Postharvest physiology
Mohammadreza Asghari; Pari Zahedipour Sheshglani; Safaa Mohammed Ali Kadhim Al-Janabi
Abstract
Introduction: Strawberry is a widely consumed fruit with high nutritional value, which the consumption plays an effective role in reducing human chronic diseases. Strawberry fruit is a source of secondary metabolites with antioxidant activity which influence nutritional value and quality attributes of ...
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Introduction: Strawberry is a widely consumed fruit with high nutritional value, which the consumption plays an effective role in reducing human chronic diseases. Strawberry fruit is a source of secondary metabolites with antioxidant activity which influence nutritional value and quality attributes of this fruit. However, strawberry is a perishable fruit with a short shelf-life and high amount of this fruit is wasted during post-harvest periods which leads to economic, food and nutritional losses. In the last decade, the use of safe and natural elicitors in order to extend the shelf-life and improve the marketability of strawberry fruit has been increasing. Brassinosteroids (BRs) are plant growth regulators that modulate molecular, physiological, and biochemical responses in plant organs. Exogenous 24- Epibrassinolide (24-EBL) as a natural analog of BRs, has multiple effects on horticultural crops. Exogenous application of 24-EBL improves postharvest quality, antioxidant compounds and extends the shelf life of fruits and vegetables. Furthermore, 24-EBL has a significant effect on improving the sensory properties and marketability of stored crops. Therefore, this study was conducted to determine the effect of postharvest application of 24-EBL on bioactive compounds concentrations, antioxidant capacity and marketability of strawberry fruits.
Material and Methods: Strawberry fruits were harvested from a commercial greenhouse in the fully red color stage and immediately transferred to the laboratory. Healthy and uniform strawberries were selected and divided in three groups. Strawberry fruits were immersed in the 24-EBL solutions for 3 minutes. Strawberry fruits were dried completely at room condition and then were packed in polyethylene boxes (20×15×12 cm) and stored for 10 days at 1±1 °C. Control samples were treated with distilled water for same duration. After 10 d storage at low temperature, strawberry fruits were kept at room temperature for 24 hours to simulate the commercial situations, and then sampling was done to evaluate quality traits and marketability, biochemical compounds, phenylalanine ammonialyase and tyrosine ammonialyase enzymes activity and total antioxidant activity. In this study, the experiment was conducted completely randomized design with three replications.
Results and Discussion: Due to the high perishability and short shelf life of harvested strawberry fruits, it is necessary to investigate new methods. The use of safe and natural elicitors in order to improve the quality and marketability of the fruit may also result in an increase in the fruit nutritional value. The results showed that postharvest application of 24-EBL (1 and 3 µM) increased total phenolic content (16.5 % and 19.5 %), total flavonoids (5.5 % and 9 %) and total anthocyanins (12 % and 17 %) compared to control, respectively. Moreover, the activities of phenylalanine ammonialyase (PAL) and tyrosine ammonialyase (TAL), as important enzymes of the phenylpropanoid pathway increased in response to 24-EBL treatment. According to correlation coefficient analysis, there was a significant correlation among the phenolic compounds concentrations, PAL and TAL enzymes activity. Increaing the phenolic compounds, flavonoide and total anthocyanins content in response to 24-EBL treatment improved total antioxidant activity of strawberry fruits. Phenolics and flavonoids play important roles in increasing stress tolerance in crops and show a remarkably high scavenging activity toward reactive oxygen species. In addition to the positive effect of 24-EBL in enhancing secondary metabolites and antioxidant activity, which leads to improve the nutritional value of strawberry fruit, it also improved the sensory properties and marketability of the fruit. Treated berries with different concentrations of 24-EBL had lower titratable acidity, more total soluble solid, better taste and firmness compared to the control ones. These indices influenced the sensory properties and marketability of strawberries.These findings suggest that postharvest application of 24-EBL, especially at 3 μM, most effective to improve the postharvest quality and extend the shelf life of strawberry fruits. This research provided a new understanding regarding the impact of 24-EBL on increasing bioactive compounds and improving antioxidant activity of strawberry fruit and elucidated the effect of BRs on improving marketability of strawberry fruit.
Conclusion: The findings of this study indicate that postharvest application of 24- Epibrassinolide increse secondary metabolite content and nutritional value of stored strawberry fruits. Inceasing the secondary metabolite by antioxidant activity can also influence the sensory properties and marketability of strawberries. The mentioned results could be clear signs that 24- Epibrassinolide is a promising agent for extend the shelf life of strawberry fruits, as well as for improving their nutritional value.
