the treatment, the fruits were placed in a refrigerator with a temperature of 4 °and 90% RH.

The results showed that the fruits treated with nanocellulose and carvacrol had less weight loss and higher tissue firmness. Byochemiucal analysis also showed the positive effect of the treatments on parameters, so that the highest TA and vitamin C and the lowest amount of pH were obtained in the combined treatments of nanocellulose and nanocellulose/carvacrol. Also, the treatments used reduced the TSS and fruit TSS/TA ratio of the fruits, and the combined treatments had the lowest amount. The nanocellulose coating prevents water loss and reduces the metabolic and respiration processes. Also, nanocellulose/carvacrol composite coatings lead to an increase in the pH of cytochrome oxidase by reducing internal oxygen, and this enzyme increases the rate of ascorbic acid decomposition. By coating on the fruit during the post-harvest period, the aging process of the fruit is reduced the production and effect of ethylene, reducing respiration and preserving the cell wall, which ultimately leads to better preservation of TSS. Therefore, any reduction in metabolic activities causes a reduction in fruit ethylene biosynthesis and action.

In general, the results of the research showed that the investigated characteristics of physalis fruit were influenced by the treatments. As treated samples, weight loss was less, pH, soluble solids and taste index were lower, tissue firmness, titratable acids and vitamin C were higher. According to the general results, it can be stated that the application of nanocellulose/carvacrol composite treatments, especially the Car 0.6+CNF 1.5% treatment, showed more favorable results than the application of each one alone in most features.
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Given that, the qualitative characteristics of olive oil are influenced by environmental conditions and cultivars. Therefore, this study was carried out to investigate some of the oil qualitative characteristics of Tarom 2 and Dezful cultivars of olive as a randomized complete block design with 3 replications at Shahid Chamran University of Ahvaz during 2016-2017. The results indicated that, the oil extracted from Tarom 2 cultivar exhibited the highest peroxide value (9.25 meq of O2/ kg of oil), chlorophyll content (8.10 mg/kg of oil), and carotenoid (0.16 mg/kg of oil) and K232 and K270 extinction coefficients of 2.32 and 0.61, respectively. However, total phenolic content of the oil extracted from Dezful cultivar (552.66 mg/kg of oil) was higher than that of the other cultivar. In addition, the highest oleic acid content (58.52%) and lowest palmitic acid content (17.6%) were measured on the oil obtained from the Tarom 2 cultivar, while the oil extracted from Dezful cultivar showed the highest linoleic acid content (18.05%). Furthermore, oleic acid-to-linoleic acid ratio was higher in the oil extracted from the Tarom 2 cultivar rather than the one taken from the Dezful cultivar. Therefore, based on the results obtained from the experiment, the oil extracted from Tarom 2 cultivar is expected to exhibit higher oxidative stability than that of the Dezful cultivar.

The experiment was carried out to study pomochemical properties of twenty superior genotypes of apricot
(Prunusarmeniaca L) during two consecutive growing seasons (2013-2014) in the Khalkhal valley, south of Ardabil province (Iran). Physical parameters (weight, flesh, skin and color) and chemical parameters (total soluble solids content and acidity) were evaluated using Principal Component Analysis (PCA) and cluster analysis Ward Method. The results indicated a high variability in the set of the evaluated apricot genotypes based on bud break season, fruit and pit weight, harvest season, fruit yield, total soluble solids (TSS), and total acidity. Most of the genotypes had a relatively small fruit size; only four had a fruit weight >39 g. In general, fruits had yellowish skin ground color and cream flesh color. There was a high correlation between fruit and pit weight(r = 0.575), but fruit weight was not correlated with TSS content and acidity. There was a high negative correlation between the TSS and total acidity (r = -0.954). Bud break season was highly correlated with harvest season (r = 0.857). The results indicated the presence of great genetic variability among local genotypes, and there was promising genotypes with appropriate pomological and phenological characteristics. Genotypes such as BG2, KG1, SG6 and EG1 deserve to be exploited for the future apricot conservation and breeding programs.

In order to study the effects of chitosan and hot water treatments on storability and fruit quality of sweet pepper "Paks", an experiment was conducted as a factorial design in the base of CRD with three replications.Fruits were treated withchitosan at four levels (0, 1, 1.5 and 2 percent) and hot water at 20 and 45ºC (dipping for 2 min time) and 60ºC (dipping for 2o sec time), then stored for 12, 24 and 35 days at 8°C and 98% RH in refrigerator. The results showed that the quality and vitamin Ccontent of fruits decreased during storage. Coating of pepper with chitosan significantly delayed loss of TSS, firmness, vitamin C, weight losses and fruit quality. Pepper coated with 2% chitosan had the highest effect on keeping fruit quality. Hot water had significant effect on fruit quality. Water with 45°C as hot water treatment improved firmness, titrable acidity, vitamin C, visual quality and activity of catalase and peroxidase enzymes. Heat damage was observed on fruit dipping at 60°C. According to the results, treatment of 2 percent chitosan with hot water 45°C had the best effect on the studied parameters.

