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Effects of Chemical Treatments on Acidity According to variance analysis table 1-4 it could be inferred that implemented chemical treatments in Cammarosa strawberry fruits are significant at 0.01 in terms of acidity. Control group fruits featured the lowest level of acidity while among the implemented treatments; maximum acidity value was related to © Copyright 2015 | Centre for Info Bio Technology (CIBTech) 29 Cibtech Journal of Zoology ISSN: 2319–3883 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/cjz.htm 2015 Vol. 4 (1) January-April, pp.26-36/Amini and Habibi Research Article the treatment of 25MM Chloride Calcium and 3MM Nitric Oxide which were both ranged in one statistical group with no difference.
0.66 0.639 0.634 0.64 0.624 0.608 0.614 0.62 0.603 0.597 0.598 0.596 0.593 0.6 0.58 0.555 0.56 0.54 0.52 0.5 Figure 2: Effects of chemical treatments on the acidity of Cammarosa strawberries Put1: 1MM Putrescine, put2: 2MM Putrescine, CaCl2 25: 25MM Chloride Calcium, CaCl2 50: 50MM Chloride Calcium, CaCl2 75: 75MM Chloride Calcium, NO3: 3MM Nitric Oxide, NO5: 5MM Nitric Oxide,COMP1: 1MM Putrescine + 50MM Chloride Calcium + 3MM Nitric Oxide, COMP2: 2MM Putrescine + 75MM Chloride Calcium + 5MM Nitric Oxide, COMP3: 1MM Putrescine + 25MM Chloride Calcium + 3MM Nitric Oxide, Control: Control treatment Application of Putrescine also leads to a lower declination of acids compared to control treatment which points to the role of Putrescine in maintenance of acids in the fruits of strawberry and pomegranate (Serrano et al., 2003). During the post-harvest period, the values of acidity and PH are respectively expected to decrease and increase.
Research conducted by Chewer et al., (1991) revealed that strawberries which were treated with Calcium had lost less acidity after 14 days of storage. This could be as a result of lowered speed of fruit's ripening process because of application of Calcium which leads to decomposition of organic acids to other compositions.
Results of this research are not in compliance with the results of researches conducted by Zakaei et al., (2009). They stated that Putrescine has no significant effects on inhibition of loss of acidity in strawberries and apricot.
Effects of Chemical Treatments on the Level of Vitamin C According to variance analysis table 1-4, chemical treatments have a significant effect on the level of Vitamin C at significance level of 0.01; in a way that according to means comparison table, the compositional treatment of 5MM Nitric Oxide had the most effective influences on maintenance of the level of Vitamin C. on the other hand, the existing data in aforementioned table shows that control group fruits and fruits treated with 1MM Putrescine had the lowest level of Vitamin C. results of this test indicated that all there compositions were significant at 0.01 in maintaining the level of acidity. This difference was bolder in seventh day. Among the treatments, the 3MM Nitric Oxide in seventh day and applied compositional treatments in 14th day had the most effects in maintaining the acidity.
As a result of consumption during aspiration, organic acids decrease while the fruit ripens and their decrease is directly related to metabolic activities. In fact, organic acids are reserved sources of energy for the fruit which are consumed at the time of ripening with increase in metabolism (Rahemi, 2006). Studies indicate that elements that cause decreased aspiration and production of ethylene prevent loss of organic
Figure 3: Effects of chemical treatments on Vitamin C levels of Cammarosa strawberry Put1: 1MM Putrescine, put2: 2MM Putrescine, CaCl2 25: 25MM Chloride Calcium, CaCl2 50: 50MM Chloride Calcium, CaCl2 75: 75MM Chloride Calcium, NO3: 3MM Nitric Oxide, NO5: 5MM Nitric Oxide,COMP1: 1MM Putrescine + 50MM Chloride Calcium + 3MM Nitric Oxide, COMP2: 2MM Putrescine + 75MM Chloride Calcium + 5MM Nitric Oxide, COMP3: 1MM Putrescine + 25MM Chloride Calcium + 3MM Nitric Oxide, Control: Control treatment Presence of relatively high values of vitamin C in strawberry has turned this fruit into one the most desirable products in the market. On this basis technics and solutions for maintaining the values of vitamin c as well as prolonging its post-harvest life can play a significant role in post-harvesting process of strawberry.
During the storage period the value of Ascorbic acid which is a main anti-oxidant decreases. The reason is consumption of this vitamin as a provider of electron for oxidants for diffusing free radicals (Semimov, 1995). Decreased vitamin C content can be a result of activity of enzymes such as Ascorbic Acid Oxidase.
These enzymes are more active in cut tissues (Clean, 1987).
Putrescine leads to a linear decrease in the level of Ascorbic Acid which is under the influence of Polyamine treatments through increased activity of Ascorbic Oxidase. Decrease in total Oxidant levels is a result of increased activities of Cytochrome Oxidase, Ascorbic Acid Oxidase and Peroxidase Enzymes.
Reduction in color development in external application of Putrescine is related to a reduced deterioration of Chlorophyll and postponed aging process. Polyamine treatments are effective on the ratio of weight © Copyright 2015 | Centre for Info Bio Technology (CIBTech) 31 Cibtech Journal of Zoology ISSN: 2319–3883 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/cjz.htm 2015 Vol. 4 (1) January-April, pp.26-36/Amini and Habibi Research Article loss which significantly increased the ratio of solid materials in the solution compared to acids during the process of ripening. Treatment of pomegranate fruits with polyamines led to maintenance of density of Ascorbic Acid and increased Phenolic compounds compared to control group fruits as a sign of reduced activity of Phenol Oxidase Enzymes and respectively decreased browning effect (Mirdehqan et al., 2007).
Chloride Calcium and Nitric Oxide also prevent decomposition of cell walls and restrict production of free radicals through preventing the production of ethylene, reduction of aspiration and delaying aging and therefore, as a result of reduced free radicals the cell's need for consumption of Ascorbic Acid also decreases and overall, the levels of vitamin C are maintained in the fruit (Semimov, 1995). It's been reported that the vitamin C content of Lebanese yellow apples treated with Chloride Calcium are significantly higher than control group fruits. This fact could be attributed to a postponed fast Oxidation of vitamin C by Chloride Calcium (Akhtar et al., 2010).
Results of this research are in compliance with the results of researches conducted by Abdulahi et al., (2011) regarding strawberry.
Effects of Chemical Treatments on Firmness According to variance analysis table 1-4, the performed treatments significantly affected fruit's firmness at the significance level of 0.01. According to means comparison table 3-4 it can be observed that among the performed treatments, the control group fruits had the least firmness while the firmness of other performed treatments was significantly highest than the control group. Results of this test indicated that among the compositional treatments, treatments which were compositions of three different materials showed the highest level of firmness after 7 and 14 days of storage. On the day 14, treatment of 75MM Chloride Calcium had also a positive effect on maintaining the firmness of fruits along other compositional treatments.
280 273.83 270 263.33 262.33 260.833 257.5 257.33 257.167 245.6
Figure 4: Effects of chemical treatments on firmness of Cammarosa strawberry
Put1: 1MM Putrescine, put2: 2MM Putrescine, CaCl2 25: 25MM Chloride Calcium, CaCl2 50: 50MM Chloride Calcium, CaCl2 75: 75MM Chloride Calcium, NO3: 3MM Nitric Oxide, NO5: 5MM Nitric Oxide,COMP1: 1MM Putrescine + 50MM Chloride Calcium + 3MM Nitric Oxide, COMP2: 2MM Putrescine + 75MM Chloride Calcium + 5MM Nitric Oxide, COMP3: 1MM Putrescine + 25MM Chloride Calcium + 3MM Nitric Oxide, Control: Control treatment During the storage period, enzymes such as Pectinestrase, Cellulase and etc. lead to decomposition of cell walls and a respective decrease in product's firmness (Hernandez et al., 2008). Aging, decomposition of cell walls and loss of weight are among factors which lead to decreased firmness of products and loss of © Copyright 2015 | Centre for Info Bio Technology (CIBTech) 32 Cibtech Journal of Zoology ISSN: 2319–3883 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/cjz.htm 2015 Vol. 4 (1) January-April, pp.26-36/Amini and Habibi Research Article marketability (Vargas et al., 2006). Results of this research indicated the positive effects of Calcium on optimization of firmness of the tissue of samples. The main role of Calcium in strengthening membranes of plant tissues reflects in different ways. A large portion of Calcium embeds in the walls of plant tissues.