Growing vegetables
Mohammad Hossein Aminifard; Mahboobeh Askarian; Mehdi Jahani; Mehdi Khayyat
Abstract
Introduction
Basil (Ocimum basilicum L.) is an annual and herbaceous plant of the family of Lamiaceae. It is used as an antispasmodic, appetizer, carminative, diuretic, lactation aid, and sedative in traditional medicine. In general, basil is rich in phenols and flavonoids. Organic and chemical ...
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Introduction
Basil (Ocimum basilicum L.) is an annual and herbaceous plant of the family of Lamiaceae. It is used as an antispasmodic, appetizer, carminative, diuretic, lactation aid, and sedative in traditional medicine. In general, basil is rich in phenols and flavonoids. Organic and chemical fertilizers are necessary for each other and both types of fertilizers are needed to create favorable conditions to improve biochemical traits. Overuse of chemical fertilizers has caused several problems in agriculture including changes in the soil structure, contamination of underground waters, and heavy metal toxicity. Agricultural scientists suggest replacing chemical fertilizers with organic products to reduce negative effects on environment and soil properties. In recent years, neglecting the importance of organic matters to improve soil fertility has led to an increase in chemical fertilizer use in Iran. Organic matters due to their positive effects on soil are identified as one of the important pillars of soil productivity. However, more than 60 percent of agricultural soils in Iran contain less than one percent of organic matter. Therefore, the objective of this study was to investigate the influence of vermicompost and copper sulfate on biochemical parameters and the antioxidant activity of basil.
Materials and Methods
To investigate the effect of vermicompost and copper sulfate on the biochemical characteristics of Basil's medicinal plant, a factorial experiment was conducted based on randomized complete block design with a field experiment at the Faculty of Agriculture, University of Birjand. The factors included vermicompost in three levels (0, 5, and 10 t.ha-1) and copper sulfate in three levels (0, 3, and 6 per thousand) with three replications. After applying the treatments and after the plants entered the flowering stage, ten plants from each plot were randomly selected taking into account the marginal effects and then samples of the developed leaves of 10 plants were randomly prepared and the biochemical traits of basil were measured. Measured traits included photosynthetic pigments, antioxidants, phenols, anthocyanins, flavonoids, total sugar, and biological function. Statistical analysis of data was performed using SAS statistical software.
Results and Discussion
The results of the mean comparison showed that vermicompost had a significant effect on chlorophyll content, antioxidant activity, anthocyanin, flavonoids, sugar, and biological function of basil so that the highest amount of flavonoids (3.26 mg.g-1) with the application of 10 t.ha-1 of vermicompost and the lowest Its amount (2.65 mg.g-1) was obtained from the control. Treatment of 10 t.ha-1 of vermicompost increased plant sugar by 37.05% compared to the control. Copper sulfate also affected chlorophyll a and total, antioxidant activity, phenol, anthocyanin content, sugar, and biological function, so that the highest activity of phenol and sugar (15.29 and 12.99 mg.g-1, respectively) of the treatment of 3 per thousand Copper sulfate and its lowest levels (10.98 and 9.19 mg.g-1, respectively) were obtained from the control. The results of interactions also showed the highest levels of chlorophyll a (1.62 mg.g-1), chlorophyll b (2.57 mg.g-1), total chlorophyll (4.19 mg.g-1), antioxidant activity (92.57%), and anthocyanins (3.03 mg.g-1) was obtained by applying 10 tons per hectare of vermicompost and 3 per thousand of copper sulfate. Furthermore, the highest increase in biological function (20968.3 kg.ha-1) with the application of 5 t.ha-1 of vermicompost and 6 per thousand copper and the lowest (16596.7 kg.ha-1) was related to the control.
Conclusion
In general, the results indicated a positive effect of vermicompost and copper sulfate on Basil's biochemical characteristics. Therefore, vermicompost (10 t.ha-1) of and copper sulfate (3 per thousand) treatments can be suggested as a suitable treatment. From the present study, it can be concluded that the combined application of organic fertilizers with chemical fertilizers has a useful and effective role in improving photosynthetic pigments, antioxidants, anthocyanins, and the biological function of basil. In the discussion of basil production as a medicinal and vegetable plant, the best results in terms of crop production were related to the combined treatments of organic and chemical fertilizers, because these treatments have increased the production relative to organic treatments alone.
Postharvest physiology
Bahareh Ghorbani; Roghayeh Najafzadeh
Abstract
Introduction
Cherry fruit has a high nutritional value and because of its favorable taste, its attractive appearance is of great importance. Iran is the origin of many horticultural products, especially cherries. The quality and quantity of the Iranian cherry crop are much more suitable in comparison ...
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Introduction
Cherry fruit has a high nutritional value and because of its favorable taste, its attractive appearance is of great importance. Iran is the origin of many horticultural products, especially cherries. The quality and quantity of the Iranian cherry crop are much more suitable in comparison with other producing countries due to suitable climatic conditions and significant areas under cultivation. This fruit has a very short shelf life due to its susceptibility to transport damage. After harvest, the cherry fruit decays quickly and in some cases, due to the time of transfer and marketing, does not reach consumers with good quality. Therefore, the use of natural compounds to increase shelf life and maintain its quality seems necessary inlcuding lower moisture, and perishability. On the other hand, storage of products involves a series of biochemical changes that take place, which is accompanied by softening of the fruit, destruction of the cell wall, and reduction of the external and internal quality of the products. Therefore, the use of appropriate compounds to increase durability and maintain its quality seems necessary. Phytohormonal treatments such as melatonin increase the cold resistance of fruits during storage and reduce the development of mechanical damage in the refrigerator during fruit storage. Melatonins have an amphiphilic indole ring structure, through which they can easily move out of the cell and play a role in the structure of the cell wall or membrane. Besides, melatonin is structurally similar to auxin and has similar effects, helping to maintain cell wall structure under stress and reducing the denaturation of cell wall proteins. Melatonin is also known as a biostimulant. These biostimulants in plants affect the production of secondary metabolites, biosynthesis of various phytohormones, facilitate plant uptake of nutrients, stimulate growth, and increase product quality and quantity. Melatonin, in interaction with other signaling agents, increases fruit metabolism and induces stress resistance.
Materials and Methods
In the present study, cherry fruits were harvested from the commercial garden at full maturity and after washing with distilled water with zero melatonin (control), 50, 100, 200 micromolar were treated by immersion for 5 minutes and Store at 1.5 with a relative humidity of 85% for 35 days. Parameters such as weight loss, titratable acidity, organic acids, soluble solids, antioxidants (DPPH), phenolic compounds, anthocyanin content, peroxidase, and ascorbate peroxidase activity were examined per week.
Results and Discussion
The results indicated that fruits treated with 200 μM melatonin showed less weight loss than other treatments and controls, and melatonin prevented fruit water loss, as well as of phenolic compounds, titratable acidity, soluble solids. The activity of peroxidase and ascorbate peroxidase enzymes have all increased. These compounds preserve the fruits during storage and increase the oxidation resistance. Melatonin coating on cherry fruit and can protect cells from stress by raising antioxidant levels. Consumption of edible coatings on horticultural products such as fruits increases durability and marketability. Edible coatings reduce fruit rot and prevent microbial growth on their surface. These coatings have a positive effect on physical properties and reduce physiological activity. Oral coatings better preserve organic acids by changing the internal atmosphere and slowing down the respiration of the fruit.
Conclusion
The use of exogenous compounds or growth regulators has in many cases been effective in reducing the effects of environmental stresses. These results show that the combination of melatonin has high antioxidant properties and can act as a protective compound and inhibit free radicals. Besides, it acts as a signaling molecule at the cellular level and manages antioxidant activity, thus preventing membrane damage and lipid peroxidation of the membrane. Melatonin also increases plant tolerance to environmental stresses and follows this mechanism by regulating gene expression in various horticultural crops. The use of melatonin improves the process of coping with oxidative stress by further regulating the biosynthesis of anthocyanins and the antioxidant-encoding gene.
Decomposition of cell wall compounds may increase total soluble solids, melatonin reduces the process of wall destruction, and preserves the appearance of the fruit. Increasing the amount of soluble solids increases the total antioxidant, phenolic and increases the activity of antioxidant enzymes. Melatonin is also at the forefront of stress management, and other antioxidants act as support after melatonin. Melatonin can prevent further stress damage by activating the plant signaling pathway.
Zahra Falati; Mohammadreza Fattahi; Ali Ebady
Abstract
Introduction: Plums (Prunus spp.) as one of the most popular stone fruits, have low calories and high nutritional value. Over the past decades global production of European and Japanese plums reached from 6,110,870 tons in 1990 to 11,528,337 tons in 2013. In the same period plum production in Iran reached ...
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Introduction: Plums (Prunus spp.) as one of the most popular stone fruits, have low calories and high nutritional value. Over the past decades global production of European and Japanese plums reached from 6,110,870 tons in 1990 to 11,528,337 tons in 2013. In the same period plum production in Iran reached from 118,936 tons to 305,262 tons. Great variety of plum fruits caused differences in chemical composition as well. Plum fruits are rich in bioactive compounds or biochemicals such as vitamins (A, C and E), anthocyanins and other phenolic compounds which have high antioxidant activity.
Materials and Methods: This research was done in a randomized complete block design with three replications in Horticultural Research Station at College of Agriculture and Natural Resources of Tehran University in 2013-2015. Fruit quality characteristics such as vitamin C content, color traits of the fruit skin and flesh, the content of carotenoids, anthocyanins, total phenolics and antioxidant capacity of 16 plum and prune cultivars and genotypes were evaluated.
Results and Discussion: Analysis of variance showed significant differences in terms of all measured factors. The highest L* index (brightness) of fruit skin was observed in 'Tanasgol" and "Compooti" and then in "Golden Drop" and "Shams" cultivars and the lowest level of that was measured in "Sugar" and "Gogeh Sabz" cultivars. "Black Star" and "Gogeh Germez" Showed the highest brightness of fruit flesh among examined cultivars and the lowest brightness of fruit flesh was investigated in "Sugar". A* color index of skin and flesh of fruit also showed significant differences among investigated cultivars and the highest level of that in "Ozarak" cultivar was observed. "Gogeh Sabz" and "Golden Drop" also had the lowest level of this index. "Gogeh Germez" had the highest of a*color index of fruit flesh and "Japanese" cultivar was in second place. The lowest level of this index was measured in "Ozarak" and "Shams" cultivars. "Tanasgol" and "Compooti" had the highest fruit skin b*color index among cultivars and "Santarsa", "Sugar," "Stanley" and "Bukhara" showed the lowest of that. "Black Star" and after that "Tanasgol" and "Dargazi" had the highest b*color index of fruit flesh. "Japanese" had also the lowest b* color index of fruit flesh. The intensity or color purity varied among cultivars and the highest of that was observed in "Tanasgol" and "Compooti" and then in "Ozarak". "Black Star" had the highest chroma of fruit skin and the highest fruit flesh color intensity. The lowest of this index in the fruit flesh was observed in "Santarosa", "Sugar" and "Japanese" cultivars. Vitamin C (ascorbic acid) content varied in investigate cultivars. "Gogeh Germez" and "Japanese" had the highest vitamin C content and "Stanley" was showed the lowest amount of vitamin C. "Golden Drop ","Santarosa" and "Compooti" showed the highest total carotenoid among examined cultivars and "Gogeh Germez" had the lowest total carotenoid. "Gogeh Germez" and "Compooti" had the highest and lowest amount of anthocyanin index respectively. The highest total phenol and antioxidant activity was measured in "Ozarak". The lowest total antioxidant capacity was in"Gogeh Sabz". The results showed that There was high correlation (r= 0.93) between antioxidant capacity and a* fruit skin color index. High correlation (r= 0.83) between phenol content and antioxidant capacity of fruits was also observed. Between a* color index of fruit skin and phenolic content was observed high correlation (r= 0.89). As well as between anthocyanin and phenolic content and between anthocyanin and a* fruit skin color index, respectively (r= 0.86) and (r= 0.59) high correlation was detected.
Conclusions: "Ozarak" in terms of antioxidant activity and total phenol component was superior. The highest amount of anthocyanin related to the "Gogeh Germez". "Golden Drop"," Santarosa" and "Compooti " had the highest total carotenoid and "Gogeh Germez" and "Japanese" had the highest vitamin C content among investigated cultivars. By identification of superior cultivars In terms of phytochemical compounds, these cultivars can be used in breeding programs to improve these nutritional quality of fruits. The results showed that the major phenolic compounds were gathered on the skin of plum fruits. Hence the "Ozarak" cultivar having the highest a*color index of fruit skin had the highest total phenol and antioxidant capacity among the investigated cultivars but "Gogeh Germez" by having the highest a*color index of fruit flesh and anthocyanins content higher than "Ozarak" cultivar, had low phenolic content and antioxidant capacity compared to the "Ozarak".