To understand germination and emergence characteristics of black henbane, ground cherry and curly dock a laboratory experiment, based on randomized complete block design with four replications, was carried out at the Faculty of Agriculture, Ferdowsi University of Mashhad in 2012. Treatments were temperature ranges (5/15, 10/20, 15/25, 15/30 and 20/35 ° C night / day) and different levels of salinity (0, 10, 20, 40, 80, 160 and 320 mM of NaCl). The effect of pH adjusted to 5-9 by using acid buffer solution. Seeds were planted at different depth (0, 1, 2, 3 and 4 cm) to study their effects on seedling emergence. Results showed that black henbane exhibited highest germination percentage at 25/15 diurnal tempratures, with 86.50 and 60.50 respectivly for daylight and complete darkness. Germination of ground cherry was highest (93%) at 10/20 diurnal temprature and 41% in complete darkness. Highest germination percentage for curly dock at diurnal temperatures of 20/10, 25/15 and 30/20 with light / dark regime of constant darkness was abserved. The seeds at diurnal temprature of 35/25 in both light regimes did not germinate. Increasing salinity reduced germination. Increasing the osmotic potential, also reduced germination significantly. Highest germination percentage of black henbane (97%) was observed at pH 7, and lowest germination (17%) at pH 9. Increasing planting depth reduced seedling emergence significantly. Germination percentages of ground cherry and curly dock at pH 6 and 7 were highest (97% and 96% respectively) and lowest 26 and 25 % respectively at pH 9.

Correct timing of fruit harvest may lead to increase in production efficiency, decrease in transportation and storage costs and prevent loss of quality. A 3-replicate factorial experiment based on a completely randomized design was conducted in order to investigate the effect of harvest time and storage on qualitative properties of red grape, the variety of Fakhri shahroud. Sampling was done in four stages (one sample before fruit ripening, two samples at the time of ripening and one sample after ripening) and the samples were stored at 0.5 - 1 ºC and 90 – 94% relative humidity. The results showed that with increase in storage time, the pH and taste index of the grapes decrease. A significant negative correlation between pH and acidity of fruit samples at the 99% probability level was observed. With increase in harvest time, the Bx and dextrose of the grapes increased. As harvest time was approached, the taste index of the fruits began to increase. Evaluation of interaction effect of harvest time and storage showed that samples which were harvested at 35th day, before transporting to the morgue, had the greatest taste value.

This study was conducted to assess the variability of physiological traits of wild types of Berberis vulgaris in different growing areas and altitudes in Shahrood. The experiment was carried out as factorial in the basis of randomized complete block design with three replications during 2011-2012 cropping season. The first factor consisted of three growing areas Tange Heidar Valley, Glierd and Valley of Ghatar Zereshk, and the second factor was three altiludes 1400-1650, 1650-1900 and 1900-2150 meter from sea level. Five physiological traits were assessed in randomized samples of the shrubs taken at different growth stages and different parts of the plants. The results showed significant differences in physiological traits in different growing areas and different altitudes. Anthocyanin content (46.44 mg/100mg), Berberin content (15.66%), pH of fruit (3.08) and total soluable solids (20.22 %) decreased with increase of height from sea level, while acidity of fruit increased with height. Significant negative and positive correlations were observed between different traits in different growing areas and different altiludes.

Optimal nutrition of grapevine is one of the most important factors that affect the quantity, quality and time of fruit ripening. In order to increase the quantity and quality of ‘Askari’ cultivar, a factorial experiment in a randomized complete block design with three replications was conducted at Shahrekord in 2010. Treatments consisted of four levels of potassium sulfate fertilizer (0, 300, 600 and 900 g per vine) and four levels of boric acid fertilizer (0, 1000, 2000, and 3000 ppm). The results showed that potassium had a significant effect on yield and yield components. Different levels of potassium sulfate and boric acid increased cluster (number, weight, length, width) and fruit soluble solids. With increasing potassium levels, the number of clusters (14, 18 and 25) and content of total soluble solid (0.54, 1.45 and 1.53%) were significantly increased in comparison with control, respectively. Also, total soluble solids of berries were increased significantly (0.76, 0.75 and 1.25%) with boron treatment compared to control. The highest TSS (18.8) obtained in 900 mg of potassium sulfate per square meter, while it caused the greatest reduction in fruit acidity compared with the control. Fruits pH was decreased by 0.3 units with application of 3000 ppm of boric acid. The results of this experiment showed that nutrient treatments, especially potassium sulfate accelerated fruit ripening and increased fruit yield and sugar content.

