مازیار فقیه نصیری

 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.
 
 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.
 
 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.
 
 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.

The decay of green and blue molds of Thomson navel oranges is one of the main causes of this product's decay and it can be a limiting factor in storing fruits. The aim of this study was to investigate the effects of wax, hot water, calcium chloride and commercial Tecto 60 fungicide treatments on reducing decay by inducing biosynthesis of flavonoid compounds and maintaining the postharvest quality of Thomson navel orange fruits. Fruits kept for three months in a cold storage at a temperature of 5 to 7 °C and a relative humidity of about 75 to 90%. Weight loss of fruits in waxed fruits was significantly lower than other treatments. The wounded and infected fruits did not have much chance of survival. None of the treatments were significantly effective on control of decay of non-wounded fruits. Total phenol content of fruit peel and flesh  decreased during storage. Hesperidin in the peel was at the highest level in Britex wax treatment. The highest amount of scoparon of fruit peel and flesh was in hot water and calcium + wounded treatments, respectively. Although the amount of scoparon in some treatments inhibited the germination of fungal spores, it did not have the expected effect in controlling decay. The use of Tecto 60™ and hot water can significantly reduce the decay of wounded and infected fruits. The treatments were not effective in controlling the deterioration of intact fruits, which indicates the importance of preventing mechanical damage to the fruit in the pre-harvest stage.

Most consumers prefer natural coatings to the chemical ones to act as an enhancement of storage quality of fruits. In this research, quality of Thomson oranges coated with chitosan-clay nano composite edible coating plus fungicide-wax chemical coating was compared with a non-coated sample during storage for a period of 3 months through a factorial design (3×4). Orange samples were kept in a cold storage at 5oC temperature and 85-90% of relative humidity. The pH, titratable acidity of orange juice, weight loss percentage, peel shear and fracture forces as well as the coefficient of elasticity were assayed during storage. Results indicated significant differences among different coatings on all the measured dependent variables except on peel shear force (p<0.01). In addition, storage duration significantly affected weight loss, fruit peel cutting and fracture forces (p<0.01). Also fruits coated with Chitosan-clay showed reduction in weight loss, increase in pH, the highest fracture force as well as the coefficient of elasticity as compared with the control samples. Therefore, it is concluded that the coating increased fruit resistance to fungal diseases, retained inner texture strength and prevented the decrease in fruit quality.

Kiwifruit softening and the spread of gray mold on the fruit are the most important factors to be considered in Kiwifruit storage life. In this study, the effect of calcium chloride (0, 1, 2, 4 and 8 percent) for 2, 4 and 8 minutes of dipping time were examined to improve the fruit physicochemical characteristics. Following fruits being dried (24 hours), they were stored at 0.5oC and 85-90% RH for 18 weeks. Samples were taken at 6th, 12th and 18th weeks and subsequently measured in some triats including water loss, firmness, TSS, TA, TSS/TA, pH, L* and a* values of color indices and ascorbic acid in comparison with control. Results showed that the fruits immersed in 4 and 8 percent of CaCl2 solution for 4 and 8 minutes had the highest firmness (3.4 kg). Water loss in control fruits was recorded higher (0.3 kg) than in all CaCl2 treatments. PH and TA parameters did not show significant changes during storage. Due to decrease in TSS through CaCl2 application, there occurred a significant difference in TSS/TA ratio. A positive relationship was observed between the L* value (47 value) and firmness especially when 2, 4 and 8 percent of CaCl2 were applied. In general, ascorbic acid increased in both control and CaCl2 treated samples but it was recorded higher in control during storage. In conclusion, CaCl2 treatments increased fruit quality and storage life due to inhibition of TSS increase and continuous firmness.

Various factors such as biological and environmental factors، harvest method as well as type and length of storage influence characteristics of agricultural products. This is particularly true for fruits and entails considerable economic consequences. The present study was undertaken to investigate the influence of fruit size، variety and length of storage time on soluble solids content، pH، moisture content and two mechanical properties i. e firmness and penetration energy of kiwifruit. Using factorial experiment with Completely Randomized design، effect of independent factors including storage time (0، 6 and 12 weeks)، fruit size (small and large)، and variety (Monty and Hayward) on measured properties of kiwifruit were investigated. Results showed that storage time and crop variety had significant effects on the measured properties. Soluble solid content and pH values increased while firmness and penetration energy decreased in both varieties with increasing storage time. Storage time (12 weeks) had no significant effect on fruit Moisture content. It was also shown that the Hayward variety could be stored longer than the Monty variety. Therefore، in order to increase storage time of fruits، sorting on the basis of variety and size before storage is recommended.

To investigate the effect of Citrus species and harvesting time on the quantity and quality of hesperidins, a falconoid used in medicine industries, an experiment was conducted at Citrus Research Institute located in Ramsar. The experiment was started in 1997 and repeated in 1998. The treatments consisted of four citrus species included Local orange (Citrus sinensis [L] Osbeck), Thomson Navel orange (Citrus sinensis [L] Osbeck), Clementine mandarin (Citrus reticulate Blanco) and Satsuma mandarin (Citrus unshiu Marcovitch), and four harvest times, as the fruits harvested from June drop every ten days. Three trees were selected for each species as three replications in the base of two-factor completely randomized design. According to the results, harvest time had significant effect on hesperidin content. As the highest hesperidins content was obtained 50 to 60 days after full bloom. Results also showed that fallen fruits at June drop or due to drought and high temperature season can be used for extracting of hesperidins. Hesperidin yield was higher in Local orange and Clementine mandarin than the other cultivars. Because of the Local orange cultivated in large scale in the north of Iran, therefore it is a suitable source for production of hesperidin.