Plant Productions

Pre-harvest application of chitosan and nano-chitosan on enzymatic activities, quality and sensory indicators of fresh pistachios (Pistacia vera L. cv 'Ahmad Aghaei')

Shirin Taghipour; Abdollah Ehtesham Nia; Hossein Hokmabadi

Volume 46, Issue 1 , June 2023, , Pages 51-63

https://doi.org/10.22055/ppd.2023.41148.2042

Abstract

Introduction Pistachio (Pistacia vera L.) is one of the most important and popular tree nuts in the world. The kernels of this product are rich in oil (more than 50%) and contain linolenic, ... Read More Introduction Pistachio (Pistacia vera L.) is one of the most important and popular tree nuts in the world. The kernels of this product are rich in oil (more than 50%) and contain linolenic, linoleic and oleic acid, which are essential for the human diet. Pistachio is also one of the important export products that is of strategic importance in the field of non-petroleum exports and currency and its role in the agricultural and national economy is significant and valuable. In addition to its economic value, pistachios are rich in essential nutrients such as phenolic compounds, anthocyanins, unsaturated and tonic fatty acids, the consumption of which has a great impact on health, well-being and community empowerment. The use of biodegradable, edible, and antimicrobial films and coatings as a suitable alternative to synthetic preservatives is important in order to maintain food security and prevent wastage of capital. Materials and Methods This study was performed in 2021 in the Faculty of Agriculture, Lorestan University and Green Tat Research Garden in Qazvin province. In this experiment, the effect of pre-harvest foliar application of chitosan (0, 500 and 1000 mg/l) and nano- chitosan (0, 250 and 500 mg/l) on the qualitative and sensory characteristics, activity of antioxidant enzymes and shelf life of fresh pistachios 'Ahmad Aghaei' cultivar in four different times (0, 25, 50 and 75 days after harvest) were stored in the cold storage at 4 ±0.5° C and 80% RH. The studied traits included, fruit kernel firmness, weight loss percentage, antioxidant enzyme activity, acid value, peroxide values (PV) and sensory properties were measured at different times. Results and Discussion The results showed that the fruits treated with nano-chitosan 500 mg/l had the highest tissue firmness (8.13 N). The lowest percentage of weight loss was observed in nano-chitosan 250 mg/l treatment on the 25th day (0.14%). The activity of superoxide dismutase enzyme in fruits treated with nano-chitosan 500 mg/l also increased. The lowest polyphenol oxidase activity belonged to nano-chitosan 250 mg/l treatment and the highest guaiacol peroxidase activity was observed in chitosan 1000 mg/l treatment. The lowest and highest amount of peroxide values was obtained in the treatment of nano-chitosan 250 mg/l and control, respectively, on days 0 and 75 days after storage. The amount of free fatty acids increased during storage and the increase was slower in chitosan and nano-chitosan treatments, so that the lowest amount of free fatty acids in nano-chitosan treatment was 250 mg/l in day 0 and the highest amount of free fatty acid in control treatment was observed on the 75th day. Fresh pistachios coated with nano-chitosan 500 and 250 mg/liter significantly showed the highest average sensory scores in marketability index, skin appearance, smile and texture crispness compared to the control. Conclusion According to the results, it can be stated that the application of nano-chitosan 250 mg/l in the pre-harvest stage, due to maintaining qualitative and sensory characteristics, and increasing the shelf life of fresh pistachios up to 75 days compared to the control, and as a natural and biodegradable compound is recommended.

Improving Quality and Antioxidant Characteristics of Pulp and Peel of Citrus During Storage by Pre-Harvest Spray of Calcium Chloride on Fruit

Javad Fatahi Moghadam; Abuzar Hashempour; Reza Fifaei

Volume 42, Issue 1 , April 2019, , Pages 1-12

https://doi.org/10.22055/ppd.2019.22511.1484

Abstract

Abstract Background and Objectives Calcium is a key plant nutrient with significant functions including reducing fruit senescence; calcium deficiency has been involved in several ... Read More Abstract Background and Objectives Calcium is a key plant nutrient with significant functions including reducing fruit senescence; calcium deficiency has been involved in several physiological disorders in fruits. Pre-harvest foliar application of calcium chloride (CaCl2) is an efficient and safe strategy to maintain or improve the fruit quality during storage. Also, calcium significantly increases the membrane and cell wall density and reduces the physiological disorders of the fruit. Thus, the aim of this study was to evaluate the effect of pre-harvest CaCl2 sprays of citrus trees at three fruit development stages on improving fruit quality and antioxidant capacity during storage. Materials and Methods To conduct this research, citrus trees of three different varieties (‘Thomson’, ‘Moro’ and ‘Page’) were sprayed with different concentrations of CaCl2 (0, 1, 2 and 4%) at three fruit development stages (120, 140 and 160 days after full bloom). After harvesting, citrus fruits were stored at 5°C and 85% relative humidity for 60 days. Then, weight loss and juice percentage, total carotenoids, superoxide dismutase (SOD) and ascorbate peroxidase (APX) activity, and total antioxidant capacity (IC50 content) of the fruits peel and pulp were determined on 0 (harvesting time), 30 and 60 days. Data were analyzed using SAS (Ver.9.1) and significance of the differences between the means was computed using Tukey test. Results Results showed that weight loss percentage in fruit treated with CaCl2 (especially in 2 and 4% treatments) of all three cultivars was significantly less than control during storage. Total carotenoid of pulp of Thomson and Moro cultivars increased with increasing of CaCl2 concentrations compared to control during storage. In Page mandarin, the carotenoid content of pulp was not affected by calcium chloride treatment. Results also showed that SOD activity in peel and pulp of treated fruits was higher than control at harvest time. At the time of harvesting, the peel APX activity of Thomson and Moro cultivars (control) was higher than those treated by calcium. Antioxidant capacity (based on IC50 content) of peel and pulp varied depending on the cultivar and the treatment. That is, the highest antioxidant capacity was determined in ‘Thomson’ at harvest time and in treated fruits with high level of CaCl2. Discussion In the present study, the CaCl2 pre-treatment was sprayed on the citrus trees and the results indicated that pre-harvest calcium chloride significantly decreases weight loss percentage and increases antioxidant capacity, SOD activity and total carotenoid contents in citrus fruits during storage. It seems that the accessibility of sufficient CaCl2 during plant growth has a strong influence on concentrations of bioactive compounds and overall antioxidant properties of citrus fruits. Overall, it is suggested that an appropriate CaCl2 pre-treatment of citrus tree can help improve or maintain pulp and peel quality during storage. It is further suggested, using chlorine-free calcium sources in southern Iran with alkaline soils.

Evaluation of storage temperature and container material effects on summer wild blackberry postharvest

M. Haddadinejad; K. Ghasemi; A.A. Mohammadi

Volume 40, Issue 2 , September 2017, , Pages 99-112

https://doi.org/10.22055/ppd.2017.19095.1376

Abstract

Background and objectives: Blackberry due to its short post-harvest shelf life and rapid perishability cannot be conserve for long time. Recently, using small plastic containers became ... Read More Background and objectives: Blackberry due to its short post-harvest shelf life and rapid perishability cannot be conserve for long time. Recently, using small plastic containers became popular that unfortunately is non-biodegradable and incompatible with environment so these materials are dangerous for environment. But using biodegradable packages which made up by natural materials like starch, corn, potato and wheat can be a suitable substitution. This research aimed to evaluate optimum conditions including temperature and container material for increasing summer wild blackberry shelf life.Materials and methods: With the aim of evaluation of summer wild blackberry optimum storage conditions, its fruits were compared via three levels of temperature (0, 4 and 25˚C) and two kinds of containers (biodegradable and non-biodegradable) during 14 days. Different characteristics comprising of visual quality (fruit weight, fruit weight loss and market acceptance), edible quality (TSS, pH, TA, TSS/TA, flavor and taste) and health value (total antioxidant activity, total phenol content, total flavonoid content and total anthocyanin) was evaluated. Results: The obtained results showed fruits weight lost, during postharvest maintenance in all of treatments the highest fruit weight recorded on the first day and after that decreased significantly. In addition to fruit weight, length, width, flavor, taste and market acceptance of fruit decreased during storage, significantly. Visual quality of fruits packed in polystyrene container was better than bio based one. Total soluble solids of blackberries stored in biodegradable package were significantly higher than non-biodegradable container. Inhibitory percentage of DPPH radicals in all treatments showed powerful antioxidant properties of blackberry. The highest phenol content (62.33 gGalicacid/ g fruit juice) of fruits was recorded in 3th day at 4˚C in polystyrene container. The lowest amount of total phenol in the same temperature was observed after 8 days storage in biodegradable container. In both of containers, the temperature of 0 ˚C showed less decrease of flavonoid content. During the experiment conduction, anthocyanin content decreased generally but in 8 and 14th day in polystyrene container and 0˚C, its content increased from 224,99 in first day at 0oC to 57.89 and 90.3 mg Cyanidin/Lit fruit juice in both containers types at 14th day, significantly.Discussion: Water loss due to transpiration and respiration is the main reason for weight loss during post-harvest period. Because of this, using Nano particles in containers materials around the fruits to control water exchange can reduce weight loss and influence different fruit characteristics as well. Conclusion: The positive effect of the 0 ˚C temperature on blackberry shelf life was significant. Using biodegradable package despite its environmental importance showed less efficiency for increasing blackberry postharvest life in comparison with plastic one and require additional researches.

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Keywords = Shelf life

Pre-harvest application of chitosan and nano-chitosan on enzymatic activities, quality and sensory indicators of fresh pistachios (Pistacia vera L. cv 'Ahmad Aghaei')

Abstract

Improving Quality and Antioxidant Characteristics of Pulp and Peel of Citrus During Storage by Pre-Harvest Spray of Calcium Chloride on Fruit

Abstract

Evaluation of storage temperature and container material effects on summer wild blackberry postharvest

Abstract