Citrus fruit quality preserve the post harvest cause marketability increased. In this research, the effect of putrescin and gibberellic acid concentrations on storage life of sweet orange fruit (Hamlen cultivar) was studied to in factorial design (3*3*6=54)based on randomized complete block with six replications. Putrescin at three concentrations(0, 1 and 2 mM) and three level of gibberellic acid (0, 50 and 100 mg/L) were sprayed on the tree at the physiological maturation stage and two weeks pre harvest. Fruit firmness, marketability, vitamin C, total acidity, total soluble solids (TSS) and ratio of total soluble solids (TSS) to total acidity were evaluated. The results showed that putrescin spraying at 1 mM significantly prevented fruit softening and preserved fruit firmness. Also putrescin treatment (1 mM) preserved ideal marketability and was superior than other treatments. Gibberellic acid significantly preserved total acidity and total soluble solids. The interaction of gibberellic acid and putrescine also preserved significantly vitamin C. Therefore, the application of putrescine at 1 mM and gibberellic at 100 mg/L was recommended for preserve marketability, appearance and quality of citrus sinensis cv. Hamlen.

Ceratocarpus arenarius is one of the problematic and noxious weeds in dryland farming of wheat, barley, lentil and peas in North Khorasan. In order to identify the effective treatments in dormancy breaking and determine the effects of light, temperature and pH on germination of this species, experiments based on CRD with 3 replications were conducted in the Research Laboratory of Birjand Faculty of Agriculture during 2009. Results showed that, all treatments except pericarp removal by hand and sulfuric acid (96%) had no considerable effect on dormancy breaking, indicating that the pericarp is responsible for Ceratocarpus seed dormancy. Ceratocarpus seed had identical germination in either light/dark or continuous dark regimes, indicating this weed species is non-photoblastic. Ceratocarpus seed germinated over 35% in the range of alternating day/night tested temperatures (10/5, 20/10, 25/15, 30/20 and 35/25ºC) and the maximum germination (96.6%) was observed at 25/15ºC. Ceratocarpus average germination percentage was about 80% over a pH range of 4 to 10. The maximum and minimum germination occurred at pH 8 (96.6%) and pH 4 (45%), respectively. The information of this study would be useful for the improvement of this weed species management programs.

(Rumex crispus) and cone catchfly (Silene conoidea), experiments were conducted based on RCBD with 3 replications at Research Laboratory of Faculty of Agriculture, Birjand University during autumn 2009 and winter 2010. Experimental treatments were light (Light/Dark and continuous dark), alternating day/night temperatures (10/5, 20/10, 25/15, 30/20 and 35/25 C), salinity stress (0 (Control), 10, 20, 40, 80, 160, 320 and 640 mM), drought stress (0 (Control), -0.1, -0.2, -0.4, -0.6, -0.8 and -1 MPa), pH (4 to 10) and sowing depth (0 to 4 cm). Results showed that seed germination of Curly dock was unaffected by either light/dark or continuous darkness conditions. Greater than 85% of curly duck seeds germinated over a broad range of alternating day/night tested temperatures under light/dark and continuous dark regimes and its germination completely ceased at 10/5 C. Cone catchfly seeds germinated greater than 70% at alternating temperature regimes equal to or lower than 25/15 C under light/dark and continuous dark regimes, but its germinability was remarkably reduced at temperature regimes warmer than 25/15 C, especially under light/dark conditions. Curly dock and Cone catchfly seeds germinated greater than 85% until the salinity level of 160 mM (NaCl), while their germination percentage at osmotic potential of -0.8 MPa were 60 and 90%, respectively. The average germinability of curly dock and cone catchfly seeds over a pH range of 4 to 10 was 90%. Seed burial significantly reduced curly dock and cone catchfly seedling emergence, so that no seedling emerged from a soil depth deeper than 3 cm and the greatest seedling emergence of curly dock and cone catchfly (98 and 74.7%, respectively) was occurred for seeds placed on the soil surface under 3 layers of filter paper.

Mouse barley (Hordeum murinum), from the poaceae family, is an abundant annual grass weed in wheat fields of South Khorasan province. Determining the ecological factors of this grass weed will contribute to development of its control programs. Effects of environmental factors on germination and emergence of mouse barley was investigated in the laboratory. Although mouse barley germination was greater than 85% at salinity level of 160 mM, further increase of salinity caused a remarkable decrease in its germination, following a 3% decrease in germination at salinity level of 320mM. Increasing osmotic potential from 0 to -0.8 MPa, resulted in an 80% decrease in its germination. Mouse barley germination was not affected by the pH and in a pH range of 4 to 10 remained approximately 90%. Emergence depth test showed that the maximum emergence of mouse barley occurred for seeds placed on the soil surface (86%) and no seedlings emerged from the seeds buried at 10cm depth. High germination ability of mouse barley under diverse environmental conditions may greatly contribute to it as a problematic weed species in the wheat fields of the region.