Postharvest physiology
Masumeh Kiaeshkevarian; Tahereh Raiesi; Bijan Moradi; Javad Fattahi Moghadam; Maziyar Faghih Nasiri
Abstract
Introduction
Consumers demand for organic products is increasing due to their awareness of health and nutritional quality. Organic manures maintain soil health and ecological balance of the region. Organic agriculture, as an alternative agricultural system to protect human health and the environment ...
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Introduction
Consumers demand for organic products is increasing due to their awareness of health and nutritional quality. Organic manures maintain soil health and ecological balance of the region. Organic agriculture, as an alternative agricultural system to protect human health and the environment can improve the quality and storability of the product. Kiwifruit is one of the most important agricultural products in north of Iran, which plays an effective role in trade and employment of the people. Fertilization is one of the main factors affecting the yield and quality of kiwifruit. Growers use organic manures and chemical fertilizers in their orchard to achieve higher yields. It is necessary to study the effect of various organic manures available in the region on the nutrition of kiwifruit vines due to increase chemical fertilizer prices and the formation of the market for organic fruits. Therefore, the aim of this study was to compare the effect of using five types of organic manures and chemical fertilizer on the quality of Hayward kiwi fruit during cold storage.
Materials and Methods
This research was conducted as randomized complete block design consisting six treatments (including complete chemical fertilizer, sheep manure, cow manure, chicken manure, vermicompost and azolla) on Hayward kiwifruit vines in orchard and factorial experiment with three replicates in cold storage during four years. The fruits were harvested at TSS: 6.5 (approximately mid-November) and then stored at 0.5 ° C and 90% RH for three months. Sampling was performed every month and physicochemical characteristics, including flesh color parameters (L*, C*, h◦), total soluble solids, titratable acidity, firmness and weight loss of fruit were measured. Sensory evaluation of fruits was also performed at the end of three months cold storage. Analysis of variance of the data was done using SAS 9.1 software. The significance of differences between the mean of treatments was determined by using Duncan’s test.
Results and Discussion
The results showed the interaction between year, type of nutrition and cold storage period affected color indices, lightness and chroma. Lightness and chroma value didn’t show significant differences between organic and chemical fertilizer treatments. In addition, their value decreased during cold storage period, significantly. The chroma value indicates the degree of saturation of the green color and is associated with fruit firmness. The hue value was also influenced by the interaction between year and cold storage period and the simple effect of the nutrition type. The highest hue value was observed in chicken manure (108.63) and the lowest in vermicompost (107.66). The hue value decreased significantly after 90 days cold storage. According to the results, a decrease in fruit firmness, TA and an increase in TSS and TSS/TA were observed during cold storage irrespective of treatments. After 90 days, total soluble solids content was higher when organic fertilizers were applied. During the storage of kiwifruit, total soluble solids content increased, significantly. The titratable acidity value in organic fertilizer treatments was higher than chemical fertilizer after 90 days cold storage, significantly. Moreover, titratable acidity value decreased at the end of the cold storage period, significantly. The highest flesh fruit firmness was obtained in cow manure (8.74 kg/cm2) in forth year and chemical fertilizer treatment had the lowest flesh firmness (3.2 kg/cm2) in third year. Fruit lost firmness gradually during the cold storage period. However, no significant difference was found in maturity index (TSS/TA) between treatments. The TSS:TA ratio is highly increased after 90 days. Based on the results of the last two years, azolla, cow and chicken manures showed less weight loss percentage than chemical fertilizer treatment. Moreover, weight loss increased significantly during cold storage period in all treatments and years. Also the results of sensory analysis showed that fruits treated with vermicompost had a higher overall acceptance than other treatments.
Conclusion
Generally, organic nutrition plays an important role in increasing the nutritional value and shelf life of kiwifruit cv.Hayward. Organically produced fruits had higher firmness than conventionally grown fruits during storage. Application of cow manure and vermicompost showed favorable effects on important properties of kiwi fruit such as firmness, weight loss, TSS, TA and sensory quality. Therefore, organic fruits will have better quality in the cold storage. As a result, it seems that by reducing the use of chemical fertilizers in the current orchards, kiwi production will be close to the standards defined for organic fruit.
Pomology
Javad Fattahi Moghadam; Seyyedeh Elham Seyedghasemi; Tahereh Raiesi
Abstract
Introduction: The foreign and domestic markets are demanding for high quality citrus varieties. The physical and chemical properties of the newly released cultivars are also important for fresh market or processing. The fruit quality is a complex combination of size, firmness, taste, texture, pleasant ...
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Introduction: The foreign and domestic markets are demanding for high quality citrus varieties. The physical and chemical properties of the newly released cultivars are also important for fresh market or processing. The fruit quality is a complex combination of size, firmness, taste, texture, pleasant aromas caused by a chemical compounds (soluble solid content, sugars, organic acids, aromas) and bioactive properties. Therefore, it is important to consider these indices for the introduction of a new cultivar. In this regard, the Citrus and Subtropical fruits Research Center has focused on improving its appearance, internal and organoleptic quality in releasing the new Jahangir cultivar compared to the Clementine as control.Materials and Methods: In this study, Jahangir fruits a hybrid between Clementine mandarin (female parent) and Salustiana orange (male parent) (Citrus clementina Hort. Ex Tanaka × C. sinensis (L.) Osbeck cv. Salustiana) was used for comparison with Clementine (Citrus clementina Hort. Ex) Tanaka) as control during the last two years lead to the cultivar introduction. Fruits were randomly selected from different locatiosn on the tree (15 fruits from three trees) and evaluated at harvesting time (zero storage point). Then 30 fruits per box selected and placed in cold storage (5 °C, 85% RH). Different physico-biochemical and sensory characteristics of fruits were evaluated at 0, 20 and 40 days intervals during storage. Characteristics evaluation were including fruit lenght, width, thickness, arithmetic, geometric, equivalent and harmonic means, fruit aspect ratio, sphericity, surface area, true volume, apparent volume, volume error, density, peel and pulp firmness, peel thickness, weight, juice percentage, seed number, peel color indices (L*, a*, b*, hue angle, chroma and CCI), total soluble solid (TSS), titratable acidity (TA), technological index (TI), pH, electrical conductivity (EC), total phenol, ascorbic acid and antioxidant capacity during experiment.Results and Discussion: Results showed that fruit size (length and two diameters), weight, means of arithmetic, geometric, equivalent and harmonic diameters, surface area and true volume of Jahangir mandarin were significantly higher than Clementine. The different mean diameters of each cultivar was the same as that equivalent diameter that is the most real mean fruit diameter. The higher spherical coefficient (>1) also indicated that Jahangir fruit was longer than the control. Additionally, aspect ratio of Jahangir was also higher than Clementine, which means that Jahangir fruit was a few flat than control. Jahangir had higher levels of L*, b*, C and hue than the control of clementine. In contrast, Jahangir's a* and CCI indices were lower than those of clementine. Therefore, except for L* which is slightly lower than citrus standard (65-70), other indices in both cultivars were conformity within the citrus standard range. Seeds of Jahangir were more than control but both were in the mid seed group (9-15 seeds) of citrus. Jahangir peel was also less easily peeled than control. The weight loss of Jahangir fruit was significantly (almost half) lower than that of clementine at each sampling but increased during storage. It seems Jahangir has a peel with higher density and adhesion than to clementine, which partly prevents the fruit from dehydration. The amount of TSS of fruit juice was higher than that of clementine at harvest and storage but increased in both cultivars during storage. In addition, TA (0.34%) was lower in Jahangir fruit than Clementine (0.45%). Therefore, the ratio of TSS to TA was much higher in Jahangir mandarin (44.25) than clementine (26.16). Juice percentage of Jahangir fruit (44.87%) was significantly higher than Clementine (40.12%). The high percentage of Jahangir fruit juice is a positive trait for this cultivar. Technology index changed depending on cultivar and also during storage. This index was higher in Jahangir fruit than in Clementine with 6.45 and 4.67, respectively. The antioxidant capacity only affected significantly by storage time which showed a decreasing trend during storage. Ascorbic acid content was only affected by cultivar and was higher in control than Jahangir. Lower levels of ascorbic acid in the Jahangir may be due to increased respiration that results in the elimination of ascorbic acid. The phenolic content of Jahangir fruit was higher (0.43 mg/g) than clementine (0.4 mg/g). PCA analysis showed that most of the Jahangir samples placed in the left part of the PCA graph which were dominated by the traits such as taste, sweetness, good peel and pulp appearance and overall acceptance and were more accepted by the sensory evaluators.Conclusion: In this study, different qualitative characteristics of Jahangir fruit compared to Clementine which are important for the producers. Accordingly, the Jahangir fruit was larger in size but slightly flatter than the Clementine fruit. Jahangir fruit peel color indices were within the standard range of citrus fruits. Jahangir fruit is favored among commercial available mandarins due to ease of peeling, high juice percentage, technology index, vitamin C, phenol and antioxidant capacity. It also had better storability than Clementine because of less water loss and decline of organoleptic properties.