This unique condition of calcium is a result of several places of consolidation of calcium in the cell walls and its extremely restricted displacement from the membrane of cytoplasm to the inside of the cell's cytoplasm. On the middle edge, calcium is connected to carboxyl groups related to Pectin and the solution's Pectate calcium decreases. On the other hand the existing Pectate on the cell walls of organic plants is decomposed by Poly Galactronase enzyme. High concentrations of calcium severely reduce the activity of the enzymes in charge of this composition. Therefore, with increase of the value of calcium in the tissue, the activity of this enzyme reduces and the decomposition of cell walls slows down. Therefore, with increase in the level Calcium present in the tissue, the activity level of this enzyme reduces and decomposition of the cell wall slows down. Calcium also causes cellular stability by attaching to groups of Phosphates, Carboxylates, Phospholipids and proteins on the surface of the membranes (Chewer, 1991). Calcium is known as an intermolecular attaching element in stabilization of the middle edge's pectin protein complex; in addition calcium reduces the softness of the tissue via preventing the process of solubility.
By being established inside the cell wall as an intermolecular connector which stabilizes the compounds of the middle edge, calcium preserves the structure of cell wall. On the other hand, calcium influences the structure and task of the cellular membrane and by connecting the enzyme proteins and non-enzyme proteins to the phospholipids of the cell membrane plays its role. In this way, reduces the activity of ethylene producing enzymes which also have a protein like structure. Ultimately, with a reduced level of ethylene production, which is the stimulator of the activity of enzymes which hydrolyze the cell wall the cell wall suffers a reduced amount of damage and calcium treated fruits will remain firm. On this basis, by establishment inside the cell wall and stabilizing it and also reducing the amount of ethylene production, calcium plays its role in maintaining the firmness of fruit's membrane (Wang et al., 1993).
The destruction of pectates is carried out by poly-Galactronase enzymes and when there are sufficient amounts of calcium, their destruction is prevented (Reddy et al., 2004) and in this way, plant shows resistance against destruction of cell walls. The operation mechanism in this case is that although the most of the calcium is established inside the cell wall, the production of ethylene is related to destruction of the plant due to destruction of the cell wall but treatment with calcium strengthens the cell wall and reduces aspiration leads to reduction and minimization of the level of produced ethylene (Convey et al., 1984). In addition, treatment with calcium chloride reduces the damages due to low temperature and freezing through preserving the fluidity of membrane and fixing the ratio of polyunsaturated fatty acids to saturated fatty acids and ultimately leads to firmness of plant's membranes (Quills et al., 2004).
The effect of Putrescine on increasing the firmness of fruit's pomace could be related to its bonding with pectin compounds of the cell wall. This bonding leads to stability and fixation of cell's wall which is detectible right after treatment. The aforementioned bonding also prevents the activity of enzymes which decompose the cell wall including PME, PE and PG (Valero et al., 2002). Decrease in softness of fruit by Putrescine could be could be as a result of reduction of activity of enzymes which decompose the cell wall including Ando Poly Galactronase, Exo poly Galactronase and Methyl-Esterase. Increase in the firmness of fruit in treatment by Polyamines: Polyamines raise on negative loads of phospholipid compounds or anionic areas on the membranes and therefore, multiples the stability of these membranes.
The bonding of polyamines with pectin materials restricts the accession of enzymes which decompose cell walls to pectin materials. Application of 1MM Putrescine on Plum fruits during the storage period in at 10 degrees of temperature led to maintenance of membrane's firmness and the result was increased storability of the fruit. Immersion of fruits in Putrescine solution led to removal of Fungi's spore and reduces contaminations and the surface of polyamines effectively increases in leaves contaminated with black spots, fungal diseases and gray mold which show the role of these compounds in plant's pervasive reactions against pathogens. It's been reported that pre harvest treatment with Putrescine on peaches increased the firmness of the fruit and delayed their ripening (Bergoli et al., 2002). Results of this © Copyright 2015 | Centre for Info Bio Technology (CIBTech) 33 Cibtech Journal of Zoology ISSN: 2319–3883 (Online) An Open Access, Online International Journal Available at http://www.cibtech.org/cjz.htm 2015 Vol. 4 (1) January-April, pp.26-36/Amini and Habibi Research Article research comply with the findings of researches conducted by Punapa et al., (1993) on strawberries and Serrano et al., (2003) on plum fruits